6 Ethernet Myths Revealed

July 17, 2014 at 10:00 AM

 

Let's challenge your Ethernet knowledge.

 

Did you know that Ethernet cabling is one of the most common cabling types? It's almost as common as electrical wiring! Ethernet is often run through walls, ceilings, under floors, and usually branches in a star topography from a central wiring closet.

 

Since it's so popular, we've put together some common assumptions about Ethernet cabling that are worth investigating.

 

See if you know the correct answers: 

 
 
 
 
 

 1. Myth or Fact:  The color of the cable jacket indicates what kind of signal the cable carries.

 

Myth! Ethernet is Ethernet, so there aren't different signal types. Although, there may be different speeds running in the same building. Usually, your IT department will use different colored cables to keep track of where the cable goes. This makes it a lot easier in the wiring closet to identify cables.

 
 
 
 

2. Myth or Fact:  If I run cables that are EIA/TIA 568 B standard, I cannot use any cables wired to the EIA/TIA 568 A standard on the same network.

 

Myth! The EIA/TIA 568 A and B standards are actually both straight-through pinned. They are pin to pin, 1 through 8. The difference is in the color code of the wires inside the jacket. These standards were originally set to improve network performance and consistency between manufacturers. 

 

For this reason, if you mix A and B standard cables in a network, the network will run perfectly fine. However, if someone has to cut a cable and re-punch it, you run the chance of punching to the wrong standard. Best practice is to have all cables that are permanently installed (behind walls, through the floor or ceiling, etc) wired to the same standard.

 
 
 
 
 

3. Myth or Fact: The distance between a workstation and a wiring closet can determine how fast the Internet runs on that person's computer.

 
 

This depends. The rule of thumb for Ethernet is that the distance between any two nodes should not be more than 100 meters (328 feet). Node to node may be understood as two items that get external power; patch panels, wall plates, and other components in the network typically don't count as nodes. If you run an Ethernet line exactly 328 feet from your wiring closet to a wall plate, when the user puts a short, 2 foot cable between the wall plate and the computer, they will actually be over the limit.

 
 

What happens if you go over the limit? Most often, users will experience very slow signal or no transmission. Your best bet is to always leave a little slack room between nodes. If you have to run cable beyond 100 meters, your best bet is to use a media converter to change the signal to fiber, then change it back to copper at the drop point.

 
 
 
 
 

4. Myth or Fact: In the wiring closet, Ethernet cables must be kept loose, not neatly tucked away, or else the internal wires could be damaged. This is why so many wiring closets are so messy.

 
 

Actually, this is partially true. The wires within Ethernet cables are twisted together, and this is important for the category rating that ensures the cable can handle the speed of the network. If the cable is bent, rotated, and flexed too much, those twists can come undone, throwing off the delay skew values. 

 

The rule of thumb is that Ethernet cables should never be stapled or tightly wound around something that would put a kink in the cable. Also, if you must make a tight 90 degree turn, you should make a 90 degree turn in the opposite direction nearby so the pressure on the twists is offset.

 

Of course, in your network closet you can easily use cable management equipment combined with angled connectors to keep the cables neatly under control. There's really no excuse for a messy wiring closet!

 
 
 
 
 

5. Myth or Fact: It doesn't matter whether you use solid conductor cables or stranded conductor cables, so long as you use a high enough category rating on the cables.

  

The difference between solid and stranded conductors is negligible, especially in short runs. So long as the category rating is high enough for the speed of your network, either should work.

 

However, that doesn't mean you can use solid and stranded cable interchangeably. Stranded conductor cables have the advantage of being much more flexible and able to take more abuse. For that reason, stranded cable is ideal for making patch cables, which may be moved and flexed as equipment moves. 

 

Solid conductor cables tend to fit better in 110 punches, and over long runs it performs slightly better. The standard suggestion is to use solid conductor in 90% of long cable runs and 10% or less of stranded conductor cable. This makes solid the preferred cable to use in permanent installations such as through the walls of a building between the wiring closet and the drop points.

 
 
 
 
 

6. Myth or Fact: If you want to dramatically improve the speed of your Ethernet network, you should use all shielded, plenum rated cables.

 

Myth! Neither shielding nor plenum rating will dramatically improve the speed of a network, though both shielding and plenum rating have their uses. The shielding on a cable helps to protect it from electromagnetic interference (EMI). In some applications, like radio stations, power stations and factories where high-power equipment may be running, EMI can be a big problem. 

 

In those situations, shielding doesn't merely help, it is essential (and yes, it does dramatically increase the speed in those situations, but only because the speed without shielding would be dramatically slower). In all other situations, shielding doesn't do anything but cost more money, and it may actually hurt a network if the shield isn't properly grounded at both ends.

 

As for plenum rating, this has to do with the material that the cable jacket is made out of. Plenum rated cables are specially designed to self-extinguish if there is a fire, thereby preventing the fire from "jumping floors" or burning through the air ducts where the cables are often run. This has nothing to do with how the cable performs. 

 

In some buildings, such as high-rise offices, schools, and hospitals, the local fire codes requires plenum rated cable because the occupants may not be able to escape as quickly in the event of a fire. But if your fire code doesn’t require this, you're better off seeking standard Ethernet cables.

 
 
 
 

Also, check our text and video tips on modular and networking products. L-com offers a plethora of Ethernet related cables and components, including panel mount couplers, patch panels, switches,  and other adapters.     

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