LevelOne GTL-2691 - Manual (Page 247)

C HAPTER 8 | Spanning Tree Algorithm
Configuring Global Settings for STA
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spanning tree is disabled globally on the switch or disabled on a specific
port.
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To VLAN: Floods BPDUs to all other ports within the receiving port’s
native VLAN (i.e., as determined by port’s PVID). This is the default.
■
To All: Floods BPDUs to all other ports on the switch.
The setting has no effect if BPDU flooding is disabled on a port (see
"Configuring Interface Settings for STA" ).
Advanced Configuration Settings
The following attributes are based on RSTP, but also apply to STP since the
switch uses a backwards-compatible subset of RSTP to implement STP, and
also apply to MSTP which is based on RSTP according to the standard:
◆ 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)
When the Switch Becomes Root
◆ 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