Dell PowerSwitch S4128F-ON EMC SmartFabric OS10 User Guide Release 10.5.0 - Page 477

Root bridge selection RSTP determines the root bridge. Assign one bridge a lower priority to increase the likelihood that it is selected as the root bridge. • Assign a number as the bridge priority or designate it as the primary or secondary root bridge in CONFIGURATION mode. Configure the priority value range, from 0 to 65535 in multiples of 4096, default 32768. The lower the number assigned, the more likely the bridge becomes the root bridge. spanning-tree rstp priority priority-value View bridge priority and root bridge assignment OS10# show spanning-tree active Spanning tree enabled protocol rstp with force-version rstp Executing IEEE compatible Spanning Tree Protocol Root ID Priority 32768, Address 3417.4455.667f Root Bridge hello time 2, max age 20, forward delay 15 Bridge ID Priority 36864, Address 90b1.1cf4.a523 Configured hello time 2, max age 20, forward delay 15 Interface Designated Name PortID Prio Cost Sts Cost Bridge ID PortID ethernet1/1/6:3 128.282 128 2000 FWD 0 32768 3417.4455.667f 128.152 ethernet1/1/6:4 128.283 128 2000 BLK 0 32768 3417.4455.667f 128.153 Interface Name Role PortID Prio Cost Sts Cost Link-type Edge ethernet1/1/6:3 Root 128.282 128 2000 FWD 0 AUTO No ethernet1/1/6:4 Altr 128.283 128 2000 BLK 0 AUTO No Spanning-tree link type for rapid state transitions As specified in IEEE 802.1w, OS10 assumes a port that runs in full-duplex mode is a point-to-point link. A point-to-point link transitions to forwarding state faster. By default, OS10 derives the link type of a port from the duplex mode. You can override the duplex mode using the spanning-tree link-type command. OS10 assumes a port that runs in half-duplex mode is a shared link, to which the fast transition feature is not applicable. Also, If you explicitly designate a port as a shared link, you cannot use the fast transition feature, regardless of the duplex setting. To hasten the spanning-tree state transitions, you can set the link type to point-to-point. To set the link type to point-to-point: • Use the following command in INTERFACE mode. spanning-tree link-type point-to-point RSTP commands show spanning-tree active Displays the RSTP configuration and information for RSTP-active interfaces. Syntax show spanning-tree active Parameters None Default Not configured Command Mode EXEC Usage Information None Example OS10# show spanning-tree active Spanning tree enabled protocol rstp with force-version rstp Executing IEEE compatible Spanning Tree Protocol Root ID Priority 32768, Address 90b1.1cf4.9b8a Root Bridge hello time 2, max age 20, forward delay 15 Bridge ID Priority 32768, Address 90b1.1cf4.9b8a Layer 2 477