Is LINEPROTO-5-UPDOWN Link Flapping?

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May 21st, 2008
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I'm trying to understand the reasons for seeing LINEPROTO-5-UPDOWN which I believe is a change in the data link layer? As seems to be the case for others, the down and up action only take a few seconds and occur at random instances.

I'm seeing these messages in our syslog trap across various switches in the network. I'm not too concerned about it happening on desktops but it's also happening on the 3560 we are using as a 'WAN link aggregator'.

We have various branch offices connected over 2MB SDH links, where the CPE equipment is a Pandatel E1 - Ethernet converter at each end (Branch-HQ).

At the HQ all these branches have their ethernet ports from the pandatel terminated on a 3560.

Two of these ports are causing LINEPROTO-5-UPDOWN issues at random. Is this Link Flapping?

I would like to better understand this to see whether this could be coming from the SDH side or not.


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Overall Rating: 3.3 (3 ratings)
cisco_lad2004 Wed, 05/21/2008 - 02:27
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if u have not done and recent config changes, issue is likely layer 1.

Ask for lines to be tested.

it might some other issue, but sart at L1.



Pravin Phadte Wed, 05/21/2008 - 02:58
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Yes i agree with cisco_lad2004.

You need to get the line tested of you are getting this link flaps on regular basis.

Also need to check the status of the interface and from where the errors are flowing.

guruprasadr Wed, 05/21/2008 - 03:02
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Refer Link below: for document having the details & description about each TRAP messages that are supported in Cisco Equipments.

Refer ITEM=>21 for the LOG message your provided and the document having the details.

Hope I am Informative.


Best Regards,

Guru Prasad R

nickpalmermorewood Fri, 02/06/2009 - 04:53
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Turned out the issue was with the Pandatel devices. Both the branch CPE device and the HQ card turned out to be faulty. Replacing them both resolved the issues


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