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Observing multiple paths to destination

Observing multiple paths to destination 
9.1.9 Multi-path algorithms permit traffic over multiple lines, provide better throughput, and are more reliable than single path algorithms.
IGRP supports unequal cost path load balancing, which is known as variance. The variance command instructs the router to include routes with a metric less than n times the minimum metric route for that destination, where n is the number specified by the variance command. The variable n can take a value between 1 and 128, with the default being 1, which means equal cost load balancing.
rt1 has two routes to network 192.168.30.0. The variance command will be set on rt1 to ensure that both paths to network 192.168.30.0 are utilized.
Figure shows the output from show ip route from rt1 before the variance is configured. FastEthernet 0/0 is the only route to 192.168.30.0. This route has an Administrative Distance of 100 and a metric of 8986.
Figure shows the output from show ip route from rt1 after the variance is configured. The preferred route is interface FastEthernet 0/0, but Serial 0/0 will also be used. After the variance command is executed, IGRP will use load balancing between the two links. 
This page concludes this lesson. The next lesson will discuss network testing. The lesson begins with an overview.

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