Cisco 5508 WLC and LAG issue

[Louise Coe]

Hi

I have a 5508 WLC connected to a 4507 SUP 6-E on 4 ports configured into a port channel. Everything works fine.

However if I then enable the extra 4 ports on the 5508 into the same port-channel on the same 4507 I start to see Giants appear on the 4507 end on the new ports. Plus I see AP's disconnecting from the controller and I lose access to the GUI.

This happens straight away. If I disable these new ports all is fine once again. The AP's re-join and I can access the GUI.

It seems as though I can only use 4 of the 8 ports on the 5508.

Can anyone explain this ? Or have come across a bug ? 

We are running WLC 8.0.120.0

We have a mixture of 1245 APs and 3702I

Thanks

[Scott Fella]

You can use all 8 ports!  Make sure that your etherchannel comes up fine when you connect the ports to the 4507.  Connect them one at a time and see if one of the ports gives your issues and look at the SFP.  To be honest, you probably don't need to use all 8, I have customers in large environments that only have one port connected.  Since you have 4, you should be good, as you will never over subscribe all 4, and maybe not even one.

-Scott

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[Louise Coe]

Thanks for these comments. 

Scott - I take your point, we probably do not need to use all 8. I think though that because we have come across this issue we want to resolve it, in case there is something else wrong.

We do have channel-group mode on and I have changed the SFP's.

I will do some more testing and see if I can come to a conclusion as to why when we add new ports we start to see Giants.

I have a feeling it may be to do with the CAPWAP path MTU, but when I next get a maintainance window and will try some things out.

[Noor Shukri]

There is no restrictions on this, you can use the 8 ports 

just make sure the port channel configurations are correct, mode is on before you connect to the controller.