CABLES and PROTOCOLS: SUGGESTED SOLUTIONS

Network Cable Types

1. Write short notes on different cable types that can be used for a network, with emphasis on the differences between each.

  1. Coaxial Cable
    • A single copper conductor at the center, with a braided metal shield
      separated by a plastic layer
    • The metal shield insulates the cable from interference
    • There are basically two types.
      • Thin Coaxial or thinnet - 10Base2 in Ethernet networks 
        maximum length 200m / 10 Mbps
      • Thick Coaxial or thicknet - 10Base5 in Ethernet networks 
        maximum length 500m / 10 Mbps
    • Connectors used
      • Most commonly used connector is call BNC connector.
        • T-connector
        • Barrel-connector
        • Terminator
    • Less susceptible to interference

    • Needs to be terminated and either end
Coaxial Cable
 
 
BNC Connector
  1. Unshielded Twisted Pair (UTP)
    • Four twisted pairs of wires inside a plastic case
    • Widely used and cheap.
    • 10BaseT in Ethernet (10Mbps)
    • Connectors used are named RJ-45
    • More susceptible for interference than co-axial cables.
UTP Cable
 
RJ-45 Connector
  1. Shielded Twisted Pair (STP)
    • Extra shielding and hence less susceptible to interference and noise
    • Bulkier than UTP because of the shielding and takes more space.
    • More expensive.
    • Mostly used in Token ring networks
 
  1. Fiber Optic
    • Consists of a center glass core surrounded by several layers of protective materials.
    • Transmits light instead of electrical signals.
    • 10BaseF in Ethernet
    • Has the ability to transmit signals over much longer distances
    • Uses ST (barrel shaped) and SC connectors (squared face)
    • Immune to electro-magnetic interference.
    • More expensive than other cable types.
    • Difficult to connect
    • Robust and takes less space.
Fiber Optic Cable

2. List the different categories of cables that are specified (mainly for UTP cables), their data rates and uses.

These are specified by EIA/TIA 568B and ISO/IEC IS11801

Category Speed Uses
Category 1/2 upto 4Mbps Suited mostly for voice - not use for data networking
Category 3 10 Mbps (can support 16 Mbps) Mostly used for backbone cabling to support voice and low speed data communication.
Category 4  upto 16 Mbps runs upto 100m but considered obsolete
Category 5 100 Mbps operates at 100 MHz, for high speed networks
Category 5e 155 Mbps Enhanced specification targeted to support Gigabit Ethernet
Category 6 1000 Mbps operates at 250 MHz - for Gigabit Ethernet and ATM at extended distances
Category 7 upto 2.4 Gbps operate at a maximum frequency of 600 MHz

3. Construct a wiring diagram for UTP cables that can be used to:
a) connect two dissimilar devices   (eg a PC NIC and a hub)
Use a Straight Through cable with Pin-to-Pin connections

b) connect two similar devices   (eg a hub to a hub, or a PC NIC to another NIC)
Use a CrossOver cable. Connect TD and RX pairs and preserve polarity

Click HERE for a completed Wiring Diagram
Click HERE for a more detailed discussion of UTP cables for Ethernet.

Network Protocols

4. Write short notes on the following protocols (you may refer to your notes and the internet)...
  1. TCP/UDP
  2. IP
  3. IPX
  4. NetBEUI
  5. Ethernet
  6. Token Ring
  7. ATM (Asynchronous Transfer Mode)
  8. NCP
  9. SMB
  10. NetBIOS