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ONFIGURATION
3-119
• Forward Delay – The maximum time (in seconds) the root 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.
• 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.