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Shared Ethernet works extremely well
under ideal conditions. When the number of devices trying to
access the network is low, the number of collisions stays well
within acceptable limits. However, when the number of users on the
network increases, the increased number of collisions can cause
intolerably bad performance. Bridging was developed to help ease
performance problems that arose from increased collisions.
Switching evolved from bridging to become the key technology in
modern Ethernet LANs.
Collisions and broadcasts are
expected events in modern networking. They are, in fact,
engineered into the design of Ethernet and higher layer
technologies. However, when collisions and broadcasts occur in
numbers that are above the optimum, network performance suffers.
The concept of collision domains and broadcast domains is
concerned with the ways that networks can be designed to limit the
negative effects of collisions and broadcasts. This module
explores the effects of collisions and broadcasts on network
traffic and then describes how bridges and routers are used to
segment networks for improved performance.
Students completing this module should be able to:
- Define bridging and switching.
- Define and describe the
content-addressable memory (CAM) table.
- Define latency.
- Describe store-and forward and
cut-through switching modes.
- Explain Spanning-Tree Protocol (STP).
- Define collisions, broadcasts,
collision domains, and broadcast domains.
- Identify the Layer 1, 2, and 3
devices used to create collision domains and broadcast domains.
- Discuss data flow and problems
with broadcasts.
- Explain network segmentation and
list the devices used to create segments.
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