SFP shows as not connected

[Rick001]

We replaced an Avaya 4850 Switch which had an Avaya 1310nm GbE BX DDI 10Km Single Mode, Single strand, SFP. It connects to a Cisco 9606R core switch. On the Core, side it has a Cisco GLC BX-D SFP.

We replaced the the 4850 with a Cisco 9300 switch with a GLC BX-D SFP (Same as the core side).

The switch is not showing any connectivity. When running the sh inv and sh idprom commands the switch recognizes the SFP.

The 9300 is running on 17.09.04a

[balaji.bandi]

Hope you using OS2 SMF cable  - Try "speed nonegotiate"

still issue -

Try giving Loop on the cable and check

and also swap RX and TX and check if that  works.

post interface output here.

[Rick001]

There is only one strand of fiber.

We connected the original Avaya SFP to the port on the 9300 Switch and it connected fine.

[balaji.bandi]

i would suggest to refer below guide :  what need to be both the side.

https://www.cisco.com/c/en/us/products/collateral/interfaces-modules/gigabit-ethernet-gbic-sfp-modules/datasheet-c78-366584.html

We connected the original Avaya SFP to the port on the 9300 Switch and it connected fine.

you mean on Cat 9300 port come up when you did a testing - is this correct - how about other side ?

[M02@rt37 · Accepted solution]

Hello @Rick001 

In order to properly communicate across a single fiber, you need GLC BX-D and on the other side GLC BX-U.

Common mistake is to use the same type of SFP on a single (BiDi - BiDirectional) fiber.

[Rick001]

That's the reason then. I looked up the datasheet for that Avaya SFP and it is indeed GLC BX-U.