Adding a 3750 switch to an existing stack

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Nov 24th, 2011
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I am looking to add a new 3750 Switcch to an existing stack shown below


Switch   Ports Model             SW Version             SW Image

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

*   1   26     WS-C3750-24P       12.2(35)SE5             C3750-IPBASE-M

     2   26     WS-C3750-24P       12.2(35)SE5             C3750-IPBASE-M

     3   26     WS-C3750-24P       12.2(35)SE5             C3750-IPBASE-M


                 Stack State Machine View

==============================================================


Switch   Master/   Mac Address         Version   Current

Number   Member                         (maj.min) State

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

1       Master   001d.e5d5.1c00         1.34      Ready

2       Member   001d.e641.9d80      1.34       Ready

3       Member   001d.e63e.3f80       1.34       Ready


                                           H/W   Current

Switch# Role   Mac Address     Priority Version State

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

*1       Master 001d.e5d5.1c00     1     0       Ready

2       Member 001d.e641.9d80     1     0       Ready

3       Member 001d.e63e.3f80     1     0       Ready


         Stack Port Status             Neighbors

Switch# Port 1     Port 2           Port 1   Port 2

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

1       Ok         Ok               2       3

2       Ok         Ok               3       1

3       Ok         Ok               1        2



The new switch version is shown below


Switch Ports Model             SW Version           SW Image

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

*   1 26   WS-C3750V2-24PS   12.2(50)SE5           C3750-IPBASEK9-M


                 Stack State Machine View

==============================================================


Switch   Master/   Mac Address         Version   Current

Number   Member                         (maj.min) State

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

1       Master   e8ba.7090.f780         1.41       Ready


I have looked on notes to add a switch to an existing stack and haven’t identified answers on how the IOS will be affected on the new switch – will it downgrade to the current stack version or will the current stack upgrade to its version. At this moment in time I would prefer if the new switch IOS downgraded to the current stack IOS version.


The new switch is a 3750V2 – will this affect how it joins the stack?

The new switch has the image of IPBASEK9-M – again will this affect how it joins the stack?


Any help appreciated


Martin

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manju.cisco Thu, 11/24/2011 - 02:26
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Hi,


As previously said,  it  can be stackable, however IOS for all switches should be same. In your  case, you must load IOS C3750-ADVIPSERVICESK 12.2(25)SEE2 to 3750V2  switch before connecting it to the existing stack.


If IOS are not same, then you would see "Version Mismatch" as Current State for the 3750V2 switch. This indicates that stack switch is not having IOS same as current stack switches.


Also, IOS upgrade or downgrade will not happen on its own when you connect to a stack.

Latchum Naidu Thu, 11/24/2011 - 04:33
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Hi Martin,


As mentioned above, you must have same IOS version on all stack switches, so in your case the new switch which you are going to add to existing stack needs to be the same IOS what the existing stack switches have.


Regarding the procedure how to add a new switch to an existing stack, see the below link.

http://www.thenetworkadministrator.net/index.php/2011/01/adding-a-cisco-3750-switch-to-an-existing-stack/


Here’s the link to the software upgrade caveats/howtos for stack configurations(if it seems like I breezed through this last step):

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


Please rate the helpfull posts.
Regards,
Naidu.

Leo Laohoo Fri, 11/25/2011 - 19:50
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Ok.  Here's the deal and here's the problem.


The way I understand your issue, you have a stack of "legacy" 3750 running 12.2(35)SE5 and you want to add a "V2" to the stack.


Here's the problem:  You CANNOT add the V2 into the stack unless you upgrade the entire stack to a minimum of 12.2(50)SE2.  Why?  The V2 will work at this minimum level.  Any IOS version below this will render your V2 useless.


Here's another problem for you, if you have legacy 3750 then chances are they have 16 mb of flash.  This means that the highest IOS version you can use is 12.2(55)SE and later.  You can't use 12.2(58)SE nor 15.0(1)SE. 

yulem1968 Mon, 11/28/2011 - 01:59
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Thanks for all the replys


I did try and downgrade the IOS on the new switch - no joy there.

Unfortunately there is not a switch in stock to add to the new one to determine compatible IOS version for legacy and V2 3750 switches.


I will look to upgrade the 3750 stack to the IOS mentioned in leolaohoo's reply. Do i just load the new IOS to the master stack member then issue commands on the other stack members so that the new IOS is applied to them? (I have confirmed that the current 3750s are 16Mb of flash).


Martin

Leo Laohoo Mon, 11/28/2011 - 13:42
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I did try and downgrade the IOS on the new switch - no joy there.

You CANNOT/COULD NOT/WOULD NOT BE ABLE TO downgrade the IOS of a V2 to 12.2(35)SE5.  The appliance will not "understand" and will go into ROMmon.  (Thus I stated "Any IOS version below this will render your V2 useless."



I will look to upgrade the 3750 stack to the IOS mentioned in leolaohoo's reply. Do i just load the new IOS to the master stack member then issue commands on the other stack members so that the new IOS is applied to them? (I have confirmed that the current 3750s are 16Mb of flash).

1.  You need to download the correct IOS, between IOS version 12.2(50)SE2 and 12.2(55)SE4.

2.  The file should be in a TAR file extension and NOT the BIN.

3.  The command to "push" the IOS from your TFTP server (where the IOS file is hopefully located) to your stack of switches is:  archive download-sw /dest 1 /dest 2 /dest 3 /overwrite tftp:///.tar


Hope this works.

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