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New Member

2960-X uplink bugs

I have a site that has 2960-X stacks with a mixture of 15.0(2)EX3 and 15.0(2)EX4 IOS versions.  The stacks are of the 1G uplink variety and are connected to a 4510R+E via WS-X4612-SFP-E modules.  The uplinks are configured as LACP channels.  Since installation a couple of months ago the site has been experiencing random drops on several of the uplinks.  There are no error messages, just line protocol up/down messages.  When the interface drops it invariably comes back up 8 seconds later.


I found this reference under the "Resolved Caveats" in the 15.0(2)EX5 release notes:

  • CSCum03574

Uplink ports in an EtherChannel on a Catalyst 2960X stack (running Cisco IOS Release 15.0(2)EX4) may go down randomly without error logs.


Thinking that this must be my issue, I upgraded a single stack to 15.0(2)EX5, but the problem remained.  So I checked the bug search tool hoping to get some more info.  Bug tool says that it is a duplicate of bug CSCul88801 which has this description:


10G/1G on SW-c2960X does not link up after reload or OIR SFP
10G/1G SFP shows unknown in sh int status.


The cause may be the same, but the symptoms for these 2 bugs seem to be quite different.  In any case EX5 did not seem to fix my dropping uplink issue.  Has anyone else experienced this and if so, have you found a cure?






Hall of Fame Super Gold

There have been several bugs

There have been several bugs with SFP/SFP+ modules on the 2960X which were found in 15.0(2)EX4 and EX5.  The recommended IOS is 15.0(2)EX3, HOWEVER, the "EX" train is just an INTERIM software.  It's main use is to allow clients to get their 2960X/XR working until the straight version comes along.  In other words, the "EX" IOS version is just to "buy time" until the main release comes out.  


The main release for the 2960X/XR is 15.2(2)E and I'd recommend you read the Release Notes and upgrade.  

New Member

Thanks Leo.  I guess I don't

Thanks Leo.  I guess I don't know how to use the bug search tool because when I select "2960-X series switches" and put in "SFP" or "interface" into the search box, (leaving everything else blank) it comes up with 3 bugs either way.  Interestingly enough the one that I mentioned previously does not show up.  Download center recommends 15.0(2)EX5 as does the software research tool.  Where do you find that the EX3 is the recommended IOS?

If you take a closer look to

If you take a closer look to the Release Notes of this IOS trail (15.0(2)EX), you'll see that the workarounds for this issue is either "Reboot the Stack" or downgrade to EX3. But, if you downgrade, you'll come up with another issue, now with SSO. So, I'd recommend you to go along with Leo.

I'm also facing this, and on the next maintenance window (next week), I'll upgrade to 15.2(2)E and see how it behaves.

But, if you want to stick with EX trail, you can go to the Download section, on the Support tab of the main page of the Cisco's website. Then, choose your switch model and download the new IOS. For that to work, you have to have a CCO ID and the contract number (SmartNET or PSS) of your devices tied to your CCO ID.

Hall of Fame Super Gold

Be wary of the new 15.2(2)E

Be wary of the new 15.2(2)E IOS.  


I have been testing this IOS version on a 3560CG & 2960S since the IOS was released to the public. 


So far I have to forcefully power reboot the 3560CG due to the infernal "Low memory.  Try again later." bug.  <EXPLETIVE>


The 2960S (knock on wood) has been OK.  


Another important thing, Cisco has (for awhile) implemented a scoring system, in regards to the IOS versions.  I strongly recommend people to use it.  If the IOS stinks, RATE IT!  If the IOS is good, RATE IT!.  

I have a 3560CG at home

I have a 3560CG at home running 15.2(2)E since it was released also. I haven't seen any problem with it. Is there a "official" bug associated to this "Low Memory" issue?! In what conditions do you have this issue?!

Hall of Fame Super Gold

I have 802.1X with PoE

I have 802.1X with PoE running.  So I don't know what triggers it.  


When this event happens, I can't console into it.  So not sure.

15.0.2a-EX5 has hit and

15.0.2a-EX5 has hit and surposedly fixes the SFP issues. We were experiencing a slightly different problem where the SFP would fall silent. It still reported it was connected and Up/Up but no traffic would go across the interface. We got to the point that we were avoiding using GLC-T for this reason and would use port 24 as an uplink. Then of course we started seeing issues on GLC-SX-MM too and were like WTF, this is screwed.

So maybe try that and see if it helps with your issue. I'll report back on our experiences with the new code as well.



New Member

Thanks Kevin-John, please

Thanks Kevin-John, please keep us posted!

New Member

Kevin, were you able to

Kevin, were you able to confirm whether or not 15.0.2a-EX5 fixed this for you?  Thanks.

New Member

A week ago I upgraded one of

A week ago I upgraded one of the stacks that I was having trouble with from 15.0(2)EX5 to 15.0(2a)EX5.  I was logging a dozen or so line protocol flaps a day and I haven't seen one since the upgrade.  I am going to upgrade 3 more stacks tomorrow.


Yes since the upgrade we have

Yes since the upgrade we have had no further issues with SFP's keeping the link up but no longer transfering data. Both GTC and SX-MM SFP's are now working fine.


I have had a few switches go funny during the upgrade. They start reporting that they are not manufactures by Cisco, the system light remains orange and they won't switch packets. Solution has been to downgrade back to 15.0.2 and then upgrade to 15.0.2a which has worked in all cases thus far.




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