Command Line Reference Guide
Rapid Spanning Tree Protocol (RSTP) | 905
Parameters
Defaults
Not configured
Command Modes
INTERFACE
Command
History
Usage
Information
The BPDU guard option prevents the port from participating in an active STP topology in case a
BPDU appears on a port unintentionally, or is misconfigured, or is subject to a DOS attack. This option
places the port into an error disable state if a BPDU appears, and a message is logged so that the
administrator can take corrective action.
If shutdown-on-violation is not enabled, BPDUs will still be sent to the RPM CPU.
cost Port cost (OPTIONAL) Enter the keyword cost followed by the port cost value.
Range: 1 to 200000
Defaults:
100 Mb/s Ethernet interface = 200000
1-Gigabit Ethernet interface = 20000
10-Gigabit Ethernet interface = 2000
Port Channel interface with one 100 Mb/s Ethernet = 200000
Port Channel interface with one 1-Gigabit Ethernet = 20000
Port Channel interface with one 10-Gigabit Ethernet = 2000
Port Channel with two 1-Gigabit Ethernet = 18000
Port Channel with two 10-Gigabit Ethernet = 1800
Port Channel with two 100-Mbps Ethernet = 180000
edge-port Enter the keyword edge-port to configure the interface as a Rapid Spanning Tree
edge port.
bpduguard (OPTIONAL) Enter the keyword portfast to enable Portfast to move the interface
into forwarding mode immediately after the root fails.
Enter the keyword bpduguard to disable the port when it receives a BPDU.
shutdown-on-v
iolation
(OPTIONAL) Enter the keyword shutdown-on-violation to hardware disable
an interface when a BPDU is received and the port is disabled.
priority priority (OPTIONAL) Enter keyword priority followed by a value in increments of 16 as
the priority.
Range: 0 to 240.
Default: 128
Version 8.3.5.0 Introduced on S55
Version 8.2.1.0 Introduced hardware shutdown-on-violation options
Version 7.6.1.0 Support added for S-Series
Version 7.5.1.0 Support added for C-Series
Version 7.4.1.0 Added the optional Bridge Port Data Unit (BPDU) guard.
Version 6.2.1.1 Introduced for E-Series
Note: A port configured as an edge port, on an RSTP switch, will immediately transition to
the forwarding state. Only ports connected to end-hosts should be configured as edge ports.
Consider an edge port similar to a port with a spanning-tree portfast enabled.