I currently have a set up where my router is terribly placed for wifi performance (basically surrounded by thick structural concrete walls).
I thought about possible solutions, and came to this one:
The router is placed there because the ethernet signal arrives there, and all LAN cables go to the rest of the house from there as well. Because of this, I bought a switch (TL-SG105E) to redistribute the signal to the LAN, and decided to put the router in another room, this requires one wire to take the signal from the modem to the router, and another to bring it back to the switch. The problem is I only have one wire going to any of the rooms with ethernet access, and it is impossible to pass another one because of lack of space on the conduits. To solve this I divided the wire in two to use the same wire to get the signal from the modem and then send it back to the switch. That is where another problem arose, and it is what I need help with.
The divided wire comes from the router in the other room, but it can't be divided before arriving at the switch, because my father doesn't want me to mess with the cables that are coming directly from the wall. What I tried then, was make the cable with both signals enter the switch coming from the wall, and come out from the switch using another port (both in a VLAN), to only then get divided again to go to the modem and back to the switch to enter the other VLAN and go to the rest of the house. I know this is confusing, I hope this drawing helps:
Both wires entering the VLAN1 ports carry two signals (8 wires being used). The wires entering the modem, router, and the left port of VLAN2 carry only one signal (4wires being used).
This sounded fine, but the switch doesn't seem to work with two signals using the same port (4 wires for each connection). The only part that works is the one using the 4 wires used for fast ethernet, the other 4 that are usually used only for gigabit doesn't seem to work to get the signal across.
Is there a way to do this with the switch (one port with two independent signals or a bridge)? I thought about using two female RJ45 to get the signal from the wall to another cable, to divide it before entering the switch, which should work, but I wanted to know if I can do this only with the switch.
Of course if you have a better idea for the setup as a whole, I'd be happy to hear it, even though I think this is the only possible setup to get the router to another room.
Best Answer
Don't split the cable, you'll never make this work properly, and you'll needlessly degrade performance. Instead, use VLAN on the single cable.
So configure your router to accept "WAN" with VLAN (say, id=1) on the same port as "LAN" with VLAN (say, id=2). If you have not rooted your router, install some router firmware where you can configure this, e.g. OpenWRT.
Configure your switch to split off both WAN and LAN from the router with the same ids, and the connect up the split ports properly.
Problem solved.