S
PANNING
T
REE
A
LGORITHM
C
ONFIGURATION
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device (except for the root device) which incurs the lowest path
cost when forwarding a packet from that device to the root device.
Then it selects a designated bridging device from each LAN which
incurs the lowest path cost when forwarding a packet from that
LAN to the root device. All ports connected to designated bridging
devices are assigned as designated ports. After determining the
lowest cost spanning tree, it enables all root ports and designated
ports, and disables all other ports. Network packets are therefore
only forwarded between root ports and designated ports,
eliminating any possible network loops.
Managing Global Settings
Global settings apply to the entire switch.
Command Attributes
The following global attributes are fixed and cannot be changed:
•Bridge ID – The priority and MAC address of this device.
•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 communicate s 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.