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• Port priority influences the likelihood that a port is selected to be a forwarding port in case that
several ports have the same port cost.
The following lists the default values for port cost by interface.
Table 45. Default Values for Port Costs by Interface
Port Cost Default Value
100-Mb/s Ethernet interfaces 200000
1-Gigabit Ethernet interfaces 20000
10-Gigabit Ethernet interfaces 2000
Port Channel with 100 Mb/s Ethernet interfaces 180000
Port Channel with 1-Gigabit Ethernet interfaces 18000
Port Channel with 10-Gigabit Ethernet interfaces 1800
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.
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.
602
Multiple Spanning Tree Protocol (MSTP)