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Cisco Switch Slow Down the Network

I have a wired problem that I never seen before. I got the message from the syslog that said:

34377: 3w2d: %LINK-CLUSTER_MEMBER_2-3-UPDOWN: Interface FastEthernet0/3, changed state to up

34375: 3w2d: %LINK-CLUSTER_MEMBER_2-3-UPDOWN: Interface FastEthernet0/3, changed state to down

1866: 3w1d: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/2, changed state to up

1866: 3w1d: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/2, changed state to down

It is giving me the error from 5 out of 9 switches we have.

Anyone has ever encounter this type of problem? Please give me some clue where I should start looking for a cause and problem.

The whole network is very slow. We try to transfer the file 40 MB, it will take 10 minutes to do so.

Thank you,


PS. I attach the whole syslog if anyone want to see.


Re: Cisco Switch Slow Down the Network

I would normally not worry about LINK_3_UPDOWN messages - I see one of these each time a PC on my LAN is rebooted, and they happen because I have configured the switch to give me link status traps. Does this mean perhaps that you have link traps enabled on 5 out of 9 of your switches?

But I am more interested to know how the ports F0/3 and G1/0/2 fit into your topology. Are they significant, or are they just access ports? So to answer your question, I think I would need to know more about your topology and your configuration.

I did notice that in your SYSLOG, each message appears twice, and I wonder what the explanationfor that could be.

Finally the slowness - yes, your network clearly has something wrong, but we don't have anough information to diagnose it. When you do a show int on the various inter-switch trunks, do they show any sign of heavy load? Perhaps you could post some show int for us to see.

Sorry, but I think we need more information.

Kevin Dorrell


VIP Purple

Re: Cisco Switch Slow Down the Network


in addition to Kevin's post, you also might want to check if you have debugging turned on on one or more of your switches. The '%SYS-3-LOGGER_DROPPED' entries in your log file indicate that somewhere, a device is generating a whole lot of messages...

Try and turn off console logging with the 'no logging console' command.

Further, make sure you have your root switch set up correctly, that is, the root switch should generally be the most powerful and most centrally placed switch in your network. You can configure the root switch with the command:

spanning-tree vlan x priority 0

for all your VLANs.

Are you running VTP in your network ? If so, turning on VTP pruning on the VTP server might also help.

I hope this makes sense, if not, post back here what you are running into...



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