Cisco Cisco IOS Software Release 12.2(53)SE

These sections describe the important notes related to this software release for the Catalyst 3750 
and3560, and 2960 switches and for the Cisco EtherSwitch service modules:

These notes apply to switch stacks:

Always power off a switch before adding or removing it from a switch stack. 

Catalyst 3560 switches do not support switch stacking. However, the show processes privileged 
EXEC command still lists stack-related processes. This occurs because these switches share 
common code with other switches that do support stacking.

Catalyst 3750 switches running Cisco IOS Release 12.2(25)SEB are compatible with Cisco 
EtherSwitch service modules running Cisco IOS Release 12.2(25)EZ. Catalyst 3750 switches and 
Cisco EtherSwitch service modules can be in the same switch stack. In this switch stack, the Catalyst 
3750 switch or the Cisco EtherSwitch service module can be the stack master.

The LED of a switch port blinks amber if MDA is configured, there is no phone behind the IP phone, 
and the default authentication control-direction both command is used. This is because the 
data vlan spanning-tree is not in forwarding the state, which causes the LED to blink in amber.

These notes apply to Cisco IOS software:

The IEEE 802.1x feature in Cisco IOS Release 12.1(14)EA1 and later is not fully 
backward-compatible with the same feature in Cisco IOS Release 12.1(11)AX. If you are upgrading 
a Catalyst 3750 switch running Cisco IOS Release 12.1(11)AX that has IEEE 802.1x configured, 
you must re-enable IEEE 802.1x after the upgrade by using the dot1x system-auth-control global 
configuration command. This global command does not exist in Cisco IOS Release 12.1(11)AX. 
Failure to re-enable IEEE 802.1x weakens security because some hosts can then access the network 
without authentication.

The behavior of the no logging on global configuration command changed in Cisco IOS 
Release 12.2(18)SE and later. In Cisco IOS Release 12.1(19)EA and earlier, both of these command 
pairs disabled logging to the console:

the no logging on and then the no logging console global configuration commands

the logging on and then the no logging console global configuration commands

In Cisco IOS Release 12.2(18)SE and later, you can only use the logging on and then the no logging 
console global configuration commands to disable logging to the console. (CSCec71490)

In Cisco IOS Release 12.2(25)SEC for the Catalyst 3750 and 3560 switches and in Cisco IOS 
Release 12.2(25)SED for the Catalyst 2960 switch, the implementation for multiple spanning tree 
(MST) changed from the previous release. Multiple STP (MSTP) complies with the IEEE 802.1s 
standard. Previous MSTP implementations were based on a draft of the IEEE 802.1s standard.