[OpenSIPS-Users] Multiple sites - Registering and NAT'ing issue -- Best options for implementing

[Josh S.]

Hi all,


We've got two twin sites sitting behind nat in different private 
networks, by twins I mean they both have the exact same config.
UACs can register only once at any site, also they can move between 
sites and place calls. (just locally though)
Each opensips instance registers the local UACs.  Opensips version is 2.3
RTTProxy is integrated, and running just fine.

UACs are being registered into the twin remote instance using 
t_replicate("sip:IP:PORT")   (although I'm not sure whether this is the 
best method to achieve this)

So, the   opensipsctl ul show  command shows:
    AOR:: 100
                 Contact:: sip:100 at 192.168.1.2:12345;ob
    AOR:: 101
                 Contact:: sip:101 at 11.22.33.44:5060;ob

and in the other site, same command shows:

    AOR:: 100
                 Contact:: sip:100 at 22.33.44.55:5060;ob
    AOR:: 101
                 Contact:: sip:101 at 192.168.1.3:54321;ob

being 11.22.33.44 and 22.33.44.55 the public IP address of each opensips 
registar.

Each opensips instance is working ok with the stock config, and the UACs 
on its private internal network can make calls between each other.
But of course not to the UACS on the remote site. And that is the issue.

So I started to play around with nat_tranversal, nathelper, 
topology_hiding, and reading all the many info in the docs/modules and 
what not, and in this list of course.
I also tried the b2bua module, to no avail.

I reached to an end route where progress is not made-....  I began to 
think this cannot be that complicated. I refuse to play 'inventing the 
wheel' again game.

I need some little help in finding the right direction to get the two 
sites routing calls between each other.
Any hint would be greatly appreciated, guys.


Just for clarifying purposes, a little drawing



                         Private Net                            Site A   
                       Public IP side

UAC1    |
              -----------------------------------------------> OpenSIPS 
                     11.22.33.44
UAC2    |                                    |
                                                  |
                                                  |
                                                  | <-------> RTTProxy





                         Private Net                             Site B 
                         Public IP side

UAC3    |
              -----------------------------------------------> 
OpenSIPS                     22.33.44.55
UAC4    |                                    |
                                                  |
                                                  |
                                                  | <-------> RTTProxy


it's required that the UACs can move around to any site, same username 
(uri), and still be reachable from any other point.

from stock config, I made the slight changes to allow for RTTProxy be 
integrated, and it's working. No NAT was involved, as yet.
The two sites share the same domain, and also the same internal IP 
network in 192.168.1.0/24 space,
although that can change if needed.
Each site works fine individually.

What changes need to be done in the config for the calls be routed 
between the two sites?
Any example around?

Thanks a lot.

Josh Smit