3750 Stack - advice on config

[paul.thomas]

I have a number of 3750 switches stacked with the cables at the back.

I now have a brand new 3750G 24-TS to install and I presume it makes sense for it to be the stack master as its the latest switch with the newest IOS.

Should I just plug it in, or clear the config from the existing ones and give this new one an IP adress before plugging it in?

I have only the default VLAN1 at the moment and none of the switches have been configured with smartports etc. Some have even just picked up DHCP IP addresses.....

Going forwards I will be creating some VLAN's and configuring certain ports for certain systems and functions so I want to ensure the stack is configured correctly from the beginning.

Thanks in advance for any help/advice/suggestions!

[Ivan Shirshin]

Hi Paul,

You should make a new switch priority higher than the others before adding it to the stack.

Please see this steps for adding a switch as a master:

http://www.cisco.com/en/US/products/hw/switches/ps5023/products_configuration_example09186a00807811ad.shtml#stack4

Also, the software on the switches should be the same.

Kind Regards,
Ivan

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[paul.thomas]

thanks for the advice.

One of the existing switches seems to be a different IOS version, its a IPSERVICESK9-M image rather than a IPBASE-M that the new Master is.

What's the easiest way for me to sort this out?

And also, how do I clear the config on this 2nd switch so its gets all its settings form the new master?

[Ivan Shirshin]

Hi Paul,

Here are the steps to upgrade the switches in a stack:

http://www.cisco.com/en/US/products/hw/switches/ps5023/products_configuration_example09186a00804799d7.shtml#cfbin1

In short, you need to (example for 2 switches in a stack):

1. Check that you have enough space:

     dir flash1:
     dir flash2:

2. Copy new image file to both switches

     copy tftp: flash1:
     copy tftp: flash2:

3. Configure the boot variable to boot the switch with the newly copied IOS:

     (config)#boot system switch all flash:/
     (config)#exit
     write memory

4. Reload and Verify    

     reload
     show version

5. To clear configuration, you have to erase both configuration and vlan database:

     write erase
     delete flash1:vlan.dat
     delete flash2:vlan.dat

5. Power down the stack. Set new master with priority 15 and connect to the stack, then boot up.

6. Verify it is master and current IOS version:

     show switch
     remote command all show version

PS: make sure that after adding a master the stack boots with correct IOS version. Master should have the boot string set properly.

Kind Regards,
Ivan

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edited by: Ivan Shirshin

[paul.thomas]

Thankyou, I will try this and let you know.

One other question, can a switch connected via fibre to a stack member participate in the stack?

[m-abooali]

Hi,

I had this problem where a stck was meant to be for two 3750s but someone connected three switches and when I removed one and modified the priorities, I didn't have connectivity and it was thinbking that there must be three switches. even teh stand alone switch which was part of teh stack, was thinking it was still a stack member!?

renumbering and write earse did not resolve my problem until I use two new switches to create a new stack of two 3750s.

I performed write erase with cables attached, with cables removed but no result!?

so I was wondering what may have gone wrong? or what imust have done that I had not done to have the original switches work as a stack of two?

thanks,

Masood

[Ivan Shirshin]

Your removed stack member could have been a provisioned one.  In such case you need to run a command to un-provision it after disconnecting from stack. E.g.:

     no switch 2 provision ws-c3750-48ts

http://www.cisco.com/en/US/products/hw/switches/ps5023/products_configuration_example09186a00807811ad.shtml#stack6

Kind Regards,
Ivan

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[Leo Laohoo]

Hey Paul,

Before you go and upgrade the IOS of your switches, make sure you know what are the flash memory capacity of each of the switch stack members.  3750/3750G comes in two sizes:  16 and 32 mb flash memory.