Wired Intelligent Edge (Campus Switching and Routing)

Sticky mac was enabled on a port. Why are the network devices unreachable if the port number is changed?

Where is it desirable to have the sticky mac to be enabled?

How to clear a stale sticky-mac entry?

Environment : This article applies to all Aruba Mobility switches with Code 7.3 and above.

Sticky MAC dynamically learns MAC addresses on an interface and retains the MAC information in case the Mobility Access Switch reboots. Thus there is need to learn the MACs after the switch has rebooted. The MAC will already be present in the MAC address table, this speeds up convergence after a switch reboot.



Issue:
1. I enabled sticky-mac on a port. I moved the device connected to it to another port That device can no longer connect to the network.

2. Switch's MAC address table includes the machine's MAC addresses which are no longer there.

Cause:
When the sticky-mac is enabled on the port, it doesn't time out the MAC addresses learned on that port anymore. In fact the addresses stay in the table even after reboot. Thus when the same machine is moved to a new port, the MAC address table on the switch still points to old port and that device is no longer reachable through the network.


Config:

Enabling the feature:

(ArubaS2500-24P) # configure t
(ArubaS2500-24P) (config) #interface-profile port-security-profile new
(ArubaS2500-24P) (Port security profile "new") #sticky-mac
(ArubaS2500-24P) (Port security profile "new") #exit

Verify that the feature has been enable:


(ArubaS2500-24P) (config) #show mac-address-table
MAC Address Table
-----------------
Destination Address  Address Type  VLAN  Destination Port
-------------------  ------------  ----  ----------------
f0:1f:af:52:44:09    Sticky        0001  GE0/0/20

Above, the mac address table will show the mac address on port g 0/020 even if the cable is unplugged and plugged into the port g 0/0/21 rendering the device unreachable.


Solution:

Remove the sticky mac address using one of the following commands:

# clear mac-address-table sticky
# clear mac-address-table vlan <id> sticky
# clear mac-address-table interface <interface-name> sticky
# clear mac-address-table vlan <id> mac <mac-address> sticky
# clear mac-address-table interface <interface-name> mac <mac address> sticky
# clear mac-address-table vlan <id> interface <interface name> sticky

Thus:

(ArubaS2500-24P)# clear mac-address-table sticky
(ArubaS2500-24P) (config) #show mac-address-table
MAC Address Table
-----------------
Destination Address  Address Type  VLAN  Destination Port
-------------------  ------------  ----  ----------------
f0:1f:af:52:44:09    Learnt        0001  GE0/0/21