Re: [Sipping] [Sip-implementors] how to response the offer

["T Satyanarayana-A12694" <satyanarayana.t at motorola.com>]

I have a different opinion here.

The answer need not be same as what A originally sent in offer.

E.g. A sent two m-lines (audio and video). B suppressed one m-line (say video) because it didn't support video. Now, B sends two m-lines one of them carrying port 0. A can't reply with that m-line having non-ZERO port.

There are more such examples.

E.g. when A originally sent b= line with certain value (if offered all formats it supports). But, in the subsequent offer, it may choose only a subset of media formats which means potentially lower b= value.

Regards
Satya T

-----Original Message-----
From: sip-implementors-bounces at lists.cs.columbia.edu [mailto:sip-implementors-bounces at lists.cs.columbia.edu] On Behalf Of Christer Holmberg
Sent: Wednesday, August 19, 2009 1:11 PM
To: 孙永光; IETF Sipping List; sip-implementors at lists.cs.columbia.edu; discussion at sipforum.org
Subject: Re: [Sip-implementors] [Sipping] how to response the offer

Hi,
 
I think A can answer however he wants.
 
However, by using the SDP o- line one can explicitly indicate that nothing has changed from the previous SDP, so normally I guess the answer then wouldn't be modified either.
 
Regards,
 
Christer


________________________________

	From: sipping-bounces at ietf.org [mailto:sipping-bounces at ietf.org] On Behalf Of ???
	Sent: 19. elokuuta 2009 10:29
	To: IETF Sipping List; sip-implementors at lists.cs.columbia.edu; discussion at sipforum.org
	Subject: [Sipping] how to response the offer
	
	

	Dear All 
	 
	   I have a question about How to respond the offer , the scenario is as following
	 
	A call B , and the offer and answer is ok , after a while , A receives a B 's REINVITE which includes the same SDP as it just answered before
	 
	now, How does A respond it ? 
	 
	does A  must respond  the B's new offer  with   the same SDP as the offer it sent previously?
	 
	could you give some advice ? 
	 
	Thanks
	 
	SunYongGuang
	 
	 
	 
	 

	-- 
	msn:yongguangsun at hotmail.com <mailto:msn%3Ayongguangsun at hotmail.com> 
	
	

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