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Catalyst 2960 and 2960-S Switch Software Configuration Guide
OL-8603-09
Chapter 16 Configuring STP
Configuring Spanning-Tree Features
Changing the Spanning-Tree Mode
The switch supports three spanning-tree modes: PVST+, rapid PVST+, or M STP. By default, the switch
runs the PVST+ protocol.
Beginning in privileged EXEC mode, follow these steps to change the spanning-tree mode. If y ou want
to enable a mode that is different from the default mode, this procedure is required.
To return to the default setting, use the no spanning-tree mode global configuration command. To return
the port to its default setting, use the no spanning-tree link-type interface configuration command.
Command Purpose
Step 1 configure terminal Enter global configuration mode.
Step 2 spanning-tree mode {pvst | mst |
rapid-pvst}
Configure a spanning-tree mode. All stack members run the same
version of spanning-tree.
Note Stacking is supported only on Catalyst 2960-S switches running
the LAN base image.
• Select pvst to enable PVST+ (the default setting).
• Select mst to enable MSTP (and RSTP) . For more configuration
steps, see Chapter 17, “Configuring MSTP.”
• Select rapid-pvst to enable rapid PVST+.
Step 3 interface interface-id (Recommended for rapid-PVST+ mode only) Specify an interfac e to
configure, and enter interface configuration mode. Valid interfaces
include physical ports, VLANs, and port channels. The VLAN ID range
is 1 to 4094. The port-channel range is 1 to 6.
Step 4 spanning-tree link-type point-to-point (Recommended for rapid-PVST+ mode only) Specify that the link type
for this port is point-to-point.
If you connect this port (local port) to a remote port through a
point-to-point link and the local port becomes a designated port, the
switch negotiates with the remote port and rapidly changes the local
port to the forwarding state.
Step 5 end Return to privileged EXEC mode.
Step 6 clear spanning-tree detected-protocols (Recommended for rapid-PVST+ mode only) If any port on the sw itch
is connected to a port on a legacy IEEE 802.1D switch, restart the
protocol migration process on the entire switch.
This step is optional if the designated switch detects that this switch is
running rapid PVST+.
Step 7 show spanning-tree summary
and
show spanning-tree interface
interface-id
Verify your entries.
Step 8 copy running-config startup-config (Optional) Save your entries in the configuration file.