Cisco Systems 3750E manual Stack-mac persistent timer, Time-value, Show switch

Chapter 5 Managing Switch Stacks

Configuring the Switch Stack

•If you enter a time delay of 1 to 60 minutes, the stack MAC address of the previous stack master is used until the configured time period expires or until you enter the no stack-mac persistent timer command.

Note If the entire switch stack reloads, it uses with the MAC address of the stack master as the stack MAC address.

Beginning in privileged EXEC mode, follow these steps to enable persistent MAC address. This procedure is optional.

	Command	Purpose
Step 1
	configure terminal	Enter global configuration mode.
Step 2
	stack-mac persistent timer [0	Enable a time delay after a stack-master change before the stack MAC
	time-value]	address changes to that of the new stack master. If the previous stack
		master rejoins the stack during this period, the stack uses that MAC
		address as the stack MAC address.
		• Enter the command with no value to set the default delay of
		approximately 4 minutes. We recommend that you always configure
		a value.
		• Enter 0 to continue using the MAC address of the current stack
		master indefinitely.
		• Enter a time-valuefrom 1 to 60 minutes to configure the time period
		before the stack MAC address changes to the new stack master.
		Note When you enter this command, a warning states that traffic
		might be lost if the old master MAC address appears elsewhere
		in the network domain.
		If you enter the no stack-mac persistent timer command after a new
		stack master takes over, before the time expires, the switch stack moves
		to the current stack master MAC address.
Step 3
	end	Return to privileged EXEC mode.
Step 4
	show running-config	Verify that the stack MAC address timer is enabled. If enabled, the
	or	output shows stack-mac persistent timer and the time in minutes.
Step 5
	show switch	If enabled, the display includes:
		Mac persistency wait time, the number of minutes configured, and
		the current stack MAC address.
Step 6
	copy running-config startup-config	(Optional) Save your entries in the configuration file.
	Use the no stack-mac persistent timer global configuration command to disable the persistent MAC
	address feature.
	This example shows how to configure the persistent MAC address feature for a 7-minute time delay and
	to verify the configuration:
	Switch(config)# stack-mac persistent timer 7
	WARNING: The stack continues to use the base MAC of the old Master
	WARNING: as the stack MAC after a master switchover until the MAC
	WARNING: persistency timer expires. During this time the Network
		Catalyst 3750-E and 3560-E Switch Software Configuration Guide
OL-9775-02			5-21