[SIPForum-discussion] Enigma

[Deepak Bhatia]

Hi,

 

I think there is an issue in the description below

 

Section 9 says 487 is sent in response to the CANCEL request by UAS but
Section 21.4.25 says 487 is not specifically sent for CANCEL.

 

==============================================================

 

 

9 Canceling a Request

 

   The previous section has discussed general UA behavior for generating

   requests and processing responses for requests of all methods.  In

   this section, we discuss a general purpose method, called CANCEL.

 

   The CANCEL request, as the name implies, is used to cancel a previous

   request sent by a client.  Specifically, it asks the UAS to cease

   processing the request and to generate an error response to that

   request.  CANCEL has no effect on a request to which a UAS has

   already given a final response.  Because of this, it is most useful

   to CANCEL requests to which it can take a server long time to

   respond.  For this reason, CANCEL is best for INVITE requests, which

   can take a long time to generate a response.  In that usage, a UAS

   that receives a CANCEL request for an INVITE, but has not yet sent a

   final response, would "stop ringing", and then respond to the INVITE

   with a specific error response (a 487).

 

 

21.4.25  487  Request Terminated

 

The request was terminated by a BYE or CANCEL request. This response is
never returned for a CANCEL request itself.




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