Users Guide

NOTE: A port congured as an edge port, on an RSTP switch, immediately transitions to the Forwarding
state. Only congure ports connected to end-hosts as edge ports. Consider an edge port similar to a
port with a spanning-tree portfast enabled.
If you do not enable shutdown-on-violation, BPDUs are still sent to the RPM CPU.
You cannot enable STP root guard and loop guard 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 displays: % Error:
RootGuard is configured. Cannot configure LoopGuard.
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.
Example
Dell(conf)#interface gigabitethernet 4/0
Dell(conf-if-gi-4/0)#spanning-tree rstp edge-port
Dell(conf-if-gi-4/0)#show config
!
interface GigabitEthernet 4/0
no ip address
switchport
spanning-tree rstp edge-port
no shutdown
Dell#
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 (conf-rstp)
Supported Modes Full–Switch
Command History
Version Description
9.9(0.0) Introduced on the FN IOM.
8.3.16.1 Introduced on the MXL 10/40GbE Switch IO Module.
Usage Information By default, the system implements an optimized ush mechanism for RSTP. This implementation helps in ushing
MAC addresses only when necessary (and less often), allowing for faster convergence during topology changes.
However, if a standards-based ush mechanism is needed, you can turn on this knob command to enable ushing
MAC addresses after receiving every topology change notication.
Rapid Spanning Tree Protocol (RSTP) 1137