Page 17-1

17 Configuring Bridging

Parameters

This chapter describes how to configure and maintain bridging parameters. Bridges are
devices that interconnect LANs using one (or more) of the available standards such as trans-
parent bridging, source route bridging, or source route to transparent bridging. Bridges prima-
rily operate at Layer 2 of the OSI reference model, which controls data flow, transmission
errors, physical addressing, and access to physical medium.
There are different types of bridging that are used to manage networks:
•Transparent Bridging. Used mainly in Ethernet environments, packets are usually forwarded
without any changes being made to the packet. An ethernet environment is shown in the
diagram below:
•Source Route Bridging. Used mainly in Token Ring environments, packets are transmitted
along routes predetermined by explorer frames sent along multiple paths. Source Route
Bridging modifies the routing information of the packet as it traverses the network. A
token ring environment is shown in the diagram below:
Segment 1
Transparent Bridge
Segment 2
Segment 1 Segment 2
Source Route Bridge