EIGRP link down - want to know cause - %DUAL-5-NBRCHANGE: EIGRP-IPv4

[Mohd Khairul Nizam]

i 
I got this log from my core to the ISP router. Recently is 21st Feb
What could be the cause ?
Last year, around 6 times

[Cristian Matei]

Hi,

   There is a problem with your layer1/layer2 connectivity. Sometimes there is a layer 1 issue, the physical interface goes down, sometimes it's a layer 2 issues, as EIGRP packets are no longer received and the hold time expires.

Regards,

Cristian Matei.

[Mohd Khairul Nizam]

Hi,
You suspect it hv to do with layer 1 & 2.From the log, last year it happen around 7 times in between April and December.
Layer 1 i may change the cable itself
How about layer 2 ?
what can i check

[Vishnu Vardhan S]

It is connectivity issue between the routers, try pinging the neighbor from this router with repeat count of 1000 and check if all the ping happens, if it fails try replacing the cable.

[paul driver]

Hello

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@Mohd Khairul Nizam wrote:

Hi 
I got this log from my core to the ISP router. Recently is 21st Feb
What could be the cause ?
Last year, around 6 times

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sh version
dir flash:

[Mohd Khairul Nizam]

IOS
Core SW -  cat4500e-universalk9.SPA.03.08.06.E.152-4.E6.bin"

Router - Cisco IOS XE Software, Version 03.13.04.S - Extended Support Release