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Chapter 1
Introduction
This section provides you with useful Fast Ethernet, hub and switching technology background.
Fast Ethernet Technology
In July 1993, the Fast Ethernet Alliance was formed by a group of networking companies with the goal of drafting the 802.3u
100BaseT specifications of the Institute of Electrical and Electronics Engineers (IEEE). This group recognized that existing
applications and the flood of new multimedia, GroupWare, imaging, and database products could easily overwhelm a traditional
10BaseT Ethernet. In order to ensure a cost effective, simple migration from 10BaseT Ethernet to 100BaseT Fast Ethernet, the
group determined to maintain the Ethernet transmission protocol Carrier Sense Multiple Access Collision Detection (CSMA/CD),
support popular cabling schemes and to maintain the upper-layer protocols and software that already ran on LAN workstations.
Because it is compatible with all other 10Mbps Ethernet environments and uses your company's existing investment in hardware,
software, and personnel training, Fast Ethernet technology is regarded as being the inevitable market dominator. This means
that you can now start to make a cost effective, incremental migration to Fast Ethernet and rest assured that the future will offer a
vast array of low cost products to keep pace with your growing LAN needs.
Cables and Connectors
Fast Ethernet supports category 5 unshielded twisted-pair (UTP) cable and category 5 shielded twisted-pair (STP) cable.
These cables use the same RJ-45 connector as used with 10BASE-T cables wired in the same configuration.
Topology
Star topology is the fundamental structure of a Fast Ethernet LAN.
A single collision domain LAN is sufficient for users with a small number of end stations and servers.
Within a single collision domain LAN, you can use one class I repeater hub or two class II repeater hubs to connect your end
stations and servers. You can use stackable hubs to increase the total number ports within each collision domain.
A switch is used to create other collision domains within your overall LAN. These collision domains are separate LANs within
your overall LAN.
A switch allows all of these collision domains to communicate with each other.
A switched line is a separate collision domain that allows you to use one Class I repeater hub or two Class II repeater hubs to
connect your end stations and servers. You can use stackable hubs to increase the total number ports within each collision
domain.
You can also dedicate a separate collision domain to heavily used servers or end stations with large bandwidth needs.
Network Diameter
The network diameter is the total length of cable between two end stations within the same collision domain.
Because of the high speed of Fast Ethernet and adherence to the EIA/TIA 568 wiring rules, the maximum diameter of a Fast
Ethernet collision domain is 205 meters.
The maximum 10Base-T Ethernet collision domain diameter is 500 meters.
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