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New Member

WS-C3850-12XS - SFP not registering following upgrade

I've recently upgraded a stacked pair of WS-C3850-12XS switches to version 03.07.05E. Following the upgrade, the primary switch in the stack no longer recognises the SFP's connected in ports 1/0/1 & 1/0/6. The secondary device has SFP's connected in the same ports and the device recognises them ok.

The SFP's are genuine Cisco parts and worked fine before the upgrade. As 03.07.05E is the latest version, I'm not sure what to do now?

The upgrade was necessary because we were previously hitting bug CSCva48439.

Any suggestions would be gratefully received!!


Everyone's tags (1)
New Member

Hi James,

Hi James,

Have you did any L1 troubleshooting i.e. reinserting or by trying to connect other working port. If yes then please update the details post physical troubleshooting and share the below details,

1) part number of the SFP module which is not working

2) show version

3) show inventory

New Member

Unfortunately the device is

Unfortunately the device is located in a remote DC, so I will need to arrange access before I can complete any L1 troubleshooting.

Here are the details requested:

1. SFP-H10GB-CU5M (Te1/0/1) & SFP-10G-SR (Te1/0/6)

2. Switch Ports Model SW Version SW Image Mode
------ ----- ----- ---------- ---------- ----
* 1 16 WS-C3850-12XS 03.07.05E cat3k_caa-universalk9 INSTALL
   2 16 WS-C3850-12XS 03.07.05E cat3k_caa-universalk9 INSTALL

3. See attachment

New Member



Both the SFP's are supported on 3850 platform and running version. Need to do some troubleshooting physically if connected but not coming up. 

I see the inventory and found only three ports are showing SFP inserted.

"Switch 1"
"Te1/0/12",  SFP-10G-LR        

"Switch 2"
"Te2/0/1",  SFP-H10GB-CU5M    

"Te2/0/12", : SFP-10G-LR        

You shared that same port on switch 2 are recognized. can you check again are those are properly inserted or not.

New Member

Actually, there is no SFP

Actually, there is no SFP installed in 2/0/6. (My mistake)

As I mentioned previously, I know the SFP's are inserted properly into ports 1/0/1 & 1/0/6, as they were recognised before the sw upgrade.

What is strange is that switch one still recognises the LH SFP inserted into 1/0/12.

I plan to re-boot the switch this evening to see if this resolves the issue. If that fails, I will have to visit the site to remove and re-insert the SFP's.

New Member

FYI - The reboot fixed the

FYI - The reboot fixed the issue.

New Member

OK. Great. Check the logs.

OK. Great. Check the logs.

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