Dell Force10 E600i FTOS Version 8.4.1.5 Configuration Guide for ExaScale - Page 788

www.dell.com | support.dell.com The bridge with the bridge value for bridge priority is elected root. Since all bridges use the default priority (until configured otherwise), lowest MAC address is used as a tie-breaker. Assign bridges a low non-default value for bridge priority to increase the likelihood that it will be selected as the STP root. Task Assign a bridge priority. Range: 0 to 61440 Default: 32768 Command Syntax vlan bridge-priority Command Mode PROTOCOL PVST Display the PVST+ forwarding topology by entering the command show spanning-tree pvst [vlan vlan-id] from EXEC Privilege mode, as shown in the following example. FTOS_E600(conf)#do show spanning-tree pvst vlan 100 VLAN 100 Root Identifier has priority 4096, Address 0001.e80d.b6d6 Root Bridge hello time 2, max age 20, forward delay 15 Bridge Identifier has priority 4096, Address 0001.e80d.b6d6 Configured hello time 2, max age 20, forward delay 15 We are the root of VLAN 100 Current root has priority 4096, Address 0001.e80d.b6d6 Number of topology changes 5, last change occurred 00:34:37 ago on Gi 1/32 Port 375 (GigabitEthernet 1/22) is designated Forwarding Port path cost 20000, Port priority 128, Port Identifier 128.375 Designated root has priority 4096, address 0001.e80d.b6:d6 Designated bridge has priority 4096, address 0001.e80d.b6:d6 Designated port id is 128.375 , designated path cost 0 Number of transitions to forwarding state 2 BPDU sent 1159, received 632 The port is not in the Edge port mode Port 385 (GigabitEthernet 1/32) is designated Forwarding Port path cost 20000, Port priority 128, Port Identifier 128.385 Designated root has priority 4096, address 0001.e80d.b6:d6 Designated bridge has priority 4096, address 0001.e80d.b6:d6 Designated port id is 128.385 , designated path cost 0 Modify Global PVST+ Parameters The root bridge sets the values for forward-delay, and hello-time and overwrites the values set on other PVST+ bridges. • Forward-delay is the amount of time an interface waits in the Listening State and the Learning State before it transitions to the Forwarding State. • Hello-time is the time interval in which the bridge sends Bridge Protocol Data Units (BPDUs). • Max-age is the length of time the bridge maintains configuration information before it refreshes that information by recomputing the PVST+ topology. 788 | Per-VLAN Spanning Tree Plus