Routing Concepts - Bay Networks Nautica 200 Reference Manual

NauticaRS Release 4.1 Reference Guide

Routing Concepts

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The cost of installing and running a network, and providing
sufficient bandwidth to communicate, has generally been
proportional to the distance over which the network extends, and
the amount of bandwidth required. Large amounts of bandwidth
can be provided easily and relatively inexpensively by local area
networks (office, department, etc.) by adding more cables and/or
equipment, providing network speeds of 10-100 megabits per
second very easily. However, interconnecting local networks at
similar speeds is prohibitively expensive, due mainly to the cost
of installing the infrastructure which can provide that level of
bandwidth.
It is therefore usual to interconnect local high-speed networks
using slower-speed links. It is likely that this will always be the
case, since it will always be cheaper to install additional
bandwidth in a localized area rather than over a wide area
network. So it is usual to select the traffic that uses the slower
wide area links and determine exactly where it is sent. This
ensures maximum throughput over the slower link. This process
is known as routing.
Techniques for routing data between high-speed LANs over
slower-speed wide area networks (WANs) have evolved over the
years, and use various media protocols. The ability to uniquely
identify the source and destination of the data is critical to allow
the success of operations across the WAN link.
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