[Bug 20135] Call fails if codec parameters are too big

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=20135

Mikhail Zabaluev <mikhail.zabaluev at nokia.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |ppessi+telepathy at gmail.com

--- Comment #7 from Mikhail Zabaluev <mikhail.zabaluev at nokia.com> 2010-12-30 04:02:37 PST ---
(In reply to comment #6)
> (In reply to comment #4)
> > RFC 5215 (the Vorbis one) has the same problem. My idea solution would be to
> > fall back to TCP and if it fails,
> 
> Falling back to tcp in order to send a jumbo invite turns out to be a bad idea.

It would be a good idea accordingly to the spec... if proxies would actually
support it. Many still don't, being effectively transport=udp destinations, but
you can't know it without explicit configuration. Perhaps it would be nicer if
"auto" tried TCP first with a short timeout and black/graylisted it if it does
not work, but this requires some serious work in sofia-sip, not to mention
changing the behavior which some sofia-sip clients probably rely on.

Forcing UDP by default will just make other cases fail with "message too big",
because the message size exceeds the sanity limit in sofia-sip (1300 by default
IIRC). With a properly set up proxy, those would work over the TCP fallback.

> I like this idea. I'll see what I can do. Do you think I should sort by codec
> id or something, or should I aim to keep the same proportion of the available
> packet length dedicated to each stream or what?

I think you should sort by length of the fmtp cruft. This will remove the worst
offenders quickly :)
Maybe video streams are less important than audio, so they could start losing
codecs first. If we are down to one codec, we could turn to audio, or drop the
whole video stream to save even more bytes (you still need to put at least one
payload number even for a rejected stream, but you can omit all the
attributes).

Some other ideas for the UDP size crunch mode:

- Turn on abbreviated header names (full names are used by default);
- Suppress User-Agent
- Remove display name in From.

See also https://bugs.freedesktop.org/show_bug.cgi?id=30434 . We could shed a
lot if only the codec intersection is passed to the answer.

Then, there is SigComp *wicked grin*

-- 
Configure bugmail: https://bugs.freedesktop.org/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are the QA contact for the bug.