Computer Science – 2.1 Networks including the internet | e-Consult

Several types of cabling are used to connect devices within a LAN, each with its own characteristics, advantages, and disadvantages. The most common types are:

1. Twisted Pair Cable (TP): This is the most common type of cabling used in LANs. It consists of pairs of wires twisted together to reduce electromagnetic interference (EMI). There are two main types:

• Unshielded Twisted Pair (UTP): The most common and least expensive type. It's susceptible to EMI and is typically used for shorter distances (up to 100 meters).
• Shielded Twisted Pair (STP): Includes a shield around each pair of wires or around the entire cable to provide protection against EMI. It's more expensive than UTP and is used in environments with high levels of electrical interference.

Advantages of TP: Relatively inexpensive, easy to install, widely available.

Disadvantages of TP: Susceptible to EMI (especially UTP), limited bandwidth (depending on category), shorter distance limitations.

2. Fiber Optic Cable: This cable transmits data as light pulses through thin strands of glass or plastic. It offers significantly higher bandwidth and longer distances than twisted pair cable.

• Single-mode Fiber: Uses a single path of light, allowing for very long distances (tens or even hundreds of kilometers).
• Multimode Fiber: Uses multiple paths of light, suitable for shorter distances (up to a few kilometers).

Advantages of Fiber Optic: Very high bandwidth, immune to EMI, long distances.

Disadvantages of Fiber Optic: More expensive than twisted pair, more difficult to install and terminate, requires specialized equipment.

3. Coaxial Cable: This cable uses a central copper conductor surrounded by insulation, a braided metal shield, and an outer jacket. It was commonly used for older Ethernet networks (e.g., 10BASE2 and 10BASE5). It's less common now.

Advantages of Coaxial Cable: Good shielding against EMI, relatively inexpensive (compared to fiber).

Disadvantages of Coaxial Cable: Lower bandwidth than fiber, more difficult to install than twisted pair, limited distance.

In summary, the choice of cabling depends on the specific requirements of the LAN, including bandwidth needs, distance requirements, and budget constraints. TP is the most common choice for general-purpose LANs, while fiber optic cable is used for high-bandwidth applications and long distances.