3550 with static mac addresses that can not be removed

[fcrooks]

In viewing the mac-address table on a 3550 I found 48 static mac address entries like the ones below:

Vlan Mac Address Type Ports

---- ----------- ---- -----

All 000c.316c.6480 STATIC CPU

All 000c.316c.6481 STATIC CPU

All 000c.316c.6482 STATIC CPU

I assume that since they are associated with a port called CPU that it must be some default setup with the 3550.

However, I can't find anything about these static mac address entries documented anywhere on the CCO

Any clues??

[Prashanth Krishnappa]

The one you listed are used by the switch for its Spanning tree bridge MAC addresses for different VLANs. Some will be for STP and other features. here are some

0100.0c00.0000 STATIC CPU - ISL

0100.0ccc.cccc STATIC CPU - CDP/VTP/DTP/PAgP/UDLD

0100.0ccc.cccd STATIC CPU - PVST+

0180.c200.0000 STATIC CPU - STP

0180.c200.0001 STATIC CPU - Pause frames

0180.c200.0002 STATIC CPU - LACP

0180.c200.0003 STATIC CPU - 802.1x

and so on. Here is an example from my lab switch

3550#sh mac-address-table static | inc 000b.4681

All 000b.4681.0000 STATIC CPU

All 000b.4681.0001 STATIC CPU

All 000b.4681.0002 STATIC CPU

All 000b.4681.0003 STATIC CPU

All 000b.4681.0004 STATIC CPU

All 000b.4681.0005 STATIC CPU

All 000b.4681.0006 STATIC CPU

All 000b.4681.0007 STATIC CPU

All 000b.4681.0008 STATIC CPU

All 000b.4681.0009 STATIC CPU

All 000b.4681.000a STATIC CPU

All 000b.4681.000b STATIC CPU

All 000b.4681.000c STATIC CPU

All 000b.4681.000d STATIC CPU

All 000b.4681.000e STATIC CPU

All 000b.4681.000f STATIC CPU

All 000b.4681.0010 STATIC CPU

All 000b.4681.0011 STATIC CPU

All 000b.4681.0012 STATIC CPU

All 000b.4681.0013 STATIC CPU

All 000b.4681.0014 STATIC CPU

All 000b.4681.0015 STATIC CPU

All 000b.4681.0016 STATIC CPU

3550# sh spanning-tree vlan 1

VLAN0001

Spanning tree enabled protocol ieee

Root ID Priority 8192

Address 000f.f8a5.a201

Cost 57

Port 8 (FastEthernet0/8)

Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 32769 (priority 32768 sys-id-ext 1)

Address 000b.4681.0000 <<<<--------

Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Aging Time 300

Interface Role Sts Cost Prio.Nbr Type

---------------- ---- --- --------- -------- --------------------------------

Fa0/8 Root FWD 19 128.8 P2p

3550#

[fcrooks]

Thanks!! I figured they were used for internal purposes (i.e. stp, vlan, etc...), but I just could not find it documented anywhere.