How to add a 3750 in the existing stack of 3 switches

As long as your IOS matches and the stack speed is full (see http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3750/hardware/quick/guide/3750GSG3.html#wp49279) then you should be able to break the stack and insert the new switch while it is powered off. Once the wired you power on the new switch and after a few minutes it should be added as switch #4.

Apart from the IOS Version #, also make sure you have the same feature set/licenses ... mismatch there will also cause the stacking to fail ...

How do I check the feature set licenses?

"show license" should display the licenses of all the switches in the stack (or single switches, too, of course)

This are the steps I'm planning:

1. Connect to Stack
2. Assign a gateway on Vlan1 using console cable
3. Get the firmware upgraded
4. Set the switch stacking priority on it

Please have in mind that this is a production environment, so obviously I would need to disconnect and reconnect the stack to add the new switch, but I need to know if I can do steps 2 through 4 with the new switch connected to the stack without interfering with 3 production switches I have in the stack right now.

Am I in the right track?

Hi Garry,
I will upgrade the IOS before stacking the swtich, as per your recommendation.

Questions:

After I connect the Switch to the Stack, do I need to configure a gateway in Vlan1 or will it just be accessible through the stack.

Also, if I connect through the console cable to a switch that is connected to the stack, what will I see the stack or just that switch configuration?

I'm making a plan to do this soon, probably on Saturday and I will close the question after that.

Again, thanks for all your help.

Hi Garry,
To do the new 3750 initial configuration ...

Is it Ok to connect the power supply to the regular outlet without using any stackpower cables?

Or do I need to have any special stackpower cable connection.

Remember this is before stacking the switch.

Thanks.

Normally, I'd just hook up the stacking cables, then power up the switch, which should then automatically copy the config of the existing stack to the new member ...

I would like to connect first to the switch just to set the switch stack priority command to 1 on the new switch prior to installing it to ensure it doesn’t take over as the master.

Can you please find out if I need to worry  about the stackpower cables?

How do you have StackPower configured at the moment? I assume power sharing?
From what I can say, you should be able to start out without adding the switch to the power sharing stack ... just hook up the normal stacking and use the built-in PS to power up the new switch. Also, the new switch should not take over as admin switch ... the default priority is 1, so it can't be higher than any master already running. To ensure your preferred switch is master, just make sure it is set to something considerably higher (like e.g. the maximum of 15 ...)

Hi Garry-G,
Ok, I just upgraded the IOS, so now it has the same version as the switches in the stack.

Switch>show switch
Switch/Stack Mac Address : d8b1.9054.c080
                                           H/W   Current
Switch#  Role   Mac Address     Priority Version  State
----------------------------------------------------------
*1       Master d8b1.9054.c080     1      3       Ready



Switch#show ver
Cisco IOS Software, C3750E Software (C3750E-UNIVERSALK9-M), Version 15.0(2)SE8,
RELEASE SOFTWARE (fc1)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2015 by Cisco Systems, Inc.
Compiled Wed 13-May-15 22:53 by prod_rel_team

ROM: Bootstrap program is C3750E boot loader
BOOTLDR: C3750E Boot Loader (C3750X-HBOOT-M) Version 15.2(3r)E, RELEASE SOFTWARE
 (fc1)

Switch uptime is 8 minutes
System returned to ROM by power-on
System image file is "flash:c3750e-universalk9-mz.150-2.SE8.bin"

As for the "show license"  this is what I get when I run that command in the stack

But this doesn't tell me anything, as this is the first time I run that command

Is this Ok?

3750_Stack#show license
Index 1 Feature: ipservices
        Period left: 8  weeks 4  days
        License Type: Evaluation
        License State: Active, Not in Use, EULA not accepted
        License Priority: None
        License Count: Non-Counted

Index 2 Feature: ipbase
        Period left: Life time
        License Type: Permanent
        License State: Active, In Use
        License Priority: Medium
        License Count: Non-Counted

Index 3 Feature: lanbase
        Period left: 0  minute  0  second

3750_Stack#

What's the output of doing the "show license" on the new switch that's not connected to the stack yet? Does it have the ipbase license, too?

Garry-G,
I will run the show lincense in a moment.

Question:
Do you have a good reference to help me find the correct order to connect the StackPower cables with 4 switches?

The Stacking cables connection order is pretty straight forward but the StackPower cables connection seems a little confusing.

This document is pretty much straight forward ...

http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3750x_3560x/hardware/installation/guide/3750x_3560x_HIG/HIGINSTL.html#wp1348161

Essentially, what you want is the same "ring" as you have with the normal stacking cables ... remember though that there is a maximum of 4 switches in a stack power ring  (which shouldn't be a problem, as you only have the four switches ...)

Excellent, all the cable connectivity information is in that document.

This is the output of the "show license" command in the new switch:

Switch#show license
Index 1 Feature: ipservices
        Period left: 8  weeks 4  days
        License Type: Evaluation
        License State: Active, Not in Use, EULA not accepted
        License Priority: None
        License Count: Non-Counted

Index 2 Feature: ipbase
        Period left: Life time
        License Type: Permanent
        License State: Active, In Use
        License Priority: Medium
        License Count: Non-Counted

Index 3 Feature: lanbase
        Period left: 0  minute  0  second

Switch#

same as the stack, so that should work fine ...

Ok, so just to recap.
The new switch IOS currently is the same version as the other 3 switches.
The new switch stack priority is 1.
The licenses are Ok.
And that's all we needed to check before the actual stacking.

tomorrow morning I will:
1. Rack the new switch under the other 3 switches.
2. Disconnect and Reconnect the StackPower cables as per the document you sent me.
3. Disconnect one stacking cable (which halves the throughput in the stack, but keeps the stack alive), then connect the new switch to it and finally hook up the fourth stacking cable to close the stacking ring again.
4. Connect the power supplies of the new switch to the UPS.

Step 3 means that I don't have to turn off the Stacked switches to connect the new one.

After that the new switch will be part of the stack and we will be able to see it through the central stack management (the new ports will come up as Gi4/0/1, Gi4/0/2, etc.).

I will wait 10 minutes to check if the new 4th switch ports are accessible.

Is all this correct?

I'm planning to this tomorrow morning.

I'd hook up the stack power cable after powering the switch with the regular PS, as otherwise the new stack should receive power once you connect the stack power cable ... apart from that, everything ought to work smoothly ...

Ok then, I will follow the steps above just moving the stackpower cables reconnection (step 2) to the end of the process.

And if everything works smoothly tomorrow I will close the question and give you the points.

Thanks.

Hi Garry-G,
I have just added my forth switch to the stack and everything is working beautifully.
I can see the new switch in the stack as new ports Gi4/0/1, Gi4/02, ... just like you said.

I want to thank you because your help was absolutely crucial for this project.

I wish you the best in your future endeavors.

Glad to hear everything worked out as planed ... with IT, there are so often minor "mishaps" with stuff not doing what it's supposed to be doing according to docs & previous experiene ;)