Session 32

Session 32
Date:6.7.2010

Activities:
- Discussed about three main types of network topology

• bus
• ring
• star



Bus topology

Bus networks (not to be confused with the system bus of a computer) use a common
backbone to connect all devices. A single cable, the backbone functions as a shared
communication medium that devices attach or tap into with an interface connector. A
device wanting to communicate with another device on the network sends a broadcast
message onto the wire that all other devices see, but only the intended recipient actually
accepts and processes the message. However, bus networks work best with a limited
number of devices. If more than a few dozen computers are added to a network bus,
performance problems will likely result. In addition, if the backbone cable fails, the entire
network effectively becomes unusable.

Ring Topology
In a ring network, every device has exactly two neighbors for communication purposes.
All messages travel through a ring in the same direction (either "clockwise" or
"counterclockwise"). A failure in any cable or device breaks the loop and can take down
the entire network.


Star Topology
Many home networks use the star topology. A star network features a central connection point called a "hub" that may be a hub, switch or router. Devices typically connect to the hub with Unshielded Twisted Pair (UTP) Ethernet.
Compared to the bus topology, a star network generally requires more cable, but a failure in any star network cable will only take down one computer's network access and not the entire LAN. (If the hub fails, however, the entire network also fails.)