3. Cabling

If you have a network, you need Network cabling (or some sort of radio). Read this to get started.

3.1 Home Ethernet Cables
3.2 Office House Cables
3.3 Office Floor Cables
3.4 Point to Point

3.1

Home Ethernet Cables

If you are building a new network in a tiny office, install the absolute minimum that you can relocate easily. IE loose 10-MB thin ethernet.

They're the cables with 'T' pieces. You string the PC's in a line with a terminator resistor plug on the end 'T' pieces. Unconnected PC's are simply unconnected. The cable is like TV arial coax.

The PC's are strung in a line.

 X---T-----T-----T-----T---X
     PC    PC          PC

There should be a cable between the PC's T-pieces and the end terminators. With a 2 machine network, it doesn't matter, but with a longer layout, you can create reflected (radio) waves, potentially standing waves, which may fry your card, or even the cable!

The terminators, should be a cable length away from the last PC, but with only 2 PC's, you will "get-away with it".

Also the missing PC is supposed to have the 'T' piece replaced with a thru cable, but usually it doesn't matter that much. For rules on what is allowed, consult the University of Internet:

3.2

Office House Cables

TP is twisted pair high-grade phone wire that runs either 100-M ethernet -or- 10-M ethernet. The difference is the quality of the cable, and the type of cards in the machine. You can also use the same cables for rs232 or phone extensions.

Every desk has a wall socket, whose cable runs to where the HUB is. At the HUB there is a spray of cables sprouting out of the wall. Each tagged wire has another 2 metres and an end plug (you need a crimping tool and box of plugs).

7 cables plug into the HUB box (100) which has a mains plug. That gives you 7 PC's on a private LAN. IE the entire building. HUBS with 15 ports are also available (200).

Specify 100-M TP cables, even if you only use standard 10-M TP cards. Burying TP cabling with a BT staple gun is expensive but easy. Digging it up ...

	 HUB
	 |||
	 |||
	 ||+-PC
	 ||   
	 |+- PC
	 |   
	 +-- PC

3.3

Office Floor Cables

If you have 100 PC's on 3 floors, every wall socket is labeled, and runs to the rack cupboard in the room adjacent to the dry riser.

Each work group has their own HUB.

Groups that have PC's with mixed 100-M and 10-M cards will need two HUBS, and a host to bridge them (or indirect connections via other work groups). You can't mix 10-M and 100-M TP ethernet on the same wire.

The group's server is located with the group, and like all their PC's, it has a TP cable to the local group's HUB. The server can also be a workstation.

The group's server also has a second (hi-speed) ethernet card, and it's TP wall socket, runs to where the HUBS are, but it then plugs into an extension cable that runs down the dry riser, to the computer room, where it joins a HUB of other groups' servers.

The group server is acting as a gateway/bridge/router, as well as providing it's services to the LAN-HUB and to the BUILDING-HUB. It doesn't have to be the server, but it probably is.

(( for performence reasons, you may wish to have a seperate router, not the server, however that requires an additional router, and it brings external traffic onto the internal LAN. For small workgroups, you probably want the server to be the router. That also makes it easier to distinguish by interface, rather than by IP address ))

Any of the group's machines can be the gateway, it just needs 2 ethernet cards of the correct types for the cables. For example, here are two groups connecting to the central LAN:

 HUB		  HUB		  HUB
 |||		  |||		  |||
 ||+-GW-----------+|+----------GW-+||
 ||                |               ||
 |+- PC           |||          PC -+|
 |                                  |
 +-- PC         RHUBLAN        PC --+

Technically speaking, the Gateway is really a Router, but it probably also acts as a gateway, and as a firewall. You might also have problems with a restricted number of external IP addresses, but choose to keep 5-32 machines on the local subnet, with the GW generally registered.

You may need to consult a cabling and networking company to get this done. If you do it yourself, you will only have yourself to blame. But at least you can start asking questions.

3.4

Point to Point

If you only have 2 machines, you can use a single special TP cable with two wires crossed over. If you use thin-ethernet cables (not TP) you still have to have the T-pieces and pair of terminators.

Whatever you decide to get, you will need cards and cables that match, or use combi-cards (that match either).