Network Topology

The term network topology refers to the shape of how the computers and other network components are connected to each other. There are several different types of network topologies, each with advantages and disadvantages. In the following discussion of network topologies:

Node:
A node is a device that is connected to the network. For our purposes here, a node is the same as a computer. Network topology deals with how the nodes of a network are connected to each other.

Packet:
A packet is a message that is sent over the network from one node to another node. The packet includes the address of the node that sent the packet, the address of the node the packet is being sent to, and data.

Bus topology

The first type of network topology is called a bus, in which nodes are strung together in a line. Bus topology is commonly used for LANs.

The key to understanding how a bus topology works is to think of the entire network as a single cable, with each node "tapping" into the cable so that it can listen in on the packets being sent over that cable. If you are old enough to remember party lines, you get the idea.

In a bus topology, every node on the network can see every packet that is sent on the cable. Each node looks at each packet to determine whether the packet is intended for it. If so, the node claims the packet. If not, the node ignores the packet. This way, each computer can respond to data sent to it and ignore data sent to other computers on the network.

If the cable in a bus network breaks, the network is effectively divided intotwo networks. Nodes on either side of the break can continue to communicate with each other, but data can't span the gap between the networks, so nodes on opposite sides of the break can't communicate with each other.