| Since the inception of local-area
networks (LANs) in the 1970s, numerous LAN technologies have come
and gone. The Attached Resource Computer Network (ARCNet), a
coaxial-based LAN technology using a token-bus access method, is one
example of an essentially defunct LAN technology. ARCNet was the
basis for some of the earliest office networks in the 1980s. ARCNet
(2-Mbps) was easy to deploy in an
office with only a few workstations. ARCNet (2-Mbps) enjoyed limited success
on the market because higher-speed technologies such as
10-megabit-per-second (Mbps) Ethernet and 4-Mbps Token Ring were
introduced soon after its inception. With the higher-bandwidth
capacity of these newer technologies and the rapid development of
high-speed workstations, ARCNet was quickly phased out of the
marketplace.
LAN technologies such as Ethernet,
Token Ring, and Fiber Distributed Data Interface (FDDI) have managed
to remain in existence.
The legacy networks (Ethernet, Token Ring, FDDI) continue to be
utilized as distribution and backbone technologies for both
manufacturing and office environments. But, like ARCNet, even these
technologies see higher-speed networks such as Fast Ethernet and ATM
crowding them out. However, due to the wide installation and use of legacy systems, they will likely remain in place for many more years.
Users
will replace Ethernet and Token Ring in phases as applications
demand more bandwidth.
In this chapter, you will learn about
legacy, or standard Ethernet, as well as Fast Ethernet and Gigabit
Ethernet. In addition, you will learn how the access methods
operate, some of the physical characteristics of each, and various
frame formats and address types.
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