Mac address table in HSRP environment

[alioune-ndiaye]

Hello Expert

I have 2 C6500 in hsrp environment.

Problem description

C6500-A------------------------------>   C6500-B, with C6500-A   the active hsrp , and C6500-B the stdby

C6500-A#sh mac address-table count

MAC Entries  for all vlans :

Dynamic Address Count:                1600

Static Address (User-defined) Count:  400

Total MAC Addresses In Use:           2000

Total MAC Addresses Available:        65536

C6500-B#sh mac address-table count

MAC Entries  for all vlans :

Dynamic Address Count:                3698

Static Address (User-defined) Count:  338

Total MAC Addresses In Use:           4036

Total MAC Addresses Available:        65536

I 'd like to know why the numbers in C6500-B doubles those in C6500-A?

Is it normal?

In addition, in vlan 225, I see there are 65 mac entries in C6500-B , and 42 in C6500-A.

Could you provide me an explanation.I thought the mac entries should have the same.

Thank u in advance.

Alioune

[Arumugam Muthaiah]

Hi Alioune,

It is not nesscessary to see the same number of MAC address count when you config the HSRP b/t two switches. It is normal that we can see this different count on MAC address.

when you see the #show mac-address-table count, we can see the mac entries for all the vlans configured on the switch

On switch C6500-B,

we can see the Dynamic address count showing as 3698, you can verify below commands

#show mac-address-table module <module number> - shows from which interface, the respective MAC addresses learnt
#show mac-address-table vlan <vlan number> - shows the number of mac addresses from vlan perspective

1. did you verify the logs on the switch C6500-B, did you see any L2 change happend on this switch?
2. please check the #show spanning-tree detail | in executing|changes|from and verify the stability of the spanning-tree topology
3. Did you check the mac-address-count on other vlan apart from 225, do you see the same behavior?

Regards,

Aru