Chapter 7. Area Design
Areas, as discussed in Chapter 2, are used to control the size of the link state database and the negative impact of flooding and SPF calculations on network bandwidth and router resources. They accomplish this control by breaking up the network into individual SPF domains. That is, rather than having a network in which every router has an identical link state database and in which the SPF process computes a single shortest-path tree spanning the entire routing domain, the routing domain is broken up into multiple SPF domains. The link state databases must be identical only within these individual areas, and the area borders are defined by the scope of the individual SPF trees calculated from these area databases.
In order ...
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