Cat6500 CAM flush

[anazarenko]

Can anybody comment this:

sw-bbone(config)#vlan 1811

sw-bbone(config-vlan)#end

% Applying VLAN changes may take few minutes.  Please wait...

sw-bbone#sh mac-address-table  count

MAC Entries  for all vlans :

Dynamic Address Count:                28633

Static Address (User-defined) Count:  984

Total MAC Addresses In Use:           29617

Total MAC Addresses Available:        65536

sw-bbone(config)#no vlan 1811

% Applying VLAN changes may take few minutes.  Please wait...

sw-bbone#sh mac-address-table  count

MAC Entries  for all vlans :

Dynamic Address Count:                4354

Static Address (User-defined) Count:  981

Total MAC Addresses In Use:           5335

Total MAC Addresses Available:        65536

Is it a normal Cat behavior to flush full CAM when just one Vlan gets removed?

System image file is "sup-bootflash:s72033-ipservicesk9-mz.122-33.SXH2a.bin"

[yashfaqu]

Can you share the output of following sequence of commands:

sh mac-address-table  count

show mac-address-table  count vlan 1811

no vlan 1811

sh mac-address-table  count

[anazarenko]

It's a new vlan without any MACs inside. I created it just before issuing count commands in my previous example:

sw-bbone(config)#vlan 1811

sw-bbone(config-vlan)#end

[anazarenko]

Same problem has been spotted on ME6524

sw-bbone5#sh ver

Cisco Internetwork Operating System Software

IOS (tm) s6523_rp Software (s6523_rp-ADVIPSERVICESK9-M), Version 12.2(18)ZU2, RELEASE SOFTWARE (fc2)

sw-bbone5#sh mac-address-table  count

MAC Entries  for all vlans :

Dynamic Address Count:                8963

Static Address (User-defined) Count:  208

Total MAC Addresses In Use:           9171

Total MAC Addresses Available:        98304

sw-bbone5#sh mac-address-table  count vlan  1811

MAC Entries for Vlan 1811 :

Dynamic Address Count:                0

Static Address (User-defined) Count:  0

Total MAC Addresses In Use:           0

Total MAC Addresses Available:        98304

sw-bbone5(config)#no vlan 1811

sw-bbone5(config)#exit

sw-bbone5#sh mac-address-table  count

MAC Entries  for all vlans :

Dynamic Address Count:                2315

Static Address (User-defined) Count:  207

Total MAC Addresses In Use:           2522

Total MAC Addresses Available:        98304

[rsimoni · Accepted solution]

Hi,

I think what you see it is expected.

How many trunk ports carrying vlan 1811 do you have on your cat6500 (after you add the vlan in the db)?

Current  hw (EARL7) has a limitation for which when a vlan is removed from a  trunk (this also happens when you delete the vlan from the db as that  vlan must be withdrawn from all trunks carrying it) all the dynamic mac  addresses IN ALL VLANS are deleted from the trunk ports. This seems to  match what you saw. After deletion of vlan 1811 the dynamic mac count dropped from 28k to 4k. I suppose that about 24k are learnt on trunk ports allowing all vlans (hence vlan 1811 too).

Riccardo

[anazarenko]

Dear Riccardo,

Thanks for your help. We have many trunk ports without VLAN filters on them.

It makes sence now.

[anazarenko]

Just curious, can you please provide a sample list of switches with a new hardware.

For example ME6524 is quite a new switch and still running EARL7?

[rsimoni]

Well, ME6524 is not so new (actually I would say the contrary) and since it is PFC3C based it has the same EARL7 as other cat6500 supervisors.

On Cat6500 only the new Sup2T has EARL8.

The other platform using it is the Nexus 7K.

Please rate the question if you are happy with it 

Riccardo