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SKYPE
Artigo
Transcrito do
WebInsider
Visite!
Voip via aparelho é melhor do que por
software
[10/01/2005 ]
Usar o Skype e falar de graça com quem está em outra máquina é bom.
Mas o uso do aparelho voip é diferente e deve ser considerado pelas
vantagens que apresenta. Entenda por quê.
Diego Moralles
Feliz Ano Novo para todos os leitores do Webinsider. Hoje vamos
falar do uso do VoIP por software e por hardware.
Qual das duas formas de utilização é a melhor e mais viável para a
sua residência ou sua empresa? Qual delas traria um retorno mais
satisfatório para você?
As respostas para essas perguntas e algumas outras estão a seguir.
O VoIP por software funciona como no hardware. A qualidade é a
mesma, os protocolos abordados são os mesmos (veja matéria ao lado).
A diferença é que, ao instalar o programa voip em uma máquina, essa
terá que atender requisitos mínimos: um kit multimídia (um microfone
e um fone de ouvido ou caixas de som) para poder se comunicar quando
efetuar uma ligação. Você só poderá ligar para uma outra pessoa
também tenha o programa no computador e atenda os mesmo requisitos
do software.
Um software muito conhecido é o Skype. Funciona muito bem em casa,
mas por uma série de motivos não é a melhor opção em empresas.
Usando o computador. Se uma empresa deseja 20 linhas voip e decide
utilizar o Skype ou outro software qualquer, precisará de 20
computadores com 20 kits multimídia.
Se um dia houver um corte de energia, o que aconteceu com as linhas
voip? A telefonia comum tem sua própria fonte de energia. Em caso de
blecaute, você ainda pode falar normalmente ao telefone. O VoIP não
tem essa fonte de energia. Neste caso a empresa teria que instalar
20 no-breaks para não perder a comunicação com seus clientes e
associados na falta de energia elétrica.
O custo deste investimento adicional pode impactar. Algumas pessoas
sugerem, para o caso de falta de energia, manter apenas cinco ou
seis linhas voip, de forma a usar apenas cinco ou seis no-breaks.
Mas seria uma boa solução? Se a empresa adquiriu um produto que dá
20 linhas, por que usar apenas cinco ou seis?
Com o aparelho voip. Se esta empresa optar pelo hardware ao invés do
software, isso não seria problema. Todo e qualquer CPD que possui um
servidor web, conta obrigatoriamente com um no-break. Possivelmente
tem também o PABX ligado em outro no-break ou no mesmo. Se a empresa
comprasse um aparelho de 8, 16 ou 32 linhas voip existente no
mercado, só teria o trabalho de ligar esse aparelho no no-break que
já existe na empresa. Em caso de queda de energia, ela iria
continuar garantindo as 20 linhas que comprou. Vocês entenderam essa
vantagem do aparelho?
Com o aparelho VoIP, você poderá ligar para qualquer pessoa que
tenha um telefone comum, um celular, um pager, um fax, um PABX ou
mesmo um aparelho voip, sem se preocupar com mais nada.
Na residência ou escritórios muito pequenos, por questões de custo,
seria melhor utilizar o programa VoIP. Mas só por questões de custo.
Do contrário, em termos de conforto e praticidade, o aparelho VoIP
traz mais vantagens do que o software no computador, mesmo nas
residências. Por exemplo:
Comprando e instalando um aparelho VoIP em sua casa, você não
precisaria necessariamente ter um computador. Ou seja, quem não tem
computador ainda assim pode fazer ligações voip. Os aparelhos se
adaptam facilmente a qualquer tipo de acesso à internet, até mesmo o
acesso discado.
Também não seria preciso pagar um provedor para acessar à internet
quem quiser utilizar um provedor gratuito. Você apenas conecta o
aparelho em sua linha telefônica comum, coloca o aparelho de
telefone no aparelho voip e pronto. Ao fazer ligações locais você
utilizaria sua linha comum; já as ligações interurbanas ou
internacionais seriam pelo VoIP, para você pagar como uma ligação
local.
Algumas pessoas perguntam: "Qual a vantagem de eu colocar um VoIP em
minha casa usando linha discada se vou ter que pagar pela ligação?".
Sim, é verdade, você pagará pela ligação, mas seria uma ligação
local. Ou seja, você pagaria somente os pulsos utilizados pela
tarifa local.
Ao fazer uma ligação DDD ou DDI, você paga as taxas do DDD ou DDI,
os minutos de conversação e os pulsos. Com o aparelho VoIP em uma
linha discada, você pagaria somente os pulsos. Bem mais em conta.
Aparelho pode ser usado em outros lugares. Outra vantagem
interessante é que os aparelhos VoIP recebem um número fixo. Hoje
com o telefone comum, o seu número de telefone fica preso à sua
residência. Se você pegar seu aparelho comum e ligá-lo na casa de
algum vizinho, o número daquele telefone será o do seu vizinho.
Com o VoIP isso não acontece. Se você pegar o seu aparelho VoIP e
ligá-lo na casa de seu vizinho, ele mantém o mesmo número de
telefone. Os aparelhos podem acessar a internet por qualquer meio.
Ou seja, você pode levá-lo na viagem de família, para a chácara do
tio, ou para seu apartamento ou uma casa alugada na praia. Basta
instalar para falar voip e receber suas ligações sem que as pessoas
percebam que você está em outro lugar, mais ou menos como funciona
com o celular.
Um argumento de quem prefere o uso do software ao aparelho voip é
dizer que se o aparelho quebrar ou der algum problema, não poderá
fazer e receber ligações. É verdade, assim como o computador também
pode dar problemas. É mais barato e rápido trocar o aparelho VoIP do
que mandar o computador para a assistência técnica.
Há vantagens são fortes e vale a pena avaliar a compra de um
aparelho.
Desconfie de preços muito baixos. Outra dica importante: existem
muitas empresas que vendem aparelhos voip a um custo muito baixo em
relação à concorrência, pois não pagam taxas e impostos pelos
produtos vendidos.
Um grande número desses aparelhos é importado ilegalmente. Como o
fornecedor está fora do Brasil, pode haver dificuldades na devolução
do aparelho por insatisfação quanto ao serviço. Por isso, antes de
comprar o aparelho, verifique com o vendedor se há garantia, qual é
a empresa que vende os aparelhos para eles, onde ela fica a empresa
caso você queira visitar e EXIJA a nota fiscal do aparelho. São
dicas importantes para que você possa utilizar o voip sem dores de
cabeça e sem incentivar a concorrência desleal que infelizmente
existe. [Webinsider]
NOTÍCIA
Empresa brasileira lança Skype no telefone fixo
Quarta-feira, 2 março de 2005 - 14:45
Daniela Braun - IDG Now!
A brasileira Leucotron lança, nesta
quarta-feira (02/03), o Skyvoice, um sistema que
permite o uso do telefone fixo, residencial ou
PABX, nas chamadas sobre IP (Internet Protocol)
pelo software Skype, da norte-americana Skype
Technologies S.A..
A solução
residencial para usuários de banda larga, que
custa 372 reais, engloba um hardware - do
tamanho de um modem ADSL - conectado ao micro e
ao aparelho telefônico, que fica dedicado à
chamada pelo Skype .
O sistema é
acompanhado de um software, também usado na
versão corporativa, que funiona como uma agenda
para gerenciar os contatos telefônicos do Skype
e agilizar as chamadas.
A vantagem,
segundo o fornecedor, é a mobilidade, já que o
equipamento substitui o microfone do micro,
embora a máquina tenha de estar ligada e
conectada para que o sistema funcione.
Para o mercado
corporativo, a empresa lança o Skyvoice TR, que
é embutido no PABX e será vendido a 171 reais
por comunicação - o equivalente a um preço por
linha. "Com isso, a empresa ganha mais uma opção
de economia com chamadas telefônicas e garante
todas as funcionalidades que o PABX oferece",
explica Antônio Cláudio de Oliveira, diretor de
marketing da Leucotron
Oliveira estima
que, este ano, sejam comercializadas 20 mil
unidades do Skyvoice, sendo 70% pra o mercado
corporativo, que é a grande aposta da empresa
para este lançamento.
O hardware
fabricado na planta da Leucotron em Santa Rita
do Sapucaí (MG) também será exportado para
países da América Latina. Em 2006, a previsão é
vender mais do que o dobro de unidades em
relação a este ano, informa Oliveira.
A novidade da
Leucotron segue uma tendência de integração do
Skype a outros serviços de comunicação, como o
SMS (Short Message Services), cujos testes foram
anunciados pela inglesa Connectotel na semana
passada, e de uso do sistema de VoIP em
celulares e dispositivos com acesso sem fio (Wi-Fi)
lançado pela operadora européia Carrier Devices
Ltd.. no início de fevereiro.
Transcrito
do site TelNext Visite!
Fonte: Google
COMUNICAÇÃO SEM CUSTO
ATRAVÉS DA
INTERNET
Comunicação de voz através da Internet já é uma realidade . Utilizando o
programa de comunicação Skype gratuitamente você pode conversar com
qualquer pessoa que tenha instalado o Skype . Além de um micro com placa
de som e acesso Internet você só precisa de um headset .
O melhor
programa para conversas de voz da atualidade é o Skype. Com ele você
realiza conversas de voz em tempo real com uma ou mais pessoas ao mesmo
tempo. Além disso o Skype não é um programa complicado, dispensa
configurações técnicas, funciona com qualquer tipo de acesso Internet, é
em português e gratuito.
Com o Skype
você pode se comunicar com outros Internautas em qualquer parte do
Brasil e do mundo aproveitando seu acesso Internet e sem pagar nada mais
por isso! Basta que você e a outra pessoa tenham o Skype instalado e
funcionando.
Siga as
orientações comece hoje mesmo a conversar com seus amigos através da
Internet. Vamos lá?
Instalação do Skype
Faça o
download do Skype no seguinte endereço:
http://www.skype.com/download.html
http://www.skype.com/skypeout/help.pricelist.html
Realizar um
download nada mais é do que copiar um programa da Internet para o seu
computador. Faça isso acessando o endereço acima, clicando no botão
DOWNLOAD e salvando o programa SkypeSetup-Beta.exe em uma pasta de sua
preferência.
Depois de
concluir o download abra a pasta onde o programa SkypeSetup-Beta.exe foi
salvo e rode-o (acione-o) clicando com o mouse 2 vezes sobre ele. Você
verá a seguinte tela:
O Skype
funciona em diversos idiomas, inclusive o Português. Selecione o idioma
de sua preferência conforme mostra a figura abaixo e clique no botão OK
para prosseguir a instalação.
O processo
de instalação é relativamente simples. A única coisa que você precisa
selecionar manualmente é a opção 'Eu aceito as condições de uso'. No
restante é só clicar várias vezes no botão 'Avançar' até terminar a
instalação. Veja:
Cadastramento inicial
Se essa é a
primeira vez que você utiliza o Skype deve criar uma nova conta.
Clique na opção 'Eu gostaria de criar uma conta no Skype' e clique no
botão 'Próximo'.
Em seguida
preencha os dados do formulário. No campo 'Escolha um nome de usuário'
digite seu apelido, e no campo 'Senha' digite uma senha para usar no
Skype. A senha é você quem define. Repita a mesma senha no campo
'Repetir Senha'. Informe também seu email correto. Isso é importante
para que você possa recuperar sua senha posteriormente, caso a esqueça.
Ative a
opção 'Sim, eu li e aceito...'. A opção 'Store my password..' faz com
que sua senha fique armazenada. Ative-a e você não precisará informar
sua senha toda vez que ligar o Skype. Em seguida clique no botão
'Terminar'.
Se o apelido
(nome de usuário) que você informar não for válido ou já estiver sendo
utilizado por outra pessoa você receberá um aviso na parte superior da
janela. Se isso acontecer simplesmente digite outro apelido. Evite
utilizar caracteres especiais ou espaços no seu apelido. Prefira
palavras simples com letras e números, como por exemplo: joao35,
paula22, marcosrj, celsocarioca, etc.
Se o apelido
for aceito uma nova janela abrirá com um formulário de dados pessoais.
Preencha seus dados para que seus amigos possam localizá-lo com
facilidade. Você não precisa preencher todos os campos mas recomendamos
que você preencha ao menos o nome, sexo, idioma e país.
Veja
o exemplo:
Ao terminar
o preenchimento clique no botão 'Atualizar'.
Pronto!
Agora você pode já pode utilizar seu Skype!
Localize
seus amigos e inclua-os na sua lista do Skype
Na primeira
vez que você usa o Skype sua lista de amigos está vazia como na imagem
abaixo.
Para poder
realizar ligações através do Skype você primeiro deve localizar a pessoa
com a qual deseja conversar e adicioná-la na sua lista de amigos. Para
isso clique na aba 'Iniciar' e em seguida clique na opção 'Encontrar um
amigo'. Clicar diretamente na lupa no topo da janela do Skype tem o
mesmo efeito. Ao fazer isso você verá uma janela onde deve digitar o
nome da pessoa que deseja encontrar. Digite o nome e clique no botão
'Encontrar'
No exemplo acima procuramos por um amigo nosso digitando seu primeiro
nome 'adnen' e clicando no botão 'Encontrar'. Digite o nome do seu amigo
para localizá-lo. Apenas pessoas que possuem o Skype instalado e o
utilizaram nos últimos 3 dias são encontradas.
Depois de localizar seu amigo (ou amiga) adicione-o ao seu Skype
clicando com o botão direito do mouse no nome dele e selecionando a
opção 'Adicionar para amigos'. Você verá uma janela com um espaço para
digitar um texto. Digite alí um pedido de autorização e clique no botão
'Ok'. Seu amigo receberá o pedido e deverá autorizá-lo a adicionar seu
nome na sua lista de amigos do Skype.
Como
realizar e atender ligações
Depois de
adicionar um amigo ao Skype clique na aba 'Amigos'. Clique 2 vezes com o
mouse no nome do amigo com o qual deseja conversar. O Skype irá chamar
seu amigo e assim que ele atender vocês poderão conversar em tempo real
por voz. Para desligar clique no botão vermelho (fone no gancho).
Quando
alguém liga para você uma campainha toca e a janela do Skype informa o
nome da pessoa. Para atender a ligação é só clicar no botão verde (fone
fora do gancho) e começar a falar. Para desligar clique no botão
vermelho (fone no gancho). Estes 2 botões aparecem na parte de baixo da
janela do Skype.
Falando com mais de uma pessoa ao mesmo tempo (Conferência)
No Skype
existem 2 maneiras de falar com mais de uma pessoa ao mesmo tempo.
A primeira
maneira é ligar para alguém e em seguida incluir uma ou mais pessoas na
conversa. Para isso basta ligar para uma pessoa e durante a conversa
clicar na aba 'Amigos', clicar uma vez no apelido da pessoa que deseja
adicionar e clicar no botão de conferência. Você também pode incluí-la
clicando com o botão direito do mouse sobre seu apelido e em seguida
selecionando a opção 'Invite to Conference'.
A segunda
forma de realizar conferências é selecionar todos os participantes antes
da ligação. Para tanto clique na aba 'Amigos', mantenha a tecla CTRL (Control)
pressionada e vá clicando nos apelidos das pessoas que deseja incluir na
conferência. Depois solte a tecla CTRL e clique no botão de conferência.
Todas as pessoas selecionadas entrarão na conversa ao mesmo tempo.
A versão
0.97 do Skype suporta até 5 usuários conversando ao mesmo tempo,
contando com você.
O Skype
possui muitos outros recursos que você irá descobrir à medida que for
utilizando-o. Lembre-se que na página do TelNext onde o Skype está
disponível para download existe um Fórum para que você possa trocar
mensagens com outros usuários e sanar suas dúvidas. Faça uso. :-)
Coleção de
Notícias - Fonte: Folha de S.Paulo
Busca Folha
1.
Folha Online - Informática - Programa habilita micro a receber ligações
de telefone convencional - 20/03/2005
... preço de uma ligação internacional. O lançamento da função SkypeIn,
que é similar, foi prometida pelo Skype, concorrente do Teleo. O
software também transfere para telefones fixos ou ... Using Teleo
(discar com o Teleo). Ainda faltam ao Teleo alguns serviços oferecidos
pelo concorrente. O Skype, além de ser gratuito, possibilita a
troca de mensagens de texto e a ...
http://www1.folha.uol.com.br/folha/informatica/ult124u18187.shtml
2.
Folha Online - Informática - Usuários de conexão sem fio poderão navegar
com Skype - 03/03/2005
... 03/03/2005 12h05 Usuários de conexão sem fio poderão navegar com
Skype da Folha Online Usuários britânicos de conexões sem fio
poderão navegar e fazer ligações gratuitamente a partir de ...
gratuitamente a partir de hoje. Isso porque a provedora de acesso
Broadreach juntou-se à empresa responsável pelo Skype e, juntas,
oferecerão o serviço em 350 hotspots. Para ...
http://www1.folha.uol.com.br/folha/informatica/ult124u18083.shtml
3.
Folha Online - Informática - 5,3 milhões de brasileiros têm banda larga
em suas casas - 23/02/2005
... impacto sobre outras atividades, como a telefonia. No mês passado,
mais de 400 mil brasileiros utilizaram o Skype, programa que
permite a conexão telefônica via web, representando ... telefônica via
web, representando um aumento de 65,8% no últimos 6 meses. O tempo médio
de utilização do Skype, por usuário, foi de 23 minutos. Leia mais
Banda larga responde por ...
http://www1.folha.uol.com.br/folha/informatica/ult124u18032.shtml
4.
Folha Online - Informática - Usuários poderão fazer ligações de VoIP em
equipamentos móveis - 15/02/2005
... 02/2005 11h56 Usuários poderão fazer ligações de VoIP em
equipamentos móveis da Folha Online Os usuários do Skype
--software que permite fazer ligações telefônicas pelo computador- ...
serviço em equipamentos móveis. Isso porque a fabricante de celulares
Motorola fez uma parceria com o Skype, responsável pelo programa
que já tem mais de 26 milhões de usuários em ...
http://www1.folha.uol.com.br/folha/informatica/ult124u17978.shtml
5.
Folha Online - Informática - Tecnologia invade a aula e muda a maneira
como alunos estudam - 09/02/2005
... do Fórum Social Mundial de Porto Alegre com boletins ao vivo,
gravados com filmadoras digitais ou via Skype, programa de voz
sobre IP. O conteúdo, disponível em cyber fam.pucrs.br ...
http://www1.folha.uol.com.br/folha/informatica/ult124u17947.shtml
6.
Folha Online - Dinheiro - Acesso à internet muda hábitos de cidade de
7.500 habitantes no interior de SP - 06/02/2005
... com a tecnologia necessária. Atualmente, o departamento de compras
da prefeitura já utiliza o software Skype -que permite fazer
ligações telefônicas pelo computador- em suas compras, ...
http://www1.folha.uol.com.br/folha/dinheiro/ult91u93212.shtml
7.
Folha Online - Informática - Alternativas ao Skype vão além da
conversa pela rede - 12/01/2005
... 12/01/2005 18h05 Alternativas ao Skype vão além da conversa
pela rede da Folha de S.Paulo Na esteira do sucesso do Skype ,
que chegou a ter mais de 1 milhão de usuários conectados ... locais e
internacionais sem custos para pessoas que também utilizam um netfone.
