Can I send a WAN and LAN connection over the same cable?

Question

My home is ethernet wired, with all cables terminating in a patch panel in a box in the master bedroom walk-in closet. I was wondering if I could send the WAN connection into one of the rooms and then have the LAN connection come back through the same wire.

Here is a drawing of what I want to do:

Will this set up work?

This is the set up I currently have:

This obviously works, but the issue is that the router is in a metal box in the wall of a room in the corner of the top floor of a three story house. The signal in the basement is, well, less than optimal. I could add another wireless AP, but I'm trying to solve this with the equipment I already have.

Answer 1

If both of your switches are smartswitches, which means they support vlan's, you can configure the switchports as follows:

1st switch

port 1          access vlan 10
port 2 thru 7   access vlan 20
port 8          trunk vlan 10,20

2nd switch

port 1          trunk vlan 10,20
port 2 thru 4   access vlan 20
port 5          access vlan 10

Here's your edited diagram:

Answer 2

Technically, yes this is possible (See this Wikipedia Article).

You would be limited to using a 100Mb connection rather than Gigabit, but typically WAN connection is going to be less than 100Mb anyway.

As the article mentions, this is not standards compliant, but 10/10 and 10/100 Ethernet only use 4 of the 8 wires found in a typical CAT5/5e/6 cable, so you would have to remove the existing RJ-45 connectors from your current cable and attach two connectors on each end using 4 wires for each connector. At that point you would have one connector that would be used for WAN and another used for LAN.

Personally, I wouldn't go this route. Its a very hacky solution and you may end up with interference if you have a lot of traffic on those lines. I'd just fork up the extra cash for a cheap router to extend your WiFi.

Answer 3

The way a network works is like this:

You have internet coming from your wall through a phoneline or cable, etc. Attached is a device called a modem which has a network plug with internet and an IP address.

Your ISP hands out this IP address, and they will only give you one unless you pay a lot. But this is not a problem, you usually only need one. But for more than one computer to connect to the internet, you need to do two things.

1. Create a network for all the comoputers so they can communicate with eachother
2. Bridge your network with the internet.

Using a device called a Router, you can bridge a WAN (Wide Area Network, also known as the internet) with a LAN (Local area network)

PC's in a network will talk to eachother by sending out and receiving data through the network cable. Basically, it sends out its data, and whomever receives it will determine if it can use it or not. By placing pc's in the same IP address range, and by using a subnet mask, you can create groups of pc's making sure some pc's can talk with eachother, where others cannot.

A switch will basically control how the data from one pc is handled to the other. By default the data is sent to all pc's until 2 pc's seem to like eachother and start talking. The switch will then connect these 2 as favorites.

This basically means, that it doesn't matter how you connect your pc's to one or more switches. It only matters how the IP assignments are set. They'll find eachother because thats what switches do for you.

So the only thing you need to do is somewhere connect the router to the switch or switches and it will work.

Just make sure the internet is connected to the WAN, and the rest of the network to the internal switch to one or more ports. So your bottom image will definitely work.

Ideally, taken your first image, I would connect it as follows:

Internet -> Router -> Port1: Switch 1, Port2: Switch 2.

Switch 1: all pc's on building 1 Switch 2 in building 2: all pc's there.

In building 2, don't use the router though. You can setup the WAN to setup as a fake ip, and not connect the WAN port at all for it to still use the wireless functionality (basically you turn it into an Access Point). You can also still use the WAN port, but know that any device on the router will then not be able to talk to other pc's on the network. They're isolated from the rest of the network, including all wireless devices.

Answer 4

It probably won't work, depending on what your WAN is. If it's the internet, I don't think your ISP will offer you multiple IP addresses, which your setup would require (each computer would be connected to the WAN with it's own outward facing IP). You probably need some type of address translation on your WAN port, so a router needs to be your outward facing access point. You can daisy chain routers depending on the model/firmware you have.