WLC 5508 intermittent loss of connectivity

[onaopemipo88]

Hi.

I have a WLC 5508 connecting directly to a distribution switch (3850) via a layer 2 etherchannel trunk fibre link with LAG enabled on the WLC.

Whenever there is a loss of power to the server room where both devices are hosted & power later gets restored, the distribution switch & WLC lose Layer 2 & 3 connectivity. Connectivity only gets restored when the WLC is power cycled or the fibre cables connecting to its SFP ports are removed & plugged back in. When this is done connectivity is restored between them, APs associate etc. Once there is a loss of power to the room for whatsoever reason again, the loss of connectivity issue re-occurs.

Disabled the etherchannel at some point, using only a single fibre trunk link between them, but the issue persists.

Also check for interface errors, CRCs, etc on both ends but there are none.

Can anyone please advice me on what the issue is & what can be done to permanently resolve this?

Thanks in anticipation.

Ope.

[Leo Laohoo]

Sounds like you have an ARP issue somewhere.  What happens if you "shut/no shut" the Port Channel interface?

[onaopemipo88]

I doubt its an ARP issue because I looked into that.

When I do a "shut/no shut" on the switch it has no effect until the physical connection is either broken or the WLC is power cycled.

[Leo Laohoo]

What version is the firmware of the 5508?

[Sandeep Choudhary]

Can you paste the config of swicth port where WLC connected ?

also paste the sh int <> from swicth.

what is the port setting on controller: it should be Fixed 1000 Mbps full duplex .

Regards

Dont forget to arte helpful posts

[onaopemipo88]

Software version is 7.4.100.0

int gig1/0/5

  switchport mode trunk

  switchport trunk encapsulation dot1q

  channel-group 1 mode on

!

int gig1/0/6

switchport mode trunk

switchport trunk encapsulation dot1q

channel-group 1 mode on

Port setting on the switch is set to auto-negotiate. Port setting on the controller is "auto". The link has been negotiated (& always negotiates) to 1000Mbps full duplex on both ends.

Presently in transit with no way of connecting to the device, but I checked the duplex & speed settings on both devices which was appropriately negotiated. Also checked for interface error counters on the switch, there was none. Checked the WLC logs too, there were no logs on issues with the interfaces or auto-negotiation.

[Leo Laohoo]

Software version is 7.4.100.0

Just to be on the safe side, I'd upgrade the firmware of your WLC to something more recent of the 7.4.X range.

[Scott Fella]

I don't know if it's an issue with the WLC, but like Leo mentioned, upgrade to v7.4.121.0 MR2.  It might be the switch and not being able to bring up the port channel.  If you only connect one port and you disable the port channel, does the problem go away or not?

Thanks,

Scott

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