Entre as alternativas ao Skype, destacam-se o Firefly 1.9 e o
GloPhone 2.0 . Além da facilidade de ...
http://www1.folha.uol.com.br/folha/informatica/ult124u17825.shtml
8.
Folha Online - Informática - Teste USP avalia IP Phone, que faz ligações
usando o micro - 24/11/2004
... aparelhos, mas a qualidade deles é baixa e prejudica a clareza das
conversas. Comparando o IP Phone com o Skype , popular programa
de voz sobre IP, o primeiro não apresenta ... o primeiro não apresenta
vantagens e perde em muitos pontos. Editoria de Arte/Folha Online Apesar
de o Skype operar com protocolo proprietário, o seu uso é
gratuito e não exige a ...
http://www1.folha.uol.com.br/folha/informatica/ult124u17529.shtml
9.
Folha Online - Informática - Novo Kazaa tem recursos de telefonia via
internet do Skype - 22/11/2004
... 22/11/2004 16h05 Novo Kazaa tem recursos de telefonia via internet
do Skype da Folha Online A partir de agora, usuários do Kazaa
poderão fazer ligações para qualquer lugar do mundo ... programa de
troca de arquivos, oferece aos internautas o Kazaa v3.0 uma nova versão
do programa integrada ao Skype --software de telefonia de voz
sobre IP. "Esse tipo de serviço, ...
http://www1.folha.uol.com.br/folha/informatica/ult124u17510.shtml
10.
Folha Online - Informática - Falha no Skype deixa PC vulnerável a
ataques virtuais - 16/11/2004
... 16/11/2004 11h07 Falha no Skype deixa PC vulnerável a ataques
virtuais da Folha Online Uma brecha de segurança no software Skype,
um dos mais populares da telefonia via internet, permite ... execução de
códigos perigosos ou à parada do sistema. A informação sobre a falha foi
divulgada pela própria Skype. "Trabalhamos para consertar o
problema e sugerimos que os ...
http://www1.folha.uol.com.br/folha/informatica/ult124u17451.shtml
11.
Folha Online - Informática - EUA eliminam barreiras para telefonia de
voz sobre IP - 10/11/2004
... cabo, telefonia e internet. Empurrão De olho nesse mercado, a
Siemens criou um adaptador com o software Skype (voz sobre IP)
com o qual o mesmo aparelho de telefone pode fazer ... De acordo com o
site News.com o maior atrativo para o equipamento é a união entre os
pedigrees Siemens e Skype. A primeira empresa está entre as
maiores fabricantes de telefone do ...
http://www1.folha.uol.com.br/folha/informatica/ult124u17400.shtml
12.
Folha Online - Informática - Mercado de voz sobre IP deve crescer 44,2%
na AL em 2004 - 04/11/2004
... do Sul desencorajou investimentos pesados nos últimos anos. Leia
mais Telefone comum poderá ligar para o Skype Especial Leia o que
já foi publicado sobre telefonia via internet ...
http://www1.folha.uol.com.br/folha/informatica/ult124u17352.shtml
13.
Folha Online - Informática - Brasil Telecom bloqueia soft de telefonia
via web, dizem usuários - 03/11/2004
... operadora de telefonia Brasil Telecom estaria bloqueando o acesso de
seus usuários de banda larga ao Skype, sistema gratuito de
telefonia pela internet. A informação está em um ... página do programa
da internet, em que usuários brasileiros discutem o problema com a
equipe de suporte do Skype. No fórum , diversos usuários reclamam
de não conseguir conectar- ...
http://www1.folha.uol.com.br/folha/informatica/ult124u17342.shtml
14.
Folha Online - Informática - Empresa reduz tarifas do Skype no
Brasil - 03/11/2004
... 03/11/2004 09h18 Empresa reduz tarifas do Skype no Brasil da
Folha de S.Paulo O que era barato ficou uma pechincha. Desde
quinta-feira, as tarifas de ligações para Brasil, França, ... Brasil,
França, Turquia, Rússia e Japão via SkypeOut foram reduzidas em 63%.
Isso quer dizer que um usuário do Skype em qualquer parte do
mundo pode ligar, via micro, para um ...
http://www1.folha.uol.com.br/folha/informatica/ult124u17324.shtml
15.
Folha Online - Informática - Telefone comum poderá ligar para Skype
- 03/11/2004
... 03/11/2004 09h07 Telefone comum poderá ligar para Skype
FERNANDO BADÔ da Folha de S.Paulo A parceira entre o sueco Niklas
Zennström, 37, e o dinamarquês Janus Friis, 27, tem demostrado ... fato
que não agradou às grandes gravadoras. Depois de vendê-lo para a Sharman
Networks, eles criaram o Skype , que simplesmente elimina a
necessidade de o usuário usar o telefone. ...
http://www1.folha.uol.com.br/folha/informatica/ult124u17323.shtml
16.
Folha Online - Informática - Veja como conversar via micro com conforto
- 25/08/2004
... entre o TeraFone e um conjunto de caixas e microfone é que, quando o
usuário recebe uma ligação (via Skype, por exemplo), ele toca
como um telefone, o que significa que o ...
http://www1.folha.uol.com.br/folha/informatica/ult124u16797.shtml
17.
Folha Online - Informática - Ligação internacional pela web custa R$
0,07 por minuto - 25/08/2004
... de S.Paulo Muito parecido com um programa de mensagens instantâneas,
como o ICQ ou o MSN Messenger, o Skype vem ganhando adeptos por
facilitar a conversa de voz via internet. O ... adeptos por facilitar a
conversa de voz via internet. O arquivo do programa é pequeno (3,1
Mbytes, em www.skype.com) e fácil de instalar. Feito isso,
qualquer internauta pode ...
http://www1.folha.uol.com.br/folha/informatica/ult124u16796.shtml
18.
Folha Online - Informática - Voz via internet reduz gasto com telefone -
25/08/2004
... Messenger-- possibilitam o bate-papo. Outro programa que viabiliza a
conversa de voz por meio da rede é o Skype. O uso de VoIP também
pode reduzir os gastos ao realizar, via micro, ...
http://www1.folha.uol.com.br/folha/informatica/ult124u16795.shtml
19.
Folha Online - Informática - Skype agora faz ligações para
telefone convencional - 04/08/2004
... 04/08/2004 10h04 Skype agora faz ligações para telefone
convencional da Folha de S.Paulo Usuários do Skype (8,7 Mbytes,
grátis em www.skype.com/download.html ), já podiam usar o PC para
fazer ... convencionais usando o computador. Chamado de SkypeOut, o
serviço foi incluído na recém-lançada versão 1.0 do Skype e antes
de usá-lo será preciso pagar uma taxa que, em algumas ...
http://www1.folha.uol.com.br/folha/informatica/ult124u16622.shtml
20.
Folha Online - Informática - Skype terá versão paga que conversa
com telefones comuns - 19/05/2004
... 19/05/2004 13h50 Skype terá versão paga que conversa com
telefones comuns da Folha Online O Skype, programa de telefonia
pela web que permite que internautas conversem entre si gratuitamente,
... um dos criadores do aplicativo nesta quarta-feira. De acordo com
Niklas Zennstrom, um dos criadores do Skype e também co-autor do
Kazaa, o serviço pago vai conectar os computadores ...
http://www1.folha.uol.com.br/folha/informatica/ult124u16001.shtml
21.
Folha Online - Informática - Programa grava telefonemas no computador -
07/04/2004
... celulares, o computador de mesa também pode ganhar funções de
telefonia. Com a instalação do programa gratuito Skype ( www.skype.com
), por exemplo, é possível fazer chamadas ... apenas o custo de uma
ligação telefônica local (os pulsos cobrados pela conexão à internet).
Para que o Skype funcione, ambos os interlocutores precisam ter
esse programa ...
http://www1.folha.uol.com.br/folha/informatica/ult124u15655.shtml
22.
Folha Online - Informática - Skype ganha versão para micros
portáteis - 06/04/2004
... 06/04/2004 12h15 Skype ganha versão para micros portáteis da
Folha Online O Skype --aplicativo de telefonia via internet que
funciona nos mesmos moldes das redes P2P (peer-to-peer), como o ...
Segundo o fundador da empresa, Niklas Zennstron --que também foi um dos
autores do programa Kazaa-- o novo Skype é um "passo lógico". Ele
acredita que o programa pode chamar a ...
http://www1.folha.uol.com.br/folha/informatica/ult124u15642.shtml
23.
Folha Online - Informática - Nova versão do Skype tem
teleconferência gratuita - 23/02/2004
... 23/02/2004 16h49 Nova versão do Skype tem teleconferência
gratuita da Folha Online Foi lançada nesta segunda-feira a versão 0.97
do Skype --aplicativo de telefonia via internet que funciona ...
desenvolve o software, será lançado, ainda neste ano, uma versão "premium"
do serviço, com mais recursos. O Skype foi baixado mais de 7
milhões de vezes desde agosto de 2003 e conta ...
http://www1.folha.uol.com.br/folha/informatica/ult124u15247.shtml
24.
Folha Online - Informática - Programa possibilita conversar via internet
- 10/12/2003
... falar pelo PC por meio da internet, gastando apenas pulsos locais
(ou a banda larga). Uma alternativa é o Skype, desenvolvido por
alguns dos criadores do trocador de arquivos ... Ele é interessante por
ser gratuito, uma vez que a maioria dos programas do gênero é pago. O
usuário do Skype só pode ligar para quem tenha o programa no seu
computador. O ...
http://www1.folha.uol.com.br/folha/informatica/ult124u14727.shtml
25.
Folha Online - Informática - Criadores do Kazaa inventam sistema de
ligação gratuita pela web - 17/10/2003
... criaram um programa que permite aos internautas fazerem ligações
pela web sem gastar nenhum centavo. A Skype , como foi chamada a
empresa de Niklas Zennstrom e Janus Friis, lançou ... muito bom semear a
desordem com finalidades positivas", disse Zennstrom. "Temos uma grande
ambição para a Skype: fazer dela uma empresa mundial de
telefonia", revelou o empresário. ...
http://www1.folha.uol.com.br/folha/informatica/ult124u14187.shtml
Skype ? The Google of VoIP?
Author: Chris Lewis, VoIPAction
Friday, 10 December 2004, 14:01 GMT
2004 has been a stellar year for adoption of Voice Over IP here in the
United States as the FCC cleared the way for open competition by ruling
that VoIP is not interstate in nature and is subject to Federal
jurisdiction for future laws and regulations.
The ruling had it?s opponents of course including the National
Telecommunications Cooperative Association (NTCA) who accused the FCC of
giving VoIP a "free ride" and an unfair competitive advantage over
copper legacy networks operators. A quick check of the NTCA?s web site
reveals that they are a non-profit association representing small and
rural telephone cooperatives here in the US. More specifically, the NTCA
has 557 telcos amongst it?s members.
The fact that telco vested interests are speaking out against VoIP and
lobbying Congress shows how seriously they are taking the issue, and so
they should.
Skype - the most popular VoIP software in the world ? is here. Already
with 38 million downloads (around 5% of all Internet users), Skype is
possibly the fastest growing free service ever offered on the web and it
has just been bundled with the Kazaa Peer 2 Peer music swapping service
that has 170 million users worldwide.
The ?Skype Out? service (you can call non-Skype phone numbers for around
2.2 cents a minute) now has 290,000 paying customers. While this number
is tiny in terms of overall telephone penetration, the real marketing
power of the Skype business model ? and something that the telco?s
cannot match - is it?s viral nature.
People really love something free on the Internet, and the fact that
telephone companies have acted as - and been perceived as - utility
services for years gives them zero brand equity in fighting off this
challenge, in fact it works against them. There is an appeal surrounding
Skype that harkens back to the early days of the Internet, a time of
technology revolution where traditional services and business models
were turned on their heads by ?disruptive? technologies.
The Early Adopter base of Skype were those techies who instinctively
understood and grasped the value of breakthrough technologies, they didn?t
need to be convinced about Skype through marketing pitches, they just
tried it and it worked.
Add to this the following. The company has received funding from Draper
Fisher Jurveston, a powerhouse venture capital firm here in Silicon
Valley; the software is being enhanced to work on multiple platforms
including wireless and PDA technologies; equipment vendors are rushing
to introduce telephone handsets that integrate with Skype.
But does Skype have the ability to break through into a market
leadership position? After all it?s going up against some very
substantial competition in the form of the telcos and cable companies.
Well, yes. Rule One of launching a successful new technology is
?Execute, Then Improve?. It worked for Microsoft and Bill Gates, and
it?s working here. We could be seeing another Google in the making.
Chris Lewis is the Founder of VoIPAction.com, an informational web site
on VoIP, what it is, how it works, and where to get it.
HTC wants Skype for MS smartphone
CBR Online
14 Dec 2004, 09:24 GMT
Smart device manufacturer High Tech Computer Corp has reputedly
approached Skype Technologies SA to create a port of its voice over IP
software for its range of Windows Mobile-powered smart phones.
^We're interested in dual mode smart phones and would like to discuss
with you the possibilities of using Skype smart phone version as our
voice over IP application solution," an HTC engineer apparently wrote to
Skype in a memo published on the MSMobiles website.
Given that a version of Skype already exists for Windows Mobile Pocket
PC, a version for the Windows Mobile Smartphone would appear a likely
next step. However, no handsets featuring the platform currently offer
the wireless LAN connectivity that make VoIP worthwhile.
This suggests that HTC, which is responsible for the design and
manufacture of many of the world's Windows Mobile devices, could be
investigating bringing WLAN to its mass-market handsets.
VoIP-enabled mobile handsets are also expected to form an important part
of future fixed-to-mobile voice migration initiatives.
VoWLAN ou VoWi-FI (Voice
over Wi-Fi)
Abaixo:
- Visão
geral das tendências - Artigo em inglês
-
Voz sobre IP se livra dos fios
- Artigo
- Posts de Eduardo Prado no "Novas Tecnologias - Novos
Negócios
- Artigos e notícias coletados no Google
- Mais
artigos e notícias (enviadas por Eduardo Prado)
Voice Over WiFi Mutates
Posted on Monday, February 21 @
10:59:31 PST by
samc
The Voice over WLAN (VoWLAN)
market has experienced much hype says a
Research and Markets report; "Voice
over Wireless LAN: Come On and Feel the Noise".
Much of the interest has surrounded the combination
cellular and Wi-Fi handsets, with a vision of the
end-user being able to switch seamlessly between
cellular and Wireless LAN (WLAN) networks, while
maintaining a call.
The VoWLAN market is
really divided into four segments at this stage, says
the report. The four areas include the following:
(1) VoWLAN handsets for the enterprise,
(2) VoWLAN handsets for the home/SOHO,
(3) soft phones,
(4) and combination cellular/VoWLAN handsets.
Enterprise VoWLAN
handsets have been shipping out the door since 2000.
SpectraLink and
Symbol have been the leaders in this market for the
past few years, selling handsets mainly to the verticals
of healthcare, education, retail/warehousing/distribution,
and manufacturing.
SpectraLink's phones use proprietary technology to
maintain quality of service (QoS) for voice traffic,
according to Ben Guderian, director of market strategy
and industry relations at SpectraLink.
SpectraLink's phones work with PBX or IP call servers
provided by companies such as Cisco Systems and Nortel
Networks, which are increasing looking toward VoIP
solutions, Guderian said.
SpectraLink plans to replace SVP with 802.11e when
the standard is ratified.
QoS is more complex in the enterprise because
applications are more varied and the physical scale of
WLANs is greater.
Cisco's Wireless IP Phone 7920, interface
with 802.11b access points.
With total handset shipments totaling less than 60
thousand in 2003, this market is still a niche market,
however.
Factors hindering large volume shipments include the
relatively high cost of handsets (generally an ASP of
$600), and the lack of standardized QoS and fast roaming.
Currently, there is no QoS standard for 802.11.
But Task Group E (working on the 802.11e QoS amendment)
may have a standard ratified by the first half of this
year, leading to Wi-Fi Multimedia (WMM) products.
WMM (Wi-Fi Multimedia) is modeled after the IETF's
DiffServ architecture, which provides four
data-access categories that can be assigned different
priorities.
The home market is
likely to grow fast as $150 WiFi phones become available.
Similar in size and appearance to cellular handsets,
they can be used with $20-$30, VoIP packages for
toll-free calling and provide
a bundle of additional services like 800 number
service, PBX services and multiple party calling.
Dedicated, wireless (WiFi)
VoIP phones include;
Pulver's Wisp Phone,
Senao's SI-7800H and SI-800H Wi-Fi sip phones and
ZyXEL VoIP WiFi Phone are offered by services like
Broadvoice. A wireless laptop running
XTen Soft Phone may also be used.
Verizon signed a multiyear deal with
Westell Technologies to sell
a phone that integrates a high-speed Internet modem and
wireless networking.
Verizon One will integrate several technologies --
including a DSL modem, 802.11g wireless router, 5.8 Ghz
cordless telephone and color touch screen -- on a single
desktop appliance.
Verizon, will offer it in the first half of this year to
customers of its digital subscriber line broadband
service. It did not disclose prices.
Verizon said the phone
would offer features such as an address book and
calendar, e-mail previews, call management and news and
weather updates.
It will also work with Verizon's
Iobi service, which controls voice mail and e-mails
over several devices.
Verizon's VoiceWing VOIP service, for $34.95/month,
provides unlimited local and domestic long distance
calling.
Cordless phones are
also going VoIP.
VTech's ip8100 phone ($119) uses the 5.8GHz band for
the cordless phone connection to a base station.
The base station connects via Ethernet to a LAN, router
or broadband modem.
It comes with two handsets and can be expanded to four.
It's a cordless VoIP phone that doesn't need WiFi.
Laptop or PocketPC software can also be used for
VoIP phone calls, of course.
PhoneScoop has the lowdown on a UMA, WiFi flip phone
from Chi Mei.
UMA stands for "Unlicensed Mobile Access".
The
BenQ P50, a Windows Mobile Pocket PC, was demoed at
CES last month.
It comes pre-loaded with
Skype
software.
HP's iPAQ h6315,
T-Mobile's MDA IV and
Motorola's MPx will also offer both WiFi and
cellular connections.
Motorola and Skype have partnered for mobile VoIP.
Unlicensed Mobile Access (UMA), provides access to
GSM, Bluetooth and 802.11.
By deploying UMA technology, service providers can
enable subscribers to roam and handover between cellular
networks and public and private unlicensed wireless
networks using dual-mode mobile handsets.
Microsoft and
Alcatel have created
an IPTV partnership.
A satellite dish with an integrated WiMax-fed hotspot
for $300? Why not. The
manufacturing cost of The Dish receiver is estimated
around $90.
Voz sobre IP se livra dos fios
Sexta-feira, 15 abril de 2005 - 11:37
No San Antonio Community Hospital, a VoIP é a
segunda aplicação na lista das que estão sendo
implementadas sobre a rede Wi-Fi já existente,
logo depois do acesso via computador a registros
e raio X de pacientes à beira de leitos e em
centros cirúrgicos, explica Irv Hoff, gerente da
rede do hospital.
Mobilidade real e custos menores foram os
principais desafios que Hoff precisou superar em
relação às redes Wi-Fi, mas agora ele está
convencido de que a tecnologia satisfaz suas
necessidades.
