Variance (EIGRP) Command on CISCO Router/Switch

Command

Variance (EIGRP)

Use

Allows EIGRP to install unequal load balancing to the routing table.

Syntax

Router(config-router)#variance [multiplier value]

Example

In this example, we will configure R4 to utilize both links to reach R5’s loopback networks.

Currently we have a basic EIGRP setup for this example

R4

router eigrp 222
network 4.4.4.4 0.0.0.0
network 150.10.0.0
network 150.11.0.0
network 200.0.0.0
no auto-summary

Lets see what the routing table looks like:

R4(config-if)#do sh ip route eigrp

200.0.0.0/32 is subnetted, 2 subnets
D 200.0.0.5 [90/156160] via 150.10.45.5, 00:00:44, FastEthernet1/0
5.0.0.0/24 is subnetted, 1 subnets
D 5.5.5.0 [90/156160] via 150.10.45.5, 00:00:44, FastEthernet1/0

Currently we are just using the fastethernet link between R4 and R5 to reach the loopbacks.

P 200.0.0.5/32, 1 successors, FD is 156160
via 150.10.45.5 (156160/128256), FastEthernet1/0
via 150.11.54.5 (2297856/128256), Serial0/0

To calculate the variance multiplier take the highest cost in this case 2297856 and divide it by the lowest cost you want to use.
2297856/156160 = 14.7 so the variance we need is 15

R4(config)#router eigrp 222
R4(config-router)#variance 15

R4(config-router)#do sh ip route eigrp
200.0.0.0/32 is subnetted, 2 subnets
D 200.0.0.5 [90/2297856] via 150.11.54.5, 00:03:55, Serial0/0
[90/156160] via 150.10.45.5, 00:03:55, FastEthernet1/0
5.0.0.0/24 is subnetted, 1 subnets
D 5.5.5.0 [90/2297856] via 150.11.54.5, 00:03:55, Serial0/0
[90/156160] via 150.10.45.5, 00:03:55, FastEthernet1/0

Related Articles

Leave a Reply

avatar