[jdev] Re: Question about Proxy65 support Voice Chat

[Ulrich Staudinger]

Richard Dobson schrieb:

>> Voice and audio is not like that. You will need to transfer it reliably.
>>
>> TCP is what SIP/SDP has selected (there's another protocol at that layer
>> too that's been drafted for use). Their model of getting around NATs and
>> firewalls is also a lot like proxy65 in that a third party server is 
>> used.
>
>
> Are you sure? I thought they used RTP, and I was under the impression 
> RTP uses UDP not TCP, as TCP is not appropriate for real time data 
> (audio) due to various reasons that are outlined in the information 
> about RTP.
>
> Richard
>
>
Richard's right. UDP is used for transmission of RTP data. The frame 
size for audio and video packets is about 20-100ms, so dropouts are not 
a serious threat to communication security.

Regards,
Ulrich