Re: [Sipping] Rollback issue: a proposal

[gaoyang <[e-mail]>]

 

Comments for http://www.ietf.org/internet-drafts/draft-camarillo-sipping-reinvite-00.txt

 

1. I think that it is BCP level. And the solution can be effective by restricting Non-2xx when Offer/Answer pair has been exchanged.

 

2. Your proposal considered legacy UAS. But currently, the situation is legacy UAC with legacy UAS. And it is the original issue.

 

3. "In order to undo changes that were already executed, the UAS uses a new
   offer/answer exchange or a target refresh request."

If the new offer/answer exchange need precondition, the other side can reject it with 504. then the modification(undo changes) may not be done by UPDATE/200OK. And Re-INVITE can not be used here(for the pending original Re-INVITE).

 

Comments for http://www.ietf.org/internet-drafts/draft-camarillo-sipping-precons-00.txt

 

1. "However, the fact that the UAs can start using the new media parameters does not mean that they need to start using them immediately." Yes.

 

More than one Offer/Answer pais before Precondition Ok, and Caller can be answerer for some and Callee for the others. Then the two sides may waiting peer using new parameters

after Precondition OK. It may be deadlock.

 

 


 
> Hi,
> 
> I have put together the following draft. It contains a proposal for the 
> rollback issue that has been discussed on the list:
> 
> http://www.ietf.org/internet-drafts/draft-camarillo-sipping-reinvite-00.txt
> 
> I have also written another short draft on an issue related to 
> preconditions that was also discussed on the list in one of the 
> rollback-related threads:
> 
> http://www.ietf.org/internet-drafts/draft-camarillo-sipping-precons-00.txt
> 
> Comments are welcome.
> 
> Cheers,
> 
> Gonzalo

_________________________________________________________________
MSN安全保护中心，免费修复系统漏洞，保护MSN安全！
http://im.live.cn/safe/