Table 230: Spanning Tree CST Fields (continued)
Field
Description
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
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.
•
If you make any configuration changes, click
Submit
to apply the new settings to the switch.
•
Click
Force
to force the port to send out 802.1w or 802.1D BPDUs.
•
Click
Refresh
to update the screen with most recent data.
Configuring Switching Information
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