Catalyst 3750-E and 3560-E Switch Cisco IOS ... - DNIP . NET

clear spanning-tree detected-protocolsChapter 2Catalyst 3750-E and 3560-E Switch Cisco IOS Commandsclear spanning-tree detected-protocolsUse the clear spanning-tree detected-protocols privileged EXEC command on the switch stack or ona standalone switch to restart the protocol migration process (force the renegotiation with neighboringswitches) on all interfaces or on the specified interface.clear spanning-tree detected-protocols [interface interface-id]Syntax Descriptioninterface interface-id(Optional) Restart the protocol migration process on the specified interface.Valid interfaces include physical ports, VLANs, and port channels. TheVLAN range is 1 to 4094. The port-channel range is 1 to 48.DefaultsNo default is defined.Command ModesPrivileged EXECCommand HistoryRelease12.2(35)SE2ModificationThis command was introduced.Usage GuidelinesA switch running the rapid per-VLAN spanning-tree plus (rapid-PVST+) protocol or the MultipleSpanning Tree Protocol (MSTP) supports a built-in protocol migration mechanism that enables it tointeroperate with legacy IEEE 802.1D switches. If a rapid-PVST+ switch or an MSTP switch receives alegacy IEEE 802.1D configuration bridge protocol data unit (BPDU) with the protocol version set to 0,it sends only IEEE 802.1D BPDUs on that port. A multiple spanning-tree (MST) switch can also detectthat a port is at the boundary of a region when it receives a legacy BPDU, an MST BPDU (Version 3)associated with a different region, or a rapid spanning-tree (RST) BPDU (Version 2).However, the switch does not automatically revert to the rapid-PVST+ or the MSTP mode if it no longerreceives IEEE 802.1D BPDUs because it cannot learn whether the legacy switch has been removed fromthe link unless the legacy switch is the designated switch. Use the clear spanning-treedetected-protocols command in this situation.ExamplesThis example shows how to restart the protocol migration process on a port:Switch# clear spanning-tree detected-protocols interface gigabitethernet2/0/1Related CommandsCommandshow spanning-treespanning-tree link-typeDescriptionDisplays spanning-tree state information.Overrides the default link-type setting and enables rapid spanning-treechanges to the forwarding state.2-108Catalyst 3750-E and 3560-E Switch Command ReferenceOL-9776-08