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New Member

Double WAN Ethernet Connection on a Router

We currently use RF links for WAN connection between our branch offices.

A Radio is usually terminated on one ethernet interface on our generic Cisco 2600 routers while the other ethernet interface connects to a LAN switch.

All the Radios are in a physical mesh and in the same vlan 10.0.8.0 which corresponds to the address of their connecting interface on the router.

Routing from branch A to B over the RF link is done by adding a static route at router A with B's Radio interface address as the destination.

e.g. router A: 10.0.4.0 255.255.252.0 10.0.8.1 no problems.

Now we wish to connect another Radio link to work alongside the present link. This new link however runs through a VPN with different ip addresses 192.168.0.0

For our branches with a free ethernet interface we just connect this new link to the free ethernet interface, but for the branches with the former radio link we find connecting this new link difficult.

How could we connect both ethernet terminators of the two radios (with different vlans) on the same Router to enable us alternately use one link when the other goes down? Thanks.

4 REPLIES
New Member

Re: Double WAN Ethernet Connection on a Router

Floating static route should do the trick

all depends on how the entire network is set up though.

Just change the administrative distance of the routing protocol you decide to use to a higher AD than the one for the primary link.

Silver

Re: Double WAN Ethernet Connection on a Router

Unless the Ethernet interface on the router goes down when the radio has a problem, floating static routes will NOT do the trick. The challenge is to detect when the prefered route is broken so that the alternate route can be selected.

Your challenge appears to be identical to the problem faced by anyone trying to provide redundant routes through VPNs. See the white paper on redundant VPNs on my web site for two approaches which might work for you. You might also look at the redundant firewall white paper for another example of detecting when a compound link goes away and routing around the problem.

Good luck and have fun!

Vincent C Jones

www.networkingunlimited.com

New Member

Re: Double WAN Ethernet Connection on a Router

Oops,

I forgot the part that the interface will still be considered up unless the RF module itself (or whatever is directly connected to the Ethernet interface) drops connectivity. I'm used to satellite shots with backup RF links. Since the MUX going to the satellite is layer 1, if the sat link drops, or the mux drops, the ethernet or serial interface will also drop, while adding the backup route into the routing table. Good point.

New Member

Re: Double WAN Ethernet Connection on a Router

Thanks a lot. I'm reading the white paper now.

Happy New Year!

Ifeanyi Muonagor

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