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Catalyst 2975 Switch Software Configuration Guide
OL-19720-02
Chapter 6 Managing Switch Stacks
Understanding Stacks
switch running the cryptographic image is excluded from the master election process that lasts
10 seconds. To avoid this problem, upgrade the switch running the noncryptographic image to a
software release later than Cisco IOS Release 12.2(46)EX, or manually start the master and wait at
least 8 seconds before starting the new member.
5.
The switch with the lowest MAC address.
A stack master keeps its role unless one of these events occurs:
•
The stack is reset.
*
•
The master is removed from the stack.
•
The master is reset or powered off.
•
The master fails.
•
The stack membership is increased by adding powered-on standalone switches 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 on or reset an entire stack, some stack members
might not
participate in the master
election.
•
All members participate in re-elections.
•
Members that are powered on within the same 20-second time frame participate in the master
election and have a chance to become the master.
•
Members that are powered on after the 20-second time frame do not participate in this initial election
and only become members.
The new master is 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.
When a new master is elected and the previous stack master becomes available, the previous master
does
not
resume its role as stack master.
For all powering considerations that affect stack-master elections, see the “Switch Installation” chapter
in the hardware installation guide.
Stack MAC Address
The MAC address of the master determines the stack MAC address.
When the stack initializes, the MAC address of the master determines the bridge ID that identifies the
stack in the network.
If the master changes, the MAC address of the
new
master determines the new bridge ID. However, when
the persistent MAC address feature is enabled, there is an approximate 4-minute delay before the stack
MAC address changes. During this time period, if the previous master rejoins the stack, the stack
continues to use its MAC address as the stack MAC address, even if the switch is now a member and not
a master. If the previous master does not rejoin the stack during this period, the stack takes the MAC
address of the new stack master as the stack MAC address. See the
“Enabling Persistent MAC Address”
for more information.
Содержание 2975 - Catalyst LAN Base Switch
Страница 36: ...Contents xxxvi Catalyst 2975 Switch Software Configuration Guide OL 19720 02 ...
Страница 40: ...xxxviii Catalyst 2975 Switch Software Configuration Guide OL 19720 02 Preface ...
Страница 62: ...1 22 Catalyst 2975 Switch Software Configuration Guide OL 19720 02 Chapter 1 Overview Where to Go Next ...
Страница 398: ...13 30 Catalyst 2975 Switch Software Configuration Guide OL 19720 02 Chapter 13 Configuring VLANs Configuring VMPS ...
Страница 424: ...15 18 Catalyst 2975 Switch Software Configuration Guide OL 19720 02 Chapter 15 Configuring VTP Monitoring VTP ...
Страница 628: ...26 8 Catalyst 2975 Switch Software Configuration Guide OL 19720 02 Chapter 26 Configuring UDLD Displaying UDLD Status ...
Страница 660: ...28 8 Catalyst 2975 Switch Software Configuration Guide OL 19720 02 Chapter 28 Configuring RMON Displaying RMON Status ...
Страница 888: ...38 32 Catalyst 2975 Switch Software Configuration Guide OL 19720 02 Chapter 38 Troubleshooting Troubleshooting Tables ...