Problems with PoE blocking ports in a trunking between switches

[Luis Perez]

Im having this problem.

I have a connection between switches, There are a 3560 (Gi0/37) and a 2960 (Gi0/1), the  problem is in the port Gi0/37 of the 3560 switch and this is the log

*Mar  2 06:44:57.519: %ILPOWER-7-DETECT: Interface Gi0/37: Power Device detected: IEEE PD

*Mar  2 06:44:58.576: %ILPOWER-5-IEEE_DISCONNECT: Interface Gi0/37: PD removed

*Mar  2 06:44:59.633: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/37, changed state to down

*Mar  2 06:45:00.631: %LINK-3-UPDOWN: Interface GigabitEthernet0/37, changed state to down

*Mar  2 06:45:03.458: %LINK-3-UPDOWN: Interface GigabitEthernet0/37, changed state to up

*Mar  2 06:45:04.481: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/37, changed state to up

interface GigabitEthernet0/37

switchport access vlan 424

switchport mode access

end

interface GigabitEthernet0/1

switchport mode trunk

media-type rj45

end

*Mar  2 06:44:57.519: %ILPOWER-7-DETECT: Interface Gi0/37: Power Device detected: IEEE PD
*Mar  2 06:44:58.576: %ILPOWER-5-IEEE_DISCONNECT: Interface Gi0/37: PD removed
*Mar  2 06:44:59.633: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/37, changed state to down
*Mar  2 06:45:00.631: %LINK-3-UPDOWN: Interface GigabitEthernet0/37, changed state to down
*Mar  2 06:45:03.458: %LINK-3-UPDOWN: Interface GigabitEthernet0/37, changed state to up
*Mar  2 06:45:04.481: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/37, changed state to up

The configuration in the ports:

------------3560---------------------

interface GigabitEthernet0/37
switchport access vlan 424
switchport mode access
end

-----------------2960-----------------------

interface GigabitEthernet0/1
switchport mode access
media-type rj45
end

I dont understand what is the problem, actually i have added the command power inline never on the port and the problem is solved, but we haven´t changed configuration and is the first time with the problem in years.

[Leo Laohoo]

I think I know what the problem is.

I am suspecting you have a power-end-device connected to this switch and there's a PC connected to the power-end-device.

I am suspecting you have a cable issue.

Try the following on the 3560:

1.  Command:  test cable tdr int g 0/37;

2.  Wait for about 10 seconds;

3.  Command:  test cable tdr int g0/37; and

4.  Post the output.

[Luis Perez]

I don`t understand where do you think i have a power-end-device connected???  In the 3560 or int he 2960 switch  because the Gi0/37 port is the trunk connection to the 2960.

[Leo Laohoo]

Look at your "sh log" output. It's showing here is something triggering the PoE.

If you say the end device isn't a PoE then this issue is now leaning towards a copper cabling issue.

Try the TDR procedure I've posted earlier.

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