Users Guide

Version Description
8.4.2.1 Introduced the loopguard and rootguard options on the E-Series TeraScale,
C-Series, and S-Series.
8.3.19.0 Introduced on the S4820T.
8.3.11.1 Introduced on the Z9000.
8.3.7.1 Introduced on the S4810.
8.2.1.0 Introduced the hardware shutdown-on-violation option.
7.6.1.0 Introduced on the S-Series.
7.5.1.0 Introduced on the C-Series.
6.1.1.0 Added support for the BPDU guard.
Usage Information
On an MSTP switch, a port congured as an edge port immediately transitions to the forwarding state. Only
ports connected to end-hosts should be congured as an edge port. Consider an edge port similar to a port
with spanning-tree portfast enabled.
If you do not enable shutdown-on-violation, BPDUs are still sent to the RPM CPU.
Root guard and loop guard cannot be enabled at the same time on a port. For example, if you congure loop
guard on a port on which root guard is already congured, 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.
Enabling Portfast BPDU guard and loop guard at the same time on a port results in a port that remains in a
blocking state and prevents trac from owing through it. For example, when Portfast BPDU guard and
loop guard are both congured:
• If a BPDU is received from a remote device, BPDU guard places the port in an err-disabled blocking state
and no trac is forwarded on the port.
• If no BPDU is received from a remote device, loop guard places the port in a loop-inconsistent blocking
state and no trac is forwarded on the port.
tc-ush-standard
Enable the MAC address ushing after receiving every topology change notication.
Syntax
tc-flush-standard
To disable, use the no tc-flush-standard command.
Defaults Disabled.
Command Modes CONFIGURATION
Multiple Spanning Tree Protocol (MSTP)
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