Alguns detalhes da implementação de VoIP ainda
precisam ser solucionados para evitar problemas
como queda de ligações entre pontos de acesso ou
bloqueio de sinais devido aos obstáculos dos
prédios. "Queremos que a qualidade da chamada
seja igual à que você espera de um telefone com
fio, tendo em vista que controlamos o ambiente",
explica Hoff.
Os problemas desse tipo de solução são complexos
porque VoIP sobre Wi-Fi reúne as
peculiaridades das redes locais wireless (wireless
LANs ou WLANs) e telefonia IP. Assim como as
WLANs para dados são cada vez mais aceitas, o
mesmo acontecerá com VoIP sobre Wi-Fi, prevê
Will Stofega, analista da IDC.
Mas, para ele, os problemas potenciais de VoIP
precisam ser enfrentados antes. "Se há retardo
ou perda de pacotes, com VoIP você ouve", diz
Stofega. E, à medida que telefones Wi-Fi VoIP
proliferarem, as ligações telefônicas vão
fomentar a demanda por redes wireless. "Se você
dá mobilidade às pessoas na LAN, você tem que
aumentar o número de pontos de acesso."
Apesar destes problemas, as redes Wi-Fi estão
crescendo e as vendas mundiais de equipamentos
de infra-estrutura para redes sem fio móveis
deverão saltar de cerca de US$ 43 bilhões no ano
passado para US$ 49 bilhões no final de 2008, de
acordo com a IDC.
À medida que os executivos se familiarizarem com
o transporte de dados através destas redes, cada
vez mais eles irão acrescentar VoIP, diz
Stofega. No momento, o uso de VoIP sobre Wi-Fi é
muito limitado. Com avanços tecnológicos para
facilitar o uso e garantir qualidade de voz,
este uso vai aumentar, segundo Stofega.
A Airespace (que está sendo adquirida pela
Cisco), a Siemens e a Trapeze Networks são
algumas das empresas que estão vendendo pontos
de acesso e switches capazes de suportar VoIP.
De acordo com a Siemens, os principais usuários
são hospitais, lojas de varejo, fabricantes e
depósitos de mercadorias.
Chaves para a implementação
Para Hoff, do San Antonio Hospital, o primeiro
passo é garantir que os pontos de acesso cubram
cada local em que um usuário possa estar. Em
seguida, ele precisa assegurar que haja pontos
de acesso sobrepostos suficientes para suportar
uma provável carga de usuários simultâneos, sem
negar serviço a nenhum deles. Hoff usa
equipamentos da Trapeze e uma ferramenta que a
empresa fornece chamada RingMaster que mapeia
prédios e a entrada eficaz de freqüências Wi-Fi
através de paredes, chãos, portas e janelas.
Esse é um aspecto particularmente importante em
hospitais, não só porque são comuns reformas que
mudam a localização de paredes, mas também
porque algumas destas paredes são blindadas
contra raios X e, portanto, também hostis a
transmissões Wi-Fi. "Fazemos muita remodelação -
novas partições, novos escritórios", diz Hoff. É
um processo em andamento, ou seja, à medida que
o hospital realiza mudanças, registra-as no
RingMaster, que identifica novos pontos cegos.
Assim, os pontos de acesso são reconfigurados
para contorná-los.
O balanço de carga entre pontos de acesso é
fundamental para a distribuição eficiente de
chamadas, dizem os fornecedores. Pontos de
acesso Airespace, por exemplo, distribuem os
usuários uniformemente em ambientes onde eles
possam estar sob o alcance de diversos
dispositivos ao mesmo tempo. Sem este recurso,
equipamento do usuário disputaria entrada no
ponto de acesso com o sinal mais forte. A
Siemens diz que sua próxima leva de dispositivos
também terá este recurso.
Presumindo que existam pontos de acesso
suficientes para garantir cobertura, executivos
de rede têm que garantir handoffs rápidos entre
os dispositivos à medida que os chamadores
entram e saem de alcance em locais diferentes. O
switchover tem que levar menos de 50
milissegundos - isso significa que é essencial
um projeto de rede cuidadoso. Com voz e dados
trafegando na mesma rede, por exemplo, os
handoffs podem levar de meio segundo a 10
segundos, com a presença ou ausência de dados na
rede afetando o tempo de maneira imprevisível.
Além do desempenho da rede, qualquer uso de VoIP
sobre Wi-Fi deveria incluir uma avaliação da
qualidade da voz. "Você quer estar no meio de
uma ligação com um cliente e mal conseguir
ouvi-lo?" pergunta Stofega.
O futuro do roaming externo
Deslocar-se dentro de um prédio pode bastar para
a equipe interna de um hospital, mas o pessoal
de vendas que viaja pelo país também pode
beneficiar-se de telefones wireless VoIP e
economizar dinheiro para os clientes, diz Keith
Waryas, analista da IDC.
O uso de telefones wireless VoIP ou mesmo de um
software de softphone VoIP em um laptop
transforma hotspots públicos em refúgios para os
usuários que não querem gastar minutos em seus
celulares onde tarifas mais caras poderiam ser
aplicadas, explica Waryas.
"A maioria dos usuários corporativos está sendo
reembolsada por seus empregadores pelo uso de
seus celulares pessoais", diz. Para resolver
esse dilema, a empresa designaria um telefone
wireless VoIP para usuários que se deslocam e
receberia menos relatórios de gastos para
reembolso de celular. Uma das limitações
expressivas para essa alternativa, no entanto, é
o número de hotspots públicos disponíveis hoje,
embora esse total esteja aumentando rapidamente.
Até mesmo quando existem hotspots públicos
suficientes, as corporações não teriam controle
sobre o design e o gerenciamento dessas redes
públicas, e por isso, a qualidade poderia ser
afetada. Além disso, cada usuário teria que
transportar dois telefones, um Wi-Fi e outro
celular, se quisesse permanecer ao alcance o
tempo todo.
Visivelmente, porém, os fornecedores de serviços
acham que existem clientes interessados em
telefones Wi-Fi em número suficiente para
justificar o suporte aos novos serviços. A
Vonage, fornecedora de serviços VoIP, anunciou
recentemente um serviço que suporta telefones
WiFi. A Net2Phone está prestes a comercializar
serviço similar nos Estados Unidos, após
lançá-lo no Canadá.
Aliada a parceiros, a Motorola também está
testando em campo os primeiros telefones
wireless dual-mode, hotspots e PABXs que
permitem aos usuários fazer ou receber chamadas
em redes Wi-Fi corporativas e continuá-las em
redes GSM quando saem do alcance Wi-Fi.
Assim, um médico que iniciasse uma conversa no
hospital via Wi-Fi poderia sair do prédio,
entrar em um carro e partir sem interromper a
ligação porque ela seria transferida para uma
rede celular.
Os sistemas compostos por telefones Motorola
híbridos requerem o uso de PABXs Avaya e pontos
de acesso da Proxim para coordenar o handoff de
chamadas e são apresentados como um meio para as
empresas reduzirem os custos de celular. As
empresas comprariam os telefones e configurariam
contas de celular corporativas, o que lhes
permitiriam negociar tarifas mais baixas do que
as que seus funcionários possuem
individualmente.
Para que a solução funcione, no entanto, os
telefones da Motorola só têm acesso a redes
Wi-Fi específicas que contam com servidores de
presença da empresa, capazes de rastrear a
localização exata dos usuários.
Os fornecedores de serviços, por sua vez,
poderiam oferecer um serviço gerenciado baseado
nesta tecnologia. Waryas, da IDC, espera que
pelo menos uma importante operadora
norte-americana anuncie a oferta do serviço em
meados desse ano. Isso daria aos usuários
transição "sem costura" de celular para Wi-Fi em
hotspots públicos.
O gerente de telecomunicações de um hospital,
que preferiu não se identificar, está cogitando
a adoção da tecnologia, mas manifestou
preocupação com o sistema de billing. A grande
dúvida, segundo ele, é saber como a rede decide
qual tecnologia vai usar e se haverá uma tarifa
diferenciada para as chamadas recebidas na rede
Wi-Fi.
Os defensores deste tipo de serviço dizem que as
empresas poderão negociar bons acordos para os
celulares porque vão precisar de muitos minutos
de chamadas. Segundo Waryas, estes serviços vão
possibilitar a criação de roteamento menos
dispendioso para manter o custo baixo. "Se o
billing não é problema, estes serviços dual-mode
poderiam acabar com algumas dificuldades de
cobertura de Wi-Fi em prédios", acrescenta
Waryas. "Quando um usuário entrasse em um ponto
sem cobertura em um prédio, a ligação
prosseguiria como uma chamada celular em vez de
cair", conclui o analista.
Sim, nós temos VoIP com Wi-Fi
Ana Paula Oliveira
Embora em um ritmo mais lento do que em outros
países, o mercado nacional também está seguindo
a tendência de aliar as soluções corporativas de
voz sobre IP (VoIP) com o uso de redes wireless
sem fio, geralmente baseadas na tecnologia
Wi-Fi.
De acordo com Bernhard Schultze, gerente de
mercado corporativo da Nortel, a solução já está
disponível para comercialização, embora nenhum
contrato ainda tenha sido fechado. "Apesar
disso, temos vários clientes interessados e
vemos um grande potencial de uso conjunto das
tecnologias em empresas das áreas de manufatura,
hospitalar e até de hotelaria. Até o fim do ano,
veremos as primeiras soluções pontuais e
acredito que as empresas de manufatura devem
sair na frente", avalia.
Para Schultze, a combinação entre VoIP e Wi-Fi
não deixa nada a desejar em questões como
segurança e qualidade de serviço, itens cruciais
para as empresas quando se fala em acesso às
redes corporativas de voz e dados. "Em relação à
segurança, mesmo quando o usuário acessar a rede
utilizando o softphone do laptop ou de um iPAQ
em um hotspot público, como em um aeroporto, por
exemplo, o software instalado no equipamento vai
abrir um canal totalmente seguro, dentro da rede
virtual privada (VPN) IP da empresa, ou seja, a
solução vai usar a internet como ponto de
entrada da VPN mas, a partir daí, o tráfego está
isolado e protegido dentro da rede corporativa",
explica.
Na avaliação do gerente da Nortel, a qualidade
do serviço também não é um problema grave quando
se usa Wi-Fi. "Os padrões que ainda estão sendo
desenvolvidos, como o 802.11c, já contam com
recursos como priorização de tráfego de voz
dentro da WLAN, o que garantirá a qualidade das
chamadas", prevê Schultze.
A Cisco, um dos nomes mais citados quando se
fala em telefonia e voz sobre IP também conta
com a solução integrada e já instalada em pelo
menos dois clientes no Brasil. Um deles é a
Alcoa, produtora de alumínio que distribuiu
iPAQs para operadores do chão-de-fábrica que
acompanham a produção das cubas de alumínio.
"A função desse profissional é avaliar o
equipamento fabricado e ligar para o cliente,
que pode estar em qualquer lugar do mundo,
passando as especificações do produto. Com a
instalação de hotspots dentro da planta, ele
avalia o produto e não precisa andar 300 metros
para falar no telefone mais próximo. Ele utiliza
o iPAQ, com acesso wireless Wi-Fi e entra na
rede de VoIP da Alcoa para fazer a chamada",
explica Carlos Borges, engenheiro de sistemas da
Cisco.
Borges também acredita que a área de manufatura
será o ambiente fabril que vai impulsionar a
adoção da tecnologia.
Outra empresa que adotou Wi-Fi para completar
sua rede de VoIP, segundo conta Borges, é a
Dacasa Financeira, sediada em Vitória, no
Espírito Santo.
Antes, para se locomover em um prédio de cinco
andares, os funcionários andavam com um celular,
para onde as chamadas eram desviadas se eles não
se encontrassem em sua mesa. "Além de ocupar
dois troncos da rede, a empresa pagava pelas
ligações recebidas quando as mesmas entravam na
rede da operadora móvel. A solução foi instalar
antenas, hotspots Wi-Fi e telefones IP sem fio.
Assim, a mobilidade está garantida e a chamada
não sai da rede IP", detalha o executivo.
Para a Cisco, o mercado brasileiro ainda tem que
cruzar algumas etapas antes de usar VoIP com
Wi-Fi em larga escala. "Ainda temos um grande
número de empresas que não oferecem equipamentos
móveis aos funcionários como laptops ou
handhelds. Essas tecnologias precisam se
massificar. Somente a partir desse ponto, a
demanda por redes VoIP móveis poderá se
intensificar", conclui Borges.
NetworkWorld
"Posts"
24/05/2004 - Segunda-feira
VoIP, WLAN e "As Águas
de Março"
Sras e Srs. embora
estejamos em Maio queremos relatar que Março foi um mês de
muitas surpresas em matéria de VoIP combinado (ou não) com
WLAN.
Veja abaixo uma coletânea
variada do Weblog
Smart
Convergence:
0.
Microsoft
Will Microsoft Dominate VoIP?
DSL Reports
March 2, 2003
Integrating a skype-like app into the OS...
Business Week argues that while smaller players like Vonage
and individuals like Jeff Pulver are getting all the
attention, Microsoft is quietly positioning itself to
dominate the VoIP industry. By integrating SIP VoIP into the
OS, some analysts worry Microsoft could quickly forge the
largest VoIP network around, one which doesn't touch the
PSTN, and doesn't require regulation. The article hints that
the Pulver victory (see our recent interview) - which frees
"pure" VoIP providers from regulation - isn't a big deal on
its own, but could spell trouble if a larger provider like
Microsoft begins to move.
The article suggests that because Windows XP already
contains the SIP software, and Microsoft recently unveiled
Live Communications Server (LCS) for corporations, it's a
quick jump to assume they could dominate the industry. Of
course, companies like Cisco, the bells, and numerous others
are not Netscape.
1.
VoWLAN market gains traction
Fierce Wireless
The market for Voice-over-WLAN (VoWLAN) is gaining traction
as vendors this year look for the technology to take off
with the enterprise market. VoWLAN offers cheap voice
coverage for corporate campuses and large facilities, such
as factories, college campuses, and hospitals. VoWLAN
start-ups, like Vocera, are targeting vertical markets such
as healthcare. Network vendors are also now marching into
this market. Alcatel and Nortel Networks yesterday launched
new VoWLAN products, and both companies also promised to
start re-selling WiFi handsets from SpectraLink.
See more ...
Wi-Fi
and VoIP: Is sum greater than parts?
Last modified: March 1, 2004, 1:48 PM PST
By Marguerite Reardon
Staff Writer, CNET News.com
Wireless local area networks and Net-based phoning have been
among the most talked-about emerging technologies for
businesses over the past year, and now, vendors are
introducing products they say will help companies combine
the two.
"Wi-Fi and VoIP are powerful technologies on their own,"
said Richard Webb, directing analyst for wireless LANs at
Infonetics Research. "But together, they are far more
powerful. It's sort of like adding one plus one and getting
three."
Equipment vendors have been targeting these markets
separately, but so far, adoption has been slow. According to
a study Forrester Research conducted, only about 20 percent
of the 818 companies Forrester surveyed said they had
completed or were in the process of rolling out Wi-Fi or
wireless LANs. About 15 percent said they had completed or
were in the process of rolling out voice over Internet
Protocol systems.
Experts agree that combining these technologies will help
push each of them further. As a result, equipment makers are
starting to beef up their offerings. On Monday, Alcatel and
Nortel Networks, both strong players in the voice market,
announced new wireless products.
Alcatel announced that it will resell wireless switches,
appliances and access points from start-up Airespace. The
products will be marketed and sold under the Alcatel
OmniAccess brand. Alcatel said the equipment adheres to the
802.11i security standard the Institute of Electrical and
Electronics Engineers ratified, which provides strong
encryption for data carried over wireless networks. Alcatel
also said the products will support the 802.11a/b/g
standards, which promise to improve security and enable
higher throughput and VoIP. The IEEE is expected to ratify
the 802.11a/b/g standards this summer.
In addition, Alcatel said it plans to start reselling
wireless LAN handsets from SpectraLink in October 2004.
These handsets are based on the 802.11b standard and will
act as extensions of the Alcatel OmniPCX family of IP-PBXs.
Nortel Networks, which started selling its family of
wireless switches last year, announced on Monday the 2210
and 2211 wireless handsets. Like Alcatel, the company is
partnering with Airespace and SpectraLink for the handset
technology.
Experts say the marriage between VoIP and Wi-Fi is a natural
one, as companies look for a common infrastructure that will
give workers more flexibility in how
they communicate. VoIP over Wi-Fi offers many benefits to
corporate users, such as eliminating the need to use
valuable cellular airtime within a campus network. What's
more, many cellular phones lose their signal when inside
steel frame buildings, so Wi-Fi phones would provide better
quality of service and reliability. It's especially useful
in vertical industries such as health care, where cellular
phones can't be used at all, because they interfere with
certain machines.
"As companies build out their next-generation IP
infrastructures, they want one highly available and secure
network for their wired LAN and their wireless LAN," said
Brian Witt, director of product marketing for Alcatel. "We
can offer them the gear to do this. Voice over wireless LAN
will be just one service that runs over this
infrastructure."
But in order for VoIP over Wi-Fi to really take off, it will
also have to combine cellular technology, said Joel Conover,
an analyst at Current Analysis. Motorola has already started
talking about delivering handsets that support both cellular
and Wi-Fi access. The company is partnering with VoIP gear
maker Avaya and Wi-Fi equipment manufacturer Proxim to
develop products that combine cellular, VoIP and wireless
technology.
Alcatel and Nortel said the handsets they announced Monday
will only support Wi-Fi access.
2.
Dailywireless
Enterprise VoIP
Tuesday, March 02 @
00:19:00 PST
Airespace has signed separate deals for wireless Voice
over IP with
Alcatel and
Nortel
for VoIP.
SpectraLink is Alcatel's incumbent's OEM partner (see
Alcatel Intros WLAN Products and
Nortel Touts VOWLAN).
Spectralink's s340 and s640 Docking Stations , which
were first announced nearly a year ago,
act as charging cradles for SpectraLink's e340 and i640
Wi-Fi handsets and add standard desktop telephone
features such as a speakerphone, keypad and display. They
will ship in April for $299. SpectraLink is also working on
a standalone desktop phone that will feature an integrated
802.11 radio. That phone will be designed for places where
it's difficult to run Ethernet or telephone wires.
Airespace already has a WLAN handset partnership deal with
SpectraLink, which supplies the phones and
quality-of-service software that allows voice traffic to be
prioritized on an 802.11 network (see
Airespace Talks Up VOIP).
Meanwhile
Lucent has teamed with Cisco Systems to develop a
carrier-class voice over Internet Protocol (VoIP) and
multimedia communications solution for mobile service
providers. It uses the
Cisco MGX 8000 Series Media Gateways to deliver
converged IP-based services -- such as VoIP, high-speed data
and multimedia communications -- across third-generation
(3G) Universal Mobile Telecommunications System (UMTS) and
CDMA2000 and CDMA450 mobile networks. "This will enable
operators to take advantage of the tremendous revenue
potential, and cost savings made possible by IP technology,"
," said John Marinho, vice president of offer management
with Lucent's Mobility Solutions Group.
