Foundry Networks OSI - Manual (Page 23)

February 2003 © 2003 Foundry Networks, Inc. 3-1
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Introduction to Switching
A network switch allows simultaneous transmission of multiple packets via
non-crossbar switching. This means that it can partition a network more
efficiently than bridges or routers. The switch has, therefore, been
recognized as one of the most important building blocks for today’s
networking technology.
When performance bottlenecks are caused by congestion at the network
access point (such as the network card for a high-volume file server), the
device experiencing congestion (server, power user or hub) can be attached
directly to a switched port. And, by using full-duplex mode, the bandwidth
of the dedicated segment can be doubled to maximize throughput.
When networks are based on repeater (hub) technology, the maximum
distance between end stations is limited. For Ethernet, there may be up to
four hubs between any pair of stations; for Fast Ethernet, the maximum is
two. This is known as the hop count. However, a switch turns the hop
count back to zero, so subdividing the network into smaller and more
manageable segments, and linking them to the larger network by means of
a switch, removes this limitation.
A switch can be easily configured in any Ethernet or Fast Ethernet
network to significantly boost bandwidth while using conventional cabling
and network cards.