Cisco Nexus 5000 Series - Specifying the Link Type

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Cisco Nexus 5000 Series Switch CLI Software Configuration Guide
OL-16597-01
Chapter 1 Configuring MST
Configuring MST
You can block this automatic feature either globally or per port.
To disable PVST simulation, perform this task:
This example shows how to prevent the specified interfaces from automatically interoperating with a
connecting switch that is not running MST:
switch# configure terminal
switch(config)# interface ethernet 1/4
switch(config-if)# spanning-tree mst simulate pvst disable
Specifying the Link Type
Rapid connectivity (802.1w standard) is established only on point-to-point links. By default, the link
type is controlled from the duplex mode of the interface. A full-duplex port is considered to have a
point-to-point connection; a half-duplex port is considered to have a shared connection.
If you have a half-duplex link physically connected point-to-point to a single port on a remote switch,
you can override the default setting on the link type and enable rapid transitions.
If you set the link to shared, STP reverts to 802.1D.
To specify the link type, perform this task:
Command Purpose
Step 1
switch# configure terminal
Enters configuration mode.
Step 2
switch(config)# interface {{type
slot/port} | {port-channel number}}
Specifies an interface to configure, and enters
interface configuration mode.
Step 3
switch(config-if)# spanning-tree mst
simulate pvst disable
Disables specified interfaces from automatically
interoperating with connected switch that is running
in Rapid PVST+ mode.
By default, all interfaces on the switch operate
seamlessly between Rapid PVST+ and MST.
switch(config-if)# spanning-tree mst
simulate pvst
Re-enables seamless operation between MST and
Rapid PVST+ on specified interfaces.
switch(config-if)# no spanning-tree mst
simulate pvst
Sets the interface to the switch-wide MST and Rapid
PVST+ interoperation that you configured using the
spanning-tree mst simulate pvst global command.
Command Purpose
Step 1
switch# configure terminal
Enters configuration mode.
Step 2
switch(config)# interface type slot/port
Specifies the interface to configure, and enters
interface configuration mode.
Step 3
switch(config-if)# spanning-tree
link-type {auto | point-to-point |
shared}
Configures the link type to be either point to point or
shared. The system reads the default value from the
switch connection. 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.