Clay Shirky explains it all;
"Where Vonage and a number of the other VoIP startups
present themselves to the customer as phone companies,
emulating the incumbents they are challenging, you can think
of Plan B as the Skype plan. Skype isn't taking on the
trappings of a phone company; instead, it offers free
two-way voice conversations over the internet."
"Wi-Fi and VoIP are powerful
technologies on their own, but together, they are far more
powerful.
It's sort of like adding one plus one and getting three,
" says Richard Webb at Infonetics Research.
But in order for VoIP over
Wi-Fi to really take off, it will also have to combine
cellular technology, said Joel Conover, an analyst at
Current Analysis. Motorola and Nokia have shown handsets
that support both cellular and Wi-Fi access. Avaya and
Proxim have teamed to develop
Proxim's new AP-4000 with Voice over IP features.
There has been an explosion of
SIP Products. VoIP operators like
Vonage,
SIPphone and
8x8, often use ordinary phones. They plug into an
adapter than connects to your broadband connection. Nothing
is hotter than
Mobilized VoIP.
"Free" VoIP services include
Skype,
Pulver's
Free World Dialup and
Asterisk,
an open-source SIP server.
Skype,
the "free" VoIP client software that runs on PCs and soon
PDAs, is creating quite a buzz on community lans. That's
partly because it brings "free" voice to users (when both
parties are connected using the internet. The other reason
that VoIP has become a hot topic on community LANs is
because it "breaks" the captive portal model. A wireless
phone has no convenient way to display a splash page and its
associated legal disclaimer.
That disclaimer, it has been
believed, helps to remove legal liability from "free"
internet providers. Currently, standalone WiFi VoIP phones
may not be able to connect or acknowledge the disclaimer. A
method to provide that needs to be developed, say some
community lan activists.
BOM DIA!
27/DEZ/2003 - Sábado
VoWLAN
RIDES AGAIN ...
Mais 1 da Série Didática de
WLAN. Hoje com VoWLAN.
O que é isto? Vejamos então...
Não existe hoje a VoIP (Voice
over Internet Protocol) tomando vulto?
Veja referências recentes de VoIP:
O Skype pode ser um fenômeno em VoIP
do site autoral Alice
Ramos
RBOC VOIP
Coming in 2004
do Magazine Board Watch:
SBC Promises VoIP
from DSL Reports
Bells
Join VoIP Push from DSL Reports
Então ... VoWLAN é Voice
over Wireless LAN.
Ué... isto é mais complicado que o VoIP que todo mundo está
falando agora? Sim, é bem mais complicado pela natureza
Wireless no "negócio".
Imagina juntar os "pacotes" da sua voz digitalizada quando
você caminha de um
Access Point para outro. Não é uma tarefa simples e
está sendo bem endereçada.
Acreditamos - pelo "andar da carruagem" - que em 2004
teremos excelentes notícias neste terreno.
VoWLAN vai ser muito
interessante no mercado Corporativo principalmente naquelas
empresas aonde vc tem uma grande parte dos empregados 80% do
seu tempo de trabalho fora das suas mesas como os segmentos
de hotel, de hospital, do varejo e de logística para citar
alguns.
1.
Veja o que já estão
pensando ...
Este WISP no Reino Unido jjá
quer fornecer o serviço de VoWLAN em 2004.
Smart Convergence
on Saturday, November 22, 2003
UK WISP to offer VoIP
Wi-Fi Planet
By Vikki Lipset
November 21, 2003
Patrons of U.K. hotspots will soon be able to make voice
calls over public wireless LANs, thanks to a new service
from Internet access provider
Broadreach Networks.
The service, called ReadytoTalk, won't officially launch
until next summer, but Broadreach will do a test run with
40,000 customers in the interim. The voice over IP (VoIP)
service will be an add-on to the company's ReadytoSurf
hotspot service, which passed the 500,000 user mark this
week.
All ReadytoSurf sites will also be ReadytoTalk-enabled,
according to Broadreach CEO Magnus McEwen-King. There are
currently 129 ReadytoSurf hotspots in coffee shops, retail
stores, hotels and other locations across the United
Kingdom.
Like ReadytoSurf, the VoIP service will be offered through
ISPs and wireless carriers. Users will need to download
software, developed by Broadreach, to their laptop or PDA
(McEwen-King said the company plans to support all the major
operating systems). Pricing for the service is not yet
available.
Broadreach has been contemplating a VoIP service for a
while, but has been waiting for the right time to enter the
market, said McEwen-King. "VoIP has always been a much
talked about proposition, but the quality levels have not
been there. However, in the last six months, a number of
companies have made significant strides in improving both
the costs and quality. We feel there's another few months to
go, but now is the time to start doing end-user testing with
our ISP and mobile phone operator partners."
See the
Press Release
2. Enquanto isto fique com
esta boa matéria ...
Voice over wireless LAN: Ready or not?
InfoWorld
By Nancy Gohring September
12, 2003
Some hurdles remain, but
ubiquitous voice communications may be the killer app for
wireless LANs
WLANs (Wireless LANs) are
still in the experimental phase at most companies. Why?
Because wireless security standards remain in flux. But a
more obvious obstacle to wholehearted adoption is the lack
of a compelling need for wireless in the average office,
which already has a perfectly functional, wired LAN in
place.
Well, here’s a thought: How
about replacing or supplementing your current phone system
with a VoWLAN (Voice over WLAN) system? Just take an
ordinary wireless network and add a VoWLAN server along with
laptops, PDAs, or newfangled Wi-Fi phones to run the client.
Instead of workers wasting time playing phone tag, they can
field calls wherever they roam on campus — or even on the
road, if there’s a Wi-Fi cloud nearby.
VoWLAN is a natural extension
of VolP (Voice over Internet Protocol), a technology that
has already taken root in enterprise telecommunications.
(Today, more IP-based PBXs are sold than conventional
models.) Yet VoWLAN presents its own unique QoS (quality of
service) challenges relating to fluctuating wireless
throughput and roaming among APs (access points), which is
why most of today's local wireless voice systems are bundles
of proprietary wireless network hardware and software.
Industries with highly mobile
workers — such as retail, manufacturing and healthcare — can
justify the premium for a proprietary network. (One of the
most popular solutions,
SpectraLink's
Wireless Telephone System, costs between $400 and $700 per
seat.) Yet the proliferation of Wi-Fi and its increasing
reliability opens the possibility of deploying VoWLANs
across commodity WLAN setups at much lower costs.
Technical hurdles remain. But
on the hardware side, at least, everyone seems to be getting
in the game. Cisco
recently introduced its first VoWLAN handset and a slew of
vendors including NEC, Qualcomm, Motorola and Dell promise
hybrid phones next year that use both Wi-Fi and mobile phone
networks.
A Very Local Exchange
“It’s just a matter of time
before [VoWLAN] catches on in the mainstream enterprise,”
says Ben Guderian, director of marketing for SpectraLink.
SpectraLink recently introduced a new, lightweight, less
rugged handset designed for mainstream enterprise users. Its
lowest priced handset costs $399, which compares to around
$350 for many desk phones with standard wiring.
Proprietary wireless voice
vendors such as SpectraLink and Symbol have been among the
first to release VoWLAN solutions for commodity wireless
infrastructure. But there’s a new breed of VoWLAN provider
as well: the softphone developers. These companies, such as
TeleSym, IP blue, and VLI have built software that can be
loaded onto PDAs or laptops, enabling users to initiate and
receive voice calls over WLANs.
Basically, VoWLAN systems work
in two different ways. Offerings from SpectraLink, Symbol,
and Cisco route calls from the phone to the WLAN AP to a
VoIP gateway — one that may already be in use to deliver
VoIP over the wired network — which translates calls between
the IP network and the PBX. That setup allows all regular
PBX functions that are available on workers’ wired desk
phones to be available on the VoWLAN phones. Calls that are
made to phones outside the enterprise go through the PBX to
the PSTN (Public Switched Telephone Network).
By contrast, softphone
developers such as
TeleSym provide systems that route calls outside the
enterprise over the Internet. In this scenario, road
warriors could use the softphone on their PDA or laptop to
place calls from a hotel that offers a WLAN. The call could
route entirely over the Internet. “Then the call is
completely free,” said Raju Gulabani, TeleSym’s CEO.
The downside is QoS. Like any
voice call that uses the Internet, users can’t control the
quality of the connection.
Voice, Interrupted
Unfortunately, even over the
local network, VoWLAN has its shortcomings. The problem is
that the 802.11 standards — including those that cover QoS,
security, and roaming — simply weren’t designed to support
voice.
For example, 802.11 entirely
lacks a QoS mechanism. This lack means that no special
priority is given to voice, so when traffic spikes on the
network, dropouts may occur. The IEEE is working on 802.11e,
a QoS standard that should be finalized next year. In the
meantime, Symbol
and SpectraLink have implemented their own proprietary QoS
mechanisms through their hardware.
But it’s security, or a lack
thereof, that’s the biggest deal breaker for VoWLAN today.
Enterprises view today's wireless security measures (such as
the Wireless Encryption Protocol) as weak, forcing them to
opt for wireless VPNs. But VoWLAN offerings that use phones,
as opposed to those that use PDAs or laptops, often can’t
employ VPNs because the client software usually can’t be
loaded onto the phone. (Several vendors, including NEC and
Cisco, plan to produce phones next year with VPN support
built in.)
But using VPNs for voice has
other problems. “A VPN tends to encapsulate voice packets,
so it obscures them from the network and it can’t discern
high priority voice from low priority data,” says Ron Seide,
product line manager for Cisco’s wireless networking
business unit. In addition, VPN’s cause latency that
degrades the quality of voice, says Richard Watson, an
engineer at Symbol and director of telephony product
marketing.
Instead of using VPNs, users
can protect against unwanted intruders by putting voice and
data on different subnets or VLANs, allowing clients in the
voice subnet to communicate only with the telephone gateway,
Watson says. With this separation, the widely used
encryption and authentication standards offer good enough
security, say some vendors. That’s because the threat of
eavesdroppers is remote as the listener would have to be
within range of the same AP as the phone user. “The joke
here is watch out if you have someone walking behind you
with an antenna,” says Watson. “It’s an overblown thing.”
An added challenge, though, is
that encryption and authentication must happen fast enough
so that a call isn’t dropped or degraded when a user moves
from the coverage area of one AP to the next. The existing
802.11 standard can’t support that handoff fast enough and
neither can the security solutions developed by gateway
vendors. Even 802.1x, the upgraded security standard in
development, won’t work quickly enough. “When standards
bodies developed all this, they were more concerned with
security on laptops,” says Watson.
The handoff between APs should
happen in under 50 milliseconds to cleanly support a voice
call, says Doug Klein, CTO of Vernier Networks, a security
gateway vendor. Vernier’s gateway does the transfer in a
matter of a few hundred milliseconds. “It’s not optimum,”
admits Klein.
As a result, vendors have
developed their own fast authentication processes. These
generally work by dispensing a certificate to the client
proving that it is authenticated, so that when a user moves
into range of another AP, the client offers that certificate
as proof of authentication.
Cisco employs a similar
scheme, where one AP is designated as a master AP within a
subnet. Rather than require each AP to acquire an encryption
key from a backend server as the user roams, the master AP
gets a master key and from that, each AP in the subnet
spawns a session key. But even Cisco’s solution takes 150
milliseconds.
Maybe Next Year
The available VoWLAN security
solutions aren’t robust enough for many enterprises. “I
don’t think it’s likely that we’ll be deploying VoIP on
Wi-Fi networks anytime soon,” says Joshua Wright, senior
network and security architect for Johnson and Wales
University, which already has an extensive WLAN for data
users. Current offerings don’t enable the kind of
reliability he wants in a voice network.
The efficiency of the security
and QoS also affects the load that APs can handle. Most AP
vendors say each AP can support 10 simultaneous calls, but
when pressed, will usually admit to half that number in live
deployments. Chris Kozup, META Group's program director of
technology research service, says his clients who have
tested VoWLAN report on average four or possibly five calls
without any data use per AP. “It becomes a problem because
there are finite resources here in terms of channel and
frequency,” Kozup indicates. “It’s not as easy as lighting
up another AP.”
New standards, including the
faster 802.11g and the QoS specification, 802.11e, should
increase the number of users an AP can support. Combined,
those upgrades could allow 15 to 25 simultaneous calls, says
Cisco's Seide.
Ultimately, although the
hurdles of deploying a robust VoWLAN are many, they are also
surmountable. The key to robust and reliable VoWLAN networks
lies in the ability to support security and all capabilities
fast enough to hand off between APs seamlessly. As more
customers demand support for voice, vendors say they’ll
deliver it. “We’ll get around to doing the work that needs
to be done,” said Vernier’s Klein.
3.
Veja Notícias do IEEE sobre
QoS (IEEE 802.11e)
Status of
Project IEEE 802.11e
MAC Enhancements for Quality
of Service
The purpose of Task Group E is
to: Enhance the current 802.11 MAC to expand support for
applications with Quality of Service requirements, and in
the capabilities and efficiency of the protocol.
4. Um Trabalho Nosso sobre o
Assunto
Voz sobre wireless LAN (VoWLAN) do site autoral
Alice Ramos
5. Uma Grande Matéria sobre o
Assunto
VoIP unwired
By Phil Hochmuth
Network World
July 28, 2003
Voice and wireless Ethernet might seem an odd mix, but for
mobile workers or hard-to-wire areas, it can be the perfect
combo.
Converged voice/data network projects can be tough,
especially if you can't use any wires. That's what Mike
Burns, a systems integrator, discovered when a client asked
him to provide voice and data services to a gold-mining
operation in the middle of a Laotian jungle. Burns faced a
sticky situation - literally.
"The ground was mostly mud, so we couldn't bury any cables,
and there were no poles where we could hang wire," says
Burns, who is president of Nationwide Computer Systems, an
ISP and integration firm in Fort Lauderdale, Fla. The
solution would obviously be a wireless one: Burns used
802.11b gear to connect 50 IP phones, PCs, a router and
satellite dish for the mining camp. The camp, which
stretches over a two-mile area, consists of 20 structures
for operations, living quarters and offices.
Eu gosto desta figura aqui ...[Figura
grande - Aguarde a carga se a conexão estiver lenta]
Wi-Fi VoIP: Behind the curtain
at one medical center
University of Southern California University Hospital uses
QoS technology on
a Wi-Fi gateway and at the LAN switch to ensure wireless IP
voice calls
get priority as they crosss the LAN
1 BOM SÁBADO COM "VOZ DIGITAL"
!!!
17/NOV/2003
- Segunda-feira
VoIP
& VoWLAN: Um Folhetim sobre estes 02 "moços" ....
Por onde começamos? ... Afinal "são tantas emoções" !
1. Definições
VoIP =
Voice
over Internet Protocol
VoWLAN = Voice over Wireless LAN (WLAN)
2. Veja algumas referências de VoWLAN ...
[a] Wi-Fi Planet
VoWLAN: Not Ready for Prime Time
Pocket PCs Dial Up Wireless VoIP
Voice over 802.11: An Emerging Market
Dartmouth Intros Wireless VoIP
[b] Outras
VoIP Unwired
Will Wi-Fi lower nurses' blood
pressure?
Dutch Hospital in Spectralinks
[c] Uma do Protocolo SIP
Carriers Say VOIP & SIP Are Hot
3. Um Texto Nosso
Voz sobre wireless LAN (VoWLAN)
Site autoral Alice Ramos
http://www.aliceramos.com/conver/0019.asp
Existem problemas? Sim... ainda existem. O site
Unstrung
mostra uma dura
realidade.
Todos esses vendors que estão trabalhando com a tecnologia
de VoIP, no padrão 802.11, antes que a especificação de WLAN
para suportar voz tenha sido finalizada pelo IEEE, podem ter
problemas -
isto é, antes que o padrão
IEEE 802.11e
seja finalizado.
4. Serviços Mundiais de VoIP
Vonage
Net2Phone
8x8 Inc
Free World Dialup
Conexão PC-para-PC:
Skype
5. Super-Informações de VoIP
Voice over IP and IP Telephony: References
Voice Over IP do Dailywireless
7. Wi-Fi Phones
Palm GPhone
Pocket GPhone 2.0
Motorola Wi-Fi Phone do Dailywireless
Palm VoIP do Dailywireless
Free Voice over Wi-Fi do Dailywireless
Wi-Fi Phones do Dailywireless
Can Wi-Fi Kill Cellular? do Dailywireless
Free World Dialup do Dailywireless
Handsets Key to VoIP do Dailywireless
8. PBX IP um importante componente para GERAR RECEITA
!!!
Spectralink's New PBX to VoIP Gateway
Start-up unveils four-channel VoIP product
Last modified: October 29, 2003, 10:21 AM PST
By Dawn Kawamoto
Staff Writer, CNET News.com
i2 Telecom announced a four-channel
Voice-over-Internet-Protocol product for small businesses on
Tuesday, marking the latest product debut for the
communications start-up.
The company unveiled its E-VoIP 4000, which aims to lower
companies' telephone bills by allowing users to make
long-distance and international calls over the Internet.
Voice over Internet Protocol (VoIP), a concept that has been
hyped for years, is finally gaining momentum as broadband
adoption accelerates.
The E-VoIP 4000 has four channels, or the equivalent of four
telephone lines, that are used to switch the last leg of
callers' calls from the Internet to traditional phone
providers.
If a company has multiple offsite locations, an E-VoIP can
be placed in each office and the entire call can be placed
via the Internet, said Rick Scherle, the company's senior
vice president of marketing.
UFA !!! Boa Semana para Todos ...
From Google:
Published: October 2004
134 Pages
Author: Bruce Hall
Related VoIP Training (Click Here)
Also see:
VoWLAN Fundamentals
Broadband Wireless
Network Planning Toolbox
and
VoWLAN Products and Services
Setembro 08, 2004
Voice over WLAN: Analysis Is The Key To Success
With VoIP comes the notion to run voice on 802.11 wireless LANs (WLANs).
But to succeed, Voice over WLAN (VoWLAN) deployments need very careful
planning and continuous monitoring.
By Scott Haugdahl, CTO, WildPackets
IP voice applications have already presented new quality of service
challenges on wired networks. Data applications could easily tolerate
fluctuations in available bandwidth, but the same typical anomalies will
drive voice users crazy.
And while most wired LANs have enough bandwidth overhead available so
that network engineers can prioritize voice traffic using standard
quality of service mechanisms, wireless LANs are bandwidth constrained;
that makes the job of offering quality voice services much harder.
However, network engineers can use wireless protocol analyzers to create
a better VoIP experience for their users. IMHO, these protocol analyzers
should include the following:
VoIP, WLAN and LAN-specific protocol decodes and filters for common
problems in these environments;
VoIP call recording and playback, with Mean Opinion Score (MOS)
evaluation;
Analytical analysis of packet delay variation and jitter;
Ability to track open calls in real-time and to post closed calls;
Quick drill down to the problem at hand without resorting to complex
filtering;
Expert system technology that parses the flood of packet capture
information and suggests sources of problems or recommends specific
actions.
With these tools in hand, there are two main steps to the VoWLAN rollout
process: pre-deployment planning and post-deployment troubleshooting and
optimization.
Pre-Deployment
Wireless LAN performance varies widely with the number of clients on the
network, their distance from the nearest access point (AP), and the
specific environmental characteristics of the coverage area (furniture,
building materials, elevator shafts, etc.).
