1-8 CHAPTER 1: INTRODUCTION
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BridgingThis section describes bridges and how they work.
Why Use A Bridge?
Bridges provide a way of joining two or more networks together
to form a single logical and physical network.
You can overcome various network restrictions that apply to large
individual networks by bridging smaller networks together. The
bridge remains transparent to the users of these networks.
The original networks that form the bridged network are called
network segments. The bridge learns, from network traffic, what
devices on the network can be reached via each o f its ports. It
reduces the amount of traffic on each network segment by
filtering traffic that does not need to be forwarded to it. Standard
filtering is described in Learning, Filtering And Forw arding on
page 1-12.
You can also apply custom filters to restrict communication
through the bridge. This allows you to add some se curity to your
network. Custom filtering is described in Bridge Filters on page
1-20.
Resilience can be built into a bridged network. The bridges on the
network can control the flow of traffic throughout the network.
Resilience is described in Spanning Tree Algorithm And Proto col
(STAP) on page 1-16.