Two ADSL lines

Discussion in '3CX Phone System - General' started by penzance, Jul 23, 2009.

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  1. penzance

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    We have two ADSL lines on fall-back (if one dies, the other takes over).

    One is at abc.ourdomain.com, the other is at xyz.ourdomain.com

    One is locally addressed as 192.168.1.1, the other as 192.168.1.254

    When one dies, (the system uses two gateways, both configured as above -- 192.168.1.254 and .1) the router is temporarily turned off, and the system stops receiving incoming calls--one should have thought this would have been transparent.

    When the non-working gateway is restored, the system still does not receive incoming calls. We have found the only way around this is to reinstall the switch :(

    Has anyone please got any better, and more sophisticated ideas?

    Many thanks in advance.

    Stephen.
     
  2. leejor

    leejor Well-Known Member

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    I assume each gateway has a unique public Ip address. When one shuts down , and it was the last one to register with your VoIP provider, then that is where the provider will try to send any calls. Once the gateways switch the 3CX would need to re-register. If you shortened the registration time to , say, 5 minutes (if that's even possible), whether your provider would allow that, some set a fixed time between registrations, I don't know. It would still mean that you would no receive calls for up to 5 minutes. 3CX should also do another STUN test so that it knows what the public IP is as well.
     
  3. penzance

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    @ leejour

    Hmm. I thought so, too.

    3cx seemed to detect it, mentioned it in its log, and then the telephones stopped ringing.

    Outgoing calls continued to work.

    Thanks for the reply.
     
  4. thenua

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    I run a similar setup. I have a Router on each 192.168.1.1 and 192.168.1.2 in my case (.254 in yours).

    I find I also need to re-boot the surviving Router. Since its also the DSL modem, it causes the DSL line to be dropped and re-acquired which is a bit of a pain. But after it comes back up, it seems to work fine. Prior to then it doesn't. Its like the network still has some surviving "memory" of the old router and the old connection and somehow gets confused. I've never really worked it out. I just re-boot the surviving Router and it seems to work fine after that.

    Hope that helps.
    thenua
     
  5. houston

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    What you need to establish are two SIP trunks, and dedicate use of each trunk to a specific public IP. I haven't found a provider yet that doesn't provide some sort of "backup" route if the call doesn't go through, the only difference in the solutions being the cost.

    Assuming you can work out with your provider how to load balance / failover between trunks, the problem is how to do so from within your network. Your current setup gives you pretty much no control. (I would really reccomend looking into a firewall that does load balancing and QoS) 3CX doesn't have the ability to bind a specific provider to a specific IP, or to control routing. So, enter the SIP Proxy:

    http://www.teksip.com/

    I have not tried this, but according to page 8 of the manual it allows you to route specific SIP "endpoints" via specific gateways. So, here's how I would set this up to test:

    Add a 2nd static IP to 3CX System
    Bind Teksip to IP A - Current one that Routers forward to
    Bind 3CX to IP B (new one)
    Configure 3CX to use TekSip as a proxy for in/out SIP trunk and remote extension calls.
    Configure TekSip to route each trunk via a specific gateway.
    Configure 3CX with redudant trunks.
    Configure remote extensions with primary and secondary servers, both being the public IPs forward to the TekSip.

    There are of course details to all of those steps, but if TekSip does what is promised, it should all work. And better, TekSip is FREE! So your added cost is merely the time to set up and test.


    Let us know how things turn out.
     
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