Hi,
I have a strange problem with hostflapping between directly connected local port and port-channel to other switch where the same router is conneted via second interface.
Setup is as follows:
SW1 (Catalyst 4506) <--> Router 2851 <--> SW2 (Catalyst 4506)
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Related configs:
1. Router 2851 - (C2800NM-SPSERVICESK9-M), Version 15.0(1)M3
bridge irb
interface GigabitEthernet0/0
no ip address
duplex auto
speed auto
bridge-group 1
!
interface GigabitEthernet0/1
no ip address
duplex auto
speed auto
bridge-group 1
interface BVI1
ip address xxx.xxx.xxx.xxx 255.255.255.0
bridge 1 protocol ieee
bridge 1 route ip
2. SW1 port config
interface GigabitEthernet4/9
description R2851-Gi0-1
switchport access vlan 100
switchport mode access
service-policy output autoqos-voip-policy
qos trust dscp
auto qos voip trust
tx-queue 3
priority high
shape percent 33
end
2. SW2 port config
interface GigabitEthernet4/9
description R2851-Gi0-0
switchport access vlan 100
switchport mode access
auto qos voip trust
service-policy input AutoQos-VoIP-Input-Cos-Policy
service-policy output AutoQos-VoIP-Output-Policy
end
On SW1 every 30 seconds I see this:
%C4K_EBM-4-HOSTFLAPPING: Host 18:EF:63:xx:xx:xx in vlan 100 is flapping between port Po3 and port Gi4/9
On router, this is output of "sh spanning-tree":
Bridge group 1 is executing the ieee compatible Spanning Tree protocol
Bridge Identifier has priority 32768, address 18ef.6363.4d00
Configured hello time 2, max age 20, forward delay 15
Current root has priority 24676, address 000f.232c.4c00
Root port is 4 (GigabitEthernet0/1), cost of root path is 4
Topology change flag not set, detected flag not set
Number of topology changes 1 last change occurred 05:25:19 ago
from GigabitEthernet0/0
Times: hold 1, topology change 35, notification 2
hello 2, max age 20, forward delay 15
Timers: hello 0, topology change 0, notification 0, aging 300
Port 3 (GigabitEthernet0/0) of Bridge group 1 is blocking
Port path cost 4, Port priority 128, Port Identifier 128.3.
Designated root has priority 24676, address 000f.232c.4c00
Designated bridge has priority 28772, address 2894.0f29.fa40
Designated port id is 128.201, designated path cost 3
Timers: message age 3, forward delay 0, hold 0
Number of transitions to forwarding state: 0
BPDU: sent 9, received 8123
Port 4 (GigabitEthernet0/1) of Bridge group 1 is forwarding
Port path cost 4, Port priority 128, Port Identifier 128.4.
Designated root has priority 24676, address 000f.232c.4c00
Designated bridge has priority 24676, address 000f.232c.4c00
Designated port id is 128.201, designated path cost 0
Timers: message age 1, forward delay 0, hold 0
Number of transitions to forwarding state: 1
BPDU: sent 2, received 9757
I have 2 more routers with identical setup, and they are just fine, no hostflapping occures (however, they have 12.4(3i) and 15.1(4)M4 IOS)
It seams that even if router port is in blocking state, SW2 is receiveing its MAC address.
Is this some bug in 15.0(1)M3 IOS or I am missing something?
Thanks,
S.
