System information

2-33
Spanning Tree Algorithm Configuration
2
• Designated Root – The priority and MAC address of the device in the Spanning
Tree that this switch has accepted as the root device.
- Root Port – The number of the port on this switch that is closest to the root. This
switch communicates with the root device through this port. If there is no root
port, then this switch has been accepted as the root device of the Spanning Tree
network.
- Root Path Cost – The path cost from the root port on this switch to the root
device.
- Root Hello Time* – Interval (in seconds) at which this device transmits a
configuration message.
- Root Maximum Age* – The maximum time (in seconds) this device can wait
without receiving a configuration message before attempting to reconfigure. All
device ports (except for designated ports) should receive configuration
messages at regular intervals. If the root port ages out STA information
(provided in the last configuration message), a new root port is selected from
among the device ports attached to the network. (References to “ports” in this
section means “interfaces,” which includes both ports and trunks.)
- Root Forward Delay* – The maximum time (in seconds) this device will wait
before changing states (i.e., discarding to learning to forwarding). This delay is
required because every device must receive information about topology
changes before it starts to forward frames. In addition, each port needs time to
listen for conflicting information that would make it return to a discarding state;
otherwise, temporary data loops might result.
- Root Hold Time* – The interval (in seconds) during which no more than two
bridge configuration protocol data units shall be transmitted by this node.
- Configuration Changes – The number of times the Spanning Tree has been
reconfigured.
- Last Topology Change – Time since the Spanning Tree was last reconfigured.
* CLI only.
Web – Click Spanning Tree, STA Information.
Figure 2-22. Displaying Spanning Tree Information