Redistribute Static into EIGRP

[Ramirov]

Hi guys , I have a little doubt , I am runing EIGRP between three SW L3 and I am redistributing static from two of them.

R1 ----- R2 -----R3 

If I redistribute static from R1 and R3 , I see in R2 routing table two routes for balancing , its okay 

R2#

D EX 10.54.180.0/24  [170/3072] via 10.0.0.3, 00:14:06, Vlan760
                                  [170/3072] via 10.0.0.2, 00:14:06, Vlan760

But If I change the weight of R3 static route for 200 , I dont see load-balancing any more I see just one route from R1

R2#

D EX 10.54.180.0/24 [170/3072] via 10.0.0.2, 00:00:02, Vlan760

I don't understand why ??

If a turn off R1 I see the route from R3 with the same AD and metric.

R2#

D EX 10.54.180.0/24 [170/3072] via 10.0.0.3, 00:00:09, Vlan760

If the weight is an attribute of the static route and can not be redistributed. Why don't see both routes??

Thanks in advance.

[Dennis Mink]

seeing there is liitle information, I am gonna have a stab at this:

D EX 10.54.180.0/24  [170/3072] via 10.0.0.3, 00:14:06, Vlan760
                                  [170/3072] via 10.0.0.2, 00:14:06, Vlan760

both routes have admin distance of 170 (external EIGRP). so bot routes are equal cost. 

as soon as you change the admin distance to 200, it no longer appears in the routing table because the remaining route with admin distance 170 is cheaper. This is how i interpret this

[luis_cordova]

Hi @Ramirov 

I have done a quick test on PacketTracer with the information you have provided.
When I change the weight of the route, both routes continue to be redistributed.

Therefore, I share my suspicion:
It is possible that on R3, where you increase the weight of the route, you have a route to the same destination learned by EIGRP.

Then, while the route on R3, has the default weight (1), the static route is chosen as the best route and is redistributed to R2.

But, when you increase the weight to 200, that route is no longer the best route, so EIRGP stops redistributing that route.
Now the best route to that destination is only R1.

If you use PacketTracer(v 7.2.1), I share the test I do.

Regards

[Jon Marshall · Accepted solution]

What do you mean by weight ? 

If you mean AD (which is not weight) then what is happening is when you modify the AD to 200 on R3 then R3 will now use the AD 170 advertised from R2 because of the lower AD.

When you shut R1 then R2 no longer receives the route from R1 and so does not advertise it to R3 which means R3 can now use it's static route with AD 200 which it then advertises to R2. 

Jon

[Ramirov]

So , for a static route to be redistributed need to appear in the routing table?

[Jon Marshall]

Yes and that applies to any redistributed routes not just static routes. 

Jon

[Ramirov]

Thanks Jon and Luis for clarify my doubts. 

have a good week ahead!!