Please enlighten on how to tweak delay on interface for eigrp variance to work

[blue phoenix]

This is in reference to
https://supportforums.cisco.com/discussion/11276296/eigrp-does-ad-fd-or-ad

Please let me know if the Successor's FD is = to FS RD, how can I manipulate delay in order to configure with a variance command to make them load balance?

R3(config-if)#do sh ip eigrp top all

P 0.0.0.0/0, 1 successors, FD is 307200, serno 23
via 192.168.1.1 (307200/281600), Ethernet0/1
via 192.168.3.2 (332800/307200), Ethernet0/0

192.168.1.1 /307200 is equal to 192.168.3.2 /307200.

I would like to know how can I tweak e0/0 interface with delay in order to use variance command to make them load-balance? Or is that not possible ?

Thanks,

[Jon Marshall]

Your question is really unclear.

Why do you need to modify the delay to use variance ie. variance is, in effect,  a multiplier of the lowest metric.

In addition where is the default route coming from in your diagram ie.which router ?

Jon

[blue phoenix]

Hi,

I am asking what metric should I tweak in order to meet the feasibility condition.... I thought I could do it by changing the delay.  Now I am asking what metric could I tweak?

Thanks,

[Jon Marshall]

Easiest way would be to use an offset list to modify the metric so you meet the feasibility condition.

Jon

[cofee]

I agree with Jon the easiest way is to use an offset list. But if you have to choose between bandwidth and delay then delay is the best choice, as tweaking bandwidth can have negative impact on protocols like qos and eigrp itself.

[blue phoenix]

Hi,

That is what I did, I tried tweaking the delay but the RD of the feasible successor is not changing, only the FD  of the feasible successor is changing.  So the feasibility condition is still not met since Successor's FD is still = to Feasible successor's RD...

Does that mean only the offset-list is the only option then?

Thanks,

[Jon Marshall]

It is difficult to answer without knowing details ie. where did you apply the delay etc.

You may be able to use delay but it would be easier to be honest to simply modify the metric directly with an offset list.

Can't say much more than that without more specifics.

Jon

[blue phoenix]

I have applied the delay on R3's 0/0, do I need to apply it in R2's 0/0 then?  I think if the 2nd option is the answer then it means you need to configure the hub router's interface facing the stub router to influence metric?

[cofee]

I am not sure on which router and interface you are tweaking delay value, but if you increase Delay either on interface e0/1 of R1 or R3 it should work. Once the FD even goes up by 1 point R2 will qualify to become feasibility successor.

If it's a lab environment you issue "clear ip eigrp neighbors" after tweaking delay value.

[Jon Marshall]

Not sure increasing delay on e0/1 on R1 will make a difference as it is the delay on the interface used to get to the destination network that counts and I am assuming the default route is coming from R4.

So e0/1 on R3 would be the only place to increase it as far as I can see.

Jon

[cofee]

Jon,

May be it won't, but I am not sure since I haven't labbed it.

Thanks!

[cofee]

Based on the information you have shared route via 192.168.3.2 doesn't meet the feasibility condition to become a feasible successor as it's reported distance is not than feasible distance. You would need to tweak the metric so the RD of 192.168.3.2 is less than 192.168.1.1 FD to the destination. Before that condition is met you can't do unequal or equal load balancing using listed links.

[Jon Marshall]

Thanks, that makes sense now and you obviously understood the question better than me :)

Jon