Connect Two Asterisk Servers Over Internet

Asterisk Asterisk General
1

I am a hobbyist looking for a solution to link two houses together to use a single PTSN line for both homes and possibly do house to house calling etc. if SIP phones are added to the first house.

House 1:
PSTN line
Cable modem w/static IP
Linux box configured for routing/traffic shaping/site to site VPN to House 2
Linux box w/Asterisk and a TDM400P with a FXO module
Standard analog phones

House 2:
Cable modem w/static IP
Linux box configured for routing/traffic shaping/site to site VPN to House 1
Linux box w/Asterisk
SIP phone(s)

My idea is to setup two Asterisk boxes and route the VoIP traffic over the VPN tunnel established between house 1 and house 2. All calls made from house 2 with the SIP phones will go out one of the Asterisk boxes to the other one through the VPN tunnel and out the TDM400P w/FXO module out the PSTN.

Does this seem logical? Is there a better way to do this? This is a learning experience but VoIP has always interested me and Asterisk + TDM400P with a FXO module seems like a pretty cheap project to mess around with and get my hands into the VoIP scene.

Both sites have identical cable connections on the same provider network. The speeds are 5Mbit down/1Mbit up on both sides. Is the 1Mbit upload enough to handle one VoIP call? Is there too much overhead with routing the VoIP traffic over an encrypted VPN tunnel? Is there a better solution to all this (short of having a PSTN at both houses and defeating my project purposes/proof of concept)?

On a side note, I may also try to combine the Linux router and the Asterisk server(s) into one for each house to cut back on running machines. The idea of converting my WRT54GS to a Asterisk server sounds pretty neat too…

2

Should work - except you’d need FXS or ATA to use analogue phones in House 1 - FXS on TDM400P would be cheaper and better). You don’t need Asterisk in House 2 as you are considering VPN. It would simplify things a lot. Also, you don’t need separate Linux boxes for VPN and Asterisk - for fun is another matter.

3

Yes your idea will work. I"ve linked my home asterisk server and my work asterisk server so I can make calls out either line from either (via IAX), and also setup my polycom SIP phones to register different lines to each, so my SIP phones ring at both locations for both lines… works great.

you have plently of bandwidth. just keep in mind there is no quality of service between your two points, so your call quality can degrade when either side is busy or the connections between the connecting networks get bad… honestly for personal use it should be fine, at worst sometimes I get an effect like a cell phone in a bad area, but that’s very rare.

for “business use” I woudn’t connect through a public ISP unless you are REALLY small and don’t care about your calls losing quality, get an ISP that does MPLS or something where you can have a virtual full mesh, and get a Committed level of bandwidth and priority for your calls.

again though, should work fine for personal use. Just be aware that if you call 911… your address will show up as the site that has the physical phone line installed :wink: