What is a SIP Trunk Anyway?!?

Jonathan Rosenberg

Cisco

Is this a SIP Trunk?

Problem Definition

• “SIP Trunk” is in common usage as a term and technology concept– Enterprise to SP Links– Inter-PBX connections– General server SIP interfaces

• However, no definition of– What it is– What it does– How to identify one

Proposed Solution

• SIP Trunk is a virtual SIP entity on a server constrained by policy

• Typically defined to support a set of extensions and perform specific request processing

• Identified by a SIP URI in Route header

• Examples: – PSTN routing trunk– IVR trunk

SIPServer

INVITE sip:+17328374233@1.2.3.4Route: sip:pstnxcnnct@example.com

This is UA loose routingapplied to servers!!