Reference Guide

950 | Multiple Spanning Tree Protocol (MSTP)
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Command
History
spanning-tree mstp
c e s
Configures a Layer 2 MSTP interface as an edge port with (optionally) a Bridge Protocol Data Unit
(BPDU) guard, or enables the root guard or loop guard feature on the interface.
Syntax
spanning-tree mstp {edge-port [bpduguard [shutdown-on-violation]] | loopguard |
rootguard}
Parameters
Command Modes
INTERFACE
Command
History
Usage
Information
On an MSTP switch, a port configured as an edge port will immediately transition to the forwarding
state. Only ports connected to end-hosts should be configured as an edge port. Consider an edge port
similar to a port with spanning-tree portfast enabled.
If shutdown-on-violation is not enabled, BPDUs will still be sent to the RPM CPU.
Root guard and loop guard cannot be enabled at the same time on a port. For example, if you configure
loop guard on a port on which root guard is already configured, the following error message is
displayed:
% Error: RootGuard is configured. Cannot configure LoopGuard.
When used in an MSTP network, if root guard blocks a boundary port in the CIST, the port is also
blocked in all other MST instances.
Version 7.6.1.0 Added support for S-Series
Version 7.5.1.0 Added support for C-Series
Version 6.5.1.0 Introduced on E-Series
edge-port
Enter the keyword edge-port to configure the interface as a Multiple Spanning Tree
edge port.
bpduguard
(OPTIONAL) Enter the keyword portfast to enable Portfast to move the interface into
forwarding mode immediately after the root fails.
Enter the keyword bpduguard to disable the port when it receives a BPDU.
shutdown-on-
violation
(OPTIONAL) Enter the keyword shutdown-on-violation to hardware disable an
interface when a BPDU is received and the port is disabled.
loopguard
Enter the keyword loopguard to enable STP loop guard on an MSTP port or
port-channel interface.
rootguard
Enter the keyword rootguard to enable root guard on an MSTP port or port-channel
interface.
Version 8.5.1.0 Introduced the loopguard and rootguard options on the E-Series ExaScale.
Version 8.4.2.1 Introduced the loopguard and rootguard options on the E-Series TeraScale, C-Series,
and S-Series.
Version 8.2.1.0 Introduced hardware shutdown-on-violation option
Version 7.6.1.0 Added support for S-Series
Version 7.5.1.0 Added support for C-Series
Version 6.1.1.0 Support for BPDU guard added