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New Member

Vlan flapping between ports

Hi all,

I have the following physical topology:

 

Router Cisco 2851 <-----> some huawei and raisecom switches <-----> Switch Cisco  WS-C2960-24TT-L <------> Ubnt in AP mode

 

In C2960 there are a lot of warnings regarding to mac flapping:

 

Jul 15 18:11:51.626: %SW_MATM-4-MACFLAP_NOTIF: Host 001b.5443.f6dx in vlan 101 is flapping between port Fa0/6 and port Fa0/20

 

Port Fa0/6 goes to Ubnt Wireless AP and Port F0/20 goes to Cisco 2851.

 

001b.5443.f6dx is the default gateway for Ubnt's MGMT and C2960 is trying to learn that MAC address from F0/6, which is a strange behavior

 

Many thx for your time,

-d

 

3 REPLIES

Hey,This mac flap

Hey,

This mac flap notification says switch is seeing host 001b.5443.f6dx on these two ports. Is there any connection between Ubnt and huawei and raisecom switches?

HTH.

Regards,

RS.

New Member

Hi rajeevsh,I was

Hi rajeevsh,

I was investigating further and I found that a couple of switches along the path have not configured STP, as follows:

 

Huawei Swtich

dis stp brief 
 MSTID  Port                        Role  STP State     Protection
   0    Ethernet0/0/1               DESI  FORWARDING      NONE
   0    Ethernet0/0/2               DESI  FORWARDING      NONE
   0    Ethernet0/0/3               DESI  FORWARDING      NONE
   0    Ethernet0/0/4               DESI  FORWARDING      NONE
   0    Ethernet0/0/6               DESI  FORWARDING      NONE
   0    Ethernet0/0/7               DESI  FORWARDING      NONE
   0    Ethernet0/0/8               DESI  FORWARDING      NONE
   0    Ethernet0/0/24              DESI  FORWARDING      NONE

 

Raisecom Switch

sh spanning-tree detail 
MSTP Admin State: Disable
Protocol Mode: MSTP

 

Would it be possible that these misconfigurations being causing mac flapping?

 

Thx,

-d

Hey,Its best to draw a layer

Hey,

Its best to draw a layer 2 topology and check how it is connected. Its a high possibility that we are seeing syslog due this switch as when STP is disabled switch starts acting like hub.

HTH.

Regards,

RS.

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