Users Guide

The range is from 0 to 240, in increments of 16.
The default is 128.
To view the current values for these interface parameters, use the show config command from INTERFACE mode.
Setting STP path cost as constant
You can set the path cost to be constant for port-channel regardless of the operation status of the port-channel member ports.
To set the STP path cost, use the port-channel path-cost custom command from the PROTOCOL SPANNING-TREE
mode.
The following is the example configuration:
DELLEMC(conf)#protocol spanning-tree pvst
DELLEMC(conf-pvst)#port-channel path-cost custom
This command is support in all STP modes such as STP, RSTP, MSTP, and PVST.
To change the path cost to achieve new IEEE standard behavior, use no port-channel path-cost custom command.
Dell EMC Networking OS behavior does not change when a new member port is added to the port-channel or an existing
member port is deleted from the configuration. The path cost reflects the cumulative speed of the port-channel member ports.
Configuring an EdgePort
The EdgePort feature enables interfaces to begin forwarding traffic approximately 30 seconds sooner.
In this mode, an interface forwards frames by default until it receives a BPDU that indicates that it should behave otherwise;
it does not go through the Learning and Listening states. The bpduguard shutdown-on-violation option causes the
interface hardware to be shut down when it receives a BPDU. When you implement only bpduguard, although the interface is
placed in an Error Disabled state when receiving the BPDU, the physical interface remains up and spanning-tree drops packets
in the hardware after a BPDU violation. BPDUs are dropped in the software after receiving the BPDU violation. This feature is
the same as PortFast mode in spanning tree.
CAUTION:
Configure EdgePort only on links connecting to an end station. EdgePort can cause loops if you
enable it on an interface connected to a network.
To enable EdgePort on an interface, use the following command.
● Enable EdgePort on an interface.
INTERFACE mode
spanning-tree mstp edge-port [bpduguard | shutdown-on-violation]
Dell EMC Networking OS Behavior: Regarding bpduguard shutdown-on-violation behavior:
○ If the interface to be shut down is a port channel, all the member ports are disabled in the hardware.
○ When you add a physical port to a port channel already in the Error Disable state, the new member port is also disabled in
the hardware.
○ When you remove a physical port from a port channel in the Error Disable state, the error disabled state is cleared on this
physical port (the physical port is enabled in the hardware).
○ You can clear the Error Disabled state with any of the following methods:
￭ Use the shutdown command on the interface.
￭ Disable the shutdown-on-violation command on the interface (using the no spanning-tree stp-id
portfast [bpduguard | [shutdown-on-violation]] command).
￭ Disable spanning tree on the interface (using the no spanning-tree command in INTERFACE mode).
￭ Disabling global spanning tree (using the no spanning-tree command in CONFIGURATION mode).
To verify that EdgePort is enabled, use the show config command from INTERFACE mode.
DellEMC(conf-if-tf-1/1)#spanning-tree mstp edge-port
DellEMC(conf-if-tf-1/1)#show config
!
interface TwentyfiveGigE 1/1
no ip address
552
Multiple Spanning Tree Protocol (MSTP)