[asterisk-users] network config

[David Gibbons]

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A client has two offices in the Virgin Islands that MUST maintain data
connectivity, and there are no available "leased line" options to run
a P2P link between them.
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Is there line of sight? I've been wanting to do a long-shot wifi link and my company would give it a shot if you want :).

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Do you lose an in progress call when the tunnel switches from one link to
the other?
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Any 'fail-over' router with links from separate providers that don't route the same subnets (cable/dsl) will have to change its default route when it 'fails-over'. As such, the VPN tunnel will be disconnected and reconnected. I'm sure you could make it brief, but yes, calls will likely be completely dropped.

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And finally - is there a device that will manage the tunnel such that a
high water mark of latency will also cause the tunnel to switch to the
other link, rather than actual packet loss?
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See above. Fail-over routers have to wait some criteria are met in order to fail over (ping latency, ping loss, etc). This means that the connection you're using as the 'default' WILL go 'down' BEFORE it switches to the other one, regardless of the criteria used.

Another plan would be to set up two routers at the site with two separate VPN tunnels across the two different links, both tunnels being always on. You could then use a SIP proxy or iptables magic to choose which tunnel was the best at any given time.

I would go for the wifi. Maybe because I want to do a long-shot link. Also because I want to go to the virgin islands :).

Good luck!

-Dave