3 Configuring the Switch

Priority – Bridge priority is used in selecting the root device, root port, and designated port. The device with the highest priority becomes the STA 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.)

-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

Configuration Settings for RSTP

The following attributes apply to both RSTP and MSTP:

Path Cost Method – The path cost is used to determine the best path between devices. The path cost method is used to determine the range of values that can be assigned to each interface.

-Long: Specifies 32-bit based values that range from 1-200,000,000. (This is the default.)

-Short: Specifies 16-bit based values that range from 1-65535.

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Accton Technology ES3528M-SFP manual Root Device Configuration, Configuration Settings for Rstp