Problems with switch 6500

[elis.gripshi]

I see mac address flapping everyday in my Switch and the mac addresses are different

I found some of these mac addresses and is nothing wrong in their connections ( clients of an ISP )

Aug  3 04:54:30.678: %MAC_MOVE-SP-4-NOTIF: Host 00c6.106e.7a06 in vlan 161 is fl

apping between port Gi2/22 and port Gi2/10

Aug  3 04:54:30.682: %MAC_MOVE-SP-4-NOTIF: Host 00c6.106e.7a06 in vlan 161 is fl

apping between port Gi3/24 and port Gi2/10

Aug  3 04:54:30.682: %MAC_MOVE-SP-4-NOTIF: Host 00c6.106e.7a06 in vlan 161 is fl

apping between port Gi2/22 and port Gi2/10

Aug  3 04:54:30.682: %MAC_MOVE-SP-4-NOTIF: Host 00c6.106e.7a06 in vlan 161 is fl

apping between port Gi3/24 and port Gi2/10

Aug  3 04:54:30.686: %MAC_MOVE-SP-4-NOTIF: Host 00c6.106e.7a06 in vlan 161 is fl

apping between port Gi2/22 and port Gi2/10

Aug  3 04:54:30.703: %L2_MMC-4-MMC_MAX: Maximum limit for MAC move counters

                                                   exceeded for vlan  161

Aug  3 04:54:30.703: %L2_MMC-4-MMC_MAX: Maximum limit for MAC move counters

                                                   exceeded for vlan  161

Aug  3 04:54:30.707: %L2_MMC-4-MMC_MAX: Maximum limit for MAC move counters

                                                   exceeded for vlan  161

Aug  3 04:54:30.707: %L2_MMC-4-MMC_MAX: Maximum limit for MAC move counters

                                                   exceeded for vlan  161

Aug  3 04:54:30.707: %L2_MMC-4-MMC_MAX: Maximum limit for MAC move counters

                                                   exceeded for vlan  161

Aug  3 04:54:30.698: %MAC_MOVE-SP-4-NOTIF: Host 00c6.106e.7a06 in vlan 161 is fl

apping between port Gi3/24 and port Gi2/10

Aug  3 04:54:30.702: %MAC_MOVE-SP-4-NOTIF: Host 00c6.106e.7a06 in vlan 161 is fl

apping between port Gi2/22 and port Gi2/10

Aug  3 04:54:30.702: %MAC_MOVE-SP-4-NOTIF: Host 00c6.106e.7a06 in vlan 161 is fl

apping between port Gi3/24 and port Gi2/10

Aug  3 04:54:30.702: %MAC_MOVE-SP-4-NOTIF: Host 00c6.106e.7a06 in vlan 161 is fl

apping between port Gi2/22 and port Gi2/10

Any idea?

there is no loop in the switching topology ( this is the vtp server switch of  an Internet Service Provider )

[answanso]

Hi Elis,

If there is no loop in the topology, the only other option I can think of is someone spoofing MAC addresses on your network. This message indicated traffic from that host is being learned on two ports on the same switch indicating a layer 2 loop. If someone spoofs their MAC address to something that also exists on on same L2 broadcast domain, it would appear as though there was a loop and thus trigger these error messages.

You need to use the CAM table to trace these back to their access ports (if possible I know this is a provider network) to determine the true cause. At a minimum you should be able to tell the customers and go from there.

HTH

Anthony

[elis.gripshi]

Hi Anthony

Its impossible to trace every single mac address,they are a lot

Aug  3 08:40:36.580: %MAC_MOVE-SP-4-NOTIF: Host 0016.d4cd.1a91 in vlan 161 is fl

apping between port Gi2/22 and port Gi3/24

Aug  3 08:40:36.592: %MAC_MOVE-SP-4-NOTIF: Host 0016.d4cd.1a91 in vlan 161 is fl

apping between port Gi2/22 and port Gi3/24

Aug  3 09:52:53.011: %MAC_MOVE-SP-4-NOTIF: Host 00e0.1c3c.0329 in vlan 161 is fl

apping between port Gi2/10 and port Gi3/9

Aug  3 09:52:53.015: %MAC_MOVE-SP-4-NOTIF: Host 00e0.1c3c.0329 in vlan 161 is fl

apping between port Gi2/10 and port Gi3/9

Aug  3 12:25:10.979: %MAC_MOVE-SP-4-NOTIF: Host 6431.5079.d0ae in vlan 161 is fl

apping between port Gi2/22 and port Gi2/6

Aug  3 09:35:22.767: %MAC_MOVE-SP-4-NOTIF: Host 001a.4d44.d924 in vlan 277 is fl

apping between port Gi2/10 and port Gi3/9

Aug  3 09:35:22.771: %MAC_MOVE-SP-4-NOTIF: Host 001a.4d44.d924 in vlan 277 is fl

apping between port Gi2/10 and port Gi3/9

Aug  3 09:35:22.771: %MAC_MOVE-SP-4-NOTIF: Host 001a.4d44.d924 in vlan 277 is fl

apping between port Gi2/10 and port Gi3/9

[rsimoni]

Hi Elis,

first impression is that there is indeed a loop instead. It should not be too difficult to spot as the ports those MAC addresses are flapping from are 3-4 in total.

First step is to create a L2 topology map for one of the affected vlans, say vlan 161.

Draw all the bridges in that vlan including the stp status of the ports belonging to such vlan. If you find out that you have redundant L2 paths make sure that STP is taking care of them (blocking one or more links).

Once you make sure that there is no actual L2 loop start investigating a given MAC addresses. I.e.

Host 00e0.1c3c.0329 what is this?

According to MAC address the NIC vendor is Cradlepoint, Inc (was: Mobility Electronicsy) which apparently produces Wifi and 3G devices. So it could easily be a mobile device. Try to get information about those mac addresses.

The important question you must be able to answer is: under normal circumstances from which port you should see that traffic coming from (in other words the mac address should be learned from which port)? Under normal circumstances the traffic must be seen coming from one port only. Other questions you must answer are: the other ports you see the mac address from, are leading to which device(s)? is it (are they) in the path to the source or the destination of the flow?

Other questions might arise along this path, but what I gave you I think is a good start to troubleshoot this phenomenon.

If you need further help please attach the topology mentioned above plus all the info I suggetsed you to get.

Riccardo

[roberto.redes]

I think this is a duo comunication (wired lan and wireless lan) from hosts. It's probably a host with two NICs (wired and wireless) and both are run. If you have a loop, the log would be the least of your problems.