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The following list contains many of the
advantages that link-state routing protocols have over the traditional
distance vector algorithms, such as Routing Information Protocol (RIP
v1) or Interior Gateway Routing Protocol (IGRP):

- Link-state protocols use cost metrics
to choose paths through the network. The cost metric reflects the
capacity of the links on those paths.
- Link-state protocols use triggered,
flooded updates and can immediately report changes in the network
topology to all routers in the network. This immediate reporting
generally leads to fast convergence times.
- Each router has a complete and
synchronized picture of the network. Therefore, it is very difficult
for routing loops to occur.
- Routers always use the latest set of
information on which to base their routing decisions because LSAs are
sequenced and aged.
- The link-state database sizes can be
minimized with careful network design. This leads to smaller Dijkstra
calculations and faster convergence.
- Every router is capable of mapping a
copy of the entire network architecture, at least of its own area of
the network. This attribute can greatly assist troubleshooting.
- Classless interdomain routing (CIDR)
and variable-length subnet masking (VLSM) are supported.
The following are some disadvantages of
link-state routing protocols:

- They require more memory and
processing power than distance vector routers, which can make
link-state routing cost-prohibitive for organizations with small
budgets and legacy hardware.
- They require strict hierarchical
network design, so that a network can be broken into smaller areas to
reduce the size of the topology tables.
- They require an administrator with a
good understanding of link-state routing.
- They flood the network with LSAs
during the initial discovery process, which can significantly decrease
the capability of the network to transport data. This flooding process
can noticeably degrade the network performance depending on the
available bandwidth and the number of routers exchanging information.
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