Asterisk VOIP Servers at Generation
After a month of wrangling, we now have two Asterisk servers running between our two offices.
Our main server, located on a fat fibre connection manages our main connection to our VOIP provider - Faktortel.
It’s been an interesting challenge getting the two servers to talk together. In the end it was a NAT issue.
I have now discovered that NAT is a VOIP technicians worst nightmare. The main reason I added a second dedicated voip server at our central campus was because of NAT (Network Address Translation).
We had a number of Grandstream SIP phones installed at the central campus to begin with, all had alot of difficulty holding a voip session open. Often when calling, you would not hear anyone at the other end. An indication that the voice packets were getting to their destination, but becuase of NAT, the returning voice packets did not know where to return to within the office network, so you could not hear the caller from the Studios.
So we added a second Asterisk server at central. Both servers would not talk. Until Dean Davis, our awesome phone tech from Withtel (who installed the servers) discovered a single line of code in the sip.conf file that treated extensions at central as though they were behind NAT, which they were not. When this was iorned out, we rebooted Asterisk and it worked!
A couple of great reasons why we added two voip servers:
- The two server talk to each other in one RTP stream
- This means that all voice calls are interleaved into one voice stream
- You can maintain many more voice connections through one rtp stream
- A single RTP stream can handle 100 concurrent connections per 1Mbit symetrical pipe
- One server at a location handles all calls at that location
- Voice streams at both offices are internal, voice packets are not routed over the internet to the head office and back again
- All call records for both offices are kept on the main server at the Studios
- We can add a Digium like the TDM400P FXO card to the central server so we can add PSTN or copper lines to our mix of VOIP lines
It’s been a bit of a trial, but I know we are going in the right track. I just have a gut feeling that this is the right move long term.
It’s pioneering, and I know the staff hate being guinea pigs, but it’s the best and most cost effective solution.
It feeling like we are cutting new ground as a church, not only in the supernatural, in people’s lives and businesses, but also in technology.
