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40G QSFP cable in C9500-24Y4C 100G port - switch doesn't recognize

My customer is trying to connect 2 C9500-24Y4C switches together via one of the 100G ports. They are using a 3rd party version of this cable/QSFP  --> QSFP-H40G-CU1M cable. Neither switch acknowledges that anything is connected to the port (see below). No log messages either. I'm thinking it's a bad cable/QSFP but customer is having the same problem with 2 of these cables.


Any thoughts on what might be the issue?


Cisco IOS XE Software, Version 17.03.04
Cisco IOS Software [Amsterdam], Catalyst L3 Switch Software (CAT9K_IOSXE), Version 17.3.4, RELEASE SOFTWARE (fc3)


Switch#sh int hundredGigE 1/0/25
HundredGigE1/0/25 is down, line protocol is down (notconnect)
Hardware is not present
Hardware is Hundred Gigabit Ethernet, address is c44d.8451.ebf9 (bia c44d.8451.ebf9)


Leo Laohoo
VIP Community Legend VIP Community Legend
VIP Community Legend

Raise a TAC Case. 
I know there are several bugs involving Cisco-branded QSFP optics. 

3rd party QSFP are not affected by the bugs.

Leonardo  Pena Davila
Rising star
Rising star

 Hello PatrickCavell85782, 


There is a bug that is hitting certain QSFP cables in that version 17.3.4. Take a look on the link below: 




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