Service Manual

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
no shutdown
Dell#
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
• 40-Gigabit Ethernet interface = 1400
• 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.
1066 Rapid Spanning Tree Protocol (RSTP)