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 |
