PJSIP Extensions with SIP Trunk

I’ve read a lot on the difference between PJSIP & SIP, and so far I haven’t found anything definitive on how they’re different – other than PJSIP is the newer driver. I haven’t seen a feature list of what’s new and better, etc.

So I’m trying to make sure I set things up correctly from the beginning. Right now I have my extensions defined as PJSIP extensions, and my trunk to CenturyLink setup as a SIP (chan_sip) trunk. I still need to have an activation call with CenturyLink to get the trunk working, but I wanted to see if anyone here had some wisdom or experience with a setup using PJSIP & SIP in this way.

Are there any issues I should look out for? Would I be better off to change all of my PJSIP extensions to SIP, etc…?

One more thing I just thought of: Since PJSIP & SIP are bound to different ports, is this going to cause problems down the road? Should I just standardize everything to one or the other?


This is a common setup, and should work fine. You can test your extensions without the trunk being active by dialing *43 (echo test, press a button to skip the recording) and by dialing between extensions. The ONLY pitfall of running both drivers is you must be very disciplined about port numbers. Each driver is bound to a different port, so when setting up clients you MUST ensure you are registering to the correct port. When configuring a router, you must keep in mind there are two SIP ports, and configure as appropriate for each.

Probably the single most common failure when getting started is attempting to register a client using the wrong port. The registration fails, repeated failures get the client IP banned, etc.

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Thanks for the prompt reply.

I have my activation call tomorrow with CenturyLink. Do you know if SIP trunk providers can use an alternate port? Their setup documentation said they come in on port 5060, but right now my chan_sip port is 5160. It may just be a question I’ll have to ask them tomorrow.

This is a question for your provider. If they are using the typical setup where your PBX REGISTERS to their server, then the PBX port bindings are irrelevant.

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You can also use PJSIP for your trunk(s). If it works, good, then you don’t have to deal with several sip drivers and bind ports, causing potential confusion.

If pjsip has issues with your sip trunk provider, revert to using chan_sip for that.

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Thanks! I will probably try that, too. Simplicity is best, especially for down the road when we’ve all forgotten how this thing was setup :slight_smile:

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