SFP module not recognised in one port

[Ray Forster]

Hi - 

Have a 385048T with a 4GB module installed. One Fibre SFP is never recognised in port G2/1/3. Same SFP works in port G2/1/4 (a Cisco 100MbaseFX SFP) and is shown in "show inventory"as being present.

We've replace the SFP, the 4Gb port module, and even the switch, but the SFP is never recognised in port G2/1/3.

This fibre circuit forms an etherchannel with another fibre circuit with exactly the same setup on another switch in the stack - identical config - 3850 with 4 port GB module, but appears as port G1/1/3.

Not critical, because as I say the whole setup works fine using the SFP in another port... but as this is new kit under warranty, I'd like to get to the bottom of it!

Regards.

R

[Julio E. Moisa]

Hi

These are the SFP modules supported on the Cisco 3850:

Catalyst 3800 Series Switches Support

Catalyst 3850 series
Network Device	Transceiver Module	Minimum Software Release Required
		DOM Support	Cisco IOS Release
C3850-NM-4-1G Uplink Module	GLC-T (10/100/1000) GLC-LH-SM GLC-LH-SMD GLC-SX-MM GLC-SX-MMD GLC-EX-SMD1 GLC-ZX-SM GLC-ZX-SMD GLC-BX-D GLC-BX-U CWDM SFP SFP-GE-S SFP-GE-L SFP-GE-T SFP-GE-Z DWDM SFP DWDM SFP (add.)	XE 3.2.0SE, 16.1.1	XE 3.2.0SE, 16.1.1
WS-C3850-12S WS-C3850-24S		XE 3.3.3SE, 16.1.1	XE 3.3.3SE, 16.1.1
	GLC-BX40-D-I GLC-BX40-DA-I GLC-BX40-U-I GLC-BX80-D-I GLC-BX80-U-I	XE 3.7.1E, 16.1.1	XE 3.7.1E, 16.1.1
	GLC-TE		XE 3.6.7E, XE 3.7.5E, 16.5.1a, 16.3.5
WS-C3850-12XS WS-C3850-16XS WS-C3850-24XS WS-C3850-32XS (with C3850-NM-8-10G NM)	GLC-T (10/100/1000) GLC-LH-SM GLC-LH-SMD GLC-SX-MM GLC-SX-MMD GLC-EX-SMD1 GLC-ZX-SM GLC-ZX-SMD GLC-BX-D GLC-BX-U CWDM SFP SFP-GE-S SFP-GE-L SFP-GE-T SFP-GE-Z DWDM SFP DWDM SFP (add.) GLC-BX40-D-I GLC-BX40-DA-I GLC-BX40-U-I GLC-BX80-D-I GLC-BX80-U-I	XE 3.7.1E, 16.1.1	XE 3.7.1E, 16.1.1
	GLC-TE	-	XE 3.7.5E, 16.5.1a, 16.3.5
WS-C3850-48XS-S WS-C3850-48XS-E WS-C3850-48XS-F-S WS-C3850-48XS-F-E WS-C3850-48XS	GLC-T (10/100/1000) GLC-LH-SM GLC-LH-SMD GLC-SX-MM GLC-SX-MMD GLC-EX-SMD1 GLC-ZX-SM GLC-ZX-SMD GLC-BX-D GLC-BX-U CWDM SFP SFP-GE-S SFP-GE-L SFP-GE-T SFP-GE-Z DWDM SFP DWDM SFP (add.) GLC-BX40-D-I GLC-BX40-DA-I GLC-BX40-U-I GLC-BX80-D-I GLC-BX80-U-I	XE 3.7.2E, 16.2.1	XE 3.7.2E, 16.2.1
	GLC-TE	-	XE 3.7.5E, 16.5.1a, 16.3.5

Now if your SFP model is included have you tried to reset the SFP, the module should be the same on both ends and supporting the same fiber type.

configure terminal

default interface g2/1/3

This parameter will reset the port to factory configuration. 

[Ray Forster]

Hi - thanks for your reply. According to this compatibility matrix, the GLC-GE-100FX isn't supported in the C3850-NM-4-1G, yes it is mentioned in the SFP compatibility list...

https://www.cisco.com/c/en/us/td/docs/interfaces_modules/transceiver_modules/compatibility/matrix/100MB_Tx_Matrix.html#_Toc503260442

Confused!! Either way, the same SFP is used in another port on the same stack, and on a duplicate of this switch in another location OK.....

[Leo Laohoo]

What firmware is the stack running on?
There are a lot (and I mean a very long list) of bugs involving 3650/3850 and fibre optic modules (SFP/SFP+).

If the fibre optic module isn't recognize then there should be some entry in the switch logs as to the reason why it isn't.

[Ray Forster]

Hi - we've had 2 versions - the original switch was f/w v7, when replaced it, the new(!) one was version 4 - it didn't work on either.....

There's nothing in the logs, and when console monitoring, no errors / notifications when the SFP is inserted - it does generate a message when removed / inserted from another port though - no lights on the port either....

[Zain Khan]

Hi,

If your SFP module not detecting first you have to check your supported SFP with your device As julia posted above. also sometimes i faced these problem in few of devices ports does not recognised SFP. this might be due to malfunctioning of your device hardware. for verify you can run a simple command and check weather your SFP is not detecting in only specific port or in all the ports. not detecting in all the port then follow Julia post if problem in specific port then must have your device hardware malfunctioning

[Ray Forster]

Hi - thanks for the reply. We've replaced the 4 port Gb module, and the SFP was not recognised - no console messages about a new SFP inserted (there is a message if you insert / remove the SFP from port 4, but not port 3). We've even replaced the switch, and the SFP, but nothing works in port 3 of the 4 port GB module!! So we've eliminated all hardware...... weird!!

[Leo Laohoo]

It is a bug with the IOS.
What IOS version is the appliance running on?

[Ray Forster]

Its version 03.06.06E



Regards..