Odd STP messages seen since CatOS upgrade.

Now I'm running 8.1(3) and I keep getting this message when certain
ports are disconnected and reconnected. As the Root mac address
doesn't seem to change I'm not overly worried but why does this say
the root has changed.

2004 Feb 24 14:31:32 gmt +01:00 %SPANTREE-7-PORTDEL_SUCCESS: 8/16
deleted from vlan 2 (EthChnlConfig)
2004 Feb 24 14:31:32 gmt +01:00 %ETHC-5-PORTFROMSTPort 8/16 left
bridge port 8/16
2004 Feb 24 14:31:49 gmt +01:00 %ETHC-5-PORTTOSTPort 8/16 joined
bridge port 8/16
2004 Feb 24 14:31:50 gmt +01:00 %SPANTREE-6-PORTFWD: Port 8/16 state
in VLAN 2 changed to forwarding
2004 Feb 24 14:33:48 gmt +01:00 %SPANTREE-5-ROOTCHANGE:Root changed
for Vlan 2:New root port 14/1. New Root mac address is
00-0a-f3-a1-e6-40.
2004 Feb 24 14:33:48 gmt +01:00 %SPANTREE-7-PORTDEL_SUCCESS: 8/16
deleted from vlan 2 (EthChnlConfig)
2004 Feb 24 14:33:48 gmt +01:00 %ETHC-5-PORTFROMSTPort 8/16 left
bridge port 8/16
2004 Feb 24 14:34:05 gmt +01:00 %ETHC-5-PORTTOSTPort 8/16 joined
bridge port 8/16
2004 Feb 24 14:34:06 gmt +01:00 %SPANTREE-6-PORTFWD: Port 8/16 state
in VLAN 2 changed to forwarding
2004 Feb 24 14:35:25 gmt +01:00 %SPANTREE-5-ROOTCHANGE:Root changed
for Vlan 2:New root port 14/1. New Root mac address is
00-0a-f3-a1-e6-40.
2004 Feb 24 14:35:25 gmt +01:00 %SPANTREE-7-PORTDEL_SUCCESS: 8/16
deleted from vlan 2 (EthChnlConfig)
2004 Feb 24 14:35:25 gmt +01:00 %ETHC-5-PORTFROMSTPort 8/16 left
bridge port 8/16
2004 Feb 24 14:35:42 gmt +01:00 %ETHC-5-PORTTOSTPort 8/16 joined
bridge port 8/16
2004 Feb 24 14:35:42 gmt +01:00 %SPANTREE-6-PORTFWD: Port 8/16 state
in VLAN 2 changed to forwarding
2004 Feb 24 14:41:04 gmt +01:00 %SPANTREE-5-ROOTCHANGE:Root changed
for Vlan 2:New root port 14/1. New Root mac address is
00-0a-f3-a1-e6-40.
2004 Feb 24 14:41:04 gmt +01:00 %SPANTREE-7-PORTDEL_SUCCESS: 8/16
deleted from vlan 2 (EthChnlConfig)
2004 Feb 24 14:41:04 gmt +01:00 %ETHC-5-PORTFROMSTPort 8/16 left
bridge port 8/16

 

It's probably just recalculating the root bridge every time this port flaps.
Do you have bridge priorities set? Its electing its root bridge by the mac
address, probably because they all have the same priority. If you set one
with a better priority, it shouldn't recalculate like this every time.
Otherwise, its not really a problem.

 

They are set, primary and secondary so despite the sys ID being added
the intended root should always be clearly in the lead.

VLAN 2
Spanning tree mode PVST+
Spanning tree type ieee
Spanning tree enabled

Designated Root 00-0a-f3-a1-e6-40
Designated Root Priority 4098
Designated Root Cost 3
Designated Root Port 1/2,2/2 (agPort 14/1)
Root Max Age 20 sec Hello Time 2 sec Forward Delay 15 sec

Bridge ID MAC ADDR 00-0a-8b-e1-99-40
Bridge ID Priority 8194 (bridge priority: 8192, sys ID ext:
2)
Bridge Max Age 20 sec Hello Time 2 sec Forward Delay 15 sec

Port Vlan Port-State Cost Prio Portfast
------------------------ ---- ------------- --------- ---- --------
1/2,2/2 2 forwarding 3 32 disabled
5/1 2 forwarding 19 32 disabled
5/2 2 forwarding 19 32 disabled