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stackwise master and stack membership


We've had some issues with 3750 stack where the master defaulted to a switch member we do not want to be master and the stack member numbers aren't in sequence.

We know that the master can be chosen using a priority number and that the member number can be assigned, however our problem follows.

Here's part one:

using sh switch the master switch is switch 2 of a stack of 2, however, switch 2 has a priority of 14 and switch 1 has a priority of 15. According to the doco, switch 1 should be the master. Why is switch 2 the master?

Part 2:

when a stack is rebooted, the order of membership is decided based on which switch came up first, second, and so on. How can you tell remotely which switch is which in the stack?

For instance, I have a stack of 4 switches-- a, b, c, and d. Currently, a is 1, b, 2; c, 3;d, 4;

I reboot the stack and c becomes 1, a, 3; b, 4; d,2.

AFAIK, the only way to know the stack sequence is to go to the site and use the front panel. Is there a way to find this out remotely?

We would like to be able to change the stack member number remotely AND set the master to switch "a" without having to make a trip to the sites.

2 Replies 2

VIP Alumni
VIP Alumni

There is a switch renumber command you can use . In config mode look at your options under switch ? I believe the renumber command is under there .



Part 1:

You are correct, the stack member with the highest priority will be elected master. When you set this value, however, it does not force the change. A reboot of the master switch or stack is required.

Part 2:

You can tell which switch is which by doing a "show switch". You can also connect to each member individually by doing "session #" where # is the stack member number. You can then verify serial numbers of each of the stack members, helping you determine which switch is which.

Once you write the configuration to memory the switch numbering should be the same through reboots, because each switch keeps a copy of the configuration. You can change switch numbering using the "switch reumber" command. For example if switch 1 is the one you want to be switch 2 in the stack you would do the following, from the config prompt.

switch 1 renumber 2

switch 2 renumber 1

This also requires a reload of the stack member. Keep in mind that when you do this the interface level configurations will be lost because you are changing the order of ports.



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