[SR-Users] Calling users on another kamailio server

Daniel-Constantin Mierla miconda at gmail.com
Mon Sep 16 13:34:57 CEST 2013


On 9/12/13 10:08 PM, Brian Wallen wrote:
> I currently have two independent kamailio servers. I'd like to set 
> them up in a way that user1 on server1 can make a call to user2 on 
> server2. After searching I've come up with two ways that this might be 
> able to be done. Can someone please sanity check these or point me in 
> the right direction?
> 1. Have one registrar server and convert the other server to a proxy
> 2. Keep them both as registrars and somehow make them each aware of 
> the users on the other server
> I like 2 better because if one server went down users on the other 
> server would still be up. The only thing is I don't know how to set 
> the servers up to communicate with each other.
the nat can create problems when a server is down - if the nat is 
symmetric, only the server that received the registrar can send back 
calls to the phone.

Communication between users on two servers is as simple as using 
t_relay_to("proto:serverip:port") after you do lookup("location") and no 
record is found. You have to add an extra check for the case the call 
was coming from the other server, not to forward back to it in case of 
no found again. Also, you should skip user authentication for calls from 
the other server (not do authenticate twice). Another aspect to take 
care is chaining rtpproxy, you have to use the flat for trusting the 
other server (r, iirc).

You can also replicate the registration, but again, it can add troubles 
to the nat. Look at t_replicate() (in tm module).


Daniel-Constantin Mierla - http://www.asipto.com
http://twitter.com/#!/miconda - http://www.linkedin.com/in/miconda
Kamailio Advanced Trainings - Berlin, Oct 21-24; Miami, Nov 11-13, 2013
   - more details about Kamailio trainings at http://www.asipto.com -

More information about the sr-users mailing list