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16-11
Catalyst 3550 Multilayer Switch Software Configuration Guide
78-11194-09
Chapter 16 Configuring STP
Configuring Spanning-Tree Features
To support VLAN-bridge spanning tree, some of the spanning-tree timers are increased. To use the
fallback bridging feature, you must have the enhanced multilayer software image installed on your
switch. For more information, see
Chapter 36, “Configuring Fallback Bridging.”
Configuring Spanning-Tree Features
These sections describe how to configure spanning-tree features:
•
Default Spanning-Tree Configuration, page 16-11
•
Spanning-Tree Configuration Guidelines, page 16-12
•
Changing the Spanning-Tree Mode, page 16-13
(required)
•
Disabling Spanning Tree, page 16-14
(optional)
•
Configuring the Root Switch, page 16-14
(optional)
•
Configuring a Secondary Root Switch, page 16-16
(optional)
•
Configuring the Port Priority, page 16-17
(optional)
•
Configuring the Path Cost, page 16-18
(optional)
•
Configuring the Switch Priority of a VLAN, page 16-20
(optional)
•
Configuring Spanning-Tree Timers, page 16-20
(optional)
Default Spanning-Tree Configuration
shows the default spanning-tree configuration.
Table 16-3 Default Spanning-Tree Configuration
Feature
Default Setting
Enable state
Enabled on VLAN 1.
For more information, see the
Spanning-Tree Instances” section on
page 16-9
.
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.