connect two seperate networks. Static Routing? VPN?

[Snugz]

Dear Everyone,

I have the following problem (see pictures below).
I have a gateway that connects me to the internet (by fast Wi-Fi and Ethernet) but is not configurable at all. See picture 1.

Furthermore it seems to isolate all clients. As this gateway is entirely non-configurable, essentially I am dealing with two seperate networks (network created by router A with subnet 192.168.1.x and the second network created by router B with subnet 192.168.2.x).
See picture 2.

Right now I have an old Router A (Asus WL500W running DD-WRT), hooked up by ethernet Lan to Wan that distributes internet access to my VoIP phone, media player, TV etcetera in the living room. This is all on subnet 192.168.1.x. Router A is WiFi capable, but this is slow WiFi. (Single Band, 54 Mbps).

I get internet access on my PC in a different room (too far away to easily run an ethernet cable to the gateway or router A), through fast WiFi access (Dual Band, 300 + 450 Mbps). Router B acts as a WiFi client to the inaccessible gateway and provides internet access to the PC. Router B is also running DD-WRT.

QUESTION:
What I would like to be able to do, is to be able to communicate from my PC (on router B) with the devices connected to router A (and the other way round).

I would like to do this without routing my traffic over the internet when it is originating from router A and destined to go to router B.
Ideally I want traffic to and from the internet to continue to be routed as they currently are, as this is the fastest and stable setup.

How can I achieve this?
I thought I can perhaps have Router B somehow act as a Wi-Fi AP to Router A (or the other way round), and use Static Routing to connect the two subnets.
Should I use a private VPN? DD-WRT supports OpenVPN.

Anyone have an idea to effectively do this in DD-WRT?

Thanks a lot!

 

[bill001g]

You are on the right track. You should be able to use router a as client to router b especially if you do not need router a to talk to end device via wireless....you can do that too but it makes it more complex. You will have to do something similar on router b to talk to the gateway. If these are dual band routers it would be best to use one radio for one connection and the other for the second.

So in the simplest configuration router a will use a IP out of the 192.168.2.x network for its wireless. You then as you state put static routes in both routers telling router a to send 192.168.2.0/24 to 192.168.2.1 and router b to send 192.168.1.0/24 to whatever address router A is using its wireless.

Most people come here and ask this question with standard firmware which is a not possible but with dd-wrt it is pretty simple.

It will be simpler if you would force all the traffic from router b to access the internet via router a, dd-wrt can support completely different subnets behind the same nat ip. In any case the trick is the static routes to make it work.