Troubles connecting 2 Catalyst 9200L switches

[nicolas.steinbusch]

Hi everyone,

I ran into a problem I never saw before this morning while installing 2 new Catalyst C9200L-24P-4G (Network Essentials and DNA Essentials).

When I tried to connect int. G1/0/24 (switch 1) to int. G1/0/24 (switch 2), they didn't even try to communicate (led weren't blinking at all). 

I removed the patch cord and tried instead to connect int.G1/0/24 (switch 1) to int G1/0/23 (switch 2), and it worked. 

Int. G1/0/24 on switch 2 is working because when I connect my PC to it, it is working well.

I didn't make any configuration on any interfaces. Every interfaces is in Default Vlan 1.

When I tried to connect both switches on int. G1/0/24, there was these log messages on both switches. It seems they try to power each other :

*Oct 15 10:51:38.322: %ILPOWER-5-DETECT: Interface Gi1/0/24: Power Device detected: Cisco PD
*Oct 15 10:51:38.553: %ILPOWER-5-POWER_GRANTED: Interface Gi1/0/24: Power granted
*Oct 15 10:51:39.559: %ILPOWER-5-IEEE_DISCONNECT: Interface Gi1/0/24: PD removed

I tried to configure power inline never on both interfaces G1/0/24, but it didn't change anything.

With my current working configuration (int. G1/0/24 (switch 1) connecting to G1/0/23 (switch 2)), there is not this logging message.

So, for now, it is working well with int. G1/0/24 (switch 1) connecting to G1/0/23 (switch 2). I just try to figure out why using G1/0/24 on both switches doesn't work while there is no configuration on interfaces.

Thank you for your help ! 

[Reza Sharifi]

Hi,

If everything works when you use G1/0/23 and does not work when you use port G1/0/24 and the configuration is exactly the same for both ports on both switches, then you may have a hardware related issue. It is also possible that it is a software bug. I would open a ticket with TAC and have them help in investigating the issue. You may have to RMA it if it is a hardware issue.

HTH