Re: [AVTCORE] draft-ietf-avtcore-multi-party-rtt-mix Issue 1: transport

Gunnar Hellström <gunnar.hellstrom@ghaccess.se> Mon, 18 May 2020 18:54 UTC

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From: Gunnar Hellström <gunnar.hellstrom@ghaccess.se>
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Subject: Re: [AVTCORE] draft-ietf-avtcore-multi-party-rtt-mix Issue 1: transport
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Hi,

Den 2020-05-18 kl. 18:00, skrev Christer Holmberg:
> Hi,
>
>> I think this means we use the WebRTC data channel, which is HTTP based, right?  Totally bypasses the SBC.  Have to be careful to not cause the SBC to get confused with the SDP.
> The WebRTC data channel is not HTTP based. It is basically an SCTP stream.

Yes, with UDP as the lowest layer.

So we are talking about two UDP based transports.

text/red and text/rex are RTP based, and may be SRTP encrypted. They are 
declared in the same m-line, and one selected and then will use one or 
two ports.

WebRTC data channels stack is UDP/DTLS/SCTP.

Both would normally use ICE to find their ways through networks.

Do we really have noticable differences in how hard it would be to get 
through the networks with any of these? And would there be any other 
transport that would be easier to get through?


Regards

Gunnar

>
> Regards,
>
> Christer
>
>
>      > On May 18, 2020, at 11:24 AM, Bernard Aboba <bernard.aboba@gmail.com> wrote:
>      >
>      > lOn May 18, 2020, at 8:09 AM, Brian Rosen <br@brianrosen.net> wrote:
>      >>
>      >> It occurs to me that the SBC may not pass text/red.  Depends on how picky they are.  Text/red is basic T.140.
>      >
>      > [BA] Legacy SBCs are indeed an issue, and a basic obstacle to deployment of RTT. I am not aware of any SIP trunk providers that support text/red, because they would need to upgrade their SBCs to do so, which would be a large cost, with no corresponding revenue source.
>
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-- 
Gunnar Hellström
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gunnar.hellstrom@ghaccess.se