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Software Configuration Guide—Release IOS XE 3.5.0SG and IOS 15.2(2)SG
OL-27597-01
Chapter 22 Configuring STP and MST
Default STP Configuration
Default STP Configuration
Table 22-4 shows the default spanning tree configuration.
Configuring STP
The following sections describe how to configure spanning tree on VLANs:
• Enabling STP, page 22-8
• Enabling the Extended System ID, page 22-9
• Configuring the Root Bridge, page 22-9
• Configuring a Secondary Root Switch, page 22-12
• Configuring STP Port Priority, page 22-13
• Configuring STP Port Cost, page 22-15
• Configuring the Bridge Priority of a VLAN, page 22-17
• Configuring the Hello Time, page 22-17
• Configuring the Maximum Aging Time for a VLAN, page 22-18
• Configuring the Forward-Delay Time for a VLAN, page 22-19
• Disabling Spanning Tree Protocol, page 22-20
• Enabling Per-VLAN Rapid Spanning Tree, page 22-20
Table 22-4 Spanning Tree Default Configuration Values
Feature Default Value
Enable state Spanning tree enabled for all VLANs
Bridge priority value 32,768
Spanning tree port priority value (configurable on a
per-interface basis—used on interfaces configured as
Layer 2 access ports)
128
Spanning tree port cost (configurable on a per-interface
basis—used on interfaces configured as Layer 2 access
ports)
• 10-Gigabit Ethernet: 2
• Gigabit Ethernet: 4
• Fast Ethernet: 19
Spanning tree VLAN port priority value (configurable on
a per-VLAN basis—used on interfaces configured as
Layer 2 trunk ports)
128
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