EIGRP Metric Manipulation issue

[csco]

Hi,

I have a question about how to influence the routes learned from a specific EIGRP neighbour. 

We have one multi-access vlan with 2 core switches and 2 routers. Switch A and Switch B have the same routes (shared VLANs). Router A and Router B have also the same routes, but different networks.

Router A and Switch A should have default EIGRP settings but routes learned from Router B or Switch B should be less attractive (influenced).

I am stuck how to do this.I have tried looking at distance, distribute-lists and route-maps but cannot get an EIGRP only solution to make this work.
Can anybody give me some pointers how to solve this?

Kind Regards, G.

[mahdymohamed]

Hi , 

 I think you might change the interface bandwidth connected to router B , and make it lower than BW connected to switch A , this should trigger the EIGRP metric and prefer the switch A side, instead of Router B or SW B.

Bandwidth interface won't affect your Original BW.

> I think also apply Route-map on the interfaces connected to SWB , Router B that increase the metric learned by those interfaces which will make these routes less attractive. 

hope this will help.

Regards, Mahdy :)

[csco]

All the problem is that the setup is that both Switch A and B are in the same VLAN connecting to routers A + B.

EIGRP-IPv4 Neighbors for AS(10)
H   Address                 Interface              Hold Uptime   SRTT   RTO  Q  Seq
                                                   (sec)         (ms)       Cnt Num
2   11.254.8.28 (RTRA)            Gi0/2/0                  13 1d11h       5   100  0  523699
1   11.254.8.17 (SWB)             Gi0/2/0                  12 1d11h      12   100  0  1237961
0   11.254.8.1 (SWA)              Gi0/2/0                  11 1d11h      14   100  0  1314074

So modifying the delay would have the same result as for router A, Switch A and Switch B. Thus not differentiating between RTRA+SWA vs SWB.

[paul driver]

Hello

Eigrp delay is calculated with all the interfaces delay in the eigrp path, so this means you can manipulate an upstream rtr on the B network to provide a less proffered  route if this is applicable to your toplology

res

Paul

[manish arora]

As mentioned by Kwillacey, Use the offset list to change the composite metric on the link between your neighbors, you can follow the direction on the following page to configure :

http://www.cisco.com/c/en/us/support/docs/ip/enhanced-interior-gateway-routing-protocol-eigrp/13673-14.html#modifycompositemetric

Look at the direction the Offset-list is applied for expected results.

Manish

[Chris Izatt]

you can useACL's and offset-list to increase one metric going in or out of an interface. 

so

access-list 1 permit 11.254.8.17 0.0.0.0

router eigrp 1

offset-list 1 in 5000 Gi0/2/0

What that does is in the topo table increases the EIGRP metric for 11.254.8.17  inbound on gi0/2/0 on RTR-A. 

You might need to switch the logic to get the result that you want, but that is the commands that can get it done for you. 

Good luck

[Kelvin Willacey]

The rule of thumb is to use delay not bandwidth to influence path selection. You can also try an offset list but modifying the delay should be sufficient.

[mahdymohamed]

you are right K (Y) , i missed this point 

[paul driver]

Hello

The best way is to increase the delay value on the handoff interface of the B network as this will make the A network more preferable..

something like this:

int xx

delay 20000

res

Paul

[Kelvin Willacey]

Can you post a diagram?