163
Configuring Switching Information
EdgeSwitch
™
Administration Guide
Ubiquiti Networks, Inc.
Spanning Tree CST Fields
Field
Description
Bridge Priority
The value that helps determine which bridge in the spanning tree is elected as the root bridge during
STP convergence. A lower value increases the probability that the bridge becomes the root bridge.
Bridge Max Age
The amount of time a bridge waits before implementing a topological change.
Bridge Hello Time
The amount of time the root bridge waits between sending hello BPDUs.
Bridge Forward Delay
The amount of time a bridge remains in a listening and learning state before forwarding packets.
Spanning Tree Maximum
Hops
The maximum number of hops a Bridge Protocol Data Unit (BPDU) is allowed to traverse within the
spanning tree region before it is discarded.
BPDU Guard
When enabled,
BPDU Guard
can disable edge ports that receive BPDU packets. This prevents a new
device from entering the existing STP topology. Thus devices that were originally not a part of STP are
not allowed to influence the STP topology.
BPDU Filter
When enabled, this feature filters the BPDU traffic on the edge ports. When spanning tree is disabled
on a port, BPDU filtering allows BPDU packets received on that port to be dropped.
Spanning Tree Tx Hold Count
The maximum number of BPDUs that a bridge is allowed to send within a hello time window.
Bridge Identifier
A unique value that is automatically generated based on the bridge priority value and the base MAC
address of the bridge. When electing the root bridge for the spanning tree, if the bridge priorities for
multiple bridges are equal, the bridge with the lowest MAC address is elected as the root bridge.
Time Since Topology Change
The amount of time that has passed since the topology of the spanning tree has changed since the
device was last reset.
Topology Change Count
The number of times the topology of the spanning tree has changed.
Topology Change
Indicates whether a topology change is in progress on any port assigned to the CST. If a change is in
progress the value is
True
; otherwise, it is
False
.
Designated Root
The bridge identifier of the root bridge for the CST. The identifier is made up of the bridge priority and
the base MAC address.
Root Path Cost
The path cost to the designated root for the CST. Traffic from a connected device to the root bridge
takes the least-cost path to the bridge. If the value is
0
, the cost is automatically calculated based on
port speed.
Root Port
The port on the bridge with the least-cost path to the designated root for the CST.
Max Age
The amount of time a bridge waits before implementing a topological change.
Forward Delay
The forward delay value for the root port bridge.
Hold Time
The minimum amount of time between transmissions of Configuration BPDUs.
CST Regional Root
The bridge identifier of the CST regional root. The identifier is made up of the priority value and the
base MAC address of the regional root bridge.
CST Path Cost
The path cost to the CST tree regional root.
Use the buttons to perform the following tasks:
• If you make any configuration changes, click
Submit
to apply the new settings to the switch.
• Click
Refresh
to update the information on the screen with the most current data.
To retain the changes across the switch’s next power cycle, click
System
>
Configuration Storage
>
Save
.
