Cisco switch LACP + 802.1q

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1

I am tearing my hair out with an issue, and I hope someone can point something out to me that I am missing.

I am setting up 2-port LACP sets on a Cisco 2960G-24TS-L, which then need to be 802.1q trunk ports.

I have set it up as follows:

interface Port-channel1
  switchport mode trunk
!
interface Port-channel2
  switchport mode trunk
!
interface Port-channel3
  switchport mode trunk
!
interface Port-channel4
  switchport mode trunk
!
interface GigabitEthernet0/1
channel-protocol lacp
channel-group 1 mode active
!
interface GigabitEthernet0/2
channel-protocol lacp
channel-group 1 mode active
!
interface GigabitEthernet0/3
channel-protocol lacp
channel-group 2 mode active
!
interface GigabitEthernet0/4
channel-protocol lacp
channel-group 2 mode active
!
interface GigabitEthernet0/5
channel-protocol lacp
channel-group 3 mode active
!
interface GigabitEthernet0/6
channel-protocol lacp
channel-group 3 mode active
!
interface GigabitEthernet0/7
switchport mode trunk
channel-protocol lacp
channel-group 4 mode active
!
interface GigabitEthernet0/8
switchport mode trunk
channel-protocol lacp
channel-group 4 mode active

The problem is that after some period of time (sometimes minutes, sometimes hours), port-channel1 loses the "switchport mode trunk"

It just disappears from the config. If I try to put it back, it adds "switchport mode trunk" to the member ports (Gi0/1, Gi0/2) as well, which does not work. I have to tear it all out and start again. It will then work for a while again.

port-channel2 and port-channel3 are not in use yet, but port-channel4 is, and works just fine.

It is running IOS 15.0(1)SE. It was running 12.2 before, and it was doing the same thing, so I upgraded it to the latest available.

What could be the issue?

thanks,
-Randy

2

My limited understanding and experience with port-channels is that the
member port configurations need to match the port channel
configuration, at least with respect to 'switchport mode trunk',
'switchport trunk encapsulation' and 'switchport trunk allowed vlan'.
This is between a 6500 and a WLC4404, so your mileage will obviously
vary. What does the configuration look on the device that is
connected to the 2960?

Jason

3

Thanks for all the suggestions.

I added the "switchport mode trunk" to the interfaces, and it did start working properly after a reload of the switch.
Before the reboot, it would not work.

-Randy