In a voice deployment, the WLAN must support higher and more
deterministic bandwidth rates. Ideally, every VoWLAN user should be
communicating at the maximum throughput (11Mbps on 802.11b, for example),
so the AP placement and configuration in a voice network will be
different than it is for a data-only WLAN. Coverage may also be needed
in areas normally not occupied by desktop and laptop users.
Protocol analyzers help in planning a VoWLAN deployment because you can
use them to:
test the networks throughput;
determine the level of channel interference between access points;
monitor the quality of voice calls at various locations on the network;
and confirm that QoS prioritization polices are working properly.
Here are some pre-deployment questions to resolve and how a protocol
analyzer can help answer them:
How many simultaneous voice calls will the WLAN handle? Using a protocol
analyzer, you can measure in real-time the quality of voice and quantity
of data of a test group of users associated with a given access point.
Investing in a small quantity of wireless VoIP phones (or having a
vendor provide evaluation units) will go a long way toward revealing
problems early on. You may discover that to maintain good quality, only
seven to eight users of full-duplex G.711 VoWLAN phones can supported in
one <@BCI>cell<@BCR> area simultaneously.
Where should the access points be placed for optimum voice performance?
One of the emerging "best practices" for VoWLAN is to have a higher
density of access points and to disable data rates below 11 Mbps, since
lower data rates propagate and can reach other access points on the same
channel even if they aren't neighbors.
Protocol analyzers can be used to confirm that you have adequate
coverage at 11 Mbps in areas where users may roam (including hallways
and stairwells) and to ensure that there is no overlapping channel
interference from other access points.
Are some segments more robust than others? Why? With a laptop or tablet
WLAN protocol analyzer, you can roam your space with ease and measure
the signal strength and interference from neighboring channels, from
access points on the same channel but some distance away, or simply from
other sources of 2.4 GHz RF, such as microwave ovens, cordless phones,
Bluetooth, and so on.
Such interference will usually cause a much higher rate of wireless
retransmissions and frames with CRC errors.
Post-Deployment
After deployment, the WLAN environment will change constantly depending
on which users are doing which activities when, and where they are doing
them.
Always keep in mind the mobile aspects of a WLAN -- the network will
need ongoing tuning and management to maintain optimum performance. WLAN
switch vendors offer ways to tune the network by adjusting AP power
levels, prioritizing traffic at the WLAN switch, or implementing QoS at
the client and AP.
However, there are a lot of other variables that affect voice
performance, such as dropped packets, handoff delays, simultaneous
two-way conversations, and security attacks.
Here's a look at how protocol analyzers can assist with identifying and
managing these problems.
Dropped Packets
VoIP is susceptible to the same momentary delays and errors that are
common to any wireless LAN application, and network performance can vary
widely as the user roams or as other users join or leave the network.
Such problems quickly degrade voice quality.
With the help of an expert system, the analyzer can determine if any
delayed VoIP packets are likely to be dropped by the receiver. This is a
somewhat complex operation that basically boils down to analyzing the
variability in packet delay and determining which packets may be outside
the receiver's jitter buffer for a given codec and arrival rate. This is
important, since it is no longer a simple matter of checking for the
absence of a packet in the analyzer's capture buffer.
Another technique for mixed LAN/WLAN systems is to put an analyzer in
the traffic path on the wired side of the internal network to perform
additional call and quality analysis. Many VoIP devices send out
periodic reports containing jitter information experienced by the
receiver. This way, one can see the real jitter as experienced by the
end-nodes at both ends of the conversation without having to place an
analyzer at each of those end points.
Hand-Off Delays
Users roaming from one AP's coverage area to another AP's coverage area
must be handed off from one AP to the next. When the handoff time is too
long, the user can experience clicks, delays in picking up the
conversation again, or even a disconnected call.
A protocol analyzer can be used to look at the re-association and
recovery of problem calls in real time in order to directly correlate
the user experience with actual packet activity and anomalies. The
analyzer's VoIP expert system can be an enormous time saver in detected
these anomalies.
Simultaneous Conversations
Simultaneous two-way conversations can double the bandwidth requirement
for IP phones and thereby slow traffic. Two people won't necessarily be
talking at the same time, but any background noise at the listener's
location is also transmitted while the other party is talking. Some
codec protocols and phones can use noise suppression (which can squelch
transmitted packets from a user that is merely listening), but most do
not.
Therefore, there is almost always a continuous stream of packets
transmitted in both directions during a call.
An analyzer can be used to measure the bandwidth consumed and jitter
characteristics of a call (since in essence we are performing full
duplex operation on a medium that only allows transmission in one
direction at a time), as well as the impact as we add more users.
Security Attacks
As an IP service, VoIP is equally susceptible to security attacks, which
can immediately and dramatically affect voice service quality. A VoIP
analyzer built on a proven core of protocol analysis and expert system
technology can help identify these attacks by triggering events on
suspect data such as a worm or unexpected spike in response time or
throughput.
Even though VoIP traffic on wireless networks should be encrypted, it's
still possible to analyze the traffic by looking for problems such as
congestion, CRC errors, wireless retransmissions, frequent drops in
wireless data rates, and frame arrival rates (to and from the physical
address of the VoWLAN phone).
For VoIP phones that use a static WEP key, network engineers can obtain
the key from an administrator and plug it into their analyzer to fully
decode all seven layers of protocols.
Conclusion
The number of variables to manage in a VoWLAN application can be
daunting, but they're by no means insurmountable. Properly armed with
the right protocol analysis tools along with an understanding of VoIP
protocols and WLAN anomalies, network engineers can go far to ensure a
relatively trouble-free deployment of voice over wireless LAN.
--------------------------------------------------------------------------------
Scott Haugdahl is the chief technology officer at WildPackets where he
developed the expert system for the AiroPeek NX 802.11 wireless
analyzer. He has more then 20 years of experience in the networking
industry and is author of the book "Network Analysis and
Troubleshooting." WildPackets, as you either knew or gleaned from his
vendor-neutral article, makes network management tools.
VoWLAN
Heats Up
By
Vikki Lipset
03/03/2004
In what could be a big boost for the
growing voice over wireless LAN (VoWLAN) market, Nortel Networks (Quote,
Chart) and Alcatel (Quote,
Chart) both announced offerings this week that add voice
capabilities to their WLAN product lines.
The companies will resell Wi-Fi
handsets, access points (AP) and switches from SpectraLink (Quote,
Chart) and Airespace. Both
Nortel and Alcatel say their versions bring something extra to the table.
"It's their hardware, but our special
sauce," said Diane Schmidt, director of marketing for Nortel's WLAN
portfolio, of the company's new Adaptive WLAN deployment solution, which
is comprised of a security switch and access ports that the company says
are optimized for VoWLAN.
She pointed to the ability to monitor
and control the radio frequency domain as an example. This is key for
customers who are looking at real-time applications such as wireless IP
telephony and need nonstop coverage over their WLAN, she said.
"If there's a gap in coverage due to
some interference or an AP drops out for some reason, because we have
control over what happens across the air, we're able to transfer those
connections to a device that can handle them, so users won't experience
any downtime."
Nortel is also offering additional
security features. "We're bringing the capabilities of our security
switch -- things like rogue access point detection, support for VPNs --
into this solution as well," Schmidt noted.
"We've brought this airtight security
into a realm that's notoriously porous," added Nortel spokesman Pat
Cooper.
The Adaptive WLAN package will be
available next month. It includes the 2230 (a/b/g) and 2231 (b/g) Access
Ports ($599 and $499 respectively) and the 2270 Security Switch (starting
at $10,999). The new Nortel VoWLAN products, which include the 2210 and
2211 handsets ($695 and $890 respectively), the WLAN IP Telephony
Manager 2245 ($2500) and the WLAN Application Gateway 2246 (starting at
$1600), are expected to be available in May.
Meanwhile, Alcatel is offering APs,
switches and appliances under the OmniAccess name. OmniAccess 4000
wireless switches start $8,250, OmniAccess 4100 wireless appliances
start at $13,685 and OmniAccess 1200 Access Points start at $400.
The company will introduce its version
of SpectraLink's wireless handsets, branded as Mobile IP Touch 300 and
600, in September. The phones will work with Alcatel's OmniPCX family of
IP-PBX systems.
Talking
about Securing VoWLAN
By
Eric Griffith
05
Embracing voice over IP (VoIP) as the
hot new thing in LANs in general -- and wireless LANs in particular --
is not exactly news these days. VoIP is the buzzword of the moment, so
it's no surprise when a company like
Aruba Networks says it's
going to have a "full solution for VoIP in the enterprise."
The difference with Aruba is, they've
got partners like SpectraLink (Quote,
Chart), Avaya (which rebrands SpectraLink phones), voice-badge maker
Vocera, and soft-phone designer Telesym -- names that encompass almost
all the major players in Voice over WLAN (VoWLAN). SpectraLink alone
held 60% of the global market for VoWLAN products in the year 2003
according to Synergy
Research Group. The nearest rival, Symbol, provides about 7% of the
world's VoWLAN products.
Aruba also says it will differentiate
its VoWLAN support from other switch vendors by concentrating on
security.
"There's a huge security hole for
voice," says Keerti Melkote, Aruba's co-founder and vice president of
product marketing. "Handsets and the technology today are a generation
behind the state of the art -- the handsets mostly use MAC address (define)
authentication and WEP (define).
Static WEP is weak and can be broken and using a MAC address [means]
that once that address is admitted, it can go wherever. Spoof that and
it can send non-voice packets into the network" to cause a disruption.
Aruba will also be doing some new radio
frequency (RF) management to reserve bandwidth and perform load
balancing for calls at the access point (AP), all for voice traffic.
The Aruba switch will be able to make a
"virtual AP in the air for voice, and operate it with specific power
management profiles that are custom built for voice," says Melkote. This
profile will take into consideration that phones aren't connected to the
network at all times, unlike most WLAN data devices. By contrast, Meru
Networks, a switch competitor of Aruba's, recently announced a
proprietary solution involving the licensing of firmware to Wi-Fi
handset vendors to do the same thing. Meru's switch system has been
previously
tested as interoperable with Symbol and Vocera products.
Melkote says the Aruba 5000 Switch
could handle 5000 calls simultaneously, with a varying number of calls
per AP depending on the type of VoWLAN clients due to the codecs and
compression schemes used by each of its partners.
Aruba is breaking its voice support
into three separate phases. The first is simply to have interoperability
with its announced partners; for example the switch will support
SpectraLink's Voice Priority Protocol. Phase 2 will include using
standards such as Quality of Service from the proposed 802.11e standard
and fast-hand off from the 802.11r standard announced at the last IEEE (define)
meeting of the 802.11 Working Group. Aruba also plans to support the
Session Initiation Protocol (SIP). Phase 3 is well down the road: they
plan to offer seamless handoff from cellular to Wi-Fi networks.
Aruba is demonstrating its VoWLAN
solution with SpectraLink in London this week at the Wireless LAN show.
VoWLAN: The
Wireless Voice Future is Here ... Almost
June 14, 2004
By Beth Cohen
Chris Taylor, Telecommunications Manager, Metro Toronto Convention
Centre had a serious problem. His mission critical Nortel "Companion"
900Mz phone system was no longer supported and he needed a replacement
system double quick. With 2 million square feet of open exhibition space
spread over two buildings, he needed a communications system that
provided roaming and instant communications, an open flexible data
network, and a minimum of wires. A year ago, he started looking at
wireless networking combined with VoIP (Voice over IP) or VoWLAN (Voice
over IP over Wireless) as part of the total networking solution. As
Taylor put it, "My three goals were to provide wireless data networking
for exhibitors, create a corporate profit center by selling services to
the exhibitors, and meet employee data/telecommunications needs. The
combination of VoIP and wireless networking fit the bill exactly."
With 55 million lines and 15% of the voice market, VoIP is an
established and rapidly maturing technology. It has been proven to be
less expensive to install and maintain; the core equipment is comparable
in cost to traditional voice, and it offers many more integration
options. Wireless technology is also rapidly maturing, so the next
obvious step is to deploy a converged technology. Until a few months ago,
the converged technology suffered from proprietary equipment, weak
security, and a lack of scalable network management tools: It was not
quite ready for prime time. All that has changed in the past year. The
VoWLAN landscape is rapidly changing with evolving standards, new
equipment, and finally some good management tools. Let us look at some
of the issues that were plaguing VoWLAN and how the fledgling industry
is successfully addressing them.
Approaching Technological Liftoff
According to Bob Myers, CTO and co-founder of Chantry Networks, a
company that develops wireless network management systems, VoWLAN is
growing rapidly in certain vertical industries like health care,
hospitality, retail and manufacturing. Industries where the flexibility,
combined voice and data requirements are so compelling that they are
willing to forgo the current lack of handset hardware, network
management tools and poorly addressed security, standards, and QoS (Quality
of Service) issues.
Part of the problem is that wireless is a contention media -- the users
share the available bandwidth -- so wireless will always have overhead
issues and more complex management requirements. Another overlooked
issue is how to determine good coverage. In an open field, coverage is
easy to determine, but most IT people don't have the specialized
knowledge required to plan an installation for a complex environment
like a hospital, with all its attendant equipment and building
structures.
Myers notes, "Health care's transition to VoWLAN came about because they
had widely deployed 802.11 so they were already comfortable with the
technology. The hospitality and retail sectors both have a widely
dispersed work force that needs to be in constant communication. Both
industries were previously using the 900Mz Walkie-Talkie systems, so
conversion to VoWLAN was a natural next step. Beyond those specific
industries, uptake has been slow because of the perceived security
issues and lake of management tools." Recently, there has been a major
change in perception as companies discover the benefits of increased
flexibility, the improved security standards, and the always popular,
substantially lower operational costs.
Wireless Network Management
A critical component to the success of VoWLAN is sophisticated wireless
network management tools. As Myers puts it, "Unlike all previous
computer technology, wireless networking, wireless came back into the
enterprise from the SOHO and home markets. With a three node network,
you don't need management tools." When rolling out enterprise wide
wireless, especially VoIP, the need for prioritized data streams,
transparent access point handoffs, and seamless security are essential.
Chantry offers a management package that is designed to specifically
address these issues. Other companies, like Avaya and Cisco who are
heavily invested in developing this market, are also working to develop
new tools.
Continued on Page 2:
What Else is There to Think About?
QoS (Quality of Service) and Reliability
Wireless service quality is technologically a step 10 years backwards.
For data packet delivery, companies are willing to trade mobility and
reduced costs for reliability, but voice packets are more sensitive to
perceptible service degradation. As Myers puts it, "You really need to
have a max of 150ms to make sure users are not bothered by QoS issues
when you are using a VoIP system. Cellular has gotten people used to a
lower QoS compared to traditional voice, but not entirely."
To make matters worse, the WME (Wireless Multimedia Extensions) 802.11e
wireless QoS standard will not be ratified until the end of 2004 or
early 2005. Most wireless equipment has not yet incorporated any QoS
because they are waiting for the emerging standards. Because this is
such a critical piece for a successful VoWLAN deployment, some companies
are implementing a subset of 802.11e. Another gotcha is that while
802.11b officially delivers 11MB with QoS, the actual useable bandwidth
is really closer to 6MB. Remember that 6MB is shared by anyone on the
access point. VoIP has a tendency to have small packets with a large
overhead. With 10 to 15 VoIP users you are quickly down to unacceptable
modem-level data rates. The reality is that with most wireless
equipment, planners should expect 6-7 voice calls maximum per channel.
With Chandra's priority queuing and predictive handoffs, they can
support up to 15 voice streams in addition to a small amount of data
traffic. By limiting the number of voice calls on a single access point,
the software can maintain the required QoS.
Security
Wireless security is finally improving with the newer WPA and WPA2
standards, but these emerging standards have not been fully adopted into
the VoWLAN equipment yet. 802.11r is a brand new IEEE taskforce created
specifically to address VoWLAN security issues. Expect to see handsets
incorporating the improved security standards in 6 to 8 months, and new
standards in this area in a year or so. According to Myers, part of the
problem is the need to re-authenticate every time users move between
access points. Session switching can cause unacceptably high delays (up
to 500ms) or dropped calls. Obviously the re-authentication process is
in direct conflict with the QoS requirements of maintaining the call
data stream. Chantry has incorporated a virtual network service that
preloads the VoIP session security at the backend as the user roams the
network so the call session is transparently switched to the new access
point minimizing signal delay.
Staffing and Operational Issues
Unless you were a tiny company that had an IT generalist, the data and
telecom support staff have, until recently, not needed to learn each
other's methodologies and equipment. The current trend is to merge the
support functions and staff for more efficient operations, but there is
still a time lag in training and operational efficiencies, as the staff
learn the new equipment and procedures.
Hardware What Hardware?
Currently there are two main companies in the VoWLAN handset market,
Vocera and SpectraLink. SpectraLink owns 75% of the total handset market
and the majority of the health care market with systems in 1600
hospitals nationwide. Vocera is startup breaking into retail and health
care. Because they were first to market, neither of these are standards
based systems. Both Cisco and Symbol (the people who invented barcode
scanners) have handsets as well. According to Chris Taylor, Symbol has
recently dropped the VoWLAN line to focus on their core market. All the
products suffer from short battery life and reliability problems. As PoE
(Power over Ethernet), standards and cellphone technology is
incorporated, expect to see a plethora of better handsets within the
next few months.
Are We There Yet?
How is Chris Taylor doing with his VoWLAN system? He reports that they
have had the beta system in place since January. They are planning a
full rollout to completely replace the old "Companion" system by
September. "The staff loves it. The voice quality is good and roaming is
completely transparent. Just make sure all the vendors' equipment is
compatible and integrated. That was the key to success for our
installation."
Should you be seriously considering Voice over IP over wireless LAN
solutions today? Well yes and no. Unless you are in the health care,
manufacturing, or retail industries where the ROI is especially
compelling, the technology is still not quite ready to be heard yet.
With the maturing of both the VoIP and wireless technologies, on the
surface merging the two emerging technologies might seem to be a
terrific idea. However, security issues, poor quality equipment, and
bandwidth prioritization considerations point to a technology that is
still too immature for anybody to deploy unless they are ready to put up
with the bleeding edge phase of the innovation curve. In the next 8 to
12 month there will be numerous new products that will be addressing
these and other issues as many innovative technology companies work on
solving the problems. Once the issues have been properly addressed and
the standards settle down, VoWLAN with its potential to merge data,
voice and mobility into one neat package, promises to be something that
could transform how companies do business.
--------------------------------------------------------------------------------
Beth Cohen is president of Luth Computer Specialists, Inc., a consulting
practice specializing in IT infrastructure for smaller companies. She
has been in the trenches supporting company IT infrastructure for over
20 years in different industries including manufacturing, architecture,
construction, engineering, software, telecommunications, and research.
She is available for consulting to help your company identify the right
IT infrastructure to meet your business objectives.
Sugestões enviadas por Eduardo Prado:
Voice on WLAN trials 1: It works!
TechWorld
By David Newman, Network World
07 February 2005
Part 01
Aruba wins - but not everyone entered...
VOIP should be an easy fit for wireless LANs, but mixing the two
technologies today is difficult. Despite VOIP's low-bandwidth profile,
even a small amount of data traffic on the same network can lead to
seriously degraded audio quality and dropped calls, even with QoS
features enabled.
