Administrator Guide

A console message appears when a new root bridge has been assigned. The following example example shows the console message after
the bridge-priority command is used to make R2 the root bridge (shown in bold).
DellEMC(conf-rstp)#bridge-priority 4096
04:27:59: %RPM0-P:RP2 %SPANMGR-5-STP_ROOT_CHANGE: RSTP root changed. My Bridge ID:
4096:0001.e80b.88bd Old Root: 32768:0001.e801.cbb4 New Root: 4096:0001.e80b.88bd
Configuring an EdgePort
The EdgePort feature enables interfaces to begin forwarding traffic approximately 30 seconds sooner.
In this mode an interface forwards frames by default until it receives a BPDU that indicates that it should behave otherwise; it does not go
through the Learning and Listening states. The
bpduguard shutdown-on-violation option causes the interface hardware to be
shut down when it receives a BPDU. When only bpduguard is implemented, although the interface is placed in an Error Disabled state
when receiving the BPDU, the physical interface remains up and spanning-tree drops packets in the hardware after a BPDU violation.
BPDUs are dropped in the software after receiving the BPDU violation. This feature is the same as PortFast mode in Spanning Tree.
CAUTION: Configure EdgePort only on links connecting to an end station. If you enable EdgePort on an interface
connected to a network, it can cause loops.
Dell EMC Networking OS Behavior: Regarding bpduguard shutdown-on-violation behavior:
• If the interface to be shut down is a port channel, all the member ports are disabled in the hardware.
• When you add a physical port to a port channel already in the Error Disable state, the new member port is also disabled in the
hardware.
• When you remove a physical port from a port channel in the Error Disable state, the error disabled state is cleared on this physical port
(the physical port is enabled in the hardware).
• You can clear the Error Disabled state with any of the following methods:
• Perform an shutdown command on the interface.
• Disable the shutdown-on-violation command on the interface (the no spanning-tree stp-id portfast
[bpduguard | [shutdown-on-violation]] command).
• Disable spanning tree on the interface (the no spanning-tree command in INTERFACE mode).
• Disable global spanning tree (the no spanning-tree command in CONFIGURATION mode).
To enable EdgePort on an interface, use the following command.
• Enable EdgePort on an interface.
INTERFACE mode
spanning-tree rstp edge-port [bpduguard | shutdown-on-violation]
To verify that EdgePort is enabled on a port, use the show spanning-tree rstp command from EXEC privilege mode or the show
config command from INTERFACE mode.
NOTE: Dell EMC Networking recommends using the show config command from INTERFACE mode.
In the following example, the bold line indicates that the interface is in EdgePort mode.
DellEMC(conf-if-te-2/1/1)#show config
!
interface TenGigabitEthernet 2/1/1
no ip address
switchport
spanning-tree rstp edge-port
shutdown
DellEMC(conf-if-te-2/1/1)#
Configuring Fast Hellos for Link State Detection
Use RSTP fast hellos to achieve sub-second link-down detection so that convergence is triggered faster. The standard RSTP link-state
detection mechanism does not offer the same low link-state detection speed.
To achieve sub-second link-down detection so that convergence is triggered faster, use RSTP fast hellos. The standard RSTP link-state
detection mechanism does not offer the same low link-state detection speed.
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Rapid Spanning Tree Protocol (RSTP)