Dell Force10 S4820T S4820T Configuration Guide - Page 749

Figure 37-4. Display the PVST+ Forwarding Topology 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. To change PVST+ parameters, use the following commands on the root bridge: Task Change the forward-delay parameter. • Range: 4 to 30 • Default: 15 seconds Change the hello-time parameter. Note: With large configurations (especially those with more ports) Dell Force10 recommends that you increase the hello-time. Range: 1 to 10 Default: 2 seconds Command Syntax vlan forward-delay vlan hello-time Command Mode PROTOCOL PVST PROTOCOL PVST Per-VLAN Spanning Tree Plus (PVST+) | 749