[c-nsp] spanning-tree flaps with BVI routed interface

[Justin M. Streiner]

On Fri, 16 Mar 2007, Brian wrote:

> Has anyone experienced this before?

I'm assuming one of the 4507s is supposed to be the root bridge for VLAN 
697?  Is it explicitly as suchon the appropriate 4507?  Also, do trunk 
types (dot1q or ISL), native VLANs, etc match in all of the right places?

jms

> On 3/9/07, Brian <bms314 at gmail.com> wrote:
>>
>> I have a 2811 multihomed to two 4507 core routers.  The router is
>> configured with a BVI to provide redundancy to the core.  However, I
>> continually see a host flapping message in the core router every 30 seconds.
>>
>>
>> Mar  9 15:18:38 Central: %C4K_EBM-4-HOSTFLAPPING: Host 00:1A:2F:C7:2E:50
>> in vlan 697 is flapping between port Gi7/31 and port Po27
>> Mar  9 15:19:08 Central: %C4K_EBM-4-HOSTFLAPPING: Host 00:1A:2F:C7:2E:50
>> in vlan 697 is flapping between port Gi7/31 and port Po27
>> Mar  9 15:19:38 Central: %C4K_EBM-4-HOSTFLAPPING: Host 00:1A:2F:C7:2E:50
>> in vlan 697 is flapping between port Gi7/31 and port Po27
>>
>> Gi7/31 is the physical connection on the 1st 4507 and Po27 is the link
>> between the 4507's.  The 2nd 4507 has similar log messages.
>>
>>
>> The config of the 2811 is as follows:
>>
>>
>> interface FastEthernet0/0
>>  no ip address
>>  duplex full
>>  speed 100
>>  bridge-group 1
>>
>> interface FastEthernet0/1
>>  no ip address
>>  duplex full
>>  speed 100
>>  bridge-group 1
>>
>> interface BVI1
>>  ip address 204.X.X.X 255.255.255.224
>>
>> bridge 1 protocol ieee
>> bridge 1 route ip
>>
>>
>> I believe spanning-tree should block one of the ports and keep the other
>> port in a forwarding state.  It seems to be bouncing back and forth.  Any
>> ideas as to what could be causing this behavior and/or how to correct it?
>>
>> Thanks,
>> Brian
>>
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