Multi-LAN question

[danthecan]

I'm not sure if this is possible but I'm hoping someone here can tell me if it is.

Setup
DSL 1 = IPTV feeds two TV set top boxes via ethernet (supplied by broadband provider and separate from DSL/router).
DSL 2 = normal broadband & WiFi.

The room that has the DSL 1 TV broadband router sits in some kind of wireless dead zone and has it's WiFi disabled anyway but I would like to connect the smart TV that is also in that room to the DSL 2 network. I've messed around with WiFi extenders and they just don't work, the room is cursed (homeplugs a no go either).

Is there any way of using the existing DSL 1 ethernet cable to connect the smart TV's ethernet to the DSL 2 network ?

I can plug the DSL 2 router into the ethernet used by DSL 1 but obviously having two broadband routers on the same network would break things.

 

[eibgrad]

You could simply route between the two networks using a router!

If you have an old router lying around (almost anything will do, doesn't even need to be wireless), and you're able to disable its firewall, then you can simply patch the LAN side to one dsl modem+router, and the WAN side to the other dsl modem+router, and route between them.

At least that's the big picture. There are a few other details, like disabling the DHCP on that router, assigning an IP on the LAN side and IP on the WAN side within their respective networks, and adding some static routes on the dsl modem+routers so each side knows how to find the gateway (which is the router) to the other network.