SMC Networks EliteConnect SMC2891W-AG User Manual page 76

6
System Configuration
Once a stable network topology has been established, all bridges listen for Hello
BPDUs (Bridge Protocol Data Units) transmitted from the root bridge. If a bridge
does not get a Hello BPDU after a predefined interval (Maximum Age), the bridge
assumes that the link to the root bridge is down. This bridge will then initiate
negotiations with other bridges to reconfigure the network to reestablish a valid
network topology.
• Bridge – Enables/disables STP on the wireless bridge or repeater.
(Default: Disabled)
• 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
• Bridge Max 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 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]
• Bridge Forwarding 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
• Link Path 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.)
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