C
ONFIGURING
THE
S
WITCH
3-124
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