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New Member

Swapping Stack cables on Stack switch.

                   Hi everyone.

Currently 2 Switch stack is config as shown.

         Stack Port Status             Neighbors

Switch#  Port 1     Port 2           Port 1   Port 2

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

  1        Ok        Down               2      None

  2        Ok        Down               1      None

Stack cables are not crossed.

    sh switch stack-ring  speed

Stack Ring Speed        : 16G
Stack Ring Configuration: Half
Stack Ring Protocol     : StackWise

Currently both stack cables are connected because they are not crossed i see one connection as down down.

Question if i unplug stack cable the switch will lose the stack connection  and as many servers are connected here what will be the impact?

Once i fix the stack cables should i reboot the switch?

Regards

Mahesh

Message was edited by: mahesh parmar

5 ACCEPTED SOLUTIONS

Accepted Solutions
Bronze

Swapping Stack cables on Stack switch.

At this point, your stack is running in Half-Duplex mode.

If you disconnect the Stack Cable that is currently passing traffic, you will break the stack and disrupt traffic.

You can safely disconnect the stack cable that is down/down, because it is NOT passing traffic.

I believe it is not recommended to connect stack cables while the switches are running - but because they are already running in a stack I believe you should be fine.

HTH

Hall of Fame Super Gold

Swapping Stack cables on Stack switch.

If switch 1 is the master ...

Power down switch 2.  Re-cable so the cable will form an "X".  Power up switch 2.

Hall of Fame Super Gold

Swapping Stack cables on Stack switch.

So while doing this i should console in to the master switch to know whats happening in real time right?

Optionally, you don't have to but I do.  I want to see the log messages when a new switch joins.

So once i power up the switch 2 stack should form and there is no need to reboot master switch right?

That's correct.  The important thing is to power DOWN the 2nd switch when you want to add/remove the switch.

Hall of Fame Super Gold

Swapping Stack cables on Stack switch.

IOS is  /c3750-ipservicesk9-mz.150-2.SE2.bin"

Careful with this IOS version.  15.0 has many CPU hog bugs which was slowly being fixed with 15.0(2)SE4.

Personally, I'd recommend running 12.2(55)SE8 for 3750 switches.

Otherwise, if you need some features only found in 15.0 then go to 15.0(2)SE4.

Super Bronze

Re: Swapping Stack cables on Stack switch.

Disclaimer

The  Author of this posting offers the information contained within this  posting without consideration and with the reader's understanding that  there's no implied or expressed suitability or fitness for any purpose.  Information provided is for informational purposes only and should not  be construed as rendering professional advice of any kind. Usage of this  posting's information is solely at reader's own risk.

Liability Disclaimer

In  no event shall Author be liable for any damages whatsoever (including,  without limitation, damages for loss of use, data or profit) arising out  of the use or inability to use the posting's information even if Author  has been advised of the possibility of such damage.

Posting

Peter Koltl wrote:

I'm wondering why X (cross-connect) is important?

I believe it's not important.  Getting both ring ports active is what's important (as it doubles your ring bandwidth and increases redundancy).

17 REPLIES
Bronze

Swapping Stack cables on Stack switch.

At this point, your stack is running in Half-Duplex mode.

If you disconnect the Stack Cable that is currently passing traffic, you will break the stack and disrupt traffic.

You can safely disconnect the stack cable that is down/down, because it is NOT passing traffic.

I believe it is not recommended to connect stack cables while the switches are running - but because they are already running in a stack I believe you should be fine.

HTH

New Member

Swapping Stack cables on Stack switch.

Hi Kyle,

If i follow the steps below

1>Disconnect the stack cable that is currently passing traffic  and connect it to other switch port.

While i do this stack will break and once it is connected stack will be up again.

2>Then i can connect the second stack cable which is down down to the other port of switch.

Then both stack connections will be up up.

Once i do this do i need to reboot the stack?

Regards

Mahesh

Hall of Fame Super Gold

Swapping Stack cables on Stack switch.

