单选题
Astute service providers realize that the continued support
of legacy X.25 and asynchronous network element using separate operations
network is cost{{U}} {{U}} 21 {{/U}} {{/U}}. For example, the
maintenance of multiple networks can require additional staff. Often, this staff
must be trained on multiple vendor technologies, sometimes requiring parallel
groups specializing in each{{U}} {{U}} 22 {{/U}} {{/U}}. Hence,
additional maintenance procedures must be maintained and administrative records
are{{U}} {{U}} 23 {{/U}} {{/U}}. The duplication of transport
facilities to carry{{U}} {{U}} 24 {{/U}} {{/U}}network traffic
is an inefficient use of resources. And not surprisingly, more technologies
installed in a central office means the necessity for more physical space, and
an increase in power connections and power consumption. Migration of
these{{U}} {{U}} 25 {{/U}} {{/U}}network elements to IP-based
DCNs is alogical strategy.