Per-VLAN Spanning Tree Plus (PVST+) | 713Figure 34-4. Display the PVST+ Forwarding TopologyModify Global PVST+ ParametersThe root bridge sets the values for forward-delay, and hello-time and overwrites the values set on otherPVST+ bridges.• Forward-delay is the amount of time an interface waits in the Listening State and the Learning Statebefore 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 thatinformation by recomputing the PVST+ topology.To change PVST+ parameters, use the following commands on the root bridge:Task Command Syntax Command ModeChange the forward-delay parameter.• Range: 4 to 30• Default: 15 secondsvlan forward-delay PROTOCOL PVSTChange the hello-time parameter.Note: With large configurations (especially those with moreports) Dell Force10recommends that you increase the hello-time.Range: 1 to 10Default: 2 secondsvlan hello-time PROTOCOL PVSTFTOS_E600(conf)#do show spanning-tree pvst vlan 100VLAN 100Root Identifier has priority 4096, Address 0001.e80d.b6d6Root Bridge hello time 2, max age 20, forward delay 15Bridge Identifier has priority 4096, Address 0001.e80d.b6d6Configured hello time 2, max age 20, forward delay 15We are the root of VLAN 100Current root has priority 4096, Address 0001.e80d.b6d6Number of topology changes 5, last change occurred 00:34:37 ago on Gi 1/32Port 375 (GigabitEthernet 1/22) is designated ForwardingPort path cost 20000, Port priority 128, Port Identifier 128.375Designated root has priority 4096, address 0001.e80d.b6:d6Designated bridge has priority 4096, address 0001.e80d.b6:d6Designated port id is 128.375 , designated path cost 0Number of transitions to forwarding state 2BPDU sent 1159, received 632The port is not in the Edge port modePort 385 (GigabitEthernet 1/32) is designated ForwardingPort path cost 20000, Port priority 128, Port Identifier 128.385Designated root has priority 4096, address 0001.e80d.b6:d6Designated bridge has priority 4096, address 0001.e80d.b6:d6Designated port id is 128.385 , designated path cost 0
