Networking / Beginners

---

Distance Depends on What You Choose to Measure

Your cable run has to connect every computer to the concentrator, but you can only buy patch cable in specific lengths. The longer the cable, the more you pay. Ethernet networking kits have one piece of cable for each connector in the kit, and each piece of cable is the same length (usually 20 or 25 feet). Given these facts, the word epicenter becomes meaningless. For example, if the midpoint between two computers is a distance of 28 feet, and you have two 25-foot lengths of cable, put the concentrator within 25 feet of one computer so that you only have to buy one longer cable.

Remember Cable doesn't run from the concentrator to a computer in a straight line. It runs along baseboards, through walls, across ceilings, and sometimes even runs along all of these conduits. You can't really measure the amount of cable you'll need between the concentrator and a computer with an "as the crow flies" mentality. The only way to measure properly (and therefore buy the right cable lengths) is to read the sections on running cable later in this tutorial. Then, depending on the way you run your cable, you'll have an idea of the length of cable you'll need to connect each computer to the concentrator.

Warning The maximum length of a single Ethernet cable run is 100 meters, which is about 328 feet. After that, the data transfer rate degrades or disappears.

You may have to account for traveling up walls as well as placing the cable across walls, ceilings, or floors. And of course, don't make your measurements too fine - you need to account for some slack. After all, why would you want the cable to come out of the wall in a straight line to the computer? You would have to leap over the cable to cross the room.

In the end, what you're looking for is a location for the concentrator that requires as few very long cable lengths as possible. Make these considerations:

• You're most likely to end up with a concentrator that is very near two computers while being very far from the third computer. In the long run (yeah, the pun was intended), you'll end up saving money, time, and hassle if you accept this fact right now.
• Find a way to position the concentrator near the conduit you're using for the cable run (you may decide to run cable through a wall or a ceiling, or along baseboards). If the cables from all your computers come out of a wall, put the concentrator very close to the wall to avoid the need for longer cables. Some concentrators come with devices that permit wall mounting so that the concentrator doesn't take up table or shelf space.