As you have a new version, I think including sipping would be better :)
Thanks for your agreement at this point.
But as RFC3261's words of "willings" is not as clear as guidance for system design and implement, I think some BCP level description vcould be better.
Thanks,
Gao
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| Paul Kyzivat <pkyzivat@xxxxxxxxx>
2010-02-26 22:17 |
|
gao.yang2@xxxxxxxxxx wrote:
>
> I just find a potential problem of
> draft-ietf-sipping-sip-offeranswer-11. I am not sure will you want have
> a new version, so I send this discussion offline.
I am working on another version. I am including sipping in my response
so others have the opportunity to comment. (I trust that is ok.)
> Section 5.2.5. of draft-ietf-sipping-sip-offeranswer-11:
> When the new offer is sent in response to an offerless (re)INVITE,
> *all codecs supported by the UA are to be included*, not just the ones
> that were negotiated by previous offer/answer exchanges. *The same is*
> * true for media types* - so if UA A initially offered audio and video
> to UA B, and they end up with only audio, and UA B sends an offerless
> (re)INVITE to UA A, A's resulting offer should re- attempt video, by
> reusing the zeroed m-line used previously.
>
>
> While Re-INVITE without Offer:
> For codecs, I think the UAS should include as many codecs that the UA is
> willing(section 14.2 of RFC3261) to support. I think we should let the
> UA has the right to decide which codecs can be use or not for this
> current call. At the same time, the UAS should be with responsibility
> for failure of session if it cut down the number of codecs. UAS's
> willing of codecs can be implemented as local policy or some other forms
> of configuration.
Yes, this just requires minor tweak to wording.
Its consistent with the recommendations on sendonly/...
> For media types, it is almost the same as codecs, about UA's willing.
> But I think we should emphasize on avoiding of introducing new media
> types without user's permission, such as just introducing new media
> types by equipment or software. Beacause I have met such charging
> arguement from users in some operating telecom-network.(If you want the
> detail of the charging arguement, I'd like to share it with you).
> So, if there is no indication of permission of introducing new media
> types from the end user, UAS should just include current using media
> types. And if the other side(user of UAC) want to add media types, it
> can using another new Offer.
I get your point and agree. Its the same concept - include everything
the UA would be willing to use, not just that which it thinks the peer
wants to use.
Thanks,
Paul
> Thanks,
>
> Gao
>
> Section 14.2 of RFC3261:
> A UAS providing an offer in a 2xx (because the INVITE did not contain
> an offer) SHOULD construct the offer as if the UAS were making a
> brand new call, subject to the constraints of sending an offer that
> updates an existing session, as described in [13] in the case of SDP.
> Specifically, this means that it SHOULD include as many media formats
> and media types that the UA *is willing to support*. The UAS MUST
> ensure that the session description overlaps with its previous
> session description in media formats, transports, or other parameters
> that require support from the peer. This is to avoid the need for
> the peer to reject the session description.
>
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>
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