In comp.dcom.lans.ethernet ps56k <firstname.lastname@example.org> wrote in part:
> this is a common question - and X-posted to - alt.internet.wireless
> "Rick Jones" <email@example.com> wrote in message
>>J <firstname.lastname@example.org> wrote:
>>> Hello, Here is my current config (downstairs in my basement) :
>>> Coax cable into cable modem (this is the only cable
>>> access I have in my house) Ethernet cable from cable modem
>>> into Linksys 4 port wireless router WAN port 2 computers
>>> plugged into ethernet ports on the router (1 from a long
>>> cable run from upstairs) Wireless access for 1 laptop
>>> The wireless access is poor upstairs in my house.
>>> I'd like to move the wireless router upstairs. I have done this,
>>> connecting the the ethernet cable with the long cable run from the WAN
>>> port on the router directly to the cable modem downstairs.
>>> The problem is I now don't have the router downstairs to plug my
>>> downstairs computer directly into.
>>> Can I put a switch between the cable modem and the router?
>>> I tried it with a hub I had laying around, and it didn't work.
>>> Would a switch do the job?
>> Probably not. Your "router" is the device fronting for your systems
>> with the cable modem. If you want your systems to speak-out the cable
>> modem, they need to go through the "router."
>> If you have poor wireless upstairs when the "router" is downstairs,
>> but need wired connections downstairs, you might consider placing an
>> "access point" (eg the WRT54GAP) upstairs, running the long cable you
>> used for your wireless "router" to connect the access point to the
>> router. (or connect your switch/hub to the router and then the access
>> point to the switch if you need wired connections upstairs as well).
> As mentioned - it won't work - because your "local network"
> is created by your router.... your IP address is coming from it,
> along with some general protection from the outside world.
> Common answer is the additional wired WAP at the other location.
> Another common option is to place the router/wap where you
> need wifi, and try using inhouse AC powerline networking
> to backhaul to your "wired" desktop. We use this for our
> Xbox and Tivo in the family room, with the WAP upstairs.
As the above replies have mentioned, neither hub nor switch
will work. You are relying upon the router to do NAT so you can
share the connection. It also has established the internet login.
At the very least you would need to configure the vampire machine
with your WAN IP, gateway and DNS. If the cablemodem will even
listen to two different MACs.
Since you have the long wire run, you can use it for the backhaul.
Standard Cat5 cable has 4 pairs and only needs two for 10baseT
(normal for modems) or 100baseTX (normal LAN) . This is not exactly
per standards, but I have never seen it fail when correctly wired
(no split pairs).
It would look like this: cablemodem in the basement, plugged into
a splitter (A-side) plugged into the Cat5 to upstairs. There it
plugs into another splitter, and out the A-side into the router.
One port from the LAN-side of the router is plugged into the B-side
of the splitter where it is sent through the same cable back downstairs
where the downstairs computer is patched into the splitter B-side.
I have not seen these splitters commercially offered, but
they are easy to make with 3 jacks in a surface mount box.
Just punchdown some cross-connect in the right pattern.