Making sense of PJSIP, relationship between AORs and Endpoints



I have been reading up on PJSIP and have a question. It’s possible to have an Endpoint associated with multiple AORs. And according to the ER diagram on the wiki, an AOR can also be associated with multiple Endpoints. And yet I see no scenario when this would be useful. I know I can just create an AOR for each Endpoint and be done with it. But I was wondering if anyone can given an example or explain when it would be useful for an Endpoint to have multiple AORs and also when it would be useful for an AOR to be assigned to multiple Endpoints.

Thanks for your time.


I don’t use PJSIP, so I can only answer this for SIP, but a number of ITSPs support multiple endpoints for address of record, and there have been demands to support this in Asterisk.

The expectation is that when someone makes a call to the address of record, all the end points that are online are rung, and the first one to answer gets the call.


Hi David,

Thanks for your time. I had a very enriching discussion on the IRC channel about this and I think I got the concept of “one endpoint -> one aor -> multiple contacts” pretty well, it makes sense to me know. Sadly I could not figure out when “one endpoint -> multiple aors -> multiple contacts” would be useful, at least for outgoing calls. If anyone can state an example of when such scenario is useful I would love to read it.