A side bene?¬?t of the bandwidth ef?¬?ciency of link-state routing protocols is that they facilitate
network scalability better than either static routes or distance vector protocols. When compared to
the limitations of static routes or distance vector protocols, you can easily see that link-state
routing is best in larger, more complex networks, or in networks that must be highly scalable.
Initially con?¬?guring a link-state protocol in a large network can be challenging, but it is well worth
the effort in the long run.
Link-state protocols do, however, have the following limitations:
?– They require a topology database, an adjacency database, and a forwarding database, in
addition to the routing table. This can require a signi?¬?cant amount of memory in large or
complex networks.
?– Dijkstra??™s algorithm requires CPU cycles to calculate the best paths through the network. If
the network is large or complex (that is, the SPF calculation is complex), or if the network is
unstable (that is, the SPF calculation is running on a regular basis), link-state protocols can
use signi?¬?cant CPU power.
?– To avoid excessive memory or CPU power, a strict hierarchical network design is required,
dividing the network into smaller areas to reduce the size of the topology tables and the length
of the SPF calculation.
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