Post the complete output to the command "sh switch details".

New Member

Swapping Stack cables on Stack switch.

Hi Leo,

HEre is info

sh switch detail
Switch/Stack Mac Address : 001e.f677.d600
                                           H/W   Current
Switch#  Role   Mac Address     Priority Version  State
----------------------------------------------------------
*1       Master 001e.f677.d600     1      0       Ready
2       Member 001e.f6bf.6e00     1      0       Ready

         Stack Port Status             Neighbors
Switch#  Port 1     Port 2           Port 1   Port 2
--------------------------------------------------------
  1        Ok        Down               2      None
  2        Ok        Down               1      None

Regards

MAhesh

Hall of Fame Super Gold

Swapping Stack cables on Stack switch.

If switch 1 is the master ...

Power down switch 2.  Re-cable so the cable will form an "X".  Power up switch 2.

New Member

Swapping Stack cables on Stack switch.

Hi Leo,

So while doing this i should console in to the master switch to know whats happening in real time right?

Also i will be doing this on this weekend maintenace window.

So once i power up the switch 2 stack should form and there is no need to reboot master switch right?

Just making sure with you as we have some critical devices connected to this stack switch.

Regards

Mahesh

Hall of Fame Super Gold

Swapping Stack cables on Stack switch.

So while doing this i should console in to the master switch to know whats happening in real time right?

Optionally, you don't have to but I do.  I want to see the log messages when a new switch joins.

So once i power up the switch 2 stack should form and there is no need to reboot master switch right?

That's correct.  The important thing is to power DOWN the 2nd switch when you want to add/remove the switch.

New Member

Swapping Stack cables on Stack switch.

Hi Leo,

Thanks for giving me steps to do this process.

I will let you know on weekend how it goes.

Regards

Mahesh

Hall of Fame Super Gold

Swapping Stack cables on Stack switch.

Thanks for the ratings, Mahesh.

On the side note, what IOS are your 3750 running on?

New Member

Swapping Stack cables on Stack switch.

Hi Leo.

IOS is  /c3750-ipservicesk9-mz.150-2.SE2.bin"

Regards

MAhesh

Hall of Fame Super Gold

Swapping Stack cables on Stack switch.

IOS is  /c3750-ipservicesk9-mz.150-2.SE2.bin"

Careful with this IOS version.  15.0 has many CPU hog bugs which was slowly being fixed with 15.0(2)SE4.

Personally, I'd recommend running 12.2(55)SE8 for 3750 switches.

Otherwise, if you need some features only found in 15.0 then go to 15.0(2)SE4.

New Member

Swapping Stack cables on Stack switch.

Thanks Leo i will make note of  this for future ios upgradations.

Hall of Fame Super Gold

Swapping Stack cables on Stack switch.

Thanks for the ratings, Mahesh.

New Member

Swapping Stack cables on Stack switch.

Stack cable change went fine without any issues.

Silver

Swapping Stack cables on Stack switch.

I'm wondering why X (cross-connect) is important?

Super Bronze

Re: Swapping Stack cables on Stack switch.

Disclaimer

The  Author of this posting offers the information contained within this  posting without consideration and with the reader's understanding that  there's no implied or expressed suitability or fitness for any purpose.  Information provided is for informational purposes only and should not  be construed as rendering professional advice of any kind. Usage of this  posting's information is solely at reader's own risk.

Liability Disclaimer

In  no event shall Author be liable for any damages whatsoever (including,  without limitation, damages for loss of use, data or profit) arising out  of the use or inability to use the posting's information even if Author  has been advised of the possibility of such damage.

Posting

Peter Koltl wrote:

I'm wondering why X (cross-connect) is important?

I believe it's not important.  Getting both ring ports active is what's important (as it doubles your ring bandwidth and increases redundancy).

New Member

Swapping Stack cables on Stack switch.

Thanks Joseph for replying the question.

Regards

Mahesh

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