Domain 1.0
Media and Topologies – 20%

1.1 Recognize the following logical or physical network topologies given a schematic diagram or description:

• Star/hierarchical
• Bus
• Mesh
• Ring
• Wireless

Star/Hierarchical

A star physical topology usually doesn’t look like a star, except on paper. The mark of this topology is what you’ll find at the center, namely a centralized hub or switch to which are connected all the network’s nodes/devices. This topology is commonly used for 10BASE5, 10BASE-T or 100BASE-TX

PROS:

• Cabling is inexpensive and easy.
• Very reliable and easy to manage and maintain.
• Locating and repairing bad cables is easier.
• Network growth is easily accommodated.

CONS:

• All nodes on the network receive the same signal, dividing the bandwidth.
• Maximum number of computers is 1,024 on a Local Area Network (LAN).
• Maximum Unshielded Twisted Pair (UTP) cable length is 100 meters (about 330 ft).
• Permissible distance between computers is 2.5 meters.

Bus

A bus physical topology means that all of the devices on the network are connected to a common backbone. The signal is sent along the bus in both directions on most buses, but some buses are unidirectional. This topology can be used for 10BASE5, 10BASE2 or 10BROAD36.

PROS:

• Not many. Good for small networks and quick or temporary installations.

CONS:

• This topology is VERY difficult to troubleshoot. (Just try and locate a break in the cable, or the device causing the fault when the entire network is down.)
• In a physical bus topology, when one device fails, the entire LAN fails.

Mesh

In a mesh physical topology, every device on the network is connected to every other device on the network. This topology is most commonly used in Wide Area Network (WAN) configurations

PROS:

• Provides redundancy and it’s always easy to find a quick route through the network.

CONS:

• Quite expensive and complicated, both of which make implementation very difficult.