Service Manual

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
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:
• If a BPDU is received from a remote device, BPDU guard places the port in an Err-Disabled Blocking state and
no traffic is forwarded on the port.
• If no BPDU is received from a remote device, loop guard places the port in a Loop-Inconsistent Blocking state
and no traffic is forwarded on the port.
Example
Dell(conf)#interface gigabitethernet 4/0
Dell(conf-if-gi-4/0)#spanning-tree rstp edge-port
Dell(conf-if-gi-4/0)#show config
!
interface GigabitEthernet 4/0
no ip address
switchport
spanning-tree rstp edge-port
Rapid Spanning Tree Protocol (RSTP) 1067