User guide – Luxul XMS-1024P User Manual

Page 91

User Guide

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Root Bridge: Identifies the Switch with the lowest Bridge ID. Configure the Switch with
the lowest latency as the Root Bridge to ensure best Network performance
and reliability.

Designated Bridge: Identifies the Switch with the lowest path cost to the Root Bridge
in each Network segment. BPDUs are forwarded to the Network segment through the
designated bridge. If more than one Switch has the same path cost the Switch with the
lowest bridge ID will be chosen as the Designated Bridge.

Root Path Cost: Indicates the sum of the path cost of the root Port and the path cost
of all the Switches that packets pass through. The root path cost of the Root Bridge is 0,
the path cost of a Designated Bridge will typically be at least 2.

Bridge Priority: The bridge priority can be set to any value in the range 0-32768. The
lower the value the higher the priority. A Switch with a higher priority has more chance
to be chosen as the Root Bridge.

Root Port: Indicates the Port that has the lowest path cost from this bridge to the Root
Bridge and forwards packets to the Root.

Designated Port: Indicates the Port that forwards packets to a downstream Network
segment or Switch.

Port Priority: The Port priority can be set to any value in the range 0-255. The lower the
value the higher the priority. The Port with the higher priority has more chance to be
chosen as the Root Port.

Path Cost: Is the parameter used for choosing the link path of the STP Topology. By
calculating the path cost, STP chooses the best links and blocks any redundant links to
form a standard topology loop-free Network.

The following Network diagram shows a map of a typical Spanning Tree Topology.
Switch A, B and C are connected together in order. After STP is enabled, Switch A is
chosen as Root Bridge and the path from Port 2 to Port 6 is blocked.

Bridge: Switch A is the Root Bridge in the Network; Switch B is the Designated Bridge
of Switch C.

Port: Port 3 is the Root Port of Switch B and Port 5 is the Root Port of Switch C; Port 1
is the Designated Port of Switch A and Port 4 is the Designated Port of Switch B; Port
6 of Switch C and Port 2 of Switch A are blocked to prevent a Network loop.