connecting two routers, different ISP's

[sugarhill]

I have a BEFSR41 on Charter broadband, at 20 Mb, and a WRT54GL connected to AT&T DSL at 1.5 Mb.  I would like the AT&T DSL to be my "fallback" if my broadband fails; but, would also like them to be on the same network, so that I can connect to either and share resources.  Is there a way to do this with my current equipment?  I do not want to slow down the broadband connections, and would love to be able to choose which network, if necessary.  (Is this bridging?)

[gv · Accepted solution]

That's not possible. Those are consumer devices and don't support router failover. The best you can do is to configure both routers to work independently with their internet connection. Than power down one of them. If you need to switch, you have to rewire and power up the other router. I think there are no other alternatives...

[sugarhill]

Thanks.  That is the way I have them configured now. I switch the cables in my IDF when I need to.  I was simply hoping to tie them together.

[gv]

The problem is if you have both powered on and in the same network (i.e. connected with an ethernet cable LAN port to LAN port) they must have different IP addresses, e.g. 192.168.1.1 (BEF) and 192.168.1.2 (WRT).

Now the IP configuration of the computer needs a default gateway address and dns servers. The problem is if your computer have 192.168.1.1 as default gateway and the internet connection on the BEF dies there is no way to tell the computer to automatically switch to 192.168.1.2 as gateway.

Thus, either all computers must change their gateway address (e.g. you disable the DHCP server on the BEF, enable the DHCP server on the WRT and renew all IP addresses on the computers)

or you do the switch: power down the BEF, change the LAN IP address on the WRT to 192.168.1.1, enable the DHCP server. Now the your computers would use the DSL connection (assuming you assign 192.168.1.1 as DNS server to your computer).

I think the latter is the closest to a failover you can get. Still it requires manual intervention. And i think the power off BEF, power on WRT seems easier than the power off BEF and reconfigure WRT option...