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Damian Gardner

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Need to know how to add another Cisco switch to my existing stack and join it to the correct VLAN

Hello.  I'm not well versed in Cisco switching, but I do know a few things.  Normally I open cases to get help from Cisco directly, but when it comes to adding a new 4th Catalyst switch to my stack, they may tell me to hire a Cisco partner.  I'd like to try and do this myself, with your help.  From what I understand, I need to connect the switch via stack cables, and then get on and configure it to be on the same VLAN as the others.  We are on VLAN2.  Is this simple enough to do?  Can someone guide me on the syntax?  And is there anything else I need to do to configure it correctly?  Or is this a complicated thing?

Thanks for your help.
Damian
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Predrag Jovic
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As soon as switch boot up (power it up already connected to working stack) - if IOS is compatible with IOS version it will become part of stack. It will become stack member. In that case you don't need to do anything special. Stack master general configuration will be applied to new member, you just need to configure ports according to your needs.

If all ports should be assigned to VLAN2 (since it is 4th device added to stack most likely it will be):

interface range gi4/0/1 - 48
 switchport mode access
 switchport access vlan 2

For more details please read Cisco article:
Managing Switch Stack

You can assign stack number to specific switch etc...
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Damian Gardner

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Pedrag - thank you for this help.  Let me try this and see if it works,  I will let you know soon.

Thank you!
Hello Pedrag - when I do a SH INT STATUS, I do not see my need switch in the stack.  perhaps the IOS is not compatible?  I am planning to connect to the console and see what I can see.  how do I see what the IOS version is and know whether its compatible?  what are your thoughts?

thnaks
Issue show switch command - you shoudl see something like:

Stack# show switch

                                           H/W   Current

Switch#  Role   Mac Address     Priority Version  State

----------------------------------------------------------

*1       Master 0018.ba60.de00     15     1       Ready

 2       Member 0018.ba60.ce00     14     1       Ready

 3       Member 0016.9d0c.7500     1      2       Version Mismatch

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Version compatibility is not the only reason for switch not to become stack member. You can typically see it in logs.
Check also link - Resolving Switch Compatibility Issues
Ok. well, I do not see my new switch at all, so now I am wondering if something is wrong with the switch cable connector...or perhaps it did not boot up corerectly.  I will have to check it.
You can connect directly to switch and check how that one sees stack.
What are the models and IOS version of switches in stack, and the new one?
I had to build the configiuration. it was waiting for me to answers questions as to how to configure it.  I have a question - do I want IP routing enabled on the switch?  I assume I do, correct?
I think theres another problem as well - the new switch is coming up as "MASTER".  its showing its interfaces as "gi1/0/1", etc.  this will conflict with the "master" in the first stack.  do I need to reboot the switch maybe? perhaps it will come up in the stack correctly, now that I completed the configuration?
sorry - the models in the stack are Catalyst 3750 G (master), and 2 other Catalyst 3750 members.  new one is Catalyst 3750 POE.  it looks like the IOS version of the stack switches is 12.2, which is the same as the new one.
I just noticed that the switch stack-ports are both "down".  do I need to change them to "up"?
Switch stack-ports nterfaces should be automatically up. you don't have to thing about stack member configuration. Master should configure any member.
Go to stack and try to provision new switch:
# conf t
Switch(config)# switch <next_stack_number> provision <switch_model>           <--- (exact model e.g    ws-3750-24fs-s or whatever)
check if your new model is listed on old stack - if it is provision device and then restart new switch (while it is connected to the rest of the stack).
Important.. make sure that old master is master before save anything... if new device is master when you save configuration will overwrite all startup configurations on all switches.
ok - let me try that.  thanks and standby
I said it just to make you aware of it, but there is no preemption in switch stacks, so as long as old master is powered on - any other devices can't become master (even if higher priority is configured). But if whole stack is reloaded - new device could boot first and become master ... in that case "don't save anything - reload stack and make sure that proper device is master!"
;)
understood. thanks for the warning sir.  question - do I issue the "Switch(config)# switch <next_stack_number> provision <switch_model>" from the new switch, or from the stack master?
sorry - dumb question - I see now you said "go to the stack".  sorry...
So far, no luck.  do you think I might need to reboot the entire stack?
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Predrag Jovic
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ok great. this is helpful.  let me try these and let you know.  thanks
ok - I found a new error that I wasn't noticing before.  I watched the new switch boot up, and it shows errors with the stack-manager app.  I haven't Googled it yet, but it says "STACKMGR-5-MAJOR_VERSION_MISMATCH WITH NEIGHBOR 0"  It also says same thing for "neighbor 1" as well.  I think this is my problem.  don't know what to do about it yet though.
Major version mismatch - means that you should upgrade or downgrade IOS version to match on all devices.
if IOS is compatible with IOS version it will become part of stack.
Major Version Number Incompatibility Among Switches

Switches with different major Cisco IOS software versions usually have different stack protocol versions. Switches with different major version numbers are incompatible and cannot exist in the same switch stack.
Fixing Incompatible Cisco IOS Versions and Switch-Stack Protocol Versions
Ok.  I'll see if theres a way to fix it so they can be stacked.  IF I cannot add the new switch to the stack, how do I use it as a standalone switch in the same VLAN?  Link it through a port on the front somehow?
On interface between devices configure trunk (both devices):

interface gix/y/z
 switchport mode trunk

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On new switch assign ports to VLAN2

interface range gi1/0/1 - 48
 switchport mode access
 switchport access vlan 2

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I talked to Cisco.  they trell me I need to buy an IPBASE license in order to stack it.  so that's what I'll have to do.  for now, I was able to use uplink ports to connect to the stack and am getting by for now.  thanks for your help Predrag.
you're welcome