FEX Serial Number Not Updating On 5K When FEX Replaced

Unanswered Question
Sep 8th, 2009
User Badges:

Hello Everyone.

Thanks for taking a moment to comment on this issue if you can!

We've noticed the following issue. When replacing a FEX that has associated to a 5K, the serial number does not automatically change to reflect the new box (when using "show fex xxx".) In fact if you try to manually change the serial number with "fex serial abcdef" to match the actual serial number, the FEX goes offline. However if you do "show sprom fex xxx backplane" you will see in the output both the old incorrect s/n and the new correct s/n.

Has anyone tested with this issue, seen a work-around, or had any feedback from Cisco?? Thanks again, Simon

  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 3 (1 ratings)
spreed Wed, 09/09/2009 - 08:45
User Badges:

Further investigation has shown the following:

- show fex xxx will show a serial number that does NOT match the serial number on top of chassis

- show sprom fex xxx backplane will include two S/Ns one of which WILL match the chassis one

- if you physically disconnect the FEX and do show fex xxx it still shows the old S/N but

show sprom fex xxx backplane will no longer display anything

- if you move the FEX to new port (and assign new FEX yyy number) the two S/Ns show up there AND

if you do show fex xxx (with xxx being old FEX number) the info for old FEX xxx has been removed.

One key item from the above is that show fex xxx does not show the S/N labeled on the top of the box. This could cause some confusion when troubleshooting issues.

johgill Thu, 11/05/2009 - 14:20
User Badges:
  • Bronze, 100 points or more

I see what you are saying, and I think I can partially simplify somewhat by saying:

The sticker on the FEX is showing the serial number of the board, the serial number show in "show fex" is from the SPROM. These are different, and I agree this is confusing.

When you run "show sprom fex xxx", you are querying the fex remotely. This is why you cannot see it when the fex is removed.

spreed Mon, 11/09/2009 - 08:41
User Badges:

Thanks John for taking the time to comment on this issue.


johgill Mon, 11/09/2009 - 11:34
User Badges:
  • Bronze, 100 points or more

Sure thing. Step 1 is understanding it, Step 2 would be to make them match. I'm not sure it can be done, but I do have a meeting with hardware folks that might be able to make a change here.


This Discussion