24-Port Layer 3 Switch Management Guide

S PANNING T REE A LGORITHM C ONFIGURATION
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device with the lowest MAC address will then become the root device.
(Note that lower numeric values indicate higher priority.)
Default: 32768
Range: 0-61440, in steps of 4096
Options: 0, 4096, 8192, 12288, 16384, 20480, 24576, 28672, 32768,
36864, 40960, 45056, 49152, 53248, 57344, 61440
Root Device Configuration
• Hello Time – Interval (in seconds) at which the root device transmits a
configuration message.
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 STA
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.
(References to “ports” in this section mean “interfaces,” which includes
both ports and trunks.)
Default: 20
Minimum: The higher of 6 or [2 x (Hello Time + 1)].
Maximum: The lower of 40 or [2 x (Forward Delay - 1)]
• 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.
Default: 15
Minimum: The higher of 4 or [(Max. Message Age / 2) + 1]
Maximum: 30