What are the physical network considerations?

Q: What are the physical network considerations?

There are many physical [network] considerations to take into account.

Meet the expert Thomas A. Limoncelli is an internationally recognized author and speaker. He is best known for his books The Practice of System and Network Administration (with Christina J. Hogan and Strata R. Chalup), Time Management for System Administration and The Complete April Fools RFCs (with Peter J. Salus). Read more about Tom and his books at Everything Sysadmin.

Specifically to LANs, what kind of copper you are going to run to the desk is one of the first considerations. There are different categories of copper cabling: CAT 5, CAT 5E, CAT 6 and so on. The better [cables] can run higher-speed networking, but they cost more. I believe that wiring is usually a 30-year investment in a building, so I usually tend toward the higher-quality cabling, because even though we might be doing 100-Megabit [speeds] to the desktop today, Gigabit to the desktop is becoming the bare standard now, and [speeds will be] even faster in the future.

If there's new construction, what I find is that the cost of running wiring is dominated by the cost of construction. If the walls are going to be opened up because it's new construction, it doesn't matter if you're running CAT 5 or 6 -- the walls are open, that's the expensive part, so run the best stuff you can.

More from our expert Download Part 1 and Part 2 of Tom's FAQ podcast or read a chapter on centralized/decentralized networks from The Practice of System and Network Administration, 2nd Edition, by Thomas A. Limoncelli, Christina J. Hogan and Strata R. Chalup.

There are other physical [network] considerations like labeling. Labeling sounds like a very simple, unimportant issue, but actually it's incredibly important to the maintainability of a network. It's important to come up with a consistent scheme for labeling the [network] jacks. Wiring closets should also be numbered. If you've been asked to build a network that's in a computer room, a labeling structure is important. I tell the engineers that I work with that if a machine is unlabeled, I'm allowed to power it off because I don't want dangerous equipment in my machine room, and an unlabeled piece of equipment is just an accident waiting to happen.