>>So, how valid is using 487 to decline a call? 

I guess it's somewhat ok because you can use any
4xx response to decline a call.  It might not be standard
usage but no equipment should experience problems when
receiving a 487.

Any equipment receiving a 4xx response should
just consider the request attempt as failed.

And the silent rejection usage is only just being explored
by the BLISS group.  It might not become standard.

Regards,

Attila



-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Iñaki Baz 
Castillo
Sent: 04 June 2008 10:03
To: [email protected]
Subject: [Sip-implementors] Is valid a 487 for a non BYE or CANCEL request?

Hi, AFAIK there are three cases where 487 occurs:

1) The UAC sends a BYE during an early-dialog so the UAS replies a 200 OK for 
the BYE and a 487 for the INVITE.

2) The UAC sends a CANCEL during an early-dialog so the UAS replies a 200 OK 
for the BYE and a 487 for the INVITE.

3)
  13.3.1 Processing of the INVITE
     1. If the request is an INVITE that contains an Expires header
         field, the UAS core sets a timer for the number of seconds
         indicated in the header field value.  When the timer fires, the
         invitation is considered to be expired.  If the invitation
         expires before the UAS has generated a final response, a 487
         (Request Terminated) response SHOULD be generated.

But I've seen 487 as the reply from some softswitches when the RURI is invalid 
(international destination not allowed for example).

And also I've seen this 487 code as recommende reply for silent rejection in 
"draft-ietf-bliss-ach-analysis":

  5.3.3.  Response codes
   o  Silent rejection/local. 487 could be used.  This is the same
      response code that would be used if a proxy were to issue a CANCEL
      request.

But RFC 3261 says clearly:

  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.


So, how valid is using 487 to decline a call?

Thanks.


--
Iñaki Baz Castillo
[EMAIL PROTECTED]

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