That's the major conclusion of our first-ever assessment of VOIP
capability in WLAN systems. Over the course of three months we tested
WLAN switches and access points from Aruba, Chantry (now acquired by
Siemens), Cisco and Colubris. in terms of audio quality, QoS enforcement,
roaming capabilities, and system features. The Cisco system, is the
company's own product, built around its Catalyst switches, rather than
the switch system it is buying in, with vendor Airespace.
Other vendors, including Airespace, Meru and Trapeze, declined to
participate.
Among our major findings:
(1) With QoS enforcement enabled, the products delivered
near-toll-quality ("nearly as good as wired telephones") audio, provided
there is only voice traffic on the network. Unfortunately, this
situation is not likely in practice, as companies move toward converged
voice-data networks.
(2) When voice traffic had to contend for bandwidth (even with a little
data traffic), dropped calls were common and audio quality on the
remaining calls was poor in many cases - and this was with QoS
enforcement enabled.
(3) With data traffic present, roaming from one access point to another
took anywhere from 0.5 to 10 seconds - in cases where roaming succeeded
at all. These long delays and dropped calls made roaming practically
impossible with some vendors' gear.
While some products struggled mightily in our tests, Aruba's A2400 and
A800 switches and A61 access points were consistently strong performers.
The Aruba products posted generally excellent numbers, regardless of how
much voice or data traffic was thrown at them. Aruba's gear just worked,
earning it the Clear Choice Award.
Two issues confounded other vendors. First, when handling voice and data
traffic on the same network, vendors need to pay attention to metrics
such as delay and jitter rather than forwarding rates.
Many vendors are only just beginning to tune their products for
voice/data convergence, even though some have touted that capability for
18 months or more. However, it's still relatively early days for VOIP
over WLANs. Test tools that accurately measure these metrics on WLANs
are only just beginning to appear (the VeriWave instruments we used were
developed for this test, and the company launched its Wi-Fi Traffic
Generator at Wi-Fi Planet in November). This test is among the first to
measure audio quality, delay and jitter in a methodical way.
Second, the emerging 802.11e standard for QoS on WLANs might bring some
relief. The 802.11e specification wasn't yet ratified when we began this
project, so by definition all QoS methods were nonstandard. Companies
might want to wait until the new 802.11e specification and products
based on it are more mature and fully tested.
How to measure quality
Our tests sought to answer a simple question: How does a VOIP over WLAN
system sound?
To find out, we worked with VeriWave, a start-up that makes WLAN test
and measurement equipment. VeriWave developed a new application, the
VOIP over WLAN Analysis Test Suite, especially for our test.
In addition to collecting delay and jitter statistics, VeriWave's test
suite and TestPoint hardware let us measure R-value, an ITU
specification (G.107) for determining call quality. R-value is an
objective measurement, computed directly from measurements of packet
loss, jitter and delay. While R-value is objective, it has a strong
correlation to the subjective Mean opinion score method in ITU standard
P.80 (see R-value ratings).
R-value ratings
An ITU specification that determines call quality, R-value measures
packet loss, jitter and delay.
We measured voice call quality with up to 14 handsets and an H.323 call
server from SpectraLink, a maker of 802.11 handsets. We measured audio
quality with up to seven concurrent calls, and in some events configured
the VeriWave TestPoint boxes to offer background data. For each system
tested, we checked call quality with QoS disabled, then enabled.
Results in Brief
Over the next three days, we will feature detailed commentary on quality
of service, roaming and architecture issues. Here is a brief summary of
the results for the four systems we tested.
Aruba Networks
A2400, A800 switches, A61 access point . Overall rating 4.58
Cost: $8,780 as tested.
Pros: Outstanding voice prioritisation capabilities; rich set of QoS and
radio frequency management features.
Con: Some call drops in most stressful test case.
Cisco
WLSM Overall rating 3.53
Cost:$51,978 as tested.
Pros: Highly scalable, rich set of routing and switching functions.
Cons: Doesn?t protect voice traffic under most stressful test case;
doesn?t dynamically adjust to changes in radio frequency environment;
pricey.
Colubris Networks
CN1250 Overall rating 3.0
Cost: $1,800 as tested; access point, $500.
Pro: Powerful and intuitive user interface.
Con: Limited prioritisation of voice traffic.
Chantry Networks (now part of Siemens)
BeaconMaster Overall rating 2.4
Cost: $9,180 as tested.
Pro: Supports Open Shortest Path First routing.
Cons: Dropped calls in six- and seven-call cases; poor voice quality in
the presence of data; no contingency for the loss of power.
Conclusions: don't mix voice and data unless the system can handle it
It's possible that overall products may improve when more of them
support the 802.11e QoS standard (read more here). All the vendors said
it was early in the evolution of VOIP over wireless, and our test
results show there is certainly room for improvement. For network
managers looking to deploy VOIP on WLANs in the near future, there are
three choices:
make very few calls;
don't ever send data;
or look for equipment - such as Aruba's - that handles time-sensitive
traffic in a timely way.
Tomorrow: Quality of Service in detail.
Wi-Fi phones don't add up to much
By Ben Charny
http://news.com.com/Wi-Fi+phones+dont+add+up+to+much/2100-7351_3-5566708.html
Mon Feb 07 16:25:00 PST 2005
A new study suggests it will be a number of years before Wi-Fi phones,
supposedly a revolutionary telephone technology, manage to fulfill
expectations.
Analysts at Infonetics Research say portable phones using Wi-Fi, the
popular technology that creates 300-foot zones of high-speed wireless
connectivity, are taking hold in hospitals and businesses, but worldwide
sales were negligible last year.
The results are disappointing. After years in development, the
much-anticipated devices were supposed to take off in 2004. But with
just 113,000 such handsets sold last year, or $45 million in total sales,
it's apparent the prognosticators were wrong. Rather, the sales "represent
a market at its birth," as Infonetics analysts put it.
Wi-Fi phones combine two very hot and potent technologies--Wi-Fi and
voice over Internet Protocol (VoIP) software, which lets Internet
connections double as extremely inexpensive phone lines. Typically, VoIP
subscribers use a wired phone line, whether a single home phone or any
number of phones in an office setting. But many service providers see an
opportunity to create wireless versions of their services using Wi-Fi.
Introducing the appropriate VoIP services and technology could turn hot
spots into giant phone booths.
But it could take at least until 2009 before the cost of Wi-Fi phones
drops enough for a mass market breakthrough, according to Infonetics.
"Voice over wireless Internet devices have the potential to be a hugely
disruptive technology," Richard Webb, Infonetics directing analyst said
a statement. "As VoIP goes wireless, this will present a challenge not
only to fixed line operators, but to mobile operators."
Copyright ©1995-2005 CNET Networks, Inc. All rights reserved.
MOBILE VoIP IS GOING TO CHANGE
THE TELCO INDUSTRY
Fierce Wireless
Mobile VoIP is dramatically altering the telecommunications industry,
according to research firm ON World. There are three developments
combining to transform the telecom landscape: Low-powered single-chip
radios with integrated protocol stacks; the adoption of standards such
as SIP; and the promise of affordable flat rate roaming. There are
already more than 400 VoIP service providers in North America.
More ...
SAN DIEGO, Feb. 8 /PRNewswire/ --
Voice over Internet protocol for mobile devices (mobile VOIP) is
dramatically altering the telecommunications industry, according to
research firm ON World
"As network operators continue to embrace VOIP and enterprises continue
to deploy WiFi networks, mobile devices that combine the advantages of
both have emerged," says Mareca Hatler, ON World's Director of Research.
"Low powered single chip radios with integrated protocol stacks, the
adoption of standards such as SIP, and the promise of affordable flat
rate roaming are setting the stage for a telecom transformation."
Mobile VOIP Service Providers
With more than 400 VOIP service providers in North America alone,
pioneer service providers such as Vonage, BroadVoice and Net2Phone are
offering Voice over WiFi (VoWiFi) handsets as a way to differentiate
their offerings and encourage more subscriber loyalty.
VoWiFi handsets are like IP based cordless phones that can be used in
the home, office and any Wi-Fi network such as hotspots. Business users
benefit by having a mobile inter-office phone that is low cost, can go
wherever they go, make calls to anywhere in the world, and pay no
roaming charges.
Roaming: A Key Enabler
For most users, the ideal mobile device is capable of dual mode voice
operation (cellular + VoWiFi). As mobile operators continue to offer
Wi-Fi enabled smart phones, ON World predicts that a large percentage of
these will also support VOIP. Eventually, this device will roam
seamlessly from cell to cell, WLAN to WLAN and cell to WLAN.
"Widespread adoption of mobile VOIP has reached an inflection point
which is the lack of roaming solutions," says Mareca Hatler, ON World's
Director of Research. "Competitors in this landscape are battling the
roaming standards problem on several fronts: development of roaming
standards, creation of roaming networks and establishment of roaming
alliances."
ON World's recently published report, "Mobile VOIP Competitive Landscape
2005," features Competitor Assessment Grids on 19 companies, actionable
competitive intelligence on six market segments and 28 in-depth
profiles. For more information, go to: http://www.onworld.com/.
About ON World Inc.:
ON World Inc. provides world class business intelligence on emerging
wireless markets. Customers include Fortune 1000 companies, service
providers, venture capitalists, and startups worldwide.
For further information please contact Mareca Hatler of ON World,
+1-888-312-2619 ext. 12, research@onworld.com.
Quelle: ON World
I AM TALKING A LOT ABOUT THAT ... VoWiFi
to grow dramatically
Fierce Wireless
VoWLAN is steadily spreading through the enterprise sector, and
a recent report says that the technology will see even more
robust growth over the next four years. Infonetics Research's
latest report says that 113,000 WiFi VoIP handsets were sold
world-wide in 2004, bringing in $45 million. Infonetics
estimates that global dual-mode WiFi/cellular handset revenue
reached $6.6 million in 2004 with more than 8,000 handsets sold.
We should note, though, that dual-mode WiFi/cellular handsets
were commercially available only in the fourth quarter of 2004.
Both revenue and the number of handsets sold are projected to
grow "dramatically" by 2009 as more enterprises offer employees
flexible mobile access over different forms of wireless networks.
Even though WiFi VoIP handsets currently represent only a small
market, this market has "great potential across several market
segments," Infonetics stated. Early adopters in the enterprise
space will be in the logistics and healthcare verticals, where
VoWLAN is already has some momentum. It will become even more
wide-spread as both VoIP and WLAN adoption continues.
There is also potential for "enormous growth in the consumer
space," as broadband service providers offer both VoIP services
and wireless gateways bundled with a broadband connection.
Infonetics' Richard Webb says that "voice over wireless internet
devices have the potential to be a hugely disruptive technology,
too... The traditional model of time and distance-based pricing
for voice calls will be eroded by VoIP, and as VoIP goes
wireless this will present a challenge not only to fixed line
operators, but to mobile operators as well."
More ...
Voice over Wi-Fi raises the volume
Robert Jaques, vnunet.com 08 Feb 2005
Dramatic growth for voice over wireless Lans predicted
Business uptake of voice over wireless Lans is slowly but
steadily ramping up, with newly published research predicting
that the technology will enjoy strong growth during the next
four years.
According to Infonetics Research's latest report, worldwide
Wi-Fi VoIP handset sales clocked up $45m in 2004 with 113,000
units shipped.
The analyst firm estimates that global dual-mode Wi-Fi/cellular
handset revenue hit $6.6m in 2004, and units totalled more than
8,000. The report noted that units were only commercially
available in the fourth quarter of 2004, so this represents a
market at its birth.
Revenue and units are projected to grow "dramatically" by 2009
as enterprises take advantage of the opportunity to offer
employees flexible mobile access over different forms of
wireless networks.
Wi-Fi VoIP handsets represent a fairly small market currently,
but one with "great potential across several market segments",
Infonetics stated.
Primary adoption is expected in the enterprise space, in
logistics and healthcare verticals in particular, where voice
over wireless Lan is already gaining momentum but will become
more widespread as both VoIP and wireless Lan adoption continue.
Infonetics added that there is potential for "enormous growth in
the consumer space" as broadband service providers offer both
VoIP services and wireless gateways bundled with a broadband
connection.
"Wi-Fi capability will eventually become a common feature in
cellphones, just as it is becoming standard in laptops today,
giving mobile operators a big opportunity with Wi-Fi voice,"
said Richard Webb, directing analyst for Infonetics and author
of the report.
"But voice over wireless internet devices have the potential to
be a hugely disruptive technology, too. One big factor is the
low cost of calling, especially long distance, overseas and
during peak hours.
"The traditional model of time and distance-based pricing for
voice calls will be eroded by VoIP, and as VoIP goes wireless
this will present a challenge not only to fixed line operators,
but to mobile operators as well."
Webb added that there are technical issues to be worked through
before wireless internet calling becomes commercially viable.
Areas that remain to be addressed include quality of service,
roaming across different wireless platforms, and the relatively
short range of Wi-Fi signals.
Voice over WLAN (VoWLAN)
24/05/2004 -
Segunda-feira
VoIP, WLAN e "As Águas
de Março"
Sras e Srs. embora
estejamos em Maio queremos relatar que Março foi um mês de
muitas surpresas em matéria de VoIP combinado (ou não) com
WLAN.
Veja abaixo uma coletânea
variada do Weblog
Smart
Convergence:
0.
Microsoft
Will Microsoft Dominate VoIP?
DSL Reports
March 2, 2003
Integrating a skype-like app into the OS...
Business Week argues that while smaller players like Vonage
and individuals like Jeff Pulver are getting all the
attention, Microsoft is quietly positioning itself to
dominate the VoIP industry. By integrating SIP VoIP into the
OS, some analysts worry Microsoft could quickly forge the
largest VoIP network around, one which doesn't touch the
PSTN, and doesn't require regulation. The article hints that
the Pulver victory (see our recent interview) - which frees
"pure" VoIP providers from regulation - isn't a big deal on
its own, but could spell trouble if a larger provider like
Microsoft begins to move.
The article suggests that because Windows XP already
contains the SIP software, and Microsoft recently unveiled
Live Communications Server (LCS) for corporations, it's a
quick jump to assume they could dominate the industry. Of
course, companies like Cisco, the bells, and numerous others
are not Netscape.
1.
VoWLAN market gains traction
Fierce Wireless
The market for Voice-over-WLAN (VoWLAN) is gaining traction
as vendors this year look for the technology to take off
with the enterprise market. VoWLAN offers cheap voice
coverage for corporate campuses and large facilities, such
as factories, college campuses, and hospitals. VoWLAN
start-ups, like Vocera, are targeting vertical markets such
as healthcare. Network vendors are also now marching into
this market. Alcatel and Nortel Networks yesterday launched
new VoWLAN products, and both companies also promised to
start re-selling WiFi handsets from SpectraLink.
See more ...
Wi-Fi
and VoIP: Is sum greater than parts?
Last modified: March 1, 2004, 1:48 PM PST
By Marguerite Reardon
Staff Writer, CNET News.com
Wireless local area networks and Net-based phoning have been
among the most talked-about emerging technologies for
businesses over the past year, and now, vendors are
introducing products they say will help companies combine
the two.
"Wi-Fi and VoIP are powerful technologies on their own,"
said Richard Webb, directing analyst for wireless LANs at
Infonetics Research. "But together, they are far more
powerful. It's sort of like adding one plus one and getting
three."
Equipment vendors have been targeting these markets
separately, but so far, adoption has been slow. According to
a study Forrester Research conducted, only about 20 percent
of the 818 companies Forrester surveyed said they had
completed or were in the process of rolling out Wi-Fi or
wireless LANs. About 15 percent said they had completed or
were in the process of rolling out voice over Internet
Protocol systems.
Experts agree that combining these technologies will help
push each of them further. As a result, equipment makers are
starting to beef up their offerings. On Monday, Alcatel and
Nortel Networks, both strong players in the voice market,
announced new wireless products.
Alcatel announced that it will resell wireless switches,
appliances and access points from start-up Airespace. The
products will be marketed and sold under the Alcatel
OmniAccess brand. Alcatel said the equipment adheres to the
802.11i security standard the Institute of Electrical and
Electronics Engineers ratified, which provides strong
encryption for data carried over wireless networks. Alcatel
also said the products will support the 802.11a/b/g
standards, which promise to improve security and enable
higher throughput and VoIP. The IEEE is expected to ratify
the 802.11a/b/g standards this summer.
In addition, Alcatel said it plans to start reselling
wireless LAN handsets from SpectraLink in October 2004.
These handsets are based on the 802.11b standard and will
act as extensions of the Alcatel OmniPCX family of IP-PBXs.
Nortel Networks, which started selling its family of
wireless switches last year, announced on Monday the 2210
and 2211 wireless handsets. Like Alcatel, the company is
partnering with Airespace and SpectraLink for the handset
technology.
Experts say the marriage between VoIP and Wi-Fi is a natural
one, as companies look for a common infrastructure that will
give workers more flexibility in how
they communicate. VoIP over Wi-Fi offers many benefits to
corporate users, such as eliminating the need to use
valuable cellular airtime within a campus network. What's
more, many cellular phones lose their signal when inside
steel frame buildings, so Wi-Fi phones would provide better
quality of service and reliability. It's especially useful
in vertical industries such as health care, where cellular
phones can't be used at all, because they interfere with
certain machines.
"As companies build out their next-generation IP
infrastructures, they want one highly available and secure
network for their wired LAN and their wireless LAN," said
Brian Witt, director of product marketing for Alcatel. "We
can offer them the gear to do this. Voice over wireless LAN
will be just one service that runs over this
infrastructure."
But in order for VoIP over Wi-Fi to really take off, it will
also have to combine cellular technology, said Joel Conover,
an analyst at Current Analysis. Motorola has already started
talking about delivering handsets that support both cellular
and Wi-Fi access. The company is partnering with VoIP gear
maker Avaya and Wi-Fi equipment manufacturer Proxim to
develop products that combine cellular, VoIP and wireless
technology.
Alcatel and Nortel said the handsets they announced Monday
will only support Wi-Fi access.
2.
Dailywireless
Enterprise VoIP
Tuesday, March 02 @
00:19:00 PST
Airespace has signed separate deals for wireless Voice
over IP with
Alcatel and
Nortel
for VoIP.
SpectraLink is Alcatel's incumbent's OEM partner (see
Alcatel Intros WLAN Products and
Nortel Touts VOWLAN).
Spectralink's s340 and s640 Docking Stations , which
were first announced nearly a year ago,
act as charging cradles for SpectraLink's e340 and i640
Wi-Fi handsets and add standard desktop telephone
features such as a speakerphone, keypad and display. They
will ship in April for $299. SpectraLink is also working on
a standalone desktop phone that will feature an integrated
802.11 radio. That phone will be designed for places where
it's difficult to run Ethernet or telephone wires.
Airespace already has a WLAN handset partnership deal with
SpectraLink, which supplies the phones and
quality-of-service software that allows voice traffic to be
prioritized on an 802.11 network (see
Airespace Talks Up VOIP).
