P-Asserted-Identity and Remote Party ID SIP header

Some wholesale providers are now requiring that packets include P-Asserted-Identity or Remote Party ID in the header of SIP packets.

I spent some time messing with this since there is little to no documentation on such things regarding Asterisk or Trixbox. Since I had such a hard time of it, I thought I would write a really short howto so that maybe others will have it bit easier.

Remote Party ID:

This was the easier of the two. In sip.conf you must set the two variables



P-Asserted-Identity:

This was more difficult to figure out and had far less documentation. To add headers we use the SipAddHeader() function in the dial plan, extensions.conf, or for trixbox, extensions_custom.conf.

in our trixbox extensions_custom.conf we have set up the following... assuming you dial from the [from-internal] context


You may substitute whatever you want in side the < > a provided ID number or whatever... we just set callerid for demonstration purposes.

Obviously you can also change, or add a dial pattern, or specific extension in place of the _NXX for example

exten => 2000,1,SipAddHeader(P-Asserted-Identity: <sip:${CALLERIDNUM}>)

would only add headers when extension 2000 dialed.

Testing:
To test that your headers are being added, start the asterisk console and make a call that would match the extension pattern. You should see some thing like the following on your cli

To further test, you can run tshark (the new name for ethereals command line packet capture tethereal) on your asterisk server when you make the call and capture sip packets to a log file

1. tshark port 5060 -w sip.cap

After you place the call hit ctrl+c to close tshark then open up sip.cap and look for the appropriate header entry in the packet.

AND


Thats it you have both P-asserted-id and Remote-party-id in your sip packet headers!

See also

• changes to sendrpid in Asterisk 1.8 with the pai argument for P-Asserted-Identity
• CONNECTEDLINE and REDIRECTING functions in Asterisk 1.8