stacking ports are unstable in 3750 cisco switch

Unanswered Question
Jul 24th, 2008

Dear All,

We have noticed on 3750 switch that the stacking ports have been unstable,

they are flapping server times a day,i couldnt able to find out any thing exeptthe below explanation

Error Message STACKMGR-4-STACK_LINK_CHANGE: Stack Port [chars] Switch [dec] has

changed to state [chars].

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

Note This message applies only to the Catalyst 3750-E switches.

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

Explanation The specified stack port status has changed state to up or down. The first [chars] is the stack port (1 or 2),

[dec] is the switch number, and the second [chars] is the new state (up or down).

Recommended Action No action is required.

Logs of the Switch are below

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

ul 24 15:35:02.028 UTC: %STACKMGR-4-STACK_LINK_CHANGE: Stack Port 1 Switch 2 has changed to state DOWN

Jul 24 15:35:02.892 UTC: %STACKMGR-4-STACK_LINK_CHANGE: Stack Port 2 Switch 1 has changed to state UP

Jul 24 15:35:03.035 UTC: %STACKMGR-4-STACK_LINK_CHANGE: Stack Port 1 Switch 2 has changed to state UP

Jul 24 15:37:30.089 UTC: %STACKMGR-4-STACK_LINK_CHANGE: Stack Port 1 Switch 2 has changed to state DOWN

Jul 24 15:37:30.123 UTC: %STACKMGR-4-STACK_LINK_CHANGE: Stack Port 2 Switch 1 has changed to state DOWN

Jul 24 15:37:31.096 UTC: %STACKMGR-4-STACK_LINK_CHANGE: Stack Port 1 Switch 2 has changed to state UP

Jul 24 15:37:31.129 UTC: %STACKMGR-4-STACK_LINK_CHANGE: Stack Port 2 Switch 1 has changed to state UP

Jul 24 15:46:41.542 UTC: %STACKMGR-4-STACK_LINK_CHANGE: Stack Port 2 Switch 1 has changed to state DOWN

Jul 24 15:46:42.549 UTC: %STACKMGR-4-STACK_LINK_CHANGE: Stack Port 2 Switch 1 has changed to state UP

Jul 24 15:50:18.392 UTC: %STACKMGR-4-STACK_LINK_CHANGE: Stack Port 2 Switch 1 has changed to state DOWN

Jul 24 15:50:21.420 UTC: %STACKMGR-4-STACK_LINK_CHANGE: Stack Port 2 Switch 1 has changed to state UP

Jul 24 15:51:23.044 UTC: %STACKMGR-4-STACK_LINK_CHANGE: Stack Port 1 Switch 2 has changed to state DOWN

Jul 24 15:51:24.051 UTC: %STACKMGR-4-STACK_LINK_CHANGE: Stack Port 1 Switch 2 has changed to state UP

Jul 24 15:56:33.144 UTC: %STACKMGR-4-STACK_LINK_CHANGE: Stack Port 1 Switch 2 has changed to state DOWN

Jul 24 15:56:34.151 UTC: %STACKMGR-4-STACK_LINK_CHANGE: Stack Port 1 Switch 2 has changed to state UP

Jul 24 15:59:43.478 UTC: %STACKMGR-4-STACK_LINK_CHANGE: Stack Port 1 Switch 2 has changed to state DOWN

Jul 24 15:59:44.484 UTC: %STACKMGR-4-STACK_LINK_CHANGE: Stack Port 1 Switch 2 has changed to state UP

Jul 24 16:05:06.748 UTC: %STACKMGR-4-STACK_LINK_CHANGE: Stack Port 1 Switch 2 has changed to state DOWN

Jul 24 16:05:07.755 UTC: %STACKMGR-4-STACK_LINK_CHANGE: Stack Port 1 Switch 2 has changed to state UP

Could some one help out on this

Thanks and regards

Sharan

I have this problem too.
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Mark Yeates Thu, 07/24/2008 - 19:56

Sharan,

Have you tried different stackwise cables or ports of possible? I have had troubles in the past with the cables not being securely tightened in the back of the switch also.

HTH,

Mark

Sebastian Helmer Thu, 07/24/2008 - 22:33

Yes, I would first check the hardware too.

My question, did you stach switch 1 port 1 -> switch 2 port 1, this is maybe why you got problems, beause it is wrong I think.

(Stupid question, but it's possible... ;-) )

PS: you can give us the output from "show switch detail"

maybe we can see a problem.

Sebastian

UCBNOCWAN Thu, 07/24/2008 - 23:06

Dear All,

Thanks very much for your valuble inputs

please find the show switch details

XXXX-2100-G-3750-1#sh switch detail

Switch/Stack Mac Address : 0091.aad8.2d00

H/W Current

Switch# Role Mac Address Priority Version State

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

1 Member 002f.c987.7300 1 0 Ready

2 Member 0032.1b8a.2200 1 0 Ready

*3 Master 0091.aad8.2c00 1 0 Ready

Stack Port Status Neighbors

Switch# Port 1 Port 2 Port 1 Port 2

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

1 Ok Ok 3 2

2 Ok Ok 1 3

3 Ok Ok 2 1

XXX-2100-G-3750-1#

XXX-2100-G-3750-1#sh switch neighbors

Switch # Port 1 Port 2

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

1 3 2

2 1 None

3 2 1

XXXX-2100-G-3750-1#sh switch stack-ports

Switch # Port 1 Port 2

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

1 Ok Ok

2 Ok Ok

3 Ok Ok

Sebastian Helmer Thu, 07/24/2008 - 23:21

Hi Sharan,

thanks for the output.

