Providing Multiple Ingress/Egress Points to Sites
Providing a diversity of circuits for disaster prevention is one main reason for not
configuring your network like the one in Figure 11.9. Just because a Frame
Relay cloud exists in one major metropolis doesn’t mean that there aren’t multiple
Frame Relay clouds extending all over the city. In Atlanta, Georgia, there are
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406 Chapter 11 • Designing and Implementing Multisite Solutions
14 major hub points circling the city to provide the backbone infrastructure.
These 14 Asynchronous Transfer Mode (ATM) nodes criss-cross the city as well
to provide a full mesh ATM network that is redundant, flexible, and has plenty of
growth.The major providers of the backbone are a shared conglomerate of the
carriers themselves, usually co-located in the existing Bell South central offices.
Because of this diversity, administrators can often get diverse routing of carrier
solutions despite originating out of the same physical building.The circuits
then go to different central offices, which connect to the different hubs across the
city. Figure 11.10 shows an example of providing such route diversity.