Routing and bridging fundamentals

This chapter deals with both bridging (joining network segments together) and routing (sending data from one network to another). Bridging is the simpler of the two concepts, so we will cover it first.

Bridging fundamentals

Network bridging occurs at the Data link layer (Layer 2) of the OSI model and the Link layer of the Network model. A simple bridge is simple to a repeater, which extends a network segment beyond the length that would normally be allowed by amplifying the signal. One of the differences is that the two network segments connected by a bridge may use different forms of media (with repeaters, the media must be the same, so you won't see a 100-Base-T segment and a 1000 Base-T segment connected by a repeater). Another difference is that bridges use a store-and-forward mechanism to forward packets. This creates two collision domains, making it possible to add more nodes to the network without the number of collisions becoming unacceptably high...