2-1023
Catalyst 6500 Series Switch Command Reference—Release7.6
78-15328-01
Chapter2 Catalyst 6500 Series Switch and ROM Monitor Commands show spantree bpdu-skewing
show spantree bpdu-skewing
To display BPDU skewing detection status, use the show spantree bpdu-skewing command.
show spantree bpdu-skewing vlan [mod/port]
show spantree bpdu-skewing {mistp-instance instance} mod/port
show spantree bpdu-skewing mst [instance | mod/port]
Syntax Description
Defaults The default is the BPDU skew status for all VLANs is displayed.
Command Types Switch command.
Command Modes Normal.
Usage Guidelines This command is not supported by the NAM.
The mistp-instance instance options are available in MISTP mode only.
You can use this command to troubleshoot slow network convergence due to skewing. Skewing occurs
when spanning tree timers lapse, expected BPDUs are not received, and spanning tre e detects topology
changes. The difference between the expected result and the BPDUs actually received is a skew. The
skew causes BPDUs to reflood the network to keep the spanning tree top ology da tab ase u p to d ate .
Examples This example shows how to display the BPDU skew status for a VLAN:
Console> show spantree bpdu-skewing 1
Bpdu skewing statistics for vlan 1
Port Last Skew (ms) Worst Skew (ms) Worst Skew Time
-------------- --------------- --------------- -------------------------
8/2 5869 108370 Tue Nov 21 2000, 06:25:59
8/4 4050 113198 Tue Nov 21 2000, 06:26:04
8/6 113363 113363 Tue Nov 21 2000, 06:26:05
.
vlan Number of the VLAN; valid values are from 1 to 1005 and from
1025 to 4094.
mod/port (Optional) Number of the module and the port on the module.
mistp-instance
instance Displays instance-specific information; valid values are from 1 to
16.
mst Displays MST instance information.
instance (Optional) Number of the instance; valid values are from 1 to 15.
mod/port (Optional) Number of the module and the port on the module.