Changing The Spanning-Tree Mode - Cisco ME 3400G-2CS - Ethernet Access Switch Software Configuration Manual

Chapter 14 Configuring STP

Changing the Spanning-Tree Mode.

The switch supports three spanning-tree modes: PVST+, rapid PVST+, or MSTP. By default, the switch
runs the rapid PVST+ protocol on all NNIs.
Beginning in privileged EXEC mode, follow these steps to change the spanning-tree mode. If you want
to enable a mode that is different from the default mode, this procedure is required.
Command
Step 1 configure terminal
Step 2
spanning-tree mode {pvst | mst |
rapid-pvst}
Step 3 interface interface-id
Step 4 spanning-tree link-type point-to-point
Step 5
end
Step 6 clear spanning-tree detected-protocols
Step 7 show spanning-tree summary
and
show spanning-tree interface
interface-id
Step 8
copy running-config startup-config
78-17058-01
Purpose
Enter global configuration mode.
Configure a spanning-tree mode on NNIs on the switch.
• Select pvst to enable PVST+.
• Select mst to enable MSTP (and RSTP). For more configuration
steps, see Chapter 15, "Configuring MSTP."
• Select rapid-pvst to enable rapid PVST+ (the default setting).
(Recommended only for rapid-PVST+ mode) Specify an NNI to
configure, and enter interface configuration mode. Valid interfaces
include physical NNIs, VLANs, and NNI port channels. The VLAN ID
range is 1 to 4094. The port-channel range is 1 to 12.
Note If a physical interface is not an NNI, enter the port-type nni
interface configuration command before attempting to
configure it as a spanning-tree link.
If the interface is a VLAN, only NNIs in the VLAN will run
spanning tree.
If the interface is a port channel, all members of the port channel
must be NNIs.
(Recommended only for rapid-PVST+ mode) Specify that the link type
for this port is point-to-point.
If you connect this NNI (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.
Return to privileged EXEC mode.
(Recommended only for rapid-PVST+ mode) If any NNI on the switch
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+.
Verify your entries.
(Optional) Save your entries in the configuration file.
Cisco ME 3400 Ethernet Access Switch Software Configuration Guide
Configuring Spanning-Tree Features
14-13