Tuesday, 9 October 2012

How to Reconize Network Cable Category

Cables are commonly used to carry communication signals within LAN. There are three common types of cable media that can be used to connect devices to a network and they are coaxial cable, twisted-pair cable, and fiber-optic cable.

  • Coaxial cable

Coaxial cable looks similar to the cable used to carry TV signal. A solid-core copper wire runs down the middle of the cable. Around that solid-core copper wire is a layer of insulation, and covering that insulation is braided wire and metal foil, which shields against electromagnetic interference. A final layer of insulation covers the braided wire.
There are two types of coaxial cabling: thinnet and thicknet. Thinnet is a flexible coaxial cable about ¼ inches thick. Thinnet is used for short-distance. Thinnet connects directly to a workstation’s network adapter card using a British Naval Connector (BNC). The maximum length of thinnet is 185 meters. Thicknet coaxial is thicker cable than thinnet. Thicknet cable is about ½ inch thick and can support data transfer over longer distances than thinnet. Thicknet has a maximum cable length of 500 meters and usually is used as a backbone to connect several smaller thinnet-based networks.
The bandwidth for coaxial cable is 10 mbps (mega bits per second).

  • Twisted Pair Cable

Twisted-pair cable is the most common type of cabling you can see in todays LAN networks. A pair of wires forms a circuit that can transmit data. The pairs are twisted to provide protection against crosstalk, the noise generated by adjacent pairs. When a wire is carrying a current, the current creates a magnetic field around the wire. This field can interfere with signals on nearby wires. To eliminate this, pairs of wires carry signals in opposite directions, so that the two magnetic fields also occur in opposite directions and cancel each other out. This process is known as cancellation. Two Types of Twisted Pairs are Shielded Twisted Pair (STP) and Unshielded Twisted Pair (UTP).
Unshielded twisted-pair (UTP) cable is the most common networking media. Unshielded twisted-pair (UTP) consists of four pairs of thin, copper wires covered in color-coded plastic insulation that are twisted together. The wire pairs are then covered with a plastic outer jacket. The connector used on a UTP cable is called a Registered Jack 45 (RJ-45) connector. UTP cables are of small diameter and it doesn’t need grounding.  Since there is no shielding for UTP cabling, it relies only on the cancellation to avoid noise. 
UTP cabling has different categories. Each category of UTP cabling was designed for a specific type of communication or transfer rate. The most popular categories in use today is 5, 5e and 6, which can reach transfer rates of over 1000 Mbps (1 Gbps).

  • Optical Fiber Cabling

Optical Fiber cables use optical fibers that carry digital data signals in the form of modulated pulses of light. An optical fiber consists of an extremely thin cylinder of glass, called the core, surrounded by a concentric layer of glass, known as the cladding. There are two fibers per cable—one to transmit and one to receive. The core also can be an optical-quality clear plastic, and the cladding can be made up of gel that reflects signals back into the fiber to reduce signal loss. There are two types of fiber optic cable: Single Mode Fibre (SMF) and Multi Mode Fibre (MMF). 1. Single Mode Fibre (SMF) uses a single ray of light to carry transmission over long distances. 2. Multi Mode Fibre (MMF) uses multiple rays of light simultaneously with each ray of light running at a different reflection angle to carry the transmission over short distances.

Category Of Cables 

Almost anyone who has connected to the Internet through a broadband connection (like cable or DSL) has used an Ethernet cable to do it. You have connected your PC’s network interface card (NIC) to your cable modem, DSL modem, or home router with an Ethernet cable.  Because of the commonality of this, if I say “use an Ethernet cable” you have a picture of a cable in your mind. However, you should know that there is more than one type of Ethernet cable.

  • Category 1 (CAT 1, Level 1)

Category 1 cabling (CAT1), one of five grades of UTP cabling described in the EIA/TIA-586 standard, is used for telephone communications and is not suitable for transmitting data.
Analog voice (POTS) Basic Rate Interface in ISDN, Doorbell wiring
Maximum Rate of Data: Up to 1Mbps (1 MHz)

  • Category 2 (CAT 2, Level 2)

Category 2 cables, also known as Cat 2, or Level 2, is a grade of unshielded twisted pair cabling designed for telephone and data communications. The maximum frequency suitable for transmission over Cat 2 cable is 4 MHz, and the maximum bandwidth is 4Mbit/s. Cat 2 cable contains 4 pair of wires, or eight wires total. Though not an official category standard established by TIA/EIA, Category 2 has become the de facto name given to Level 2 cables originally defined by Anixter International, the distributor. Mainly used in the IBM cabling system for Token Ring networks.
Maximum Rate of Data: Up to 4Mbps (4 MHz)
  • Category 3 (CAT 3)

Cat 3 cable is an unshielded twisted pair cable (UTP). UTP is used in scenarios where electromagnetic interference is of little concern; the wire architecture shields the individual wires from crosstalk. In using UTP, network architecture spending can remain low while offering sufficient reliability for short- to mid-range signal transmission.

Voice Transmission Cat 3 cables are prominently used as telephone wiring, as it works especially well for voice transmission. Cat 3 is capable of supporting frequencies up to 16 MHz; this is more than sufficient for telephone calls.
This category was widely used among computer network administrators in the 1990s.

