Cisco Systems N3KC3048TP1GE manual Verifying Rapid PVST+ Configurations, Restarting the Protocol

Configuring Rapid PVST+

Restarting the Protocol

If you set the link to shared, STP moves back to 802.1D.

Procedure

Command or Action

Step 1 switch# configure terminal

Step 2 switch(config)# interface type slot/port

Step 3 switch(config-if)# spanning-treelink-type{auto point-to-point shared}

Purpose

Enters configuration mode.

Specifies the interface to configure, and enters the interface configuration mode.

Configures the link type to be either a point-to-point link or shared link. The system reads the default value from the switch connection, as follows: half duplex links are shared and full-duplex links are point-to-point. If the link type is shared, the STP reverts to 802.1D. The default is auto, which sets the link type based on the duplex setting of the interface.

This example shows how to configure the link type as a point-to-point link:

switch# configure terminal

switch (config)# interface ethernet 1/4 switch(config-if)# spanning-treelink-typepoint-to-point

You can only apply this command to a physical Ethernet interface.

Restarting the Protocol

A bridge running Rapid PVST+ can send 802.1D BPDUs on one of its ports when it is connected to a legacy bridge. However, the STP protocol migration cannot determine whether the legacy switch has been removed from the link unless the legacy switch is the designated switch. You can restart the protocol negotiation (force the renegotiation with neighboring switches) on the entire switch or on specified interfaces.

Command	Purpose
switch# clear spanning-tree detected-protocol	Restarts Rapid PVST+ on all interfaces on the switch
[interface interface [interface-num port-channel]]	or specified interfaces.

The following example shows how to restart Rapid PVST+ on an Ethernet interface:

switch# clear spanning-tree detected-protocol interface ethernet 1/8

Verifying Rapid PVST+ Configurations

To display Rapid PVST+ configuration information, perform one of these tasks:

Command	Purpose
switch# show running-config spanning-tree [all]	Displays the current spanning tree configuration.

	Cisco Nexus 3000 NX-OS Layer 2 Switching Configuration Guide, Release 5.0(3)U3(1)
86	OL-26590-01