Routing Issue

[lovefunlove]

Hello Guys,

Please go through the attached Network diagram for the referrence.

In this scenario PC-2 & PC-3 have same IP Address. All the router are running eigrp routing protocol.

When i ping 25.1.1.2 from PC-1 to which PC ( 2 or 3) should ping.

what i have observerd that it ping any one of the PC. but on what basis the router decide or learns the 25.1.1.0 network as it is same for both R1 & R2.

if i shut a serial link between r1 and r2 it pings the other 25.1.1.0 network.

Please let me if any one of you have any idea.

Regards,

MAX

[ankurbhasin]

HI MAX,

According to me your router R1 will learn 20.1.1.0 network from both R2 nd R3 via EIGRP. Now EIGRP default behavior is equal cost load balancing and it will see that to reach the network 20.1.1.0 it has 2 routes via 2 different serial links.

So when you ping it will be load balance 2 both the PCs (2 &3) and when you shut one serial interface R1 will only learn 20.1.1.0 network from one serial link and R1 will have a single leraning of this network and will ping as usual.

So what you are observing is because of EIGRP default behaviour and if you change the delay value on R3 you will observe that R1 will only learn 20.1.1.0 from one serial link which will be having the best metric.

HTH

Ankur