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6
System Configuration
Forward Delay – The maximum time (in seconds) this device waits 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. (Range: 4-30 seconds)
• Default: 15
• Minimum: The higher of 4 or [(Max. Message Age / 2) + 1]
• Maximum: 30
Hello Time – Interval (in seconds) at which the root device transmits a configuration
message. (Range: 1-10 seconds)
• Default: 2
• Minimum: 1
• Maximum: The lower of 10 or [(Max. Message Age / 2) -1]
Maximum Age – The maximum time (in seconds) a 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.
Any port that ages out STP information (provided in the last configuration message)
becomes the designated port for the attached LAN. If it is a root port, a new root port
is selected from among the device ports attached to the network. (Range: 6-40
seconds)
• Default: 20
• Minimum: The higher of 6 or [2 x (Hello Time + 1)].
• Maximum: The lower of 40 or [2 x (Forward Delay - 1)]
Bridge Priority – Used in selecting the root device, root port, and designated port.
The device with the highest priority becomes the STP root device. However, if all
devices have the same priority, the device with the lowest MAC address will then
become the root device. (Note that lower numeric values indicate higher priority.)
• Range: 0-65535
• Default: 32768
Port Cost – This parameter is used by the STP to determine the best path between
devices. Therefore, lower values should be assigned to ports attached to faster
media, and higher values assigned to ports with slower media. (Path cost takes
precedence over port priority.)
• Range: 1-65535
• Default: Ethernet interface: 19; Wireless interface: 40
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