Specifications

12-10
Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide
78-11380-07
Chapter 12 Configuring STP
Configuring Spanning-Tree Features
Configuring Spanning-Tree Features
These sections describe how to configure spanning-tree features:
• Default STP Configuration, page 12-10
• STP Configuration Guidelines, page 12-11
• Disabling STP, page 12-11
• Configuring the Root Switch, page 12-12
• Configuring a Secondary Root Switch, page 12-14
• Configuring the Port Priority, page 12-15
• Configuring the Path Cost, page 12-16
• Configuring the Switch Priority of a VLAN, page 12-18
• Configuring the Hello Time, page 12-18
• Configuring the Forwarding-Delay Time for a VLAN, page 12-19
• Configuring the Maximum-Aging Time for a VLAN, page 12-20
• Configuring STP for Use in a Cascaded Stack, page 12-20
Default STP Configuration
Table 12-3 shows the default STP configuration.
Table 12-3 Default STP Configuration
Feature Default Setting
Enable state Enabled on VLAN 1.
Up to 64 spanning-tree instances can be
enabled.
Spanning-tree mode PVST (PVRST and MSTP are disabled).
Switch priority 32768.
Spanning-tree port priority (configurable on a per-interface basis) 128.
Spanning-tree port cost (configurable on a per-interface basis) 1000 Mbps: 4.
100 Mbps: 19.
10 Mbps: 100.
Spanning-tree VLAN port priority (configurable on a per-VLAN basis) 128.
Spanning-tree VLAN port cost (configurable on a per-VLAN basis) 1000 Mbps: 4.
100 Mbps: 19.
10 Mbps: 100.
Hello time 2 seconds.
Forward-delay time 15 seconds.
Maximum-aging time 20 seconds.