Stack Member Numbers

Cisco EtherSwitch Service Modules Feature Guide

Information About the Cisco EtherSwitch Service Modules

The Cisco EtherSwitch service module or switch using the versions listed below are ordered from highest to lowest priority:

–Cryptographic IP services image

–Noncryptographic IP services image

–Cryptographic IP base image

–Noncryptographic IP base image

5.The Cisco EtherSwitch service module or switch with the longest system uptime

6.The service module or switch with the lowest MAC address

A stack master retains its role unless one of these events occurs:

•The switch stack is reset.*

•The stack master is removed from the switch stack.

•The stack master is reset or powered off.

•The stack master has failed.

•The switch stack membership is increased by adding powered-up standalone modules or switch stacks.*

In the events marked by an asterisk (*), the current stack master might be re-elected based on the listed factors.

When you power up or reset an entire switch stack, some stack members might not participate in the stack master election. Stack members that are powered up within the same 10-second timeframe participate in the stack master election and have a chance to become the stack master. Stack members that are powered up after the 10-second timeframe do not participate in this initial election and only become stack members. All stack members participate in re-elections.

The new stack master becomes available after a few seconds. In the meantime, the switch stack uses the forwarding tables in memory to minimize network disruption. The physical interfaces on the other available stack members are not affected while a new stack master is elected and is resetting.

If a new stack master is elected and the previous stack master becomes available, the previous stack master does not resume its role as stack master.

You can use the Master LED on the Cisco EtherSwitch service module to see if the service module is the stack master.

Switch Stack Bridge ID and Router MAC Address

The bridge ID and router MAC address identify the switch stack in the network. When the switch stack initializes, the MAC address of the stack master determines the bridge ID and router MAC address.

If the stack master changes, the MAC address of the new stack master determines the new bridge ID and router MAC address.

The stack member number (1 to 9) identifies each member in the switch stack. The member number also determines the interface-level configuration that a stack member uses. You can display the stack member number by using the show switch user EXEC command.

Cisco IOS Release 12.2(25)SEC