If both of these conditions are met, the route is determined to be feasible and can be added to the
routing table.
In Figure 5-6, three paths to network 172.16.0.0 exist with the following metrics:
?– Path 1: 30 (through B)
?– Path 2: 20 (through C)
?– Path 3: 45 (through D)
B
D
C E
Network
172.16.0.0
FD = Feasible Distance
AD = Advertised Distance
20
10
20
10
10
25
(config) #router eigrp 200
(config??“router) #variance 2
Network
172.16.0.0
Neighbor
B
C
D
FD
30
20
45
AD
10
10
25
184 Chapter 5: Implementing EIGRP
By default, the router places only path 2 (through C) in the routing table because it is the least-cost
path. To load-balance over paths 1 and 2, use a variance of 2 because 20 * 2 = 40, which is greater
than the metric through path 1.
In Figure 5-6, Router E uses Router C as the successor because it has the lowest feasible distance
(20). With the variance 2 command applied to Router E, the path through Router B meets the
criteria for load balancing. In this case, the feasible distance through Router B is less than twice
the feasible distance for the successor (Router C).
Router D is not considered for load balancing with this variance because the feasible distance
through Router D is greater than twice the feasible distance for the successor (Router C).
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