Dell Force10 C150 FTOS Command Line Reference Guide FTOS 8.4.2.7 E-Series Tera - Page 1173

Command History Version 8.5.1.0 Version 8.4.2.1 Version 8.2.1.0 Version 7.6.1.0 Version 7.5.1.0 Version 7.4.1.0 Version 6.2.1.1 Introduced the loopguard and rootguard options on the E-Series ExaScale. Introduced the loopguard and rootguard options on the E-Series TeraScale, C-Series, and S-Series. Introduced hardware shutdown-on-violation option Support added for S-Series Support added for C-Series Added the optional Bridge Port Data Unit (BPDU) guard Introduced Usage Information The BPDU guard option prevents the port from participating in an active STP topology in case a BPDU appears on a port unintentionally, or is misconfigured, or is subject to a DOS attack. This option places the port into an error disable state if a BPDU appears, and a message is logged so that the administrator can take corrective action. Note: A port configured as an edge port, on a PVST switch, 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 a 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 a PVST+ network, loop guard is performed per-port or per-port channel at a VLAN level. If no BPDUs are received on a VLAN interface, the port or port-channel transitions to a loop-inconsistent (blocking) state only for this VLAN. 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: Example • 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. Figure 46-7. spanning-tree pvst vlan Command Example FTOS(conf-if-gi-1/1)#spanning-tree pvst vlan 3 cost 18000 FTOS(conf-if-gi-1/1)#end FTOS(conf-if-gi-1/1)#show config ! interface GigabitEthernet 1/1 no ip address switchport spanning-tree pvst vlan 3 cost 18000 no shutdown FTOS(conf-if-gi-1/1)#end FTOS# Related Commands show spanning-tree pvst View PVST+ configuration Per-VLAN Spanning Tree plus (PVST+) | 1173