D-Link DXS-3227 - xStack Switch - Stackable, Web/Installation Manual

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Configuring Spanning Tree
Defining STP on Interfaces
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Fast Link — Indicates if Fast Link is enabled on the port. If Fast Link mode is enabled for a port, the Port
State is automatically placed in the Forwarding state when the port link is up. Fast Link optimizes the STP
protocol convergence. STP convergence can take 30-60 seconds in large networks.
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Root Guard — Restricts the interface from acting as the root port of the switch.
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BPDU Guard — BPDU Guard expands network administrator’s ability to enforce STP borders and to main-
tain STP topologies reliability. BPDU is utilized when Fast Link ports is enabled and/or if the Spanning Tree
Protocol is disabled on ports. If a BPDU message is sent to a port on which STP is disabled, BPDU Guard
shuts down the port, and generates a SNMP message. Indicates that BDPU is enabled for the selected inter-
face. The possible field values are:
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Enable — Enables BPDU guard on the selected port or LAG.
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Disable — Disables BPDU guard on the selected port or LAG. This is the default value.
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Port State — Displays the current STP state of a port. If enabled, the port state determines what forwarding
action is taken on traffic. Possible port states are:
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Disabled — Indicates that STP is currently disabled on the port. The port forwards traffic while learning
MAC addresses.
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Blocking — Indicates that the port is currently blocked and cannot forward traffic or learn MAC
addresses. Blocking is displayed when Classic STP is enabled.
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Port Role — Displays the port role assigned by the STP algorithm to provide to STP paths. The possible field
values are:
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Root — Provides the lowest cost path to forward packets to the root switch.
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Designated — Indicates the port or LAG through which the designated switch is attached to the LAN.
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Alternate — Provides an alternate path to the root switch from the root interface.
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Backup — Provides a backup path to the designated port path toward the Spanning Tree leaves. Backup
ports occur only when two ports are connected in a loop by a point-to-point link, or when a LAN has two
or more connections connected to a shared segment.
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Disabled — The port is not participating in the Spanning Tree.
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Speed — Indicates the speed at which the port is operating.
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Path Cost — Indicates the port contribution to the root path cost. The path cost is adjusted to a higher or
lower value, and is used to forward traffic when a path is re-routed.
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Priority — Priority value of the port. The priority value influences the port choice when a bridge has two ports
connected in a loop. The priority value is between 0 -240. The priority value is determined in increments of 16.
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Designated Bridge ID — Indicates the bridge priority and the MAC Address of the designated bridge.
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Designated Port ID — Indicates the selected port D-Link priority and interface.
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Designated Cost — Indicates the cost of the port participating in the STP topology. Ports with a lower cost
are less likely to be blocked if STP detects loops.
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Forward Transitions — Indicates the number of times the port has changed from Forwarding state to Block-
ing state.
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LAG — Indicates the LAG to which the port belongs.