03-07-2002 05:24 AM - edited 03-01-2019 08:46 PM
In the log on a 4912 I am geting a message about flapping. Can someone tell me what flapping is and what's causing it?
03-07-2002 08:55 AM
could you post the exact message.
03-08-2002 04:43 AM
Here is the exact error message in the log:
2002 Mar 07 06:28:40 CST -06:00 %SYS-4-P2_WARN: 1/Host 00:40:96:37:70:fa is flap
ping between port 2/1 2/2 and port 2/6
Thanks
03-08-2002 12:05 PM
This is telling you it is seeing this mac address on all these ports , possible loop or something . I would look and see what is attached to these ports that might cause this .
03-10-2002 02:16 PM
Do you have wireless access points on the switch in question? A wireless user switching back and forth between two access points on different ports will appear to the switch to be flapping. The only "solution" is to plug all your access points into a hub and plug that into the switch, which will mask the flapping from the switch. Or just ignore the messages.
03-11-2002 12:08 AM
Hi,
This could be due to spanning tree or physical layer problems. Please refer to the troubleshooting steps outlined in this document:
http://www.cisco.com/warp/public/473/62.shtml#casestudy4
Nash
03-10-2002 02:21 PM
"Flapping" means the switch is seeing the mac address (nic card hardware address) appearing on different switch ports. If the address changes ports a lot, the switch tells you about it. The switch cares because it has to keep a table of which mac is on which port, so it knows where to send packets. The switch is grumbling about having to update its tables a lot.
03-11-2002 05:48 AM
One thing that does'nt seem to be metioned is etherchannelling.
Maybe the host has etherchannelling enabled and the switch has'nt.
Barry.
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