Multiple WAN gateways - setup


Does anyone have any suggestions on how to setup 1 asterisk/freepbx server in a call centre environment with up to 30 callers and multiple WAN ADSL gateways?

The obvious problem is that 1 gateway is not enough to support 30 callers so we need more than 1 WAN gateway (frame relay/SDSL is not available in my area) and then the ability to route an acceptable amount of callers to each gateway.

Then the ideal situation would be to set the system to change the routes should 1 line go down.

Am thinking that the solution lies in multiple network cards for the asterisk box.

I understand that there are more obvious solutions like expensive multi-wan load balancing routers but before i go down that route i would like to investigate other options.

Many thanks

I would think you might be able to do something with PfSense w/multiple nics. Or multiple nics in your PBX and routes to match. Load balancing would be tricky.

How much bandwidth does each connection supply?


Thanks for your response.

Each connection gives 6mb down / 320k up but at best we are lucky to get 210k up.

That is our problem, ADSL is very unstable here so we tend to over compensate with more ADSL lines than we need.

One “gotcha” with a multi-wan environment will be SIP and its need to know the outside IP address. I think it will be tough to get a load balancing router to work well if you trunks are SIP. IAX will work fine. The only way I could think to accomplish this with SIP would be to put multiple NIC’s on the phone server and let it do the load balancing. I am not sure how to set that up, though.

Like a lot more. Are you talking 30 concurrent calls? You would need at least 3 or 4, possibly 7 lines. I gotta think there is a better way.

Just some “out of the box” thinking…

If the ADSL (and cable-based) broadband is that bad, perhaps you can do a wireless shot (802.11a/g, or microwave link) just far enough to a building or tower THAT HAS better ISP connectivity and bridge from where you are to where the high(er) quality/speed links are.

Ubiquiti networks ( makes some excellent and decently-priced back haul/long haul (50km) 802.11-based products, if this is an option for you (look at ubnt’s PowerStation or the NanoStation.)


try this hardware it might solve your problem.



Thanks all for your input.

Currently we are working through multiple nic´s with pfsense as load balancer, will see how we get on.