HP 200 Series Services And Applications page 302

Frame Relay Network Design: Fleet Call, Inc.
Network Topology
The backbone sites are equipped with a larger network router that
concentrates the lines from all the tail sites and also provides a connection
to the backbone network. The backbone router will also concentrate the
local LAN subnets within the building itself.
This network design offers several advantages. By using routers at each
remote site, the network traffic will be filtered and localized to the specific
workgroups. Two levels of filtering are used: first, at the local site itself, and
second, at the backbone. Thus, any network traffic with destinations within
a particular office, or within offices in that specific market area, will be
filtered from transmission onto the backbone. This preserves the backbone
bandwidth for essential traffic.
Second, using the backbone/tail-site approach, the cost of the wide area
links can be optimized. The tail-site links will fall principally within a LATA
(Local Access and Transport Area—the service area) boundary, allowing a
local operating company, such as Pacific Bell, to provide the link service.
The link costs are usually based on distance between connection points, and
the short intra-LATA links from the backbone to the tail sites will be much
more cost effective than providing multiple inter-LATA links directly to the
data center on the backbone. Since network traffic will be concentrated at
the backbone router, Fleet Call can take advantage of lower-bandwidth lines
out to the tail sites and higher-bandwidth lines on the backbone itself.
In evaluating an appropriate backbone technology for Fleet Call, the
following basic requirements were considered:
high-bandwidth transmission media
built-in link redundancy
easy growth and reconfiguration
cost-effective operation
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