circuit-switched technology, it is a great backup technology due to its ability to connect to
multiple locations by using the Public Switched Telephone Network (PSTN). Select ISDN if
you need a flexible backup solution or if you have a need for low-volume intermittent traffic
(e-mail).
with a shared connection, but they are costly.
depending on which QoS is purchased. ATM has emerged as one of the technologies for
integrating LANs and WANs. ATM has inherent QoS and can support any traffic type in
separate or mixed streams, delay-sensitive traffic, and nondelay-sensitive traffic.
increasingly turning to affordable DSL to expand the use of telecommuting, provide Internet-
based services, and reduce spending.
sometimes described as 24/7/365, which suggests that the network is up 24 hours a day, 7 days
a week, 365 days a year. The customer should be asked to specify availability requirements.
These requirements will help you determine how much downtime is acceptable. An uptime of
99.999% is considered high availability. The design of connectivity in the core is crucial. The
WAN core is often the most expensive and critical resource because it supports connectivity for
the whole organization. Goals for designing the core should focus on the following:
are optimized: