Installation guide

Release Notes for the Cisco ME 3400 Ethernet Access Switch, Cisco IOS Release 12.2(44)SE

OL-14632-01

Limitations and Restrictions

You should review this section before you begin working with the switch. These are known limitations

that will not be fixed, and there is not always a workaround. Some features might not work as

documented, and some features could be affected by recent changes to the switch hardware or software.

These limitations apply to the Cisco ME switches:

• “Configuration” section on page 8

• “EtherChannel” section on page 9

• “IP” section on page 10

• “MAC Addressing” section on page 10

• “Multicasting” section on page 10

• “Routing” section on page 11

• “QoS” section on page 11

• “SPAN and RSPAN” section on page 12

• “Trunking” section on page 12

• “VLAN” section on page 13

Configuration

These are the configuration limitations:

• When the logging event-spanning-tree interface configuration command is configured and logging

to the console is enabled, a topology change might generate a large number of logging messages,

causing high CPU utilization. CPU utilization can increase with the number of spanning-tree

instances and the number of interfaces configured with the logging event-spanning-tree interface

configuration command. This condition adversely affects how the switch operates and could cause

problems such as STP convergence delay.

High CPU utilization can also occur with other conditions, such as when debug messages are logged

at a high rate to the console.

Use one of these workarounds:

–

Disable logging to the console.

–

Rate-limit logging messages to the console.

–

Remove the logging event spanning-tree interface configuration command from the interfaces.

(CSCsg91027)

• The far-end fault optional facility is not supported on the GLC-GE-100FX SFP module.

The workaround is to configure aggressive UDLD. (CSCsh70244).

• A static IP address might be removed when the previously acquired DHCP IP address lease expires.

This problem occurs under these conditions:

–

When the switch is booted without a configuration (no config.text file in flash memory).

–

When the switch is connected to a DHCP server that is configured to give an address to it (the

dynamic IP address is assigned to VLAN 1).

–

When an IP address is configured on VLAN 1 before the dynamic address lease assigned to

VLAN 1 expires.