Details: Our head office is located in Canada. We have a branch office in the US, and a branch office in the UK. All three locations have their own Asterisk server, and each has a T1 PRIs for calling out through PSTN.
Our phones in the UK and US offices have two lines configured, one to their local server, and one to the server in Canada.
Each location has no quality problems making calls through their local T1 PRI, as you would expect.
The problem is with interoffice calls with the second line that connects back to the Canada server, which does through a VPN tunnel.
In general, the remote extensions connecting through the VPN is not reliable enough in terms of voice quality. The delay, jitter, and voice drops are significant enough to be more than an annoyance to some users.
It gets even worse when, for example, one user in the US is talking to another user in the UK. Both legs are connected to the server in Canada. In this case, the VoIP traffic is going through two VPNs.
Does anyone have any suggestions on what we can do to improve things here?