[SIPForum-discussion] difference between INFO and OPTIONS method?

[Andrea Puddu]

I answer to first question (correct me if I am wrong):

  CANCEL request is sent when response to INVITE message is not received. If 
this INVITE request is lost and UA may still send a CANCEL request. Is this 
possible? Can CANCEL request be sent without sending an INVITE message? 

A CANCEL request can be sent if the 200 OK to the INVITE request has not been received yet from the Caller. Otherwise you have to send a BYE request. Furthermore I guess that if you send a CANCEL not related to an INVITE you will probably receive a "
481 Call/Transaction Does Not Exist" message. _In fact which Call-ID do you mean to use? It has to be the same of the INVITE request. Just try.


Andrea



Date: Fri, 7 Dec 2007 15:09:33 +0000
From: nidhi_jain6680 at yahoo.co.in
To: discussion at sipforum.org
Subject: [SIPForum-discussion] difference between INFO and OPTIONS method?

Hello, 

        CANCEL request is sent when response to INVITE message is not received. If 
this INVITE request is lost and UA may still send a CANCEL request. Is this 
possible? Can CANCEL request be sent without sending an INVITE message? 

        What is the basic difference between INFO and OPTIONS method? can OPTIONS 
used for mid-call signalling? 

        Why is ACK request required? Is it just to avoid retransmission of response 
message. This could be done even by starting the media transmission. 

        How are DTMF digits sent before the session setup? 

Please reply. 

Thank you. 
 


       Get the freedom to save as many mails as you wish. Click here to know how.
_________________________________________________________________
Scarica GRATIS la versione personalizzata MSN di Internet Explorer 7!
http://optimizedie7.msn.com/default.aspx?mkt=it-it
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://sipforum.org/pipermail/discussion/attachments/20071207/9b0a5b5d/attachment-0002.html>