Dell S3100 Command Line Reference Guide for the Series 9.82.0 - Page 1525

Version 8.2.1.0 7.6.1.0 7.5.1.0 7.4.1.0 6.2.1.1 Description Introduced the hardware shutdown-on-violation options. Introduced on the S-Series. Introduced on the C-Series. Added the optional bridge port data unit (BPDU) guard. Introduced on the E-Series. 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 an RSTP switch, immediately transitions to the Forwarding state. Only configure ports connected to endhosts as edge ports. Consider an edge port similar to a port with a spanningtree 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 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 gigabitethernet 4/1 Dell(conf-if-gi-4/0)# spanning-tree rstp edge-port Dell(conf-if-gi-4/0)# show config ! interface GigabitEthernet 4/1 no ip address switchport spanning-tree rstp edge-port no shutdown Dell# Rapid Spanning Tree Protocol (RSTP) 1525