[VoiceOps] SIP 404 Not Found vs 603 Decline

Calvin Ellison calvin.ellison at voxox.com
Tue Jun 2 17:26:50 EDT 2015

In my experience, some systems will not route advance on a non-200 response
if pre-session media exists, e.g. a 183 voice reject before 603 final
response, but will route advance if there is no pre-session media. In this
context, calling parties using least-cost routing with multiple vendors
would be expected to produce one call attempt total if there is pre-session
media, and one attempt *per vendor/route* if there is no pre-session media.

If you can spare the media bandwidth and channels to provide a brief voice
reject, this may reduce the total number of attempts regardless of cause


*Calvin Ellison*
Voice Services Engineer
calvin.ellison at voxox.com
+1 (213) 285-0555

*voxox.com <http://www.voxox.com/> *
9276 Scranton Rd, Suite 200
San Diego, CA 92121
[image: Voxox]

On Tue, Jun 2, 2015 at 1:58 PM, Peter Beckman <beckman at angryox.com> wrote:

> I offer a feature to our customers that allows them to configure their DID
> to respond with "This number is disconnected" message for specific,
> annoying callers, based on their CallerID.
> Some customers send a Busy signal (486 BUSY) for these annoying callers. It
> seems that some Robocallers will retry numbers that ring busy repeatedly,
> sometimes annoyingly aggressively.
> I'm switching the default to declining the call, which brings me to which
> SIP response is correct and/or ideal.
> From the RFC: https://www.ietf.org/rfc/rfc3261.txt
>     Section 21.4.5 404 Not Found
>         The server has definitive information that the user does not
>         exist at the domain specified in the Request-URI.  This status
>         is also returned if the domain in the Request-URI does not match
>         any of the domains handled by the recipient of the request.
>     Section 21.6.2 603 Decline
>         The callee's machine was successfully contacted but the user
>         explicitly does not wish to or cannot participate.  The response
>         MAY indicate a better time to call in the Retry-After header field.
>         This status response is returned only if the client knows that no
>         other end point will answer the request.
> We are currently sending a 603 Decline, which seems appropriate given the
> nature.
> However we also get calls to numbers we service which are not active, in
> which case 404 Not Found seems more appropriate.
> What is the real-world behavior of the calling party for these responses?
> If I change the cause code, will there be unintended consequences?
> Any suggestions or experience is appreciated.
> Beckman
> ---------------------------------------------------------------------------
> Peter Beckman                                                  Internet Guy
> beckman at angryox.com
> http://www.angryox.com/
> ---------------------------------------------------------------------------
> _______________________________________________
> VoiceOps mailing list
> VoiceOps at voiceops.org
> https://puck.nether.net/mailman/listinfo/voiceops
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://puck.nether.net/pipermail/voiceops/attachments/20150602/0e15b964/attachment.html>

More information about the VoiceOps mailing list