3 Configuring the Switch

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: 30Configuration Settings for RSTPThe 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.

Transmission Limit – The maximum transmission rate for BPDUs is specified by setting the minimum interval between the transmission of consecutive protocol messages. (Range: 1-10; Default: 3)

Configuration Settings for MSTP

Max Instance Numbers – The maximum number of MSTP instances to which this switch can be assigned. (Default: 65)

Configuration Digest – An MD5 signature key that contains the VLAN ID to MST ID mapping table. In other words, this key is a mapping of all VLANs to the CIST.

Region Revision15 – The revision for this MSTI. (Range: 0-65535; Default: 0)Region Name15 – The name for this MSTI. (Maximum length: 32 characters)

Max Hop Count – The maximum number of hops allowed in the MST region before a BPDU is discarded. (Range: 1-40; Default: 20)

15. The MST name and revision number are both required to uniquely identify an MST region.

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