There are essentially three classes of routing protocols:
1) Distance Vector (hops);uses
frequent broadcasts on all interfaces to determine the direction and
distance to other links and accumulate distance vector.As this process
continues,routers discover the best path to non-directly connected
networks.The metric values are cumulative.each distance vector protocol
uses a different routing algorithm to determine the best route,which
generates a number called the metric value for each path through the
network.Typically,the smaller the metric,the better the path.EX:RIP and
IGRP.
Benefits of Distance Vector protocols:
Simple design for smaller networks
2) Link State;recreates
the exect topology of the entire network for route computation. .Link
State takes bandwidth into account using a cost metric. .Link State
protocols only send updates when a change occurs,which makes them more
attractive for larger networks. .Link –Statealgorithm maintain a complex
database of topology information including LSPs (link-State Packets),a
topological database,the SPF (Shortest Path First) algorithm,the
resulting SPF tree,and finally,a routing table of paths and ports to
each network.Bandwidth and delay are the most heavily weighed parts of
the metric when using .Link –State protocols.EX:OSPF and NLSP.
Benefits of Link- State protocols:
Allows the use of a more robust addressing scheme
Allows for a larger scalable network
Reduces convergence time
Allows “supernetting”
3) Balanced Hybrid;combines
aspects of Link State and Distance Vector routing protocols.Balanced
Hybrid uses distance vectors with more accurate metrics to determine the
best path to destination networks.EX:EIGRP.
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