ip summary-address eigrp

[lopezj]

I have two routers in a central site with a frame-relay PVC each to the remote sites. I send to the remote sites a default summary-address in each PVC to the remote site of each central router.

ip summary-address eigrp 10 0.0.0.0 0.0.0.0 5

in one central router I have configured delay 2100 (because I want than the remote site prefers the route received from the other router)

But when I show the ip routes in the remote site I see the default route sended by de router configured with de delay and I expected the other one. I run a show ip eigrp topology 0.0.0.0 and I see that the delay for the default route sended by the router configured without delay is 25000 (it should be 20000) and the second is 21000 as I expected (as it is configured).

I return to the central site and I run a show ip eigrp topology 0.0.0.0 in both routers. The router without the delay configured has a delay in the default route of 5000 (the the remote site receives de default route with de delay 20000+5000=25000 as I have mentioned) and the router with de delay of 2100

when I run show ip eigrp topology 0.0.0.0 has a delay of 0 then the remote site for the default route received from this second router has a delay of (21000+0) and it prefers this route

My question is: Why in the summary default route to null0 in the central routers the calculation of the delay is different?

[smahbub]

You should not use the ip summary-address eigrp summarization command to generate the default route (0.0.0.0) from an interface. This causes the creation of an EIGRP summary default route to the null 0 interface with an administrative distance of 5. The low administrative distance of this default route can cause this route to displace default routes learned from other neighbors from the routing table. If the default route learned from the neighbors is displaced by the summary default route, or if the summary route is the only default route present, all traffic destined for the default route will not leave the router, instead, this traffic will be sent to the null 0 interface where it is dropped.

The recommended way to send only the default route out a given interface is to use a distribute-list command. You can configure this command to filter all outbound route advertisements sent out the interface with the exception of the default (0.0.0.0).

For more information :

http://www.cisco.com/en/US/products/sw/iosswrel/ps1828/products_configuration_guide_chapter09186a00800ca56e.html#34396