[c-nsp] STP funnies - moving from forwarding to forwarding

[Daniel Roesen]

Hi,

%SPANTREE-SP-6-PORT_STATE: Port Gi4/1 instance 100 moving from
forwarding to forwarding

This message comes in irregular intervals:

May 2 16:18:52.397 CEST
May 3 00:33:56.521 CEST
May 3 00:38:21.368 CEST
May 3 00:40:09.240 CEST
May 3 00:40:31.392 CEST
May 3 05:01:27.559 CEST
May 3 05:01:32.399 CEST
May 3 14:37:48.635 CEST
May 3 15:13:35.544 CEST
May 4 00:33:57.542 CEST
May 4 00:38:14.874 CEST
May 4 00:39:33.046 CEST
May 4 00:40:22.966 CEST
May 4 05:01:27.725 CEST
May 4 05:01:33.497 CEST
May 4 15:09:08.701 CEST
May 4 15:16:33.355 CEST
May 4 15:39:45.707 CEST

System image file is "sup-bootflash:s72033-pk9sv-mz.122-18.SXD6.bin"

spanning-tree mode rapid-pvst

interface GigabitEthernet4/1
no ip address
logging event link-status
logging event spanning-tree status
switchport
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 100,702
switchport mode trunk
switchport nonegotiate
no cdp enable
spanning-tree portfast trunk
end

#sh spanning-tree int g4/1
Vlan Role Sts Cost Prio.Nbr Type
---------------- ---- --- --------- -------- -------------
VLAN0100 Desg FWD 4 128.385 Edge P2p
VLAN0702 Desg FWD 4 128.385 Edge P2p

#sh spanning-tree int g4/1 detail
Port 385 (GigabitEthernet4/1) of VLAN0100 is designated forwarding
...
Number of transitions to forwarding state: 19
The port is in the portfast mode by portfast trunk configuration
Link type is point-to-point by default
BPDU: sent 100744, received 0

Port 385 (GigabitEthernet4/1) of VLAN0702 is designated forwarding
...
Number of transitions to forwarding state: 1
The port is in the portfast mode by portfast trunk configuration
Link type is point-to-point by default
BPDU: sent 100744, received 0


Other end is a 7200 with unknown IOS release. Interestingly, it happens
only on VLAN 100, not 702. No other log entries on the switch.

Any ideas?


Best regards,
Daniel

[Daniel Roesen]

Post by Daniel Roesen
%SPANTREE-SP-6-PORT_STATE: Port Gi4/1 instance 100 moving from
forwarding to forwarding

Nobody ever seen that happening?

Google cannot find a single reference to "moving from forwarding to
forwarding" (except my posting).


Best regards,
Daniel

[Dale W. Carder]

Post by Daniel Roesen

Post by Daniel Roesen
%SPANTREE-SP-6-PORT_STATE: Port Gi4/1 instance 100 moving from
forwarding to forwarding

Nobody ever seen that happening?

Ok, now you made me look...

I see that message coming from 6500's only. These are running
SXE2. Here's a sample "transaction" when that message seems
to occur. In this example, fa7/43 bounces and the message
from the other ports on that vlan occur.

May 10 12:11:13 switch-23 12766: May 10 12:11:12: %LINK-3-UPDOWN: Interface FastEthernet7/43, changed state to down
May 10 12:11:14 switch-23 12767: May 10 12:11:12: %SPANTREE-SP-6-PORT_STATE: Port Fa7/43 instance 632 moving from forwarding to disabled
May 10 12:11:51 switch-23 12768: May 10 12:11:51: %SPANTREE-SP-6-PORT_STATE: Port Fa7/33 instance 632 moving from forwarding to forwarding
May 10 12:11:51 switch-23 12769: May 10 12:11:51: %SPANTREE-SP-6-PORT_STATE: Port Fa7/34 instance 632 moving from forwarding to forwarding
May 10 12:11:51 switch-23 12770: May 10 12:11:51: %SPANTREE-SP-6-PORT_STATE: Port Fa7/44 instance 632 moving from forwarding to forwarding
May 10 12:11:51 switch-23 12771: May 10 12:11:51: %SPANTREE-SP-6-PORT_STATE: Port Gi8/1 instance 632 moving from forwarding to forwarding
May 10 12:11:51 switch-23 12772: May 10 12:11:51: %SPANTREE-SP-6-PORT_STATE: Port Gi8/2 instance 632 moving from forwarding to forwarding
May 10 12:11:51 switch-23 12773: May 10 12:11:51: %SPANTREE-SP-6-PORT_STATE: Port Fa9/2 instance 632 moving from forwarding to forwarding
May 10 12:11:51 switch-23 12774: May 10 12:11:51: %LINK-3-UPDOWN: Interface FastEthernet7/43, changed state to up


It must not mean anything bad, because I set SEC to ignore it
over a year ago:

# Stupid STP message from 6500's
type=Suppress
ptype=RegExp
pattern=SPANTREE-SP-6-PORT_STATE.+from forwarding to forwarding


:-)

Dale

-----------------------------------
Dale W. Carder - Network Engineer
University of Wisconsin at Madison
http://net.doit.wisc.edu/~dwcarder
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[Marko Milivojevic]

Do you have portfast configured on these ports?

