Edge Products ES3528-WDM - Manual (Page 176)

Spanning Tree Algorithm
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• Instance – Instance identifier of this spanning tree. (This is always 0 for the CIST.)
• VLANs configuration – VLANs assigned to the CIST.
• Priority – Bridge priority is used in selecting the root device, root port, and
designated port. The device with the highest priority (i.e., lower numeric value)
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.
• Root Hello Time – Interval (in seconds) at which this device transmits a
configuration message.
• Root Maximum Age – The maximum time (in seconds) this 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. If the root port ages out STA information (provided in the last
configuration message), a new root port is selected from among the device ports
attached to the network. (References to “ports” in this section means “interfaces,”
which includes both ports and trunks.)
• Root 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.
• Max hops – The max number of hop counts for the MST region.
• Remaining hops – The remaining number of hop counts for the MST instance.
• Transmission limit – The minimum interval between the transmission of
consecutive RSTP/MSTP BPDUs.
• 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.
Web – Click Spanning Tree, STA, Information.
Figure 11-1 STA Information