Meanwhile
Lucent has teamed with Cisco Systems to develop a
carrier-class voice over Internet Protocol (VoIP) and
multimedia communications solution for mobile service
providers. It uses the
Cisco MGX 8000 Series Media Gateways to deliver
converged IP-based services -- such as VoIP, high-speed data
and multimedia communications -- across third-generation
(3G) Universal Mobile Telecommunications System (UMTS) and
CDMA2000 and CDMA450 mobile networks. "This will enable
operators to take advantage of the tremendous revenue
potential, and cost savings made possible by IP technology,"
," said John Marinho, vice president of offer management
with Lucent's Mobility Solutions Group.
Clay Shirky explains it all;
"Where Vonage and a number of the other VoIP startups
present themselves to the customer as phone companies,
emulating the incumbents they are challenging, you can think
of Plan B as the Skype plan. Skype isn't taking on the
trappings of a phone company; instead, it offers free
two-way voice conversations over the internet."
"Wi-Fi and VoIP are powerful
technologies on their own, but together, they are far more
powerful.
It's sort of like adding one plus one and getting three,
" says Richard Webb at Infonetics Research.
But in order for VoIP over
Wi-Fi to really take off, it will also have to combine
cellular technology, said Joel Conover, an analyst at
Current Analysis. Motorola and Nokia have shown handsets
that support both cellular and Wi-Fi access. Avaya and
Proxim have teamed to develop
Proxim's new AP-4000 with Voice over IP features.
There has been an explosion of
SIP Products. VoIP operators like
Vonage,
SIPphone and
8x8, often use ordinary phones. They plug into an
adapter than connects to your broadband connection. Nothing
is hotter than
Mobilized VoIP.
"Free" VoIP services include
Skype,
Pulver's
Free World Dialup and
Asterisk,
an open-source SIP server.
Skype,
the "free" VoIP client software that runs on PCs and soon
PDAs, is creating quite a buzz on community lans. That's
partly because it brings "free" voice to users (when both
parties are connected using the internet. The other reason
that VoIP has become a hot topic on community LANs is
because it "breaks" the captive portal model. A wireless
phone has no convenient way to display a splash page and its
associated legal disclaimer.
That disclaimer, it has been
believed, helps to remove legal liability from "free"
internet providers. Currently, standalone WiFi VoIP phones
may not be able to connect or acknowledge the disclaimer. A
method to provide that needs to be developed, say some
community lan activists.
BOM DIA!
27/DEZ/2003 - Sábado
VoWLAN
RIDES AGAIN ...
Mais 1 da Série Didática de
WLAN. Hoje com VoWLAN.
O que é isto? Vejamos então...
Não existe hoje a VoIP (Voice
over Internet Protocol) tomando vulto?
Veja referências recentes de VoIP:
O Skype pode ser um fenômeno em VoIP
do site autoral Alice
Ramos
RBOC VOIP
Coming in 2004
do Magazine Board Watch:
SBC Promises VoIP
from DSL Reports
Bells
Join VoIP Push from DSL Reports
Então ... VoWLAN é Voice
over Wireless LAN.
Ué... isto é mais complicado que o VoIP que todo mundo está
falando agora? Sim, é bem mais complicado pela natureza
Wireless no "negócio".
Imagina juntar os "pacotes" da sua voz digitalizada quando
você caminha de um
Access Point para outro. Não é uma tarefa simples e
está sendo bem endereçada.
Acreditamos - pelo "andar da carruagem" - que em 2004
teremos excelentes notícias neste terreno.
VoWLAN vai ser muito
interessante no mercado Corporativo principalmente naquelas
empresas aonde vc tem uma grande parte dos empregados 80% do
seu tempo de trabalho fora das suas mesas como os segmentos
de hotel, de hospital, do varejo e de logística para citar
alguns.
1.
Veja o que já estão
pensando ...
Este WISP no Reino Unido jjá
quer fornecer o serviço de VoWLAN em 2004.
Smart Convergence
on Saturday, November 22, 2003
UK WISP to offer VoIP
Wi-Fi Planet
By Vikki Lipset
November 21, 2003
Patrons of U.K. hotspots will soon be able to make voice
calls over public wireless LANs, thanks to a new service
from Internet access provider
Broadreach Networks.
The service, called ReadytoTalk, won't officially launch
until next summer, but Broadreach will do a test run with
40,000 customers in the interim. The voice over IP (VoIP)
service will be an add-on to the company's ReadytoSurf
hotspot service, which passed the 500,000 user mark this
week.
All ReadytoSurf sites will also be ReadytoTalk-enabled,
according to Broadreach CEO Magnus McEwen-King. There are
currently 129 ReadytoSurf hotspots in coffee shops, retail
stores, hotels and other locations across the United
Kingdom.
Like ReadytoSurf, the VoIP service will be offered through
ISPs and wireless carriers. Users will need to download
software, developed by Broadreach, to their laptop or PDA
(McEwen-King said the company plans to support all the major
operating systems). Pricing for the service is not yet
available.
Broadreach has been contemplating a VoIP service for a
while, but has been waiting for the right time to enter the
market, said McEwen-King. "VoIP has always been a much
talked about proposition, but the quality levels have not
been there. However, in the last six months, a number of
companies have made significant strides in improving both
the costs and quality. We feel there's another few months to
go, but now is the time to start doing end-user testing with
our ISP and mobile phone operator partners."
See the
Press Release
2. Enquanto isto fique com
esta boa matéria ...
Voice over wireless LAN: Ready or not?
InfoWorld
By Nancy Gohring September
12, 2003
Some hurdles remain, but
ubiquitous voice communications may be the killer app for
wireless LANs
WLANs (Wireless LANs) are
still in the experimental phase at most companies. Why?
Because wireless security standards remain in flux. But a
more obvious obstacle to wholehearted adoption is the lack
of a compelling need for wireless in the average office,
which already has a perfectly functional, wired LAN in
place.
Well, here’s a thought: How
about replacing or supplementing your current phone system
with a VoWLAN (Voice over WLAN) system? Just take an
ordinary wireless network and add a VoWLAN server along with
laptops, PDAs, or newfangled Wi-Fi phones to run the client.
Instead of workers wasting time playing phone tag, they can
field calls wherever they roam on campus — or even on the
road, if there’s a Wi-Fi cloud nearby.
VoWLAN is a natural extension
of VolP (Voice over Internet Protocol), a technology that
has already taken root in enterprise telecommunications.
(Today, more IP-based PBXs are sold than conventional
models.) Yet VoWLAN presents its own unique QoS (quality of
service) challenges relating to fluctuating wireless
throughput and roaming among APs (access points), which is
why most of today's local wireless voice systems are bundles
of proprietary wireless network hardware and software.
Industries with highly mobile
workers — such as retail, manufacturing and healthcare — can
justify the premium for a proprietary network. (One of the
most popular solutions,
SpectraLink's
Wireless Telephone System, costs between $400 and $700 per
seat.) Yet the proliferation of Wi-Fi and its increasing
reliability opens the possibility of deploying VoWLANs
across commodity WLAN setups at much lower costs.
Technical hurdles remain. But
on the hardware side, at least, everyone seems to be getting
in the game. Cisco
recently introduced its first VoWLAN handset and a slew of
vendors including NEC, Qualcomm, Motorola and Dell promise
hybrid phones next year that use both Wi-Fi and mobile phone
networks.
A Very Local Exchange
“It’s just a matter of time
before [VoWLAN] catches on in the mainstream enterprise,”
says Ben Guderian, director of marketing for SpectraLink.
SpectraLink recently introduced a new, lightweight, less
rugged handset designed for mainstream enterprise users. Its
lowest priced handset costs $399, which compares to around
$350 for many desk phones with standard wiring.
Proprietary wireless voice
vendors such as SpectraLink and Symbol have been among the
first to release VoWLAN solutions for commodity wireless
infrastructure. But there’s a new breed of VoWLAN provider
as well: the softphone developers. These companies, such as
TeleSym, IP blue, and VLI have built software that can be
loaded onto PDAs or laptops, enabling users to initiate and
receive voice calls over WLANs.
Basically, VoWLAN systems work
in two different ways. Offerings from SpectraLink, Symbol,
and Cisco route calls from the phone to the WLAN AP to a
VoIP gateway — one that may already be in use to deliver
VoIP over the wired network — which translates calls between
the IP network and the PBX. That setup allows all regular
PBX functions that are available on workers’ wired desk
phones to be available on the VoWLAN phones. Calls that are
made to phones outside the enterprise go through the PBX to
the PSTN (Public Switched Telephone Network).
By contrast, softphone
developers such as
TeleSym provide systems that route calls outside the
enterprise over the Internet. In this scenario, road
warriors could use the softphone on their PDA or laptop to
place calls from a hotel that offers a WLAN. The call could
route entirely over the Internet. “Then the call is
completely free,” said Raju Gulabani, TeleSym’s CEO.
The downside is QoS. Like any
voice call that uses the Internet, users can’t control the
quality of the connection.
Voice, Interrupted
Unfortunately, even over the
local network, VoWLAN has its shortcomings. The problem is
that the 802.11 standards — including those that cover QoS,
security, and roaming — simply weren’t designed to support
voice.
For example, 802.11 entirely
lacks a QoS mechanism. This lack means that no special
priority is given to voice, so when traffic spikes on the
network, dropouts may occur. The IEEE is working on 802.11e,
a QoS standard that should be finalized next year. In the
meantime, Symbol
and SpectraLink have implemented their own proprietary QoS
mechanisms through their hardware.
But it’s security, or a lack
thereof, that’s the biggest deal breaker for VoWLAN today.
Enterprises view today's wireless security measures (such as
the Wireless Encryption Protocol) as weak, forcing them to
opt for wireless VPNs. But VoWLAN offerings that use phones,
as opposed to those that use PDAs or laptops, often can’t
employ VPNs because the client software usually can’t be
loaded onto the phone. (Several vendors, including NEC and
Cisco, plan to produce phones next year with VPN support
built in.)
But using VPNs for voice has
other problems. “A VPN tends to encapsulate voice packets,
so it obscures them from the network and it can’t discern
high priority voice from low priority data,” says Ron Seide,
product line manager for Cisco’s wireless networking
business unit. In addition, VPN’s cause latency that
degrades the quality of voice, says Richard Watson, an
engineer at Symbol and director of telephony product
marketing.
Instead of using VPNs, users
can protect against unwanted intruders by putting voice and
data on different subnets or VLANs, allowing clients in the
voice subnet to communicate only with the telephone gateway,
Watson says. With this separation, the widely used
encryption and authentication standards offer good enough
security, say some vendors. That’s because the threat of
eavesdroppers is remote as the listener would have to be
within range of the same AP as the phone user. “The joke
here is watch out if you have someone walking behind you
with an antenna,” says Watson. “It’s an overblown thing.”
An added challenge, though, is
that encryption and authentication must happen fast enough
so that a call isn’t dropped or degraded when a user moves
from the coverage area of one AP to the next. The existing
802.11 standard can’t support that handoff fast enough and
neither can the security solutions developed by gateway
vendors. Even 802.1x, the upgraded security standard in
development, won’t work quickly enough. “When standards
bodies developed all this, they were more concerned with
security on laptops,” says Watson.
The handoff between APs should
happen in under 50 milliseconds to cleanly support a voice
call, says Doug Klein, CTO of Vernier Networks, a security
gateway vendor. Vernier’s gateway does the transfer in a
matter of a few hundred milliseconds. “It’s not optimum,”
admits Klein.
As a result, vendors have
developed their own fast authentication processes. These
generally work by dispensing a certificate to the client
proving that it is authenticated, so that when a user moves
into range of another AP, the client offers that certificate
as proof of authentication.
Cisco employs a similar
scheme, where one AP is designated as a master AP within a
subnet. Rather than require each AP to acquire an encryption
key from a backend server as the user roams, the master AP
gets a master key and from that, each AP in the subnet
spawns a session key. But even Cisco’s solution takes 150
milliseconds.
Maybe Next Year
The available VoWLAN security
solutions aren’t robust enough for many enterprises. “I
don’t think it’s likely that we’ll be deploying VoIP on
Wi-Fi networks anytime soon,” says Joshua Wright, senior
network and security architect for Johnson and Wales
University, which already has an extensive WLAN for data
users. Current offerings don’t enable the kind of
reliability he wants in a voice network.
The efficiency of the security
and QoS also affects the load that APs can handle. Most AP
vendors say each AP can support 10 simultaneous calls, but
when pressed, will usually admit to half that number in live
deployments. Chris Kozup, META Group's program director of
technology research service, says his clients who have
tested VoWLAN report on average four or possibly five calls
without any data use per AP. “It becomes a problem because
there are finite resources here in terms of channel and
frequency,” Kozup indicates. “It’s not as easy as lighting
up another AP.”
New standards, including the
faster 802.11g and the QoS specification, 802.11e, should
increase the number of users an AP can support. Combined,
those upgrades could allow 15 to 25 simultaneous calls, says
Cisco's Seide.
Ultimately, although the
hurdles of deploying a robust VoWLAN are many, they are also
surmountable. The key to robust and reliable VoWLAN networks
lies in the ability to support security and all capabilities
fast enough to hand off between APs seamlessly. As more
customers demand support for voice, vendors say they’ll
deliver it. “We’ll get around to doing the work that needs
to be done,” said Vernier’s Klein.
3.
Veja Notícias do IEEE sobre
QoS (IEEE 802.11e)
Status of
Project IEEE 802.11e
MAC Enhancements for Quality
of Service
The purpose of Task Group E is
to: Enhance the current 802.11 MAC to expand support for
applications with Quality of Service requirements, and in
the capabilities and efficiency of the protocol.
4. Um Trabalho Nosso sobre o
Assunto
Voz sobre wireless LAN (VoWLAN) do site autoral
Alice Ramos
5. Uma Grande Matéria sobre o
Assunto
VoIP unwired
By Phil Hochmuth
Network World
July 28, 2003
Voice and wireless Ethernet might seem an odd mix, but for
mobile workers or hard-to-wire areas, it can be the perfect
combo.
Converged voice/data network projects can be tough,
especially if you can't use any wires. That's what Mike
Burns, a systems integrator, discovered when a client asked
him to provide voice and data services to a gold-mining
operation in the middle of a Laotian jungle. Burns faced a
sticky situation - literally.
"The ground was mostly mud, so we couldn't bury any cables,
and there were no poles where we could hang wire," says
Burns, who is president of Nationwide Computer Systems, an
ISP and integration firm in Fort Lauderdale, Fla. The
solution would obviously be a wireless one: Burns used
802.11b gear to connect 50 IP phones, PCs, a router and
satellite dish for the mining camp. The camp, which
stretches over a two-mile area, consists of 20 structures
for operations, living quarters and offices.
Eu gosto desta figura aqui ...[Figura
grande - Aguarde a carga se a conexão estiver lenta]
Wi-Fi VoIP: Behind the curtain
at one medical center
University of Southern California University Hospital uses
QoS technology on
a Wi-Fi gateway and at the LAN switch to ensure wireless IP
voice calls
get priority as they crosss the LAN
1 BOM SÁBADO COM "VOZ DIGITAL"
!!!
17/NOV/2003
- Segunda-feira
VoIP
& VoWLAN: Um Folhetim sobre estes 02 "moços" ....
Por onde começamos? ... Afinal "são tantas emoções" !
1. Definições
VoIP =
Voice
over Internet Protocol
VoWLAN = Voice over Wireless LAN (WLAN)
2. Veja algumas referências de VoWLAN ...
[a] Wi-Fi Planet
VoWLAN: Not Ready for Prime Time
Pocket PCs Dial Up Wireless VoIP
Voice over 802.11: An Emerging Market
Dartmouth Intros Wireless VoIP
[b] Outras
VoIP Unwired
Will Wi-Fi lower nurses' blood
pressure?
Dutch Hospital in Spectralinks
[c] Uma do Protocolo SIP
Carriers Say VOIP & SIP Are Hot
3. Um Texto Nosso
Voz sobre wireless LAN (VoWLAN)
Site autoral Alice Ramos
http://www.aliceramos.com/conver/0019.asp
Existem problemas? Sim... ainda existem. O site
Unstrung
mostra uma dura
realidade.
Todos esses vendors que estão trabalhando com a tecnologia
de VoIP, no padrão 802.11, antes que a especificação de WLAN
para suportar voz tenha sido finalizada pelo IEEE, podem ter
problemas -
isto é, antes que o padrão
IEEE 802.11e
seja finalizado.
4. Serviços Mundiais de VoIP
Vonage
Net2Phone
8x8 Inc
Free World Dialup
Conexão PC-para-PC:
Skype
5. Super-Informações de VoIP
Voice over IP and IP Telephony: References
Voice Over IP do Dailywireless
7. Wi-Fi Phones
Palm GPhone
Pocket GPhone 2.0
Motorola Wi-Fi Phone do Dailywireless
Palm VoIP do Dailywireless
Free Voice over Wi-Fi do Dailywireless
Wi-Fi Phones do Dailywireless
Can Wi-Fi Kill Cellular? do Dailywireless
Free World Dialup do Dailywireless
Handsets Key to VoIP do Dailywireless
8. PBX IP um importante componente para GERAR RECEITA
!!!
Spectralink's New PBX to VoIP Gateway
Start-up unveils four-channel VoIP product
Last modified: October 29, 2003, 10:21 AM PST
By Dawn Kawamoto
Staff Writer, CNET News.com
i2 Telecom announced a four-channel
Voice-over-Internet-Protocol product for small businesses on
Tuesday, marking the latest product debut for the
communications start-up.
The company unveiled its E-VoIP 4000, which aims to lower
companies' telephone bills by allowing users to make
long-distance and international calls over the Internet.
Voice over Internet Protocol (VoIP), a concept that has been
hyped for years, is finally gaining momentum as broadband
adoption accelerates.
The E-VoIP 4000 has four channels, or the equivalent of four
telephone lines, that are used to switch the last leg of
callers' calls from the Internet to traditional phone
providers.
If a company has multiple offsite locations, an E-VoIP can
be placed in each office and the entire call can be placed
via the Internet, said Rick Scherle, the company's senior
vice president of marketing.
UFA !!! Boa Semana para Todos ...
From Google:
Published: October 2004
134 Pages
Author: Bruce Hall
Related VoIP Training (Click Here)
Also see:
VoWLAN Fundamentals
Broadband Wireless
Network Planning Toolbox
and
VoWLAN Products and Services
Setembro 08, 2004
Voice over WLAN: Analysis Is The Key To Success
With VoIP comes the notion to run voice on 802.11 wireless LANs (WLANs).
But to succeed, Voice over WLAN (VoWLAN) deployments need very careful
planning and continuous monitoring.
By Scott Haugdahl, CTO, WildPackets
IP voice applications have already presented new quality of service
challenges on wired networks. Data applications could easily tolerate
fluctuations in available bandwidth, but the same typical anomalies will
drive voice users crazy.
And while most wired LANs have enough bandwidth overhead available so
that network engineers can prioritize voice traffic using standard
quality of service mechanisms, wireless LANs are bandwidth constrained;
that makes the job of offering quality voice services much harder.
However, network engineers can use wireless protocol analyzers to create
a better VoIP experience for their users. IMHO, these protocol analyzers
should include the following:
VoIP, WLAN and LAN-specific protocol decodes and filters for common
problems in these environments;
VoIP call recording and playback, with Mean Opinion Score (MOS)
evaluation;
Analytical analysis of packet delay variation and jitter;
Ability to track open calls in real-time and to post closed calls;
Quick drill down to the problem at hand without resorting to complex
filtering;
Expert system technology that parses the flood of packet capture
information and suggests sources of problems or recommends specific
actions.
