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Help with EIGRP and variance

John Blakley
VIP Alumni
VIP Alumni

All,

I have set up a lab in gns3 with eigrp to test the variance command. I have the following routes on one router:

<b>D 100.100.100.0 [90/435200] via 10.0.0.2, 00:01:24, Ethernet0/2

[90/435200] via 50.50.50.2, 00:01:24, Ethernet0/1</b>

My topology table shows three entries:

<b>P 100.100.100.0/24, 2 successors, FD is 435200

via 50.50.50.2 (435200/409600), Ethernet0/1

via 10.0.0.2 (435200/409600), Ethernet0/2

via 10.25.25.2 (45893376/153856), Ethernet0/0</b>

With a variance of 3 (3*153856=461568), I should see the third entry via e0/0 in my routing table, correct? Am I miscalculating, or will only two routes at a time only show up in the routing table?

Thanks,

John

HTH, John *** Please rate all useful posts ***
2 Accepted Solutions

Accepted Solutions

lamav
Level 8
Level 8

John:

Good morning.

You are making a mistake with the calculation.

Its not 3 x 152,856...

It should be 3 x 435,200...which is about 1,300,000

Your total metric cost for the 3rd route is 45,893,376...

That is more than 100 times the cost of the primary routes (successors).

You have to compare the overall metrics, not just the FD of one candidate route to the FD of the successor...

HTH

Victor

View solution in original post

John,

via 10.25.25.2 (45893376/153856), Ethernet0/0. Well,153856-RD < 435200-FD. But 45893376 divided by 435200. The result is 105.45. What about the following commands.

!

router eigrp XXX

variance 106

!

HTH,

Toshi

View solution in original post

4 Replies 4

lamav
Level 8
Level 8

John:

Good morning.

You are making a mistake with the calculation.

Its not 3 x 152,856...

It should be 3 x 435,200...which is about 1,300,000

Your total metric cost for the 3rd route is 45,893,376...

That is more than 100 times the cost of the primary routes (successors).

You have to compare the overall metrics, not just the FD of one candidate route to the FD of the successor...

HTH

Victor

John,

via 10.25.25.2 (45893376/153856), Ethernet0/0. Well,153856-RD < 435200-FD. But 45893376 divided by 435200. The result is 105.45. What about the following commands.

!

router eigrp XXX

variance 106

!

HTH,

Toshi

Hi Victor,

How are you going? Seems we did at the same time. Let's start with math calculation for today. (grin)

Toshi

That was it =) Thanks!

HTH, John *** Please rate all useful posts ***
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