Cisco WLC 2504 LAG Problem - Controller is shutting down when all four ports are connected

[Christian Engelbrecht]

Hi all,

I'm struggeling on a very strange phenomen.

One customer of mine is using a Cisco WLC 2504 controller (AirOS Version 8.2.100.0) connected to a HP switch (I don't know the type of model).

LAG is configured correctly as per configuration guide but it is only working as long as only two out of the four ports are connected.

As soon as port 3 and 4 are plugged in the WLC is not reacting anymore and reboots. There is nothing visible in the show msglog output or traplog output as well as there is no crashinfo available so it seems like a silent crash. However also when having a console cable connected to the WLC nothing is visible.

We have already replaced the WLC but without success.

Any ideas what could cause this?

Regards,

Christian

[Mikey Boy]

The WLC 2504 will only support 1Gb throughput regardless of the LAG configuration, so is there really any point in up linking 4 ports?

Also, a stipulation is that the bundled ports must not be on different switches in a stack, they must be on the same switch.

https://www.cisco.com/c/en/us/support/docs/wireless/2500-series-wireless-controllers/113034-2500-deploy-guide-00.html#anc24

[dean.nash@va>gov]

Understand, but is not the point of LAG here redundancy?  Requiring all the LAG ports to be on the same switch kinda defeats the point, yes?

[redexcamgd]

Thanks for your post, helped a lot to show my boss that in IT world many times technical limitations are the problem and not the engineer's knowledge.

[dean.nash@va>gov]

Wow....  What a jacked up device!  4 Port LAG worked with ports 2-4 on blade 2 and port 1 on blade 3.  For giggles, I tried putting ports 1 and 3 on bade 2 and 2 and 4 on blade 3, no joy.  Put ports 1 and 2 on blade 3 and 4 on blade 2 and up she comes like a dream.  I'm a little OCD so I wanted 1&2 on blade 2 and 3&4 on blade 3.  Guess what?  No workie.  WTH?  Who makes something like this?????

[Mikey Boy]

It is definitely one of the quirks that came with the 2504 but it has been end of lifed. I never really classed it as a device for larger mission critical deployments tbh. The 3504 is better and has replaced it from this perspective.

From a redundancy point of view we have always supplied 2 2504's that way you just lag the second one into a different switch.......

[michael.wade]

I apologize for waiting almost a year to post a follow up. I did resolve this,  and had it happen a few times again when doing a factory reset on the 2504. Certainly isn't a fix in my opinion, but it worked every time. Connected to ports 1 and 2 then In the GUI, click Controller - then Ports. Then "ConfigureAll" in the upper right hand corner. Changed the Admin Status to "Disable" then Applied. Immediately went back and changed the Admin Status to "Enable", then Applied. Then I was able to plug in ports 3 and 4 and have been good since running on all 4 ports.

When I posted back in 2018, I was enabling/disabling every individual port but that never worked. Just sharing my experience as this may not apply to other's. 

[jimmy.thomson]

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@michael.wade wrote:

I apologize for waiting almost a year to post a follow up. I did resolve this,  and had it happen a few times again when doing a factory reset on the 2504. Certainly isn't a fix in my opinion, but it worked every time. Connected to ports 1 and 2 then In the GUI, click Controller - then Ports. Then "ConfigureAll" in the upper right hand corner. Changed the Admin Status to "Disable" then Applied. Immediately went back and changed the Admin Status to "Enable", then Applied. Then I was able to plug in ports 3 and 4 and have been good since running on all 4 ports.

When I posted back in 2018, I was enabling/disabling every individual port but that never worked. Just sharing my experience as this may not apply to other's. 

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this works!  how long it stays working...time will tell

[ilkadmin-cco]

How can this work ?

when i go thru the GUI and disable all ports (shutdown) and press the apply buttom,

i will lose my network connection to the air-ct2504, it does not have a 

dedicated mgmt-ethernet like the 5508.

So i could try it thru the serial CON, but here i do not have the GUI.

BTW, our 2504 loses power when connected even to an unpowered 2960L Switchport ,

but was/is fine with an old 2960S switch. (both sides poe disable/power inline never)

[ilkadmin-cco]

just tried, and yes, good that i have a rollover-cable from router aux to wlc con port (flowcontrol none) .

(Cisco Controller) >config port adminmode all enable

to re-anable all Ports