With these tools in hand, there are two main steps to the VoWLAN rollout
process: pre-deployment planning and post-deployment troubleshooting and
optimization.
Pre-Deployment
Wireless LAN performance varies widely with the number of clients on the
network, their distance from the nearest access point (AP), and the
specific environmental characteristics of the coverage area (furniture,
building materials, elevator shafts, etc.).
In a voice deployment, the WLAN must support higher and more
deterministic bandwidth rates. Ideally, every VoWLAN user should be
communicating at the maximum throughput (11Mbps on 802.11b, for example),
so the AP placement and configuration in a voice network will be
different than it is for a data-only WLAN. Coverage may also be needed
in areas normally not occupied by desktop and laptop users.
Protocol analyzers help in planning a VoWLAN deployment because you can
use them to:
test the networks throughput;
determine the level of channel interference between access points;
monitor the quality of voice calls at various locations on the network;
and confirm that QoS prioritization polices are working properly.
Here are some pre-deployment questions to resolve and how a protocol
analyzer can help answer them:
How many simultaneous voice calls will the WLAN handle? Using a protocol
analyzer, you can measure in real-time the quality of voice and quantity
of data of a test group of users associated with a given access point.
Investing in a small quantity of wireless VoIP phones (or having a
vendor provide evaluation units) will go a long way toward revealing
problems early on. You may discover that to maintain good quality, only
seven to eight users of full-duplex G.711 VoWLAN phones can supported in
one <@BCI>cell<@BCR> area simultaneously.
Where should the access points be placed for optimum voice performance?
One of the emerging "best practices" for VoWLAN is to have a higher
density of access points and to disable data rates below 11 Mbps, since
lower data rates propagate and can reach other access points on the same
channel even if they aren't neighbors.
Protocol analyzers can be used to confirm that you have adequate
coverage at 11 Mbps in areas where users may roam (including hallways
and stairwells) and to ensure that there is no overlapping channel
interference from other access points.
Are some segments more robust than others? Why? With a laptop or tablet
WLAN protocol analyzer, you can roam your space with ease and measure
the signal strength and interference from neighboring channels, from
access points on the same channel but some distance away, or simply from
other sources of 2.4 GHz RF, such as microwave ovens, cordless phones,
Bluetooth, and so on.
Such interference will usually cause a much higher rate of wireless
retransmissions and frames with CRC errors.
Post-Deployment
After deployment, the WLAN environment will change constantly depending
on which users are doing which activities when, and where they are doing
them.
Always keep in mind the mobile aspects of a WLAN -- the network will
need ongoing tuning and management to maintain optimum performance. WLAN
switch vendors offer ways to tune the network by adjusting AP power
levels, prioritizing traffic at the WLAN switch, or implementing QoS at
the client and AP.
However, there are a lot of other variables that affect voice
performance, such as dropped packets, handoff delays, simultaneous
two-way conversations, and security attacks.
Here's a look at how protocol analyzers can assist with identifying and
managing these problems.
Dropped Packets
VoIP is susceptible to the same momentary delays and errors that are
common to any wireless LAN application, and network performance can vary
widely as the user roams or as other users join or leave the network.
Such problems quickly degrade voice quality.
With the help of an expert system, the analyzer can determine if any
delayed VoIP packets are likely to be dropped by the receiver. This is a
somewhat complex operation that basically boils down to analyzing the
variability in packet delay and determining which packets may be outside
the receiver's jitter buffer for a given codec and arrival rate. This is
important, since it is no longer a simple matter of checking for the
absence of a packet in the analyzer's capture buffer.
Another technique for mixed LAN/WLAN systems is to put an analyzer in
the traffic path on the wired side of the internal network to perform
additional call and quality analysis. Many VoIP devices send out
periodic reports containing jitter information experienced by the
receiver. This way, one can see the real jitter as experienced by the
end-nodes at both ends of the conversation without having to place an
analyzer at each of those end points.
Hand-Off Delays
Users roaming from one AP's coverage area to another AP's coverage area
must be handed off from one AP to the next. When the handoff time is too
long, the user can experience clicks, delays in picking up the
conversation again, or even a disconnected call.
A protocol analyzer can be used to look at the re-association and
recovery of problem calls in real time in order to directly correlate
the user experience with actual packet activity and anomalies. The
analyzer's VoIP expert system can be an enormous time saver in detected
these anomalies.
Simultaneous Conversations
Simultaneous two-way conversations can double the bandwidth requirement
for IP phones and thereby slow traffic. Two people won't necessarily be
talking at the same time, but any background noise at the listener's
location is also transmitted while the other party is talking. Some
codec protocols and phones can use noise suppression (which can squelch
transmitted packets from a user that is merely listening), but most do
not.
Therefore, there is almost always a continuous stream of packets
transmitted in both directions during a call.
An analyzer can be used to measure the bandwidth consumed and jitter
characteristics of a call (since in essence we are performing full
duplex operation on a medium that only allows transmission in one
direction at a time), as well as the impact as we add more users.
Security Attacks
As an IP service, VoIP is equally susceptible to security attacks, which
can immediately and dramatically affect voice service quality. A VoIP
analyzer built on a proven core of protocol analysis and expert system
technology can help identify these attacks by triggering events on
suspect data such as a worm or unexpected spike in response time or
throughput.
Even though VoIP traffic on wireless networks should be encrypted, it's
still possible to analyze the traffic by looking for problems such as
congestion, CRC errors, wireless retransmissions, frequent drops in
wireless data rates, and frame arrival rates (to and from the physical
address of the VoWLAN phone).
For VoIP phones that use a static WEP key, network engineers can obtain
the key from an administrator and plug it into their analyzer to fully
decode all seven layers of protocols.
Conclusion
The number of variables to manage in a VoWLAN application can be
daunting, but they're by no means insurmountable. Properly armed with
the right protocol analysis tools along with an understanding of VoIP
protocols and WLAN anomalies, network engineers can go far to ensure a
relatively trouble-free deployment of voice over wireless LAN.
--------------------------------------------------------------------------------
Scott Haugdahl is the chief technology officer at WildPackets where he
developed the expert system for the AiroPeek NX 802.11 wireless
analyzer. He has more then 20 years of experience in the networking
industry and is author of the book "Network Analysis and
Troubleshooting." WildPackets, as you either knew or gleaned from his
vendor-neutral article, makes network management tools.
VoWLAN
Heats Up
By
Vikki Lipset
03/03/2004
In what could be a big boost for the
growing voice over wireless LAN (VoWLAN) market, Nortel Networks (Quote,
Chart) and Alcatel (Quote,
Chart) both announced offerings this week that add voice
capabilities to their WLAN product lines.
The companies will resell Wi-Fi
handsets, access points (AP) and switches from SpectraLink (Quote,
Chart) and Airespace. Both
Nortel and Alcatel say their versions bring something extra to the table.
"It's their hardware, but our special
sauce," said Diane Schmidt, director of marketing for Nortel's WLAN
portfolio, of the company's new Adaptive WLAN deployment solution, which
is comprised of a security switch and access ports that the company says
are optimized for VoWLAN.
She pointed to the ability to monitor
and control the radio frequency domain as an example. This is key for
customers who are looking at real-time applications such as wireless IP
telephony and need nonstop coverage over their WLAN, she said.
"If there's a gap in coverage due to
some interference or an AP drops out for some reason, because we have
control over what happens across the air, we're able to transfer those
connections to a device that can handle them, so users won't experience
any downtime."
Nortel is also offering additional
security features. "We're bringing the capabilities of our security
switch -- things like rogue access point detection, support for VPNs --
into this solution as well," Schmidt noted.
"We've brought this airtight security
into a realm that's notoriously porous," added Nortel spokesman Pat
Cooper.
The Adaptive WLAN package will be
available next month. It includes the 2230 (a/b/g) and 2231 (b/g) Access
Ports ($599 and $499 respectively) and the 2270 Security Switch (starting
at $10,999). The new Nortel VoWLAN products, which include the 2210 and
2211 handsets ($695 and $890 respectively), the WLAN IP Telephony
Manager 2245 ($2500) and the WLAN Application Gateway 2246 (starting at
$1600), are expected to be available in May.
Meanwhile, Alcatel is offering APs,
switches and appliances under the OmniAccess name. OmniAccess 4000
wireless switches start $8,250, OmniAccess 4100 wireless appliances
start at $13,685 and OmniAccess 1200 Access Points start at $400.
The company will introduce its version
of SpectraLink's wireless handsets, branded as Mobile IP Touch 300 and
600, in September. The phones will work with Alcatel's OmniPCX family of
IP-PBX systems.
Talking
about Securing VoWLAN
By
Eric Griffith
05
Embracing voice over IP (VoIP) as the
hot new thing in LANs in general -- and wireless LANs in particular --
is not exactly news these days. VoIP is the buzzword of the moment, so
it's no surprise when a company like
Aruba Networks says it's
going to have a "full solution for VoIP in the enterprise."
The difference with Aruba is, they've
got partners like SpectraLink (Quote,
Chart), Avaya (which rebrands SpectraLink phones), voice-badge maker
Vocera, and soft-phone designer Telesym -- names that encompass almost
all the major players in Voice over WLAN (VoWLAN). SpectraLink alone
held 60% of the global market for VoWLAN products in the year 2003
according to Synergy
Research Group. The nearest rival, Symbol, provides about 7% of the
world's VoWLAN products.
Aruba also says it will differentiate
its VoWLAN support from other switch vendors by concentrating on
security.
"There's a huge security hole for
voice," says Keerti Melkote, Aruba's co-founder and vice president of
product marketing. "Handsets and the technology today are a generation
behind the state of the art -- the handsets mostly use MAC address (define)
authentication and WEP (define).
Static WEP is weak and can be broken and using a MAC address [means]
that once that address is admitted, it can go wherever. Spoof that and
it can send non-voice packets into the network" to cause a disruption.
Aruba will also be doing some new radio
frequency (RF) management to reserve bandwidth and perform load
balancing for calls at the access point (AP), all for voice traffic.
The Aruba switch will be able to make a
"virtual AP in the air for voice, and operate it with specific power
management profiles that are custom built for voice," says Melkote. This
profile will take into consideration that phones aren't connected to the
network at all times, unlike most WLAN data devices. By contrast, Meru
Networks, a switch competitor of Aruba's, recently announced a
proprietary solution involving the licensing of firmware to Wi-Fi
handset vendors to do the same thing. Meru's switch system has been
previously
tested as interoperable with Symbol and Vocera products.
Melkote says the Aruba 5000 Switch
could handle 5000 calls simultaneously, with a varying number of calls
per AP depending on the type of VoWLAN clients due to the codecs and
compression schemes used by each of its partners.
Aruba is breaking its voice support
into three separate phases. The first is simply to have interoperability
with its announced partners; for example the switch will support
SpectraLink's Voice Priority Protocol. Phase 2 will include using
standards such as Quality of Service from the proposed 802.11e standard
and fast-hand off from the 802.11r standard announced at the last IEEE (define)
meeting of the 802.11 Working Group. Aruba also plans to support the
Session Initiation Protocol (SIP). Phase 3 is well down the road: they
plan to offer seamless handoff from cellular to Wi-Fi networks.
Aruba is demonstrating its VoWLAN
solution with SpectraLink in London this week at the Wireless LAN show.
VoWLAN: The
Wireless Voice Future is Here ... Almost
June 14, 2004
By Beth Cohen
Chris Taylor, Telecommunications Manager, Metro Toronto Convention
Centre had a serious problem. His mission critical Nortel "Companion"
900Mz phone system was no longer supported and he needed a replacement
system double quick. With 2 million square feet of open exhibition space
spread over two buildings, he needed a communications system that
provided roaming and instant communications, an open flexible data
network, and a minimum of wires. A year ago, he started looking at
wireless networking combined with VoIP (Voice over IP) or VoWLAN (Voice
over IP over Wireless) as part of the total networking solution. As
Taylor put it, "My three goals were to provide wireless data networking
for exhibitors, create a corporate profit center by selling services to
the exhibitors, and meet employee data/telecommunications needs. The
combination of VoIP and wireless networking fit the bill exactly."
With 55 million lines and 15% of the voice market, VoIP is an
established and rapidly maturing technology. It has been proven to be
less expensive to install and maintain; the core equipment is comparable
in cost to traditional voice, and it offers many more integration
options. Wireless technology is also rapidly maturing, so the next
obvious step is to deploy a converged technology. Until a few months ago,
the converged technology suffered from proprietary equipment, weak
security, and a lack of scalable network management tools: It was not
quite ready for prime time. All that has changed in the past year. The
VoWLAN landscape is rapidly changing with evolving standards, new
equipment, and finally some good management tools. Let us look at some
of the issues that were plaguing VoWLAN and how the fledgling industry
is successfully addressing them.
Approaching Technological Liftoff
According to Bob Myers, CTO and co-founder of Chantry Networks, a
company that develops wireless network management systems, VoWLAN is
growing rapidly in certain vertical industries like health care,
hospitality, retail and manufacturing. Industries where the flexibility,
combined voice and data requirements are so compelling that they are
willing to forgo the current lack of handset hardware, network
management tools and poorly addressed security, standards, and QoS (Quality
of Service) issues.
Part of the problem is that wireless is a contention media -- the users
share the available bandwidth -- so wireless will always have overhead
issues and more complex management requirements. Another overlooked
issue is how to determine good coverage. In an open field, coverage is
easy to determine, but most IT people don't have the specialized
knowledge required to plan an installation for a complex environment
like a hospital, with all its attendant equipment and building
structures.
Myers notes, "Health care's transition to VoWLAN came about because they
had widely deployed 802.11 so they were already comfortable with the
technology. The hospitality and retail sectors both have a widely
dispersed work force that needs to be in constant communication. Both
industries were previously using the 900Mz Walkie-Talkie systems, so
conversion to VoWLAN was a natural next step. Beyond those specific
industries, uptake has been slow because of the perceived security
issues and lake of management tools." Recently, there has been a major
change in perception as companies discover the benefits of increased
flexibility, the improved security standards, and the always popular,
substantially lower operational costs.
Wireless Network Management
A critical component to the success of VoWLAN is sophisticated wireless
network management tools. As Myers puts it, "Unlike all previous
computer technology, wireless networking, wireless came back into the
enterprise from the SOHO and home markets. With a three node network,
you don't need management tools." When rolling out enterprise wide
wireless, especially VoIP, the need for prioritized data streams,
transparent access point handoffs, and seamless security are essential.
Chantry offers a management package that is designed to specifically
address these issues. Other companies, like Avaya and Cisco who are
heavily invested in developing this market, are also working to develop
new tools.
Continued on Page 2:
What Else is There to Think About?
QoS (Quality of Service) and Reliability
Wireless service quality is technologically a step 10 years backwards.
For data packet delivery, companies are willing to trade mobility and
reduced costs for reliability, but voice packets are more sensitive to
perceptible service degradation. As Myers puts it, "You really need to
have a max of 150ms to make sure users are not bothered by QoS issues
when you are using a VoIP system. Cellular has gotten people used to a
lower QoS compared to traditional voice, but not entirely."
To make matters worse, the WME (Wireless Multimedia Extensions) 802.11e
wireless QoS standard will not be ratified until the end of 2004 or
early 2005. Most wireless equipment has not yet incorporated any QoS
because they are waiting for the emerging standards. Because this is
such a critical piece for a successful VoWLAN deployment, some companies
are implementing a subset of 802.11e. Another gotcha is that while
802.11b officially delivers 11MB with QoS, the actual useable bandwidth
is really closer to 6MB. Remember that 6MB is shared by anyone on the
access point. VoIP has a tendency to have small packets with a large
overhead. With 10 to 15 VoIP users you are quickly down to unacceptable
modem-level data rates. The reality is that with most wireless
equipment, planners should expect 6-7 voice calls maximum per channel.
With Chandra's priority queuing and predictive handoffs, they can
support up to 15 voice streams in addition to a small amount of data
traffic. By limiting the number of voice calls on a single access point,
the software can maintain the required QoS.
Security
Wireless security is finally improving with the newer WPA and WPA2
standards, but these emerging standards have not been fully adopted into
the VoWLAN equipment yet. 802.11r is a brand new IEEE taskforce created
specifically to address VoWLAN security issues. Expect to see handsets
incorporating the improved security standards in 6 to 8 months, and new
standards in this area in a year or so. According to Myers, part of the
problem is the need to re-authenticate every time users move between
access points. Session switching can cause unacceptably high delays (up
to 500ms) or dropped calls. Obviously the re-authentication process is
in direct conflict with the QoS requirements of maintaining the call
data stream. Chantry has incorporated a virtual network service that
preloads the VoIP session security at the backend as the user roams the
network so the call session is transparently switched to the new access
point minimizing signal delay.
Staffing and Operational Issues
Unless you were a tiny company that had an IT generalist, the data and
telecom support staff have, until recently, not needed to learn each
other's methodologies and equipment. The current trend is to merge the
support functions and staff for more efficient operations, but there is
still a time lag in training and operational efficiencies, as the staff
learn the new equipment and procedures.
Hardware What Hardware?
Currently there are two main companies in the VoWLAN handset market,
Vocera and SpectraLink. SpectraLink owns 75% of the total handset market
and the majority of the health care market with systems in 1600
hospitals nationwide. Vocera is startup breaking into retail and health
care. Because they were first to market, neither of these are standards
based systems. Both Cisco and Symbol (the people who invented barcode
scanners) have handsets as well. According to Chris Taylor, Symbol has
recently dropped the VoWLAN line to focus on their core market. All the
products suffer from short battery life and reliability problems. As PoE
(Power over Ethernet), standards and cellphone technology is
incorporated, expect to see a plethora of better handsets within the
next few months.
Are We There Yet?
How is Chris Taylor doing with his VoWLAN system? He reports that they
have had the beta system in place since January. They are planning a
full rollout to completely replace the old "Companion" system by
September. "The staff loves it. The voice quality is good and roaming is
completely transparent. Just make sure all the vendors' equipment is
compatible and integrated. That was the key to success for our
installation."
Should you be seriously considering Voice over IP over wireless LAN
solutions today? Well yes and no. Unless you are in the health care,
manufacturing, or retail industries where the ROI is especially
compelling, the technology is still not quite ready to be heard yet.
With the maturing of both the VoIP and wireless technologies, on the
surface merging the two emerging technologies might seem to be a
terrific idea. However, security issues, poor quality equipment, and
bandwidth prioritization considerations point to a technology that is
still too immature for anybody to deploy unless they are ready to put up
with the bleeding edge phase of the innovation curve. In the next 8 to
12 month there will be numerous new products that will be addressing
these and other issues as many innovative technology companies work on
solving the problems. Once the issues have been properly addressed and
the standards settle down, VoWLAN with its potential to merge data,
voice and mobility into one neat package, promises to be something that
could transform how companies do business.
--------------------------------------------------------------------------------
Beth Cohen is president of Luth Computer Specialists, Inc., a consulting
practice specializing in IT infrastructure for smaller companies. She
has been in the trenches supporting company IT infrastructure for over
20 years in different industries including manufacturing, architecture,
construction, engineering, software, telecommunications, and research.
She is available for consulting to help your company identify the right
IT infrastructure to meet your business objectives.
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