Post by Dale W. Carder

Post by Daniel Roesen

Post by Daniel Roesen
%SPANTREE-SP-6-PORT_STATE: Port Gi4/1 instance 100 moving from
forwarding to forwarding

Nobody ever seen that happening?

Ok, now you made me look...
I see that message coming from 6500's only. These are running
SXE2. Here's a sample "transaction" when that message seems
to occur. In this example, fa7/43 bounces and the message
from the other ports on that vlan occur.
May 10 12:11:13 switch-23 12766: May 10 12:11:12: %LINK-3-UPDOWN: Interface FastEthernet7/43, changed state to down
May 10 12:11:14 switch-23 12767: May 10 12:11:12: %SPANTREE-SP-6-PORT_STATE: Port Fa7/43 instance 632 moving from forwarding to disabled
May 10 12:11:51 switch-23 12768: May 10 12:11:51: %SPANTREE-SP-6-PORT_STATE: Port Fa7/33 instance 632 moving from forwarding to forwarding
May 10 12:11:51 switch-23 12769: May 10 12:11:51: %SPANTREE-SP-6-PORT_STATE: Port Fa7/34 instance 632 moving from forwarding to forwarding
May 10 12:11:51 switch-23 12770: May 10 12:11:51: %SPANTREE-SP-6-PORT_STATE: Port Fa7/44 instance 632 moving from forwarding to forwarding
May 10 12:11:51 switch-23 12771: May 10 12:11:51: %SPANTREE-SP-6-PORT_STATE: Port Gi8/1 instance 632 moving from forwarding to forwarding
May 10 12:11:51 switch-23 12772: May 10 12:11:51: %SPANTREE-SP-6-PORT_STATE: Port Gi8/2 instance 632 moving from forwarding to forwarding
May 10 12:11:51 switch-23 12773: May 10 12:11:51: %SPANTREE-SP-6-PORT_STATE: Port Fa9/2 instance 632 moving from forwarding to forwarding
May 10 12:11:51 switch-23 12774: May 10 12:11:51: %LINK-3-UPDOWN: Interface FastEthernet7/43, changed state to up
It must not mean anything bad, because I set SEC to ignore it
# Stupid STP message from 6500's
type=Suppress
ptype=RegExp
pattern=SPANTREE-SP-6-PORT_STATE.+from forwarding to forwarding
:-)
Dale
-----------------------------------
Dale W. Carder - Network Engineer
University of Wisconsin at Madison
http://net.doit.wisc.edu/~dwcarder
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[Dale W. Carder]

Post by Marko Milivojevic
Do you have portfast configured on these ports?

all more or less look like this:

interface FastEthernet7/43
description foo
switchport
switchport access vlan 632
switchport mode access
no ip address
logging event spanning-tree status
logging event bundle-status
logging event trunk-status
speed 100
duplex full
no mdix auto
spanning-tree portfast
spanning-tree bpduguard enable
spanning-tree guard root


Dale

Post by Marko Milivojevic

Post by Daniel Roesen

Post by Daniel Roesen
%SPANTREE-SP-6-PORT_STATE: Port Gi4/1 instance 100 moving from
forwarding to forwarding

Nobody ever seen that happening?

----------------------------------
Dale W. Carder - Network Engineer
University of Wisconsin at Madison
http://net.doit.wisc.edu/~dwcarder

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[Marko Milivojevic]

Post by Daniel Roesen
[...]
spanning-tree portfast

Just a guess...

Portfast bypasses all STP states and immediately goes into forwarding. When
the port is down, technically, it's not blocking (I could be mistaken). When
the port comes up, STP state moves from the current state to forwarding.
Internal state could as well be forwarding.


Marko.

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[Dale W. Carder]

Post by Marko Milivojevic

Post by Daniel Roesen
[...]
spanning-tree portfast

Just a guess...
Portfast bypasses all STP states and immediately goes into forwarding. When
the port is down, technically, it's not blocking (I could be mistaken).
When the port comes up, STP state moves from the current state to
forwarding. Internal state could as well be forwarding.

That doesn't have much to do with this issue:

1) something happens to access port A, vlan 2
2) for every other access port on that switch in vlan 2, the "moving
from forwarding to forwarding" syslog message is generated.

I don't think it's anything to be too concerned about. Now, if
topology changes and other nonsence were going on that would be
another story.

Dale

----------------------------------
Dale W. Carder - Network Engineer
University of Wisconsin at Madison
http://net.doit.wisc.edu/~dwcarder

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