D-Link DXS-3400 Emulator - Page 956

DXS-3400 Series Lite Layer 3 Stackable 10GbE Managed Switch CLI Reference Guide Command Default Level Level: 12. Usage Guideline BPDU guard prevents a port from becoming a root port. This feature is useful for the service provider to prevent external bridges to a core region of the network influencing the spanning tree active topology, possibly because those bridges are not under the full control of the administrator. When a port is guarded from becoming a root port, the port will only play the role as a designated port. If the port receives the configuration BPDU with a higher priority, the port will change to the alternate port, which is in the blocking state. The received superior factor will not participate in the STP computation. The port will listen for BPDUs on the link. If the port times out the received superior BPDU, it will change to the designated port role. When a port changes to the alternate port state, due to the root guard, a system message will be generated. This configuration will take effect for all the spanning-tree versions. Example This example shows how to configure to prevent interface ethernet 1/0/1 from being a root port. Switch# configure terminal Switch(config)# interface ethernet 1/0/1 Switch(config-if)# spanning-tree guard root Switch(config-if)# 98-19 spanning-tree link-type This command is used to configure a link-type for a port. Use the no form of this command to revert to the default setting. spanning-tree link-type {point-to-point | shared} no spanning-tree link-type Parameters point-to-point shared Specifies that the port's link type is point-to-point. Specifies that the port's link type is a shared media connection. Default The link type is automatically derived from the duplex setting unless explicitly configuring the link type. Command Mode Interface Configuration Mode. Command Default Level Level: 12. Usage Guideline A full-duplex port is considered to have a point-to-point connection; on the opposite, a half-duplex port is considered to have a shared connection .The port can't transit into forwarding state rapidly by setting link type to shared-media. Hence, auto-determined of link-type by the STP module is recommended. This configuration will take effect for all the spanning-tree modes. 952