Re: [Sipping] how to response the offer

Essentially, it is safer for A:

1. to run the incoming offer through the answer generation process when the previous transaction involved an offer from it and not an answer. i.e. treat this as if it is a new offer.
2. to reply with the previous answer (if no local settings changed), if the previous transaction was an offer from A

Regards
Satya T

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of T Satyanarayana-A12694
Sent: Wednesday, August 19, 2009 8:11 PM
To: Christer Holmberg; 孙永光; IETF Sipping List; [email protected]; [email protected]
Subject: Re: [Sip-implementors] [Sipping] how to response the offer


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: [email protected] [mailto:[email protected]] On Behalf Of Christer Holmberg
Sent: Wednesday, August 19, 2009 1:11 PM
To: 孙永光; IETF Sipping List; [email protected]; [email protected]
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: [email protected] [mailto:[email protected]] On Behalf Of ???
	Sent: 19. elokuuta 2009 10:29
	To: IETF Sipping List; [email protected]; [email protected]
	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:[email protected] <mailto:msn%[email protected]> 
	
	

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