Administrator Guide

Port Cost Default Value
100-Gigabit Ethernet interfaces 200
Port Channel with 100 Mb/s Ethernet interfaces 100000
Port Channel with 1-Gigabit Ethernet interfaces 10000
Port Channel with 10-Gigabit Ethernet interfaces 1000
Port Channel with 25-Gigabit Ethernet interfaces 400
Port Channel with 50-Gigabit Ethernet interfaces 200
Port Channel with 100-Gigabit Ethernet interfaces 100
To change the port cost or priority of an interface, use the following commands.
1. Change the port cost of an interface.
INTERFACE mode
spanning-tree msti number cost cost
The range is from 0 to 200000.
For the default, refer to the default values shown in the table..
2. Change the port priority of an interface.
INTERFACE mode
spanning-tree msti number priority priority
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]
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Multiple Spanning Tree Protocol (MSTP)