01-14-2014 02:17 AM - edited 03-07-2019 05:33 PM
We have an odd problem on our network where our mac-address tables on our endpoint switches are filling up very quickly. At first I thought it could be mac-flooding, and started to investigate which part of the network this could be coming from, however when looking at the mac-address-table count for each vlan I'm seeing quite an even spread of macs in each vlan, no obvious spiked anywhere. Another curious thing is that vlans that have only ever had 3 devices (2 servers, and the vlan interface) in are showing a much higher mac-address count than they should.
Is it possible that this is something is looping somewhere?
This is an example snippet from one of the endpoint 2960 switches. We have a mixture of 2950 and 2960s, and a 6509 core switch.
2960switch#sh mac-address-table count
Mac Entries for Vlan 1:
---------------------------
Dynamic Address Count : 271
Static Address Count : 0
Total Mac Addresses : 271
Mac Entries for Vlan 700:
---------------------------
Dynamic Address Count : 262
Static Address Count : 0
Total Mac Addresses : 262
Mac Entries for Vlan 703:
---------------------------
Dynamic Address Count : 264
Static Address Count : 0
Total Mac Addresses : 264
Mac Entries for Vlan 704:
---------------------------
Dynamic Address Count : 265
Static Address Count : 0
Total Mac Addresses : 265
Mac Entries for Vlan 705:
---------------------------
Dynamic Address Count : 260
Static Address Count : 0
Total Mac Addresses : 260
This continues across all the vlans, of which there are 50. Vlan705 for example is one where there have never been more than 3 mac addresses on that segment.
I can provide configs from the core.
Solved! Go to Solution.
01-14-2014 11:51 AM
It's a wireless contoller.
01-14-2014 11:21 AM
Andi
How exactly have you configured the bridge group ?
It sounds like what you have done is bridged all the vlans together. If you have then that is why you are seeing all the mac addresses in all vlans. I'm not familiar with the WLC but i wouldn't have thought that is what you want to do. If you have redundant connections in your network this could create potential STP problems.
Jon
01-14-2014 11:51 AM
Yes, all of our vlans are in the same bridge group. I don't know why it's like this, perhaps something from a legacy setup. I've now removed a few vlans from the group with no obvious degradation in service, so I'll continue to remove the vlans out of the group.
01-15-2014 02:08 AM
Removing the vlans from the bridge group has resolved this.
Thanks everyone for your help.
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