The "None" in your output you see on the button ist a mistake. It does not really match to your error messages, but can be in relation to that. I have stacks but never this problem bevor. I think the Stack cable or port is damaged.

I can check that in my lab, but only next tuesday. Maybe some others have more ideas and experience. If you dont't get reply until there, I will try check that in lab.

XXX-2100-G-3750-1#

XXX-2100-G-3750-1#sh switch neighbors

Switch # Port 1 Port 2

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

1 3 2

2 1 None

3 2 1

Willem de Groot Wed, 07/30/2008 - 05:50

Hi Sharan,

you are not the only one with this problem :-(

I see the same log entries.

New Stack, IOS 12.2(44)SE2

My Stack has only 2 of once 3 members!

Have there been another member in your stack, which was removed?

Willem

UCBNOCWAN Wed, 07/30/2008 - 21:45

HI all

I have 5 stack switches with the same IOS,Version 12.2(44)SE2. but this problem exist only in 2 stack,i am not sure it is related to IOS

thanks

sharan

Sebastian Helmer Thu, 07/31/2008 - 12:22

First Sorry for my late replay, lt of work...

I check it today with a Stack and i haven't the problem or can see andy point which could be that.

Second I check some troubleshooting guides, config guides and else. No idea.

Google didn't help too..

I'M really Sorry :(

Maybe this helps, my last Idea

http://www.cisco.com/univercd/cc/td/doc/product/lan/cat3750/12235se/scg/swgold.pdf

I will stay on that problem, if i have new, it old you of course

best regards

Sebastian

Danilo Dy Fri, 08/01/2008 - 08:14

Hi,

Thus your stackwise cable in a full ring?

Try configuring the stack-ring speed to full.

Regards,

Dandy

UCBNOCWAN Mon, 08/04/2008 - 01:49

Hi,

please find the out put

G-3750-1#sh switch stack-ring speed

Stack Ring Speed : 32G

Stack Ring Configuration: Full

Stack Ring Protocol : StackWise

#

Could you please tell me how to go abt from here

regards

Sharan

Willem de Groot Thu, 08/28/2008 - 21:45

Hi Sharan,

as i wrote before, i have the same problem.

Down/Ups every 30 Sec.

The same as in your case mostly the same link (sw2 Port 1 to SW1 port 2).

So i decided to change this Cable -> YES it changed it got even worse! Now i have Down/ups every 10 Sec.

After "reload slot 2" (I have only 2 switches) it came to Down/Up times from 1-2 Sec.

After a "reload" (i think this will reload the hole stack) the Down/Ups show up every 20-30 sec somtimes even longer. (Same switch is master again)

Sharan (and others) can you do a ping from a windows client, not connected at the switch to a device connected to this 3750?

I notice here a TTL of 63 or even 59 (different clients)!!!

Pinging a device on the same vlan on a other switch (3524) a have a TTL of 254.

a Tracert only shows 2 Hops.

Can sombody explain this last behavior?

What are the TTLs on a "working" stack?

Thanks

Willem

Willem de Groot Wed, 09/03/2008 - 10:05

Hi Sharan,

Do you still have this problem?

My problem seems to go away if a plug in the 3rd., provisioned switch.

(the Stack was setup originaly with 3 Switches, in Production I only used 2 of them)

if I did a show run, I saw/see

switch 1 provision ws-c3750e-24pd

switch 2 provision ws-c3750e-24pd

switch 3 provision ws-c3750e-24pd

But I only had 2 Swiches in my stack and got the same messages as you have.

Now I Pluged in the 3rd. switch, runnung now for 25 Minutes with the same cables, without a down/up.

doing a sh switch detail:

chspn175#sh switch detail

Switch/Stack Mac Address : 0022.5529.1680

H/W Current

Switch# Role Mac Address Priority Version State

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

*1 Master 0022.5529.1680 10 1 Ready

2 Member 0022.5529.0900 1 1 Ready

3 Member 0022.5529.0980 1 1 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

Can you Post the same parts of your config (show run, the switch part and show switch detail).

As soon as i go back to 2 switches I will have the same problem again ;-(

Thanks

Willem

HI all.

Did anyone get a resolution to this problem?

I have a customer with a stack of 6 3750's. We often have problems with stack up/down messages in the log, usually between switches 1&2 but sometimes with other stack members. I've replaced individual switches, all stackwise cables, upgraded the IOS - still we have the same problem.

I'm wondering if there is an IOS problem or a batch of faulty hardware out there.

glen.grant Fri, 01/09/2009 - 04:30

First thing to check is to make sure they are tight , we have found they can look tight and seem tobe tight to the hand but you have to use a screwdriver to tighten them down the way they should be . Then check to see how they are cabled , we always go from port 1 switch 1 to port 2 switch , then port 1 switch 2 to port 2 switch 3 and then port 1 switch 3 back to switch 1 port 2 . I have never seen any stack bouncing messages to this point . That being said I think remember seeing some TSB somewhere that cisco had delivered some bad stack cables but I can't swear to it. As far as I'm concerned those connectors are shakey at best. They could have used a better design.In the old days Synoptics had better stack cables for there hubs than the design they used for these.

stormfidus Fri, 01/09/2009 - 05:14

Hi Brian

I have now changed about 8 switches with the flapping stack-ports. The TAC cases I've opened all came with the solution was to insert a new working switch between the 2 flapping switches, to see whether it was switch1 or 2 which was faulty, after that I changed the switch, and the flapping ports stopped right away. Before that solution I also tried to replace stack-cables with no difference and also upgraded the IOS serval times with no change.

So as I see it, the only solution is to isolate the switch which is flapping and replace it with a new one.. - hell of a work, but we dont like flapping stack ports!

-Claus

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