Link two PBX's

Hi, I have two newly built FreePBX phone system at different offices. One system has around 30 extensions the other around 12. The two offices are connected by VPN via ADSL with around 12Mb Download and 1.6Mb upload. The current VPN is used for thin clients.

Each system has it’s own SIP trunks provided by the same ISP connected by it’s own ADSL again with 12Mb down and 1.5Mb up.

The two systems need to be connected to each other so each side can call other extensions via internal extension numbers.

I’m not sure what’s the best way to do this, as I see it my options are as follows

  1. AIX trunk between each office although I’m not sure if I would use external IP addresses or internal ones. I would prefer not to route any extra traffic over the existing VPN.

  2. Create a new VPN and move the 12 remote extensions onto the same system and do away with one of the PBX servers

  3. Create extensions at each end that really point to a real phone number as all calls made over the SIP trunks are free to phone numbers hosted by the same provider.

Can anyone let me know the best way to do this or if there is a better way than my 3 options.

Many Thanks

IMHO I would give <a href=>interconnection through IAX2 a try.

As parnassus said IAX is a good choice. Sending the traffic over VPN would be more secure because you would not need to open up the firewall. What is the reluctance to sending it open the existing VPN? Bandwidth?

Do the extension ranges overlap at the sites?

Hi Alan_Mousty… The concern with using the existing VPN is bandwidth as you say however I do have 2 more ADSL connections at each site that are dedicated to the SIP trunks that I could re allocate to a Voice VPN by means of a new subnet. Not opposed to doing it but just wondering what’s best bearing in mind future management. The AIX2 trunk would be simpler I think and my firewalls will manage the security ( WatchGuard XTM’s at each end locked down by protocol ) the only issue are extensions as they are not tidy… in the past it’s been one big system so extension numbers are spread over both sites so would have to list each one separately in the AIX trunk rather than using ranges of numbers… again not an issue as long as it’s documented properly. :slight_smile:

So is the consensus to go down the route of AIX trunks connecting via external static public IP addresses ?

Also… not sure if this will work but will BLF monitor extensions at both ends via AIX2 or just those on the same PBX ?

Mate…give up with AIX! AIX is a very famous Operating System while IAX (and the current IAX2 one), about which we’re discussing here, is a Communication Protocol :wink:

brain thinking one thing and fingers typing another…

It happens to me too.