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13-11
Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide
OL-10101-02
Chapter 13 Configuring STP
Configuring Spanning-Tree Features
• Configuring the Root Switch, page 13-14 (optional)
• Configuring a Secondary Root Switch, page 13-16 (optional)
• Configuring the Port Priority, page 13-17 (optional)
• Configuring the Path Cost, page 13-18 (optional)
• Configuring the Switch Priority of a VLAN, page 13-19 (optional)
• Configuring Spanning-Tree Timers, page 13-20 (optional)
Default Spanning-Tree Configuration
Table 13-3 shows the default spanning-tree configuration.
Spanning-Tree Configuration Guidelines
If more VLANs are defined in the VTP than there are spanning-tree instances, you can enable PVST+
or rapid PVST+ on only 64 VLANs. If the number of VLANs exceeds 64, we recommend that you enable
the MSTP to map multiple VLANs to a single spanning-tree instance. For more information, see
Chapter 14, “Configuring MSTP.”
Ta b l e 13-3 Default Spanning-Tree Configuration
Feature Default Setting
Enable state Enabled on VLAN 1.
For more information, see the “Supported
Spanning-Tree Instances” section on
page 13-9.
Spanning-tree mode PVST+. (Rapid PVST+ 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.
Spanning-tree timers Hello time: 2 seconds.
Forward-delay time: 15 seconds.
Maximum-aging time: 20 seconds.