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spanning-tree rstp
Configure an RSTP interface with one of these settings: port cost, edge port with optional bridge port data unit (BPDU) guard,
port priority, loop guard, or root guard.
Syntax
spanning-tree rstp {cost port-cost | edge-port [bpduguard [shutdown-on-
violation]] | bpdufilter | priority priority | {rootguard}}
Parameters
cost port-cost Enter the keyword cost then the port cost value. The range is from 1 to 200000.
The defaults are:
● 10-Gigabit Ethernet interface = 2000
● Port Channel interface with one 10 Gigabit Ethernet = 2000
● Port Channel interface with one 40 Gigabit Ethernet = 1400
● Port Channel with two 10 Gigabit Ethernet = 1800
● Port Channel with two 40 Gigabit Ethernet = 600
edge-port Enter the keywords 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-
violation
(OPTIONAL) Enter the keywords shutdown-on-violation to hardware disable
an interface when a BPDU is received and the port is disabled.
bpdufilter (OPTIONAL) Enter the keyword bpdufilter to enable BPDU Filter to stop
sending and receiving BPDUs on port enabled interfaces.
priority priority Enter keyword priority then a value in increments of 16 as the priority. The
range is from 0 to 240. The default is 128.
rootguard Enter the keyword rootguard to enable root guard on an RSTP port or port-
channel interface.
Defaults Not configured.
Command Modes INTERFACE
Supported Modes Full–Switch
Command
History
Version Description
9.9(0.0) Introduced on the FN IOM.
8.3.16.1 Introduced on the MXL 10/40GbE Switch IO Module.
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.
NOTE: A port configured as an edge port, on an RSTP switch, immediately transitions to the
Forwarding state. Only configure ports connected to end-hosts as edge ports. Consider an edge
port similar to a port with a spanning-tree portfast enabled.
If you do not enable shutdown-on-violation, BPDUs are still sent to the RPM CPU.
You cannot enable STP root guard and loop guard at the same time on a port. For example, if you
configure loop guard on a port on which root guard is already configured, the following error message
displays: % Error: RootGuard is configured. Cannot configure LoopGuard.
Enabling Portfast BPDU guard and loop guard at the same time on a port results in a port that remains
in a Blocking state and prevents traffic from flowing through it. For example, when Portfast BPDU guard
and loop guard are both configured:
1004 Rapid Spanning Tree Protocol (RSTP)