Re: [MMUSIC] BUNDLE and RTCP

Christer,

of course there are many possibilities.
However it would be good to have some explicit signalling.
Without inventing new signalling elements, you could use the first RTP 
m-line that appears in the   a=group:BUNDLE attribute in the answer.

So if you have in the offer:

a=group:BUNDLE foo bar baz
m=data channel 10000
a=mid:foo
m=rtp 11111
a=mid:bar
a=rtcp: 15000
m=rtp 11222
a=mid:baz
a=rtcp: 20000

If you get back in the answer:

a=group:BUNDLE foo bar baz
...
then your RTCP port is 15000
If you get back a=group:BUNDLE foo baz bar then RTCP would go to 20000.

Although I haven't thought it through completely it too much this could 
also work reasonably well of the answerer accepts only a subset of the 
offered m-lines.

What do yo think?

Regards
Thomas

Am 18.10.2015 um 19:53 schrieb Christer Holmberg:
>
> Hi,
>
> Note that the issue exists even without bundle-only m- lines:
>
> m=data channel 10000
>
> m=rtp 11111
>
> a=rtcp: 15000
>
> m=rtp 11222
>
> a=rtcp: 20000
>
> Again, if the data channel m-  line is selected as the offerer BUNDLE 
> address, which port will be used for RTCP?
>
> Regards,
>
> Christer
>
> *From:*mmusic [mailto:mmusic-bounces@ietf.org] *On Behalf Of *Christer 
> Holmberg
> *Sent:* 18 October 2015 20:47
> *To:* mmusic@ietf.org
> *Subject:* [MMUSIC] BUNDLE and RTCP
>
> Hi,
>
> During the proto write-up process of BUNDLE, an issue came up.
>
> Assume the following BUNDLE offer, with one non-bundle-only data 
> channel m- line and one bundle-only RTP m- line:
>
> m=data channel 10000
>
> m=rtp 0
>
> a=bundle-only
>
> Now, if bundle is accepted, the RTP m- line will get port 10000, as 
> defined in BUNDLE. So far so good.
>
> Now, if bundle is accepted, the data channel m- line will be selected 
> as the offerer BUNDLE address, and RTP will use port 1000.
>
> So far so good.
>
> Next, assume we want to negotiate an explicit RTCP port for RTP. As 
> the non-bundle-only m- line is not RTP (and therefore cannot contain 
> an rtcp attribute), we have to add the actual RTCP port value to the 
> bundle-only m- line:
>
> m=data channel 10000
>
> m=rtp 0
>
> a=bundle-only
>
> a=rtcp: 20000
>
> So far so good.
>
> Now, assume we also have one non-bundle-only RTP m- line:
>
> m=data channel 10000
>
> m=rtp 11111
>
> a=rtcp: 15000
>
> m=rtp 0
>
> a=bundle-only
>
> a=rtcp: 20000
>
> Now, assume the data channel m- line is selected as the offerer BUNDLE 
> address. It means that port 10000 will also be used for RTP. But, 
> which port will be used for RTCP? 15000 or 20000?
>
> Regards,
>
> Christer
>
>
>
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