3G router with WAN failover setup

[ajax]

So I decided that sharing a 384k line with a mate of mine is too slow and I got the Cell C speed stick and 3G router. So now I want to setup automatic failover by using the 3G connection as primary and WDS (ADSL) connection as failover. For now, I'm only focussing on getting the WAN connection going on the 3G router.

The WDS router (Linksys WRT54GL) connects wirelessly to my mate's ADSL line across the street and PPPOE is running on the Linksys. From the Linksys out of the LAN port runs an ethernet crossover cable into the WAN port of the 3G router (TP-Link MR3420). The PC connects to the LAN port of the 3G router.

The Linksys LAN ip is fixed at 192.168.1.4. DHCP is disabled.
The 3G router's LAN ip is fixed at 192.168.2.1. DCHP is enabled for 192.168.2.2-20

I am not sure how to setup the WAN port of the 3G router. I've chosen:
static IP = 192.168.1.5 (i.e. 1 higher than the Linksys)
default gateway = Linksys i.e. 192.168.1.4

In this state I can't ping the Linksys. If I make the WAN's IP the same as the Linksys I can ping it, but I still can't ping my mate across the street.

I will appreciate any pointers

 

[Shred]

LOL this was No.1 in Google for my search result

I am trying to do something similar due to the issues that I am having with Cell C. I have a B970 that I want to use as a backup. Did you come right? If not I will let you know if I have any luck.

 

[Windpomp]

Not sure if this will work.

All PC and linsys router and adls router should have a static ip same as the 3 G router range making it a flat network and the default gateway should be the ip of the 3 g router if you want to connect via 3 g for now, if you want to switch to adsl you must change GW to adls's router static IP, i think the devices are not intelligent enough to handle the auto fail over .

All PC static ip just change GW on pc between 3g or adsl

 

[syntax]

YEah, i dont see how you will get automatic failover with just this equipment.
You will have to manually change routes or gateways.

 

[RVQ]

Basically you need a 'smart gateway', so you setup all machines to use that gateway which in turns monitors the lines and fails over when required. I had this setup a while back using a Mikrotik device.

I know you can do some interesting stuff with 3rd party firmware and the WRT54GL