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Catalyst 6500 Series Switch Command Reference—Release 8.4
OL-6244-01
Chapter 2 Catalyst 6500 Series Switch and ROM Monitor Commands
clear spantree mst
clear spantree mst
To clear the mapping of VLANs to an MST instance or to revert a port that is in pre-standard MST mode
back to standard MST mode, use the clear spantree mst command.
clear spantree mst instance [vlan vlans]
clear spantree mst mod/port pre-std
Syntax Description
Defaults This command has no default settings.
Command Types Switch command.
Command Modes Privileged.
Usage Guidelines If you enter only one instance number, you also can enter a VLAN number. If you enter a range of
instance numbers, you cannot enter a VLAN number.
If you do not specify a VLAN, all VLANs are unmapped from the specified instance and added to MST
instance 0 (IST).
Entering the clear spantree mst mod/port pre-std commands reverts a port that is in pre-standard MST
mode back to standard MST mode. Pre-standard MST is the implementation of MST that is not
compliant with with IEEE Std 802.1s. MST implementation is pre-standard on Catalyst 6500 series
switches that are running software before release 8.3(1) . MST implementation is pre-standard on
Catalyst 6500 series switches that are running any Cisco IOS software release. In standard MST mode,
a port on a neighbor that is in pre-standard MST mode might become a boundary port, even though both
switches have the same MST configuration.
The set spantree mst mod/port auto command also reverts a port back to standard MST mode.
Examples This example shows how to clear VLAN 2 from MST instance 2:
Console> (enable) clear spantree mst 2 vlan 2
Console> (enable)
This example shows how to revert a port back to standard MST mode:
Console> (enable) clear spantree mst 4/47 pre-std
Pre-Std Neighbor type cleared on port 4/47.
Console> (enable)
instance Number of the instance; valid values are from 0 to 4094.
vlan vlans (Optional) Specifies the VLAN number; valid values are from 1 to 4094.
mod/port Number of the module and the port on the module
pre-std Reverts a port that is in pre-standard MST mode back to standard MST mode
(IEEE Std 802.1s). See the “Usage Guidelines” section for more information.