Meraki MS and WLAN APs causing mac-flapping events

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MK2
Getting noticed

Meraki MS and WLAN APs causing mac-flapping events

As I have read in some posts there is a "problem" with Meraki MS and WLAN clients roaming from one AP to another. A customer asked me about this. Even if this is only cosmetic, should it stay like this or is there something wrong configured? For example, I see that a Samsung cell phone is supposed to report on 3 ports, but here MR APs are connected. Possibly a problem with the internal timers?
 
I am grateful for any support.
1 ACCEPTED SOLUTION
rbnielsen
Head in the Cloud

The thing is, it's not an error per se. The wireless client is roaming between APs so fast that the switch is essentially seeing the same MAC address out two or more switchports. I see the same at large warehouses, where clients, in this case scanners, are onboard those palletmovers, that can do almost 40 kilometers per hour. That's a quick roam. Afair, it's the MAC address table that gets a new entry from the same client on a new AP, before the old MAC address table entry ages out.

If you have Cisco Classic with APs in Flexconnect Mode, you'll see the exact same thing, and on Cisco Classic the "fix" here is to simply suppres the MAC flapping event.

 

But like I said, instead of bridging directly to a VLAN on the switchport (which in reality is the same concept as Flexconnect), configure Client IP Assignment to Layer 3 Roaming with a Concentrator, and concentrate traffic on the MX instead. This worked for me.

It may also work with Layer 3 Roaming only, but I haven't tried this yet.

LinkedIn ::: https://blog.rhbirkelund.dk/

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rbnielsen
Head in the Cloud

One way I've found to mitigate those log messages, is changing the Client IP Assignment to Layer 3 with a Concentrator, and concentrate traffic to the MX.

I have yet to conclude if there is a performance boost, though.

LinkedIn ::: https://blog.rhbirkelund.dk/

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GIdenJoe
Kind of a big deal

It's purely cosmetic.  It might be a good idea that you list your ports where there are access points and just ignore those messages from those ports.

MK2
Getting noticed

So guys, seriously, how am I supposed to analyze a log where most of it is a cosmetic error?
 
Is there by chance a Meraki employee who can bring this to the development? To build a filter for this is possible via the API, but who wants that?
 
Does no one else have this problem? 🙂
rbnielsen
Head in the Cloud

The thing is, it's not an error per se. The wireless client is roaming between APs so fast that the switch is essentially seeing the same MAC address out two or more switchports. I see the same at large warehouses, where clients, in this case scanners, are onboard those palletmovers, that can do almost 40 kilometers per hour. That's a quick roam. Afair, it's the MAC address table that gets a new entry from the same client on a new AP, before the old MAC address table entry ages out.

If you have Cisco Classic with APs in Flexconnect Mode, you'll see the exact same thing, and on Cisco Classic the "fix" here is to simply suppres the MAC flapping event.

 

But like I said, instead of bridging directly to a VLAN on the switchport (which in reality is the same concept as Flexconnect), configure Client IP Assignment to Layer 3 Roaming with a Concentrator, and concentrate traffic on the MX instead. This worked for me.

It may also work with Layer 3 Roaming only, but I haven't tried this yet.

LinkedIn ::: https://blog.rhbirkelund.dk/

Like what you see? - Give a Kudo ## Did it answer your question? - Mark it as a Solution 🙂
MK2
Getting noticed

I can partially agree with you there. Maybe Meraki will manage to suppress flapping for wireless clients when an MR is connected to a port. With a WLAN bridge, the information is again very helpful ;=)

 

Then I will include it in our documentation for now.

 

Thank you so much 🙂

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