attack. This option places the port into an Error Disable state if a BPDU appears and a messageis logged so that the administrator can take corrective action.NOTE: A port configured as an edge port, on an RSTP switch, immediately transitions tothe Forwarding state. You should only configure ports connected to end-hosts as edgeports. Consider an edge port similar to a port with a spanning-tree portfastenabled.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, ifyou configure loop guard on a port on which root guard is already configured, the followingerror message displays: % Error: RootGuard is configured. Cannotconfigure LoopGuard.Enabling Portfast BPDU guard and loop guard at the same time on a port results in a port thatremains in a Blocking state and prevents traffic from flowing through it. For example, whenPortfast 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 FTOS(conf)#interface gigabitethernet 4/0FTOS(conf-if-gi-4/0)#spanning-tree rstp edge-portFTOS(conf-if-gi-4/0)#show config!interface GigabitEthernet 4/0no ip addressswitchportspanning-tree rstp edge-portno shutdownFTOS#tc-flush-standardEnable the MAC address flushing after receiving every topology change notification.C-Series, E-Series, S-Series, Z-Series, S4810Syntax tc-flush-standardTo disable, use the no tc-flush-standard command.Defaults DisabledCommand Modes CONFIGURATIONCommand History Version 8.3.11.1 Introduced on the Z9000.Version 8.3.7.0 Introduced on the S4810.Version 7.6.1.0 Introduced on the S-Series.1283
