Replacing 3750 24 port with 3750 48 port

[fredareid]

We have a stack of switches that is at the max number of members allowed in the stack. Problem is we are running out of port density and need to add more ports. So instead of adding a whole new stack I would rather replace 2 of the 24-port swicthes with 48-port switches.

I just want to check to make sure my thinking is correct.

If the two 24-port swicthes we are removing are stack members and neither of them are the stack master, I should be able to replace the 24-port switches with the 48-port switches without bringing the master offline?

If the new 48-port switches are running the same IOS version as the current 24-port swicthes, they should add themselves to the stack?

Would I have to tell the new 48-port swicthes what switch numbers they are replacing in order for them to be added to the stack since we are at the max number of members?

Also since the 48-port swicthes are replacing 24-port switches will the master give the 48-port switches the configuration for only the 24-ports?

Any help would be nice. I think I know how this is supposed to work, but I just want to make sure that my thought process is correct.

Thanks

[smehrnia]

hi,

there said the switch's model numbers should be same.

and you replace it one at a time.

http://www.cisco.com/en/US/docs/switches/lan/catalyst3750/hardware/installation/guide/HGTRBL.html#wp1064020

AND

http://www.cisco.com/en/US/products/hw/switches/ps5023/products_configuration_example09186a00807811ad.shtml#stack3

plz Rate if it helped.

Soroush.

[fredareid]

I do not believe that they are the same model as one is a 24-port and the other a 48-port.

[Ivan Shirshin]

Hi Aj,

What Soroush mentioned is partially correct  - the models have to be the same in case of hot swap replacement. You can stack different models, though.See the "note" in this document:

    Note:

    A Cisco 3750 switch can be stacked with any other model of Cisco 3750 switches.

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

You have to make sure the newly added switch is offline when connected to stack, though.

Note that you can use the offline configuration feature to  provision (to supply a configuration to) a new switch before it joins the switch  stack. You can configure in advance the stack member number, the switch  type, and the interfaces associated with a switch that is not currently  part of the stack. Do read this guide before doing that:

http://www.cisco.com/en/US/docs/switches/lan/catalyst3750e_3560e/software/release/12.2_50_se/configuration/guide/swstack.html#wp1178943

Also, here are a helpful links on working with stacks.

http://www.cisco.com/en/US/docs/switches/lan/catalyst3750/software/release/12.2_44_se/configuration/guide/swstack.html

http://www.cisco.com/en/US/docs/switches/lan/catalyst3750e_3560e/software/release/12.2_50_se/configuration/guide/swstack.html#wp1142379

Kind Regards,
Ivan

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[Ivan Shirshin]

Hi,

Answering your other questions  - you have to bring master offline only if you want new switch to become master.

Kind Regards,
Ivan

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[fredareid]

Actually the models are pretty close. WS-C3750V2-48PS and WS-c375V2-24PS. Would I be able to do a hot swap with these?

[Ivan Shirshin]

Hi Aj,

I don't think so, it is still a different part number. I think a good way for this would be to add new 48-port switch to stack, configure it and move the links, remove old 24-port switch.

Kind Regards,
Ivan

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[fredareid]

Ivan.

That would be the way I would like to do it, but the stack is already at the max of 9 switches. I need to remove 2 of the 24 port switches and add in two 48 port switches.

[Ivan Shirshin]

Hi Aj,

Sorry, I missed that you are already at max # of members in the stack. In that case it seems you are out of options. Switch offline provision would not work either as you don't have any stack IDs free.

So you need to remove the 24-port switch from stack, connect 48-port, power it up and put proper configuration on it.

Kind Regards,
Ivan

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[fredareid]

Alright that is what I figured.

So can I unprovision the 24 port switch while it is in the stack to free up the stack id?

[Ivan Shirshin · Accepted solution]

Hi Aj,

Yes, but you need to power off that switch first.

For removing regular switches:

1. Make sure that the stack is fully connected so that, when you remove the member, the stack will be at least in half connectivity, and do not partition.

2. Power off the member to be removed.

3. If the member was the stack master, the stack master election will occur, otherwise no election will occur.

4. Remove the StackWise cables from the member and close the stack ring.

5. Issue the command show switch to verify the stack membership.

For removing provisioned switches:

1. Power off the new stack member to be removed.       
2. Remove the StackWise cable from the switch.  

   Note: The switch stack operation continues uninterrupted during membership  changes unless the stack master is removed or powered-on standalone  switches or switch stacks are added.
   
   

3. Issue the command no switch stack-member-number provision command.       

Note:  You must remove the specified switch from the switch stack before you  use this command in order to delete a provisioned configuration.

Kind Regards,
Ivan

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[fredareid]

Just as I thought.

So power down old 24-port > remove stack member from switch > add in new 48-port > configure

Got it!

Thanks