Dell PowerSwitch S4820T Configuration Guide for the S4820T System 9.100.0 - Page 548

To change the port cost or priority of an interface, use the following commands. 1 Change the port cost of an interface. INTERFACE mode spanning-tree msti number cost cost The range is from 0 to 200000. For the default, refer to the default values shown in the table.. 2 Change the port priority of an interface. INTERFACE mode spanning-tree msti number priority priority The range is from 0 to 240, in increments of 16. The default is 128. To view the current values for these interface parameters, use the show config command from INTERFACE mode. Configuring an EdgePort The EdgePort feature enables interfaces to begin forwarding traffic approximately 30 seconds sooner. In this mode, an interface forwards frames by default until it receives a BPDU that indicates that it should behave otherwise; it does not go through the Learning and Listening states. The bpduguard shutdown-on-violation option causes the interface hardware to be shut down when it receives a BPDU. When you implement only bpduguard, although the interface is placed in an Error Disabled state when receiving the BPDU, the physical interface remains up and spanning-tree drops packets in the hardware after a BPDU violation. BPDUs are dropped in the software after receiving the BPDU violation. This feature is the same as PortFast mode in spanning tree. CAUTION: Configure EdgePort only on links connecting to an end station. EdgePort can cause loops if you enable it on an interface connected to a network. To enable EdgePort on an interface, use the following command. • Enable EdgePort on an interface. INTERFACE mode spanning-tree mstp edge-port [bpduguard | shutdown-on-violation] Dell Networking OS Behavior: Regarding bpduguard shutdown-on-violation behavior: • If the interface to be shut down is a port channel, all the member ports are disabled in the hardware. • When you add a physical port to a port channel already in the Error Disable state, the new member port is also disabled in the hardware. • When you remove a physical port from a port channel in the Error Disable state, the error disabled state is cleared on this physical port (the physical port is enabled in the hardware). • You can clear the Error Disabled state with any of the following methods: • Use the shutdown command on the interface. • Disable the shutdown-on-violation command on the interface (using the no spanning-tree stp-id portfast [bpduguard | [shutdown-on-violation]] command). • Disable spanning tree on the interface (using the no spanning-tree command in INTERFACE mode). • Disabling global spanning tree (using the no spanning-tree command in CONFIGURATION mode). Example of Enabling an EdgePort on an Interface To verify that EdgePort is enabled, use the show config command from INTERFACE mode. Dell(conf-if-te-3/11)#spanning-tree mstp edge-port Dell(conf-if-te-3/11)#show config ! interface TenGigabitEthernet 3/11 548 Multiple Spanning Tree Protocol (MSTP)