05-28-2007 10:08 AM - edited 03-05-2019 04:20 PM
hi all,
today every thing was going good at the university where i work in network support, until the following appeared on one 4506 switch
01:56:29: %C4K_EBM-4-HOSTFLAPPING: Host 02:01:0A:00:00:01 in vlan 1 is flapping
between port Gi1/2 and port Gi6/26
01:56:30: %C4K_EBM-4-HOSTFLAPPING: Host 00:01:2E:08:53:01 in vlan 1 is flapping
between port Gi1/2 and port Gi6/17
01:56:31: %C4K_EBM-4-HOSTFLAPPING: Host 00:02:B3:0B:59:99 in vlan 1 is flapping
between port Gi1/2 and port Gi6/14
01:56:33: %C4K_EBM-4-HOSTFLAPPING: Host AA:00:04:00:32:08 in vlan 1 is flapping
between port Gi1/2 and port Gi6/2
01:56:37: %C4K_EBM-4-HOSTFLAPPING: Host AA:00:04:00:33:08 in vlan 1 is flapping
between port Gi1/2 and port Gi6/27
01:56:38: %C4K_EBM-4-HOSTFLAPPING: Host 00:14:6A:A8:7D:80 in vlan 1 is flapping
between port Gi1/2 and port Gi6/15
01:56:44: %C4K_EBM-4-HOSTFLAPPING: Host 02:01:0A:00:00:01 in vlan 1 is flapping
between port Gi1/2 and port Gi6/26
01:56:46: %C4K_EBM-4-HOSTFLAPPING: Host AA:00:04:00:32:08 in vlan 1 is flapping
between port Gi6/2 and port Gi1/2
01:56:50: %C4K_EBM-4-HOSTFLAPPING: Host 00:15:62:54:88:40 in vlan 1 is flapping
between port Gi1/2 and port Gi6/15
it is not only those lines... it kept going and going with defferent MACs and ports until i unpluged the Gi1/2 wich is the connection between the old campus to the new campus. can any one tell me what is the problem?
also when the problem appeared, all the netowrk in the university was down, we use cisco switches 2950, and 2970 in addition to four 4000 series switches.
when i unpluged the Gi1/2 the problem stop. but some switches still down and are not any more on the network.
?????? any help please.??? it is argent.
05-28-2007 10:52 AM
Hi
There is a loop in u r network.
Check if u have redundant links between u r switches,and check the STP topology.
Thanks
Mahmood
05-28-2007 11:58 AM
thank you Mahmood,
but when i elemenate the segment that seems to cause the problem, there are some switches that did not work, i meane; when i unpluged the source of the problem on the root switch, switches on the 1st layer start to work, but the layers after that did not.
for example: assume
RootSwitch ----> SwitchA ----> SwitchB
now RootSwitch can see SwitchA but not SwitchB until i changed the uplink on SwitchB, even though i did not change any configuration on those switches.
any ideas ??
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