Modifying Interface Stp Parameters; Enabling Portfast - Dell Force10 C150 Configuration Manual

View the current values for global parameters using the
privilege mode. See

Modifying Interface STP Parameters

You can set the port cost and port priority values of interfaces in Layer 2 mode.
• Port cost is a value that is based on the interface type. The greater the port cost, the less likely the port
will be selected to be a forwarding port.
• Port priority influences the likelihood that a port will be selected to be a forwarding port in case that
several ports have the same port cost.
The default values are listed in
To change the port cost or priority of an interface:
Task
Change the port cost of an interface.
Range: 0 to 65535
Default: see Table
Change the port priority of an interface.
Range: 0 to 15
Default: 8
View the current values for interface parameters using the
privilege mode. See

Enabling PortFast

The PortFast feature enables interfaces to transition to a forwarding state and start to transmit traffic
approximately 30 seconds sooner.
Interfaces forward frames by default until they receive a BPDU that indicates that they should behave
otherwise; they do not go through the Learning and Listening states. The
option causes the interface hardware to shut down when it receives a BPDU. When only
configured, although the interface is placed in an Error Disabled state when receiving the BPDU, the
physical interface remains up and spanning-tree will drop packets in the hardware after a BPDU violation.
BPDUs are dropped in the software after receiving the BPDU violation.
Caution:
interface connected to a network.
1056 | Spanning Tree Protocol
Figure 52-5.
Table
52-2.
Figure 52-5.
Enable PortFast only on links connecting to an end station. PortFast can cause loops if it is enabled on an
show spanning-tree 0
52-2.
Command Syntax
spanning-tree 0 cost cost
spanning-tree 0 priority
priority-value
show spanning-tree 0
command from EXEC
Command Mode
INTERFACE
INTERFACE
command from EXEC
bpduguard shutdown-on-violation
bpduguard
is