  • Category 4 (CAT 4)

Cat 4 was mainly used in token ring networks and the cable consists of four unshielded twisted-pair (UTP) wires, with a data rate of 16 Mbit/s, and performance of up to 20 MHz.
  • Category 5 (CAT 5 )

CAT5 (also, CAT 5) is an Ethernet network cable standard defined by the Electronic Industries Association and Telecommunications Industry Association (commonly known as EIA/TIA). CAT5 is the fifth generation of twisted pair Ethernet technology and the most popular of all twisted pair cables in use today.
CAT5 cable contains four pairs of copper wire. It supports Fast Ethernet speeds (up to 100 Mbps). As with all other types of twisted pair EIA/TIA cabling, CAT5 cable runs are limited to a maximum recommended run length of 100m (328 feet).
  • Category 5 (CAT 5e)

This category is an enhanced version of Cat 5 that prevents interference between one unshielded twisted pair to another twisted pair running in parallel within the same cable (Far End Crosstalk - FEXT).
As network and telecommunication applications become more complex, increased data transport is required to accommodate fast data transfer speeds. CAT 5 is typically used in Local Area Networks (LAN) and premise cabling. Category 5e cabling is an enhanced version of CAT 5 cabling. The main difference between CAT 5 and CAT 5e cabling is the specifications. The amended specifications provide full-duplex Fast Ethernet cabling. CAT 5e uses better insulation to improve attenuation and crosstalk performance. An additional plastic rib has been placed in the center of CAT 5e cabling to reduce crosstalk. A twist internal to the jack prevents untwisting and crosstalk to other wire pairs. Some of the benefits of CAT 5e interconnect include:
  • Speed: can carry speeds up to 100 Mb/second, will expand to 10 Gigabits/second in the future.
  • Bandwidth: greater bandwidth than CAT 3, 4
  • Distance: Cables support distances up to 50 ft
  • Price: CAT 5e cabling is much cheaper than fiber and coax cable
  • Reliable: the most implemented and proven standards
  • Size, weight and flexibility: smaller connectors allow for high port density, the cable is lightweight, and the jacket is flexible hp CAT 5e networking and telecommunications connectivity cables
  • Better noise immunity: twisted pair cabling and balanced transmission provide less noise

  • Category 6 (CAT 6)

Short for Category 6, Cat-6 network cabling is used as the cabling infrastructure for 10BASE-T (Ethernet), 100BASE-TX (Fast Ethernet),1000BASE-T (Gigabit Ethernet, or GbE) and 10GBASE-T (10-Gigabit Ethernet, or 10 GbE) networks. The Cat 6 standard provides performance of up to 250MHz (500 MHz for the newer Cat 6a standard) and can be used up to a maximum length of 100 meters (55 meters for 10GBASE-T networks).
The Cat 6 standard was first released in 2002 as part of the Telecommunications Industry Association’s TIA/EIA-568-B.2-1 document specification.  Cat 6 is backward compatible with the Cat 3, Cat 5 and Cat 5e cable standards, and as with Cat 5 and Cat 5e cabling, Cat 6 cables consist of four unshielded twisted pairs (UTP) of copper wire terminated by RJ45connectors. 
In addition to its support for higher performance than the Cat 5 specification, the Cat 6 standard also includes more stringent specifications for crosstalk and system noise. While Cat 6 is expected to supersede both Cat 5 and Cat 5e cabling in the future, all three types of cables continue to be popular for use in network installations.
Category 6 cables are by definition a twisted pair, 100 Ohm cable which has transmission parameters specified up to 250 MHz, Category 6 cable is also a recognized cable in addition to those specified in 4.2.2 of ANSI/TIA/EIA-568-B.2.

  • Category 6e (CAT 6e)

Category 6E cables also exceed TIA/EIA-568-B.2-1 Category 6 and ISO/IEC 11801 Class E performance requirements by substantial margins on all parameters. The AMP NETCONNECT Category 6 System complies with all of the performance requirements for current and proposed applications such as Gigabit Ethernet (1000BASE-Tx), 10 and 100BASE-Tx, token ring, 155 Mbps ATM, 100 Mbps TP-PMD, ISDN, analog and digital video, and analog and digital voice

  • Category 7 (CAT 7)

Category 7 cable (Cat 7), (ISO/IEC 11801:2002 category 7/class F), is a cable standard for Ethernet and other interconnect technologies that can be made to be backwards compatible with traditional Cat 5 and Cat 6 Ethernet cable. Cat 7 features even more strict specifications for crosstalk and system noise than Cat 6. To achieve this, shielding has been added for individual wire pairs and the cable as a whole.

The Cat 7 cable standard has been created to allow 10 Gigabit Ethernet over 100 m of copper cabling (also, 10-Gbit/s Ethernet now is typically run on Cat 6a). The cable contains four twisted copper wire pairs, just like the earlier standards. Cat 7 can be terminated either with 8P8C compatible GG45 electrical connectors which incorporate the 8P8C standard or with TERA connectors. When combined with GG45 or TERA connectors, Cat 7 cable is rated for transmission frequencies of up to 600 MHz.
Category 7a (or Augmented Category 7) operates at frequencies up to 1000 MHz, suitable for multiple applications in a single cable including 40 Gigabit Ethernet, 100 Gigabit Ethernet, and CATV (862 MHz). Simulation results have shown that 40 Gigabit Ethernet is possible at 50 meters and 100 Gigabit Ethernet is possible at 15 meters. Mohsen Kavehrad and researchers at Pennsylvania State University believe that either 32 nm or 22 nm circuits will allow for 100 Gigabit Ethernet at 100 meters.
 This cable type is a standard for Ethernet and other interconnect technologies, that are backward compatible with traditional Cat 5 and Cat 6 Ethernet cables. As it has more strict specifications for crosstalk and system noise than Cat 6 and Cat 5e, its cables and the wires, within are completely shielded. the cable contains four twisted copper wire pairs and supports up to 600Mhz.