Installation manual

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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.
• 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.
• Configuration Changes – The number of times the Spanning Tree has been
reconfigured.
• Last Topology Change – Time since the Spanning Tree was last reconfigured.
These additional parameters are only displayed for the CLI:
• Spanning Tree Mode – Specifies the type of spanning tree used on this switch:
- STP: Spanning Tree Protocol (IEEE 802.1D)
- RSTP: Rapid Spanning Tree (IEEE 802.1w)
- MSTP: Multiple Spanning Tree (IEEE 802.1s)
• Instance – Instance identifier of this spanning tree. (This is always 0 for the CIST.)
• VLANs Configuration – VLANs assigned to the CIST.
• Priority – Bridge priority is used in selecting the root device, root port, and designated
port. The device with the highest priority becomes the STA root device. However, if all
devices have the same priority, the device with the lowest MAC address will then
become 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.
• Max Hops – The max number of hop counts for the MST region.
• Remaining Hops – The remaining number of hop counts for the MST instance.