This example shows
how to prevent the switch from automatically interoperating with a connecting
switch that is running Rapid PVST+:
Switch# configure terminal
Switch(config)# no spanning-tree mst simulate pvst global
This example shows
how to prevent a port from automatically interoperating with a connecting
device that is running Rapid PVST+:
Switch(config)# interface1/0/10/1
Switch(config-if)# spanning-tree mst simulate pvst disable
The following sample
output shows the system message you receive when a SSTP BPDU is received on a
port and PVST+ simulation is disabled:
Message
SPANTREE_PVST_PEER_BLOCK: PVST BPDU detected on port %s [port number].
Severity
Critical
Explanation
A PVST+ peer was detected on the specified interface on the switch. PVST+ simulation feature is disabled, as a result of which the interface was moved to the spanning tree
Blocking state.
Action
Identify the PVST+ switch from the network which might be configured incorrectly.
The following sample
output shows the system message you receive when peer inconsistency on the
interface is cleared:
Message
SPANTREE_PVST_PEER_UNBLOCK: Unblocking port %s [port number].
Severity
Critical
Explanation
The interface specified in the error message has been restored to normal spanning tree state.
Action
None.
This example shows the spanning tree status when port 1/0/10/1 has been configured to disable PVST+ simulation and is currently in the peer type inconsistent state:
Switch# show spanning-tree
VLAN0010
Spanning tree enabled protocol mstp
Root ID Priority 32778
Address 0002.172c.f400
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32778 (priority 32768 sys-id-ext 10)
Address 0002.172c.f400
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300
Interface Role Sts Cost Prio.Nbr Type
---------------- ---- --- --------- -------- -------------------------
Gi1/0/10/1 Desg BKN*4 128.270 P2p *PVST_Peer_Inc
This example shows
the spanning tree summary when PVST+ simulation is enabled in the MSTP mode:
Switch# show spanning-tree summary
Switch is in mst mode (IEEE Standard)
Root bridge for: MST0
EtherChannel misconfig guard is enabled
Extended system ID is enabled
Portfast Default is disabled
PortFast BPDU Guard Default is disabled
Portfast BPDU Filter Default is disabled
Loopguard Default is disabled
UplinkFast is disabled
BackboneFast is disabled
Pathcost method used is long
PVST Simulation Default is enabled
Name Blocking Listening Learning Forwarding STP Active
---------------------- -------- --------- -------- ---------- ----------
MST0 2 0 0 0 2
---------------------- -------- --------- -------- ---------- ----------
1 mst 2 0 0 0 2
This example shows
the spanning tree summary when PVST+ simulation is disabled in any STP mode:
Switch# show spanning-tree summary
Switch is in mst mode (IEEE Standard)
Root bridge for: MST0
EtherChannel misconfig guard is enabled
Extended system ID is enabled
Portfast Default is disabled
PortFast BPDU Guard Default is disabled
Portfast BPDU Filter Default is disabled
Loopguard Default is disabled
UplinkFast is disabled
BackboneFast is disabled
Pathcost method used is long
PVST Simulation Default is disabled
Name Blocking Listening Learning Forwarding STP Active
---------------------- -------- --------- -------- ---------- ----------
MST0 2 0 0 0 2
---------------------- -------- --------- -------- ---------- ----------
1 mst 2 0 0 0 2
This example shows
the spanning tree summary when the switch is not in MSTP mode, that is, the
switch is in PVST or Rapid-PVST mode. The output string displays the current
STP mode:
Switch# show spanning-tree summary
Switch is in rapid-pvst mode
Root bridge for: VLAN0001, VLAN2001-VLAN2002
EtherChannel misconfig guard is enabled
Extended system ID is enabled
Portfast Default is disabled
PortFast BPDU Guard Default is disabled
Portfast BPDU Filter Default is disabled
Loopguard Default is disabled
UplinkFast is disabled
BackboneFast is disabled
Pathcost method used is short
PVST Simulation Default is enabled but inactive in rapid-pvst mode
Name Blocking Listening Learning Forwarding STP Active
---------------------- -------- --------- -------- ---------- ----------
VLAN0001 2 0 0 0 2
VLAN2001 2 0 0 0 2
VLAN2002 2 0 0 0 2
---------------------- -------- --------- -------- ---------- ----------
3 vlans 6 0 0 0 6
This example shows
the interface details when PVST+ simulation is globally enabled, or the default
configuration:
Switch# show spanning-tree interface1/0/10/1 detail
Port 269 (GigabitEthernet1/0/10/1) of VLAN0002 is forwarding
Port path cost 4, Port priority 128, Port Identifier 128.297.
Designated root has priority 32769, address 0013.5f20.01c0
Designated bridge has priority 32769, address 0013.5f20.01c0
Designated port id is 128.297, designated path cost 0
Timers: message age 0, forward delay 0, hold 0
Number of transitions to forwarding state: 1
Link type is point-to-point by default
PVST Simulation is enabled by default
BPDU: sent 132, received 1
This example shows
the interface details when PVST+ simulation is globally disabled:
Switch# show spanning-tree interface1/0/10/1 detail
Port 269 (GigabitEthernet1/0/10/1) of VLAN0002 is forwarding
Port path cost 4, Port priority 128, Port Identifier 128.297.
Designated root has priority 32769, address 0013.5f20.01c0
Designated bridge has priority 32769, address 0013.5f20.01c0
Designated port id is 128.297, designated path cost 0
Timers: message age 0, forward delay 0, hold 0
Number of transitions to forwarding state: 1
Link type is point-to-point by default
PVST Simulation is disabled by default
BPDU: sent 132, received 1
This example shows
the interface details when PVST+ simulation is explicitly enabled on the port:
Switch# show spanning-tree interface1/0/10/1 detail
Port 269 (GigabitEthernet1/0/10/1) of VLAN0002 is forwarding
Port path cost 4, Port priority 128, Port Identifier 128.297.
Designated root has priority 32769, address 0013.5f20.01c0
Designated bridge has priority 32769, address 0013.5f20.01c0
Designated port id is 128.297, designated path cost 0
Timers: message age 0, forward delay 0, hold 0
Number of transitions to forwarding state: 1
Link type is point-to-point by default
PVST Simulation is enabled
BPDU: sent 132, received 1
This example shows
the interface details when the PVST+ simulation feature is disabled and a PVST
Peer inconsistency has been detected on the port:
Switch# show spanning-tree interface1/0/10/1 detail
Port 269 (GigabitEthernet1/0/10/1) of VLAN0002 is broken (PVST Peer Inconsistent)
Port path cost 4, Port priority 128, Port Identifier 128.297.
Designated root has priority 32769, address 0013.5f20.01c0
Designated bridge has priority 32769, address 0013.5f20.01c0
Designated port id is 128.297, designated path cost 0
Timers: message age 0, forward delay 0, hold 0
Number of transitions to forwarding state: 1
Link type is point-to-point by default
PVST Simulation is disabled
BPDU: sent 132, received 1