Filter
Top Products
13-7
Software Configuration Guide—Release 12.2(25)SG
OL-7659-03
Chapter 13 Understanding and Configuring STP
Configuring STP
Configuring STP
The following sections describe how to configure spanning tree on VLANs:
• Enabling STP, page 13-7
• Enabling the Extended System ID, page 13-8
• Configuring the Root Bridge, page 13-9
• Configuring a Secondary Root Switch, page 13-12
• Configuring STP Port Priority, page 13-13
• Configuring STP Port Cost, page 13-15
• Configuring the Bridge Priority of a VLAN, page 13-16
• Configuring the Hello Time, page 13-17
• Configuring the Maximum Aging Time for a VLAN, page 13-18
• Configuring the Forward-Delay Time for a VLAN, page 13-18
• Disabling Spanning Tree Protocol, page 13-19
• Enabling Per-VLAN Rapid Spanning Tree, page 13-20
Note The spanning tree commands described in this chapter can be configured on any interface except those
configured with the no switchport command.
Enabling STP
Note By default, spanning tree is enabled on all the VLANs.
You can enable a spanning tree on a per-VLAN basis. The switch maintains a separate instance of
spanning tree for each VLAN (except on VLANs on which you have disabled a spanning tree).
Spanning tree VLAN port cost (configurable on a
per-VLAN basis—used on interfaces configured as
Layer 2 trunk ports)
• 10-Gigabit Ethernet: 2
• Gigabit Ethernet: 4
• Fast Ethernet: 19
Hello time 2 sec
Forward delay time 15 sec
Maximum aging time 20 sec
Table 13-4 Spanning Tree Default Configuration Values (continued)
Feature Default Value