Re: [Sipbrandy] WGLC: draft-ietf-sipbrandy-osrtp-04 - Christer's review

[Christer Holmberg <[e-mail]>]

Hi,

>>>>Has there been discussions on whether the subsequent offer really is
>>>>the same?
>>>
>>> Not sure whether this has been discussed explicitly with regard to
>>>this draft.
>>
>> Where has it been discussed? The MMUSIC draft doesn't say anything
>>about subsequent offers either.
>>
>>>> For example, if the initial O/A has resulted in SAVP, would you still
>>>>use AVP in a subsequent offer?
>>>
>>> Yes the recommendation would be to use AVP in a subsequent offer
>>>otherwise things can go wrong when you consider things like 3PCC etc.
>>
>> What if the answerer, who included SAVP in the initial answer, sends a
>>subsequent offer? Will it keep SAVP in that offer, or will it switch to
>>AVP?
>>
>
>This really depends on the preferences of the answerer as to whether
>it requires SRTP or is willing to try OSRTP it is the same
>considerations as made when sending the initial offer.


So, that endpoint is allowed to require SRTP, but the endpoint that sent
the initial offer must try OSRTP if it sends a subsequent offer???

I think the rules for subsequent offers shall be the same for both
endpoints, i.e., either shall both endpoints be allowed to ³require² SRTP
in a subsequent offer, OR both endpoints must try OSRTP in a subsequent
offer.

In addition, if security was NOT negotiated in the in the initial o/a
exchange, then I guess each endpoint can choose whether to use OSRTP or
not in subsequent offers?

Regards,

Christer