In the early days of networking,
primarily research universities and the military experimented with
computer networks. The term campus network derives from networks
built on university campuses. Today, the term is used more broadly
to include networks that span corporate "campuses." Campus
size is an important factor in network design. A large campus has
several or many collocated buildings, a medium campus is one or
several collocated buildings, while a small campus has one
building.
Historically, campus networks consisted of a single LAN to which new
users were added simply by connecting anywhere on the LAN. Because
of distance limitations of the networking media, campus networks
usually were confined to a building or several buildings in close
proximity to each other as shown in Figure .
The LAN was a physical network that connected the devices. In the
case of Ethernet, all the devices shared the available (half-duplex)
10-megabit-per-second (Mbps) network. Because of the Carrier-Sense Multiple-Access w/
Collision Detection (CSMA/CD) access method used by
Ethernet, the whole LAN was considered a single collision domain.
You may have noticed that few design
considerations were needed to provide user access to the network
backbone. Because of the inherent limitations of Ethernet,
physically adjacent users were sometimes connected to a single
access device to minimize the number of taps into the backbone.
Although hubs met this requirement and became standard devices for
multiple network access, as shown in Figure ,
increased user demand quickly slowed the performance of the network.
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