?– Because each router has a complete and synchronized picture of the network, it is dif?¬?cult for
routing loops to occur.
?– Because LSPs are sequenced and aged, routers always base their routing decisions on the
latest set of information.
?– With careful network design, the link-state database sizes can be minimized, leading to
smaller SPF calculations and faster convergence.
Router Destination Next Hop Cost
C 10.0.0.0 A 1
185.134.0.0 B 1
192.168.157.0 D 1
D 10.0.0.0 B 2
10.0.0.0 C 2
185.134.0.0 B 1
192.168.33.0 C 1
Table 3-2 Link-State Routing Database (Continued)
Reviewing Dynamic Routing 121
The link-state approach to dynamic routing can be useful in networks of any size. In a welldesigned
network, a link-state routing protocol enables your network to gracefully adapt to
unexpected topology changes. Using events, such as changes, to drive updates, rather than ?¬?xedinterval
timers, enables convergence to begin that much more quickly after a topological change.
The overhead of the frequent, time-driven updates of a distance vector routing protocol is also
avoided. This makes more bandwidth available for routing traf?¬?c rather than for network
maintenance, provided you design your network properly.
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