Dedicated, full-time connectivity is provided by point-to-point
serial links.
Connections are
made using the router's synchronous serial ports with typical
bandwidth use of up to 2 Mbps (E1) available through the use of a CSU/DSU.
Different encapsulation methods at the data link layer provide
flexibility and reliability for user traffic. Dedicated lines of this
type are ideal for high-volume environments with a steady-rate traffic
pattern. Use of available bandwidth is a concern because you have to
pay for the line to be available even when the connection is idle.
Dedicated lines also are referred to as point-to-point links
because their established path is permanent and fixed for each remote
network reached through the carrier facilities. A point-to-point link
provides a single, pre-established WAN communications path from the
customer premises through a carrier network, such as a telephone
company, to a remote network. The service provider reserves
point-to-point links for the private use of the customer. Figure
illustrates a
typical point-to-point link through a WAN. Point-to-point is
used for direct physical links or for virtual links consisting of
multiple physical links.
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Threaded
Case
Study |
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Washington
Project: Dedicated Lines
The
Washington School District should use dedicated
lines (T1) for its WAN core. You need to determine
how many links this will involve and what kinds of
equipment must be purchased (such as CSUs/DSUs).
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