[asterisk-dev] chan_sip.c - no reply to critical packet

Gregory Boehnlein damin at nacs.net
Fri Jan 30 19:17:05 CST 2009

> Hmm.. I wonder why the Cisco is sending an Info request? The only thing
> that I think that might be causing this is the setting "isdn supp-service
> name calling" which is supposed to map Q.931 calling-name attributes into
> SIP message. Since the Q.931 message comes a split-second after the
> call setup on the PRI, the Cisco probably sends a second packet w/ the
> Calling Name. All the Cisco documentation says about the feature is:
> "isdn supp-service name calling
> To set the calling name display parameters sent out an ISDN serial
> interface, use the isdn supp-service name calling command in interface
> configuration mode. To disable calling name delivery, use the no form
> of this command."

Preliminarily, here is what I have found out.

On the Cisco, if I enable:

voice service voip
  signaling forward rawmsg

It seems to work.. the QSIG messages are forwarded over and I am receiving
Calling Name attributes.

If, however, I disable that command and/or use "signaling forward
unconditional" then I see the INFO packet, followed by the 403 and finally
the 6 "200 OK" messages followed by a hangup.

I came across the following article that helped me out:


I'll see how this works over the weekend, and see if it reduces the number
of Hangup messages I get..

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