Re: [MMUSIC] JSEP Issue #394: What appears in m= lines.

Eric Rescorla <ekr@rtfm.com> Tue, 17 January 2017 00:21 UTC

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From: Eric Rescorla <ekr@rtfm.com>
Date: Mon, 16 Jan 2017 16:20:53 -0800
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To: Roman Shpount <roman@telurix.com>
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Cc: Magnus Westerlund <magnus.westerlund@ericsson.com>, mmusic WG <mmusic@ietf.org>, Christer Holmberg <christer.holmberg@ericsson.com>
Subject: Re: [MMUSIC] JSEP Issue #394: What appears in m= lines.
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On Mon, Jan 16, 2017 at 4:11 PM, Roman Shpount <roman@telurix.com> wrote:

> On Mon, Jan 16, 2017 at 6:59 PM, Eric Rescorla <ekr@rtfm.com> wrote:
>
>> On Mon, Jan 16, 2017 at 3:37 PM, Roman Shpount <roman@telurix.com> wrote:
>>
>>> For JSEP, is there a reason not to require UDP/TLS/RTP/SAVPF and
>>> UDP/DTLS/SCTP in both the offer and the answer?
>>>
>>>
>> As an answerer, you may get TCP/<blah> from non-JSEP endpoints and the
>> consensus was that echoing them was better
>>
>>
> Is there a reason why this would ever happen?
>

It's permitted behavior.



> You use ICE TCP to go through UDP firewalls when communicating with a
> server on a public IP. Why would you ever do only tcp candidates in offer
> or answer? This is inefficient and will work worse then offering both udp
> and tcp candidates. I am all for options, but they should have some reason
> for existence. I see no reason why TCP/anything would ever be used for JSEP
> offer/answer, unless ICE is complete and tcp candidate pair is selected.
>

Well, as I stated above, this isn't about what JSEP endpoints offer but
what they answer
when other endpoints send TCP/<blah>, however foolish you might think it is.


> BTW, we made UDP required protocol for default candidates for
> UDP/DTLS/SCTP. I see no reason not to do the same thing for
> UDP/TLS/RTP/SAVPF at least in JSEP. It will only make things interop with
> non JSEP endpoints better.
>

What's the evidence that answering TCP/TLS/RTP/SAVP with UDP/TLS/RTP/SAVPF
will improve interop?

-Ekr


> Regards,
> _____________
> Roman Shpount
>
>