Solved: Re: EIGRP missing Topology table entry - Page 2

Kishore Chennupati · ‎11-13-2011

Hello fellow engineers,

Got a setup

Default route Default Route

R1 R2 .21

| | .22

R3 R4 .25

| | .26

sw1---------------------------sw2

.33 .34

Now, the above network is all layer 3 and running Eigrp. Now , on R1 and R2 default static is redistrributed into eigrp.

when I check the topology table on sw2 I should be seeing 2 entries for default route right? but I dont Howver I can see it on R4

sw2:

#sh ip eigrp topology 0.0.0.0

EIGRP-IPv4:(180) (AS 180): Topology Default-IP-Routing-Table(0) entry for 0.0.0.0/0

State is Passive, Query origin flag is 1, 1 Successor(s), FD is 3840

Descriptor Blocks:

10.183.2.33 (Port-channel1), from 10.183.2.33, Send flag is 0x0

Composite metric is (3840/3584), Route is External

Vector metric:

Minimum bandwidth is 1000000 Kbit

Total delay is 50 microseconds

Reliability is 255/255

Load is 1/255

Minimum MTU is 1500

Hop count is 4

External data:

Originating router is 10.183.20.253

AS number of route is 0

External protocol is Static, external metric is 0

Administrator tag is 0 (0x00000000)

Exterior flag is se

R4

#sh ip eigrp topology 0.0.0.0/0

IP-EIGRP (AS 180): Topology entry for 0.0.0.0/0

State is Passive, Query origin flag is 1, 1 Successor(s), FD is 4096

Routing Descriptor Blocks:

10.183.2.26 (GigabitEthernet0/1), from 10.183.2.26, Send flag is 0x0

Composite metric is (4096/3840), Route is External

Vector metric:

Minimum bandwidth is 1000000 Kbit

Total delay is 60 microseconds

Reliability is 255/255

Load is 1/255

Minimum MTU is 1500

Hop count is 5

External data:

Originating router is 10.183.20.253

AS number of route is 0

External protocol is Static, external metric is 0

Administrator tag is 0 (0x00000000)

Exterior flag is set

10.183.2.21 (GigabitEthernet0/0), from 10.183.2.21, Send flag is 0x0

Composite metric is (28672/3072), Route is External

Vector metric:

Minimum bandwidth is 100000 Kbit

Total delay is 120 microseconds

Reliability is 255/255

Load is 1/255

Minimum MTU is 1500

Hop count is 2

External data:

Originating router is 10.183.252.2

AS number of route is 0

External protocol is Static, external metric is 0

Administrator tag is 0 (0x00000000)

Exterior flag is set

so why is the sw2 not seeing the default route from .25 in its topology table. If you need me to provide you an info, please let me know and I provide it here

Regards

Kishore

dslice · ‎11-15-2011

It looks like the metric on the default route is changing. Since its a static route, I'm trying to understand why the metric is changing. As for configs, just the Routing protocol configs and the static routes should be enough.

Sent from Cisco Technical Support iPad App

Kishore Chennupati · ‎11-21-2011

Hi Don,

Sorry I couldnt get back to this thread. I will post the relevant configs as per your adivse shortly.

Also, If I am not mistaken did you present" The care and feeding of EIGRP at Cisco Live?" If yes, then boy I am excited to talk to the presenter and EIGRP guru and I am sure I will get the right answer here Its a true honor to speak to you sir and I really mean it.

Regards,

Kishore

dslice · ‎11-21-2011

Kishore,

Thanks for the kind words. I've presented that session at Cisco Live for the past couple of years (and "EIGRP Troubleshooting" before that.) I stumbled across this forum a couple of months ago and decided to try to contribute to it whenever time allows.

Kishore Chennupati · ‎11-21-2011

Hi Don,

I was having a chat with Peter Paluch who is one of the esteemed engineers on CSC this morning and we discussed this issue. He has explained to me what the situation is and its exactly what you have mentioned as well. spolit horizon.(route poisining). I couldnt see the max metric which is 4294967295 hence i got confused.

Now its clear to me. Thanks. I have another issue though is that when R1 lost its default route it should query R3--->sw1-->>sw2----R4 and then R4 should calculate new FD and advertise it to sw2 and then sw2 will send it across to sw1--R3----R1 right?

However, this didnt seem to happen. R1 lost the default route and the traffic got blackholed. It's as if the queries never went out or something.

BTW, this is a production network that I am talking about.

Below are the configs

R1

router eigrp 180

redistribute static

network 10.180.0.0 0.0.255.255

network 10.183.0.0 0.0.255.255

no auto-summary

ip route 0.0.0.0 0.0.0.0 10.183.20.1

R3

router eigrp 180

network 10.183.0.0 0.0.255.255

no auto-summary

sw1:

router eigrp 180

passive-interface default

no passive-interface GigabitEthernet1/0/1

no passive-interface Port-channel1

no auto-summary

network 10.180.0.0 0.0.255.255

network 10.183.0.0 0.0.255.255

sw2

router eigrp 180

passive-interface default

no passive-interface GigabitEthernet1/0/1

no passive-interface Port-channel1

no auto-summary

network 10.180.0.0 0.0.255.255

network 10.183.0.0 0.0.255.255

R4

router eigrp 180

network 10.183.0.0 0.0.255.255

no auto-summary

Your help will be deeply appreciated.

Regards,

Kishore

Kishore Chennupati · ‎11-22-2011

Hi Don,

I figured it out Thanks

Regards

Kishore

dslice · ‎11-15-2011

Shahaludeen,

Whether a path is feasible or not doesn't impact whether it is retained in the topology table by a router. If a router receives an update for a prefix from a peer with a valid metric, the path is stored in the topo table until it is removed via a Query or an update with an infinity metric or the peer the prefix is learned from goes away.

By doing "show ip eigrp topology " all paths in the table are displayed. If you do "show ip eigrp topology" without the prefix or all-links option, then only successors and feasible successors are shown and therfore the display is impacted by whether a path is feasible or not. In Kishore's case, he's doing the show command that displays everything known and thus the feasibility of the path is irrelevant.