Everything you ever wanted to know about network cabling technology

• Published: 18 Jul 2005

Technology changes fast - so do data center networking options. By now, you've all heard the terms. Cabling. Networking. CAT-3. CAT-5e. RJ-45. Unshielded twisted pair. Shielded twisted pair. Coaxial cable. Fiber optics. By the end of it, the reaction can be: shielded twisted what? Chances are what you learned in IT school no longer applies. Cabling standards are reviewed and changed every 5 to 10 years., so we've checked with our networking expert Carrie Higbie, Global Network Applications Market Manager for Siemon, and created this valuable up-to-date basics guide.

First things first.

In order to understand anything cable-related, you need to understand the lingo.

 

The Basics

• UTP Cabling (Unshielded Twisted Pair)

  This cable has four pairs of wires inside the outer sleeve. The amount of twists per inch vary to prevent interference from the other twisted wires. This type of wiring also comes in different types. However, with advancing technology, some of the older categories of cabling are no longer approved.

  
  

  Category	Standard data rate	Usual application
  CAT 1	Up to 1 Mbps (1 MHz)	analog voice (POTS) Integrated Services Digital Network Basic Rate Interface in ISDN Doorbell wiring Dead - no longer supported
  CAT 2	4 Mbps	Mainly used in the IBM Cabling System for Token Ring networks Dead - no longer supported
  CAT 3	16 Mbps	Used predominantely for POTS Voice
  CAT 4	20 Mbps	No longer approved Was used in 16 Mbps Token Ring
  CAT 5	100 Mbps	100 Mbps TPDDI 155 Mbps ATM No longer approved; replaced by 5E Seen in legacy environments
  CAT 5E	1000 Mbps (10000 Mbps prototype)	100 Mbps TPDDI 155 Mbps ATM Gigabit Ethernet Offers better near-end crosstalk than CAT 5
  CAT 6	250 MHz	Super-fast broadband applications Vendor recommended, minimum required and most popular cabling for new installs
  CAT 6E	500 MHz	Required for 10 Gigabit Ethernet (10GBASE-T)
  CAT 7 (ISO Class F)	1 GHz per pair with Siemon connector	Full-motion video Teleradiology Required for 10 Gigabit Ethernet (10GBASE-T) Government and manufacturing environments Shielded system

  UTP cables are connected with the RJ(Registered Jack)-45 connector. It looks like a slightly large telephone jack connector. 100BaseT is the shorthand for this type of cable carrying Ethernet.

  Drawbacks: UTP cables are vulnerable to radio and electrical frequencies. That brings us to...

   

• STP Cabling (Shielded Twisted Pair)

  STP is wonderful when there's a possibility of electrical interference. But, the extra shielding makes it bulky. 100BastTX is the shorthand for STP carrying Ethernet. Next:

   

• Coaxial Cabling

  Coaxial cables use a single copper conductor at the center, insulated by a plastic layer and a braided metal shield, which blocks interference. Coaxial cables are hard to install, but can support greater cable lengths than twisted pair. There are two types:

  •  

  • Thin coaxial (Thinnet)

    10Base2 refers to thin coaxials carrying Ethernet. The '2' is for the approximate 200 meters maximum length.

     

  • Thick coaxial (Thicknet)

    10Base5 is for (you guessed it) thick coaxials carrying Ethernet. The '5' is for the approximate max length of 500 meters. This type has an extra plastic layer to keep moisture out. Downsides: it doesn't bend easily, and is hard to install.

  Coaxial cables are connected with BNC (Bayone-Neill-Concelman) connectors. Since the connectors are always the weakest part of a network, always use BNC connectors that crimp, not screw, onto the cable.

   

• Fiber Optic Cabling

  Fiber optics are made of a glass center with many protective layers. It's designed to transmit light, not electronic signal, so there is no problem with electrical interference. It can transmit signals further than coaxial and twisted cable, and at faster speeds. It is often used for video conferencing. 10BaseF is the standard for Fiber Optic Cable carrying Ethernet.

  Connections are made with an ST connector, which is similar to a BNC connector.

  There are various grades of fiber, but 50 micron laser optimized is the most widely used today.

The Latest News

It's important to be up-to-date on technology news to maximize the efficiency of your data center. After all, if you don't the company will find someone who does--technology is constantly changing, and businesses need to to stay current.

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Vativ Technologies unveiled a new 10 Gigabit Ethernet network offering for the data center backbone

 

Expert Advice

SearchDataCenter expert Carrie Higbie answers your cabling questions. You can also ask her your own cabling question.

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Things to consider when moving your data center
We're moving our data center to an older building in an urban area that is currently being renovated. I'm working with consultants on our cabling infrastructure, but I was wondering if you could provide me with some sort of check list of things to be aware of as we plan this move out?

 

Additional Resources

Hungry for more cabling information? Check out these links:

www.siemon.com

SearchNetworking.com