Influencing Rstp Root Selection; Configuring An Edgeport - Dell C9000 Series Networking Configuration Manual

The range is from 0 to 15.
The default is 128.
To view the current values for interface parameters, use the show spanning-tree rstp command from
EXEC privilege mode.

Influencing RSTP Root Selection

RSTP determines the root bridge, but you can assign one bridge a lower priority to increase the likelihood that
it is selected as the root bridge.
To change the bridge priority, use the following command.
• Assign a number as the bridge priority or designate it as the primary or secondary root.
PROTOCOL SPANNING TREE RSTP mode
bridge-priority priority-value
• priority-value The range is from 0 to 65535. The lower the number assigned, the more likely this
bridge becomes the root bridge.
The default is 32768. Entries must be multiples of 4096.
Example of the bridge-priority Command
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).
Dell(conf-rstp)#bridge-priority 4096
04:27:59: %SYSTEM-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 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.
Rapid Spanning Tree Protocol (RSTP) 965