In order for every computer and network to be able to communicate with each other there is a need for devices which facilitate the communications. These are Routers, Bridges, Repeaters and Gateways.

Routers - Routers connect LANs at the Network layer of the OSI model. Routers are used for the following reasons (10):

• to effeciently direct packets from one network to another, reducing excessive traffic
• to join a neighbouring or distant networks
• to connect dissimilar networks
• to prevent network bottlenecks by isolating portions of a network
• to secure portions of a network from intruders

Bridges - A bridge is a network device that connects one LAN segment to another. A Bridge is used for the following reasons (10):

• To extend a LAN when the maximum connection limit has been reached
• to segment LANs to reduce data traffic bottlenecks
• for security, to prvent unauthoised access to a LAN