Reference Guide

You cannot enable STP root guard and loop guard 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 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 traffic from flowing through it.
For example, when Portfast BPDU guard and loop guard are both configured:
• If a BPDU is received from a remote device, BPDU guard places the port in an
Err-Disabled Blocking state and no traffic 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 traffic is forwarded on the port.
Example
Dell(conf)#interface tengigabitethernet 4/0
Dell(conf-if-te-4/0)#spanning-tree rstp edge-port
Dell(conf-if-te-4/0)#show config
!
interface TenGigabitEthernet 4/0
no ip address
switchport
spanning-tree rstp edge-port
no shutdown
Dell#
tc-flush-standard
Enable the MAC address flushing after receiving every topology change notification.
S5000
Syntax
tc-flush-standard
To disable, use the no tc-flush-standard command.
Defaults Disabled
Command
Modes
CONFIGURATION
Command
History
Version 9.0(1.3) Introduced on the S5000.
Usage
Information
By default, Dell Networking OS implements an optimized flush mechanism for
RSTP. This helps in flushing MAC addresses only when necessary (and less often),
allowing for faster convergence during topology changes. However, if a standards-
based flush mechanism is needed, you can turn on this knob command to enable
flushing MAC addresses after receiving every topology change notification.
1192
Rapid Spanning Tree Protocol (RSTP)