Attached devices not listed in MAC address table

[johnoliphant1]

Yesterday I attached three SiriusXM radios to a stack of 3750s. The radios were/are working great, on ports Gi5/0/24, 27, and 29.

This morning I have a bunch of errors filling the log:

Mar 24 08:13:34.198: %SW_MATM-4-MACFLAP_NOTIF: Host 76c2.5e30.1599 in vlan 110 is flapping between port Gi5/0/24 and port Gi5/0/29

Mar 24 08:13:54.842: %SW_MATM-4-MACFLAP_NOTIF: Host 76c2.5e30.1599 in vlan 110 is flapping between port Gi5/0/27 and port Gi5/0/24

Mar 24 08:14:24.318: %SW_MATM-4-MACFLAP_NOTIF: Host 76c2.5e30.1599 in vlan 110 is flapping between port Gi5/0/24 and port Gi5/0/27

I can find the offending MAC in the address-table at Gi5/0/24, but the others are not in the table. Unfortunately, the devices won't give up their MACs  in the device menus or on any labels.

So I'm confused....how can they be working, transmitting and receiving, yet no MAC in the address table?

-John

[rakeshvelagala]

I have seen similar case in stack. Can you please post #show version

Where the mac addresses do not sync between the switches 

[johnoliphant1]

Thanks, I have attached the show ver result.

I should clarify...the address table shows ONE of the mac addresses, and the router gives me the IP address for that device. Also, here's the interface config for all three devices. It's a generic config we use for lots of stuff.

interface GigabitEthernet5/0/24
 switchport access vlan 110
 switchport mode access
 switchport voice vlan 250
 srr-queue bandwidth share 1 30 35 5
 priority-queue out
 mls qos trust device cisco-phone
 mls qos trust cos
 auto qos voip cisco-phone
 spanning-tree portfast
 service-policy input AUTOQOS-SRND4-CISCOPHONE-POLICY
end

[rakeshvelagala]

Previously also same version as yours and we downgraded to

flash:c3750e-ipbasek9-mz.150-2.SE5.bin

Let me check and see if I can find the TAC case we opened previously. I cannot remember the case fully.

[rakeshvelagala]

Can you please paste the output of below

rem com all show mac address-table count | i Space

[johnoliphant1]

Here ya go:

PHS_3750X-MDF#rem com all show mac address-table count | i Space
Switch : 2 : (Master)
---------------------
Total Mac Address Space Available: 5915

Switch : 1 :
------------
Total Mac Address Space Available: 5915

Switch : 3 :
------------
Total Mac Address Space Available: 5915

Switch : 4 :
------------
Total Mac Address Space Available: 5915

Switch : 5 :
------------
Total Mac Address Space Available: 5915

Switch : 6 :
------------
Total Mac Address Space Available: 5915

[Charles Hill]

Bug CSCuo17293 sounds similar, where mac addresses are missing in one or two switches.  The work around in CSCuo17293 is

Workaround:
clear mac address table will resolve the issue.

Hope this helps.

[rakeshvelagala]

Hi Cehill,

The mac address looks like they are in sync.From the command

PHS_3750X-MDF#rem com all show mac address-table count | i Space

Let us see what is the config of the access ports 

[johnoliphant1]

interface GigabitEthernet5/0/24
 switchport access vlan 110
 switchport mode access
 switchport voice vlan 250
 srr-queue bandwidth share 1 30 35 5
 priority-queue out
 mls qos trust device cisco-phone
 mls qos trust cos
 auto qos voip cisco-phone
 spanning-tree portfast
 service-policy input AUTOQOS-SRND4-CISCOPHONE-POLICY
end

I condensed one of the ports as follows, but it's still in the game flapping:

interface GigabitEthernet5/0/24
 switchport access vlan 110
 switchport mode access
 spanning-tree portfast
 

[Jon Marshall]

I'm not familiar with the devices you are connecting but do the clients connect using wireless ?

If so are you actually experiencing any performance issues other than the logs.

If it is wireless and the client is roaming between the devices then you will see these messages.

Jon

[johnoliphant1]

The "radios" are wired. I'm not seeing any issues other than the logs, the stack isn't heavily used right now, other than one switch handling surveillance, and it's working pretty hard, but no problems.

FWIW these are the devices:

https://gracedigital.com/shop/siriusxm-for-business/

[Jon Marshall]

Forgive my ignorance but the client mac in the logs, what is that in relation to the radio devices ?

I can't see how it can be an issue of mac address table synchronisation between stack members because all the radios are connected to the same switch so there is no synchronisation needed.

Jon

[johnoliphant1]

The bigger issue is the errors noted at the top, mac address flapping.

It's when troubleshooting this problem that I noted the address table weirdness. I should be able to associate each radio with a mac, and then an IP address, but that's not possible right now.

[Jon Marshall]

The bigger issue is the errors noted at the top, mac address flapping

Not sure I understand.

That is what I was talking about ie. someone else suggested you might be seeing these errors because the stack members had different mac address tables.

I was just saying they are all on the same switch.

What does the arp table look like in the L3 device for vlan 110 ie. can you see the radios ?

The reason I asked about the client was I was trying to understand how this related to the radios ie. I don't have any experience with them so I was trying to work out whether the client mac in the logs was connecting via the radio devices or whether this was just a client that is connected to a normal switchport.

Jon

[johnoliphant1]

Yep, just a client connected to a normal switchport. Sorry for the confusion.

At the router, I only see the one mac and one IP address.