Got a plan, need a sanity check

I run an ISP over a satellite link in a remote area. I want to add a VoIP offering to our services. I plan on setting up a local Asterisk PBX and running the phones on the G.729a codec. There will be an IAX2 trunk with jitter buffer to a termination point. I expect to have about 30 outgoing lines. Just wanted to run the idea through the foreign veterans to make sure nothing I’m thinking won’t work. Specifically the IAX2 trunk with jitter buffer


It’s a PITA, but it can be done. It will not be perfect.
Things that you have to have are:

  • C-band connection (don’t even try it on KU)
  • QoS tagging support at the NOC or VPN channel to TISP OR some other traffic shaper that you throw-in between your router and the modem.

What you have to keep in mind is the latency. Depending on provider, user ration etc. it’s 800ms to 2000ms. We found that users who used sat phones had no problem with it, but PSTN users had to “get used to it”. The other part is packet loss. Can be really bad on some (oversubscribed) birds. G729 was unusable, G711 was so so. Had to go with iLBC.
Run a test on your connection for at least week and see the avg for latency & packet loss. PingPlotter Pro can give you a quick idea about feasibility.