does higher Prefix length prefer over metric in eigrp

[Binu Steephen]

i have two routers and one switch connected between the routers,eigrp is enabled in the lan and wan, one link connected on each router.routing protocol is eigrp..

A router is learning destination 10.155.10.0/24 and B router is learning destination 10.155.10.0/26 when i do a sh ip route 10.155.10.20, A router metric to reach destination is 200 and through B router is 500. which link will be prefered for destination 10.155.10.20 from the local lan.

Please advise. I need to prepare configuration before applying..

[Binu Steephen]

okie..last question, .i think if i put static route 10.155.10/24 pointing null0 200 and two network advertisemnet in BGP 10.155.10.100/32 and 10.155.10.0/24 will not help to pass specific 10.155.10.100/32 to its bgp neighbor..correct?

[Jon Marshall]

It's not about passing the advertisement. Its about what happens when the traffic arrives at B. Yes you can get B to advertise a /32 using a route to Null0 but when traffic arrives at B from C B will drop the packets and not forward on to A.

Jon

[Binu Steephen]

we apply static route to null0 with distance 200 so it will go to A router as ospf AD is less...correct me if i am wrong..

ip route 10.155.10.0 255.255.255.0 null0 200

[Jon Marshall]

Yes that would work for 10.155.10.0/24 but that is not the issue. The issue is that you need a route for 10.155.10.100 pointing to Null0 and that would black hole traffic.

Jon

[Binu Steephen]

okie...BGP router will not generate route for 10.155.10.100/32 unleass and until we put

ip route 10.155.10.100 255.255.255.255 null0 200

packect coming from C to B with destination 10.155.10.100 will drop on BGP router B as high prefix length prefer over AD even if we put AD 200 with null0 static route..

correct me if i am wrong..

[Jon Marshall]

Correct, that is why PBR is a better option to achieve what you want.

Jon

[Binu Steephen]

Thanks a lot it was so nice checking with you...have a nice day

[Binu Steephen]

BTW, how do we define redundancy in PBR...

on E router LAN interface need to apply PBR, I need to define next hop router C's WAN IP connects to E, but how traffic will switch over to router D when link between E and C went down?

router E and D lan is common

[Jon Marshall]

Just use 2 next-hops in PBR -

set ip next-hop x.x.x.x y.y.y.y

Jon