Re: [MMUSIC] WGLC on draft-ietf-mmusic-rfc8843bis-00

Hi Christer,

I think this change is in scope since the problem with 3PCC was introduced
by the changes you just made. Before the JSEP alignment fix, subsequent
offers would have port 0 in the m= line and a=bundle-only on all the
bundled m= lines. This would make it a valid initial offer for 3PCC. With
the new changes,  bundled m= lines will have the address and port reused,
which is not a valid initial offer.

I am generally ok with the text but based on the confusion that the term
"Initial SDP Offer" caused Paul, I would suggest omitting it and changing
the text to:

7.6. SIP Considerations

The Session Initiation Protocol (SIP) [RFC3261] allows a User Agent Client
(UAC) to send a re-INVITE request without an SDP body (sometimes referred
to as an empty re-INVITE). In such cases, the User Agent Server (UAS) will
include an SDP Offer in the associated 200 OK response. This is typically
used for 3rd Party Call Control (3PCC) scenarios. From a BUNDLE
perspective, such SDP Offer SHOULD be generated using procedures defined in
[Section7.2].

Best Regards,
_____________
Roman Shpount

On Tue, Jun 22, 2021 at 1:12 PM Christer Holmberg <
christer.holmberg@ericsson.com> wrote:

> Hi,
>
> I think it is important to keep in mind that the scope of 8843bis was only
> to fix the BUNDLE/JSEP alignment, and to implement some of the erratas.
>
> Having said that, unless someone objects I am fine adding something like:
>
> ---
>
> 7.6. SIP Considerations
>
> The Session Initiation Protocol (SIP) [RFC3261] allows a User Agent Client
> (UAC) to send a re-INVITE request without
> an SDP body (sometimes referred to as an empty re-INVITE). In such cases
> the User Agent Server (UAS) will include an
> SDP Offer in the associated 200 OK response. This is typically used for
> 3rd Party Call Control (3PCC)
> scenarios. From a BUNDLE perspective, such SDP Offer SHOULD be generated
> as an Initial SDP Offer [Section7.2].
>
> ---
>
> Regards,
>
> Christer
>
> -----Original Message-----
> From: mmusic <mmusic-bounces@ietf.org> On Behalf Of Paul Kyzivat
> Sent: perjantai 18. kesäkuuta 2021 20.49
> To: Roman Shpount <roman@telurix.com>
> Cc: mmusic WG <mmusic@ietf.org>
> Subject: Re: [MMUSIC] WGLC on draft-ietf-mmusic-rfc8843bis-00
>
> On 6/18/21 1:14 PM, Roman Shpount wrote:
> > Let me be more specific -- I meant rules defined for initial SDP offer
> > in
> > https://www.ietf.org/archive/id/draft-ietf-mmusic-rfc8843bis-02.html#s
> > ection-7.2
> > <https://www.ietf.org/archive/id/draft-ietf-mmusic-rfc8843bis-02.html#
> > section-7.2>, not all rules for initial SDP offers. Specifically, all
> > m= lines should either have a different address:port for each bundled
> > m= line and be prepared to receive media on these addresses or should
> > have port 0 and a=bundle-only
>
> Ahh. OK.
>
>         Thanks,
>         Paul
>
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