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

[Geo Paul]

CANCEL is send only if you receive a 100 trying and did not receive a
final response (200Ok) from the next node. So if your INVITE did not
make it to the next node then you need not a send a CANCEL.

 

Geo

 

  _____  

From: Andrea Puddu [mailto:androjoker at hotmail.com] 
Sent: Friday, December 07, 2007 1:29 PM
To: nidhi jain; discussion at sipforum.org
Subject: Re: [SIPForum-discussion] difference between INFO and OPTIONS
method?

 

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





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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. 

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