[c-nsp] Host xxxx.xxxx.xxxx in vlan x is flapping between port Po1 and port Gi0/1

[Anton Yurchenko]

Hi Farooq,

I see this happening most of the time when I have a host, dual homed to 
2 different switches for HA purposes , and the host link 
bonding/aggregation is configured to do load balancing instead of 
active/backup.
Essentially its sending the traffic down both links, and switches learns 
the MAC address from directly connected host port and from port that is 
connected to the second switch.

check how link bonding is configured on the end host.

Anton


On 8/7/2011 10:14 AM, Farooq Razzaque wrote:
>
> Hi All
>
> I noticed the following messages with different timestamp on IPT SW01 (connected to IPT servers - C2960G-24TC-L)
>
>
>
> %SW_MATM-4-MACFLAP_NOTIF: Host 001c.f6e5.17b0 in vlan 119 is flapping between port Po1 and port Gi0/1
>
> Here :
>
> 1) Gi0/1 is connected to Voice Gateway router
>
> interface GigabitEthernet0/0 (Connected to IPT SW02 - Gi0/1)
>   no ip address
>   duplex auto
>   speed auto
>   media-type rj45
>   bridge-group 1
> !
> interface GigabitEthernet0/1  (Connected to IPT SW01 - Gi0/1)
>   no ip address
>   duplex auto
>   speed auto
>   media-type rj45
>   bridge-group 1
>
> interface BVI1
>   ip address xxxxx
>   ntp broadcast client
>   ntp broadcast
>   h323-gateway voip interface
>   h323-gateway voip bind srcaddr xxxxx
>
> 2) Mac-address 001c.f6e5.17b0 is the address of interface Gi0/0 of Voice Gateway Router and same address for BVI1
>
> GigabitEthernet0/0 is up, line protocol is up
>    Hardware is BCM1125 Internal MAC, address is 001c.f6e5.17b0 (bia 001c.f6e5.17b0)
>
> GigabitEthernet0/1 is up, line protocol is up
>    Hardware is BCM1125 Internal MAC, address is 001c.f6e5.17b1 (bia 001c.f6e5.17b1)
>
> BVI1 is up, line protocol is up
>    Hardware is BVI, address is 001c.f6e5.17b0 (bia 001c.f6e5.17b0)
>
> 3) Po1 is the port channel on IPT SW01 (Gi0/22 and Gi0/23) and Core switch (VSS)
>
>
> interface GigabitEthernet0/22
> description ++++ L2 Trunk to Coreswitch ++++
>   switchport trunk native vlan 999
>   switchport trunk allowed vlan 119
>   switchport mode trunk
>   logging event trunk-status
>   logging event bundle-status
>   channel-protocol lacp
>   channel-group 1 mode active
> !
> interface GigabitEthernet0/23
> description ++++ L2 Trunk to Coreswitch ++++
>   switchport trunk native vlan 999
>   switchport trunk allowed vlan 119
>   switchport mode trunk
>   logging event trunk-status
>   logging event bundle-status
>   channel-protocol lacp
>   channel-group 1 mode active
>
> Appreciate your help
>    		 	   		
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