What is Network Cabling?

Cable is the medium through which information usually moves from one network device to another. There are several types of cable which are commonly used with LANs. In some cases, a network will utilize only one type of cable, other networks will use a variety of cable types. The type of cable chosen for a network is related to the network's topology, protocol, and size. Understanding the characteristics of different types of cable and how they relate to other aspects of a network is necessary for the development of a successful network.
The following sections discuss the types of cables used in networks and other related topics.

• Unshielded Twisted Pair (UTP) Cable
• Shielded Twisted Pair (STP) Cable
• Coaxial Cable
• Fiber Optic Cable
• Cable Installation Guides
• Wireless LANs
• Unshielded Twisted Pair (UTP) Cable

Unshielded twisted pair

Category	Speed	Use
1	1 Mbps	Voice Only (Telephone Wire)
2	4 Mbps	LocalTalk & Telephone (Rarely used)
3	16 Mbps	10BaseT Ethernet
4	20 Mbps	Token Ring (Rarely used)
5	100 Mbps (2 pair)	100BaseT Ethernet
	1000 Mbps (4 pair)	Gigabit Ethernet
5e	1,000 Mbps	Gigabit Ethernet
6	10,000 Mbps	Gigabit Ethernet

1.Unshielded Twisted Pair Connector

The standard connector for unshielded twisted pair cabling is an RJ-45 connector. This is a plastic connector that looks like a large telephone-style connector (See fig. 2). A slot allows the RJ-45 to be inserted only one way. RJ stands for Registered Jack, implying that the connector follows a standard borrowed from the telephone industry. This standard designates which wire goes with each pin inside the connector.

2.Shielded Twisted Pair (STP) Cable

Although UTP cable is the least expensive cable, it may be susceptible to radio and electrical frequency interference (it should not be too close to electric motors, fluorescent lights, etc.). If you must place cable in environments with lots of potential interference, or if you must place cable in extremely sensitive environments that may be susceptible to the electrical current in the UTP, shielded twisted pair may be the solution. Shielded cables can also help to extend the maximum distance of the cables.

Shielded twisted pair cable is available in three different configurations:

1. Each pair of wires is individually shielded with foil.
2. There is a foil or braid shield inside the jacket covering all wires (as a group).
3. There is a shield around each individual pair, as well as around the entire group of wires (referred to as double shield twisted pair).

3.Coaxial Cable

Coaxial cabling has a single copper conductor at its center. A plastic layer provides insulation between the center conductor and a braided metal shield (See fig. 3). The metal shield helps to block any outside interference from fluorescent lights, motors, and other computers.

4.Coaxial Cable Connectors

The most common type of connector used with coaxial cables is the Bayone-Neill-Concelman (BNC) connector (See fig. 4). Different types of adapters are available for BNC connectors, including a T-connector, barrel connector, and terminator. Connectors on the cable are the weakest points in any network. To help avoid problems with your network, always use the BNC connectors that crimp, rather screw, onto the cable.

5.Fiber Optic Cable

Fiber optic cabling consists of a center glass core surrounded by several layers of protective materials. It transmits light rather than electronic signals eliminating the problem of electrical interference. This makes it ideal for certain environments that contain a large amount of electrical interference. It has also made it the standard for connecting networks between buildings, due to its immunity to the effects of moisture and lighting.

Fiber optic cable

Specification	Cable Type
10BaseT	Unshielded Twisted Pair
10Base2	Thin Coaxial
10Base5	Thick Coaxial
100BaseT	Unshielded Twisted Pair
100BaseFX	Fiber Optic
100BaseBX	Single mode Fiber
100BaseSX	Multimode Fiber
1000BaseT	Unshielded Twisted Pair
1000BaseFX	Fiber Optic
1000BaseBX	Single mode Fiber
1000BaseSX	Multimode Fiber

6.Wireless standards and speeds

The Wi-Fi Alliance is a global, non-profit organization that helps to ensure standards and interoperability for wireless networks, and wireless networks are often referred to as WiFi (Wireless Fidelity). The original Wi-Fi standard (IEEE 802.11) was adopted in 1997. Since then many variations have emerged (and will continue to emerge). Wi-Fi networks use the Ethernet protocol.

Standard	Max Speed	Typical Range
802.11a	54 Mbps	150 feet
802.11b	11 Mbps	300 feet
802.11g	54 Mbps	300 feet
802.11n	100 Mbps	300+ feet

Network topology

-Is the study of the  arrangement or mapping of the element link,nodes etc.

Physical topology

Any given node in the LAN will have one or more links to one or more other nodes in the network and the mapping of these link and nodes onto a graph result in a geometrical shape that determines the physical topology of the network.

Logical topology

The mapping of the flow of data

1.       Linear bus

2.       Star

3.       Star-wired ring

4.       Tree

1.Linear bus

-continuos length of cable that connects TWO or MORE device together

BUS = backbone network

-only ONE computer can transfer info at a time

-The info moves through the entire length of a cable

each END of the cable must have a

TERMINATOR.

-device that absorbs the signals transmitted on a network cable

prevents signals from being bounced back along the cable and causing interference...

advantages

~ simple

~each computer is connected to a single length of cable

~often connected to a small area (office)

disadvantages

~expansion is exisiting can be difficult ! > cable must be broken to extend the cable and attach to the additional computer

~thus, other computer cannot exchange info

~if the computer is MALFUNCTIONING and causing problem on the cable > entire network will be infected !

~expensive ! most use a single piece of copper cable to connect its computers together

2.star

-central point on the network = HUB

-currently connectd to 4, 8 or 16 computers

-length between computers cable and hub must be LESS than 100m

advantages

~easy as long as there is a FREE port on the HUB

~no need to shut down when adding another computers

~when error occured, other computers not affected !

disadvantage

~hub fails = information can no longer transfer from one computer to another

~the COST is more implement than other types of network

~LARGE amount of cable is used because computer on the network must be independently connected to the hub

3.RING

-travels in ONE direction only

-information in transfer located next to it

-if it is not adress to the computer.then info will send to the next computer and so on

there is no beginning and end

Advantages

~   This type of network topology is very organized. Each node gets to send the data when it receives an   empty token. This helps to reduces chances of collision. Also in ring topology all the traffic flows in only one  direction at very high speed.

~   Even when the load on the network increases, its performance is better than that of Bus topology.

~  There is no need for network server to control the connectivity between workstations.

~   Additional components do not affect the performance of network.

~  Each computer has equal access to resources.

Disadvantages

~  Each packet of data must pass through all the computers between source and destination. This makes it slower than Star topology.

~  If one workstation or port goes down, the entire network gets affected.

~   Network is highly dependent on the wire which connects different components.

~  MAU’s and network cards are expensive as compared to Ethernet cards and hubs.

4.TREE

-Same with star and linear bus

-One type of star topology

-Also have terminator

-Hybrid(combine of 2 topology)

Advantage

Point to point for individual segments

Disadvantages

More difficult to configure and wire

Backbone line break,the intire segment goes down