Dual WAN Router Help

B5 BDJ

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Apr 23, 2013
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10,510
Hi, thanks in advance for any help!

I work for a race team and currently at each circuit we recieve internet through one network and circuit timing through another. At present we run 2 Netgear FVG318 routers with a cable linking the 2 together.

Im looking at moving to a dual WAN router and just wanted to confirm that they recieve through both input and dont just pick the 'strongest' signal as such.

Many thanks
 
It depends how you have it configured. The primary rule for route selection for almost any router/PC is "most specific prefix" sometimes called longest match. So for example say you have a bunch of networks on a interface in say 10.0.0.0/8 but you have one at 10.50.0.0/16 out a second interface. Since the /16 network is more specific it will override and force the traffic out the second interface.

The problem comes when you have exactly the same route and prefix length going out both interfaces..the worst offender being the default route. Most routers will have a tie break to select one....or worse they will load balance over both which does not work well for internet applications.
 
Granted we've been given limited information, but based solely on that information, it's not clear to me why a dual WAN router is necessary, or what advantages it would offer.

Typically a dual WAN router (at least for consumers) would be used to allow multiple connections to the internet, then hide that fact behind a single network. And that's why dual WAN routers typically offer load balancing, failover protection, etc. It only makes sense given the fact that users don’t particularly care which ISP is used, to them it doesn’t make a difference.

But you’re describing something much different. For YOU, it DOES matter. In fact, each WAN represents a different network for completely different purposes. And while you can use a dual WAN for these purposes, the question becomes, why? It’s not (as I described above) as if you can obscure the network differences (e.g., 192.168.1.x of the circuit system, vs. internet addresses) behind the dual WAN router. Every client behind the dual WAN still has to appropriately address the right network. But you can do that (and perhaps already are) using a single WAN router, patching the second network to its LAN, and using static routing to route clients of one network to the other.

My point is, it’s not clear to me that using a dual WAN really solves anything based on what’s you’ve described so far. As far as I can see, a dual WAN will merely push the routing decision from inside the LAN to outside the LAN. What’s the advantage? If anything, it offers a serious disadvantage; like the internet, users on the circuit system are blocked from accessing the other network by the WAN’s firewall!

Understand, I'm not saying the case can't be made, it's just that I haven't heard it as yet.