[SIPForum-discussion] why not ACK ???????????????????

alexzhang at gdnt.com.cn alexzhang at gdnt.com.cn
Fri Nov 23 13:29:52 UTC 2007

Of cource, there could be SDP Parm in the PRACK message to initiate the
2nd Offer/Answer for codec re-negotiation.


From: discussion-bounces at sipforum.org
[mailto:discussion-bounces at sipforum.org] On Behalf Of darshan b n
Sent: Friday, November 23, 2007 8:07 PM
To: Anthony Orlando
Cc: discussion at sipforum.org
Subject: Re: [SIPForum-discussion] why not ACK ???????????????????


I want to know it is possible to Send an SDP parameter in PRACK  similar
to What an ACK message  does in a SIP seesion?

Darshan B N

On 23/11/2007, Anthony Orlando <avorlando at yahoo.com> wrote: 

	There are other forms of ACK's called a PRACK that act
	in the same manor.  The idea behind the ACK is that
	you want reliable delivery of the SDP.  So you ACK the
	200 OK.  SDP is usually contained in the 200 OK.  In 
	some cases SDP is delivered in a 18x. If you receive a
	18x with SDP you should require a PRACK to the 18x.
	Hope this helps.
	--- darshan b n <bn.darshan at gmail.com > wrote:
	> Hi all,
	> > "Why ACK is not send for messages otherthan INVITE
	> transaction ??????????
	> >
	> please reply
	> --
	> Darshan B N 
	> Thanks & Regards
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Darshan B N

Thanks & Regards 
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