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EIGRP Flapping through Subinterface

Jason Wong
Level 1
Level 1

Dear All Guy,

I get some EIGRP flapping on my CE router (c2921) 2 subinterface to another two site. The router IOS version "c2900-universalk9-mz.SPA.152-2.T1". I capture the debug log as attached. I know understand some log meaning from the debug, Can anybody help to explain the log detail who flapping will happen. Thank you so much.

1 Accepted Solution

Accepted Solutions

Hello Jason,

as Dan has noted the link is not stable at OSI layer2 and layer1 as a result of this EIGRP flaps.

You need to fix the problems at physical layer and then also EIGRP will be stable

What is connected to gi0/1 of the device with IP 10.7.10.5 ?

show interface gi0/1

is your starting point

Hope to help

Giuseppe

View solution in original post

3 Replies 3

Hi Jason,

Your phisical interface is flapping :

9 00:37:37.787: %LINK-3-UPDOWN: Interface GigabitEthernet0/1, changed state to down

00:37:39.787: %LINK-3-UPDOWN: Interface GigabitEthernet0/1, changed state to up

00:40:18.785: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/1, changed state to down

Dan

Thank Dan,

But do you understand the EIGRP log, why flapping will happen?

Hello Jason,

as Dan has noted the link is not stable at OSI layer2 and layer1 as a result of this EIGRP flaps.

You need to fix the problems at physical layer and then also EIGRP will be stable

What is connected to gi0/1 of the device with IP 10.7.10.5 ?

show interface gi0/1

is your starting point

Hope to help

Giuseppe

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