3Com 3CRUS2475 User Manual page 237

Alternate — Provides an alternate path to the root switch from the
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root interface.
Backup — Provides a backup path to the designated port path
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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.
Disabled — The port is not participating in the Spanning Tree.
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Mode — Indicates the STP mode by which STP is enabled on the
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device. The possible field values are:
Classic STP — Classic STP is enabled on the device. This is the
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default value.
Rapid STP — Rapid STP is enabled on the device.
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Multiple STP — Multiple STP is enabled on the device.
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Type — Indicates whether the port is a Boundary or Master port. The
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possible field values are:
Boundary Port — Indicates that the port is a Boundary port. A
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Boundary port attaches MST bridges to LANs in an outlying region.
If the port is a Boundary port, this field also indicates whether the
device on the other side of the link is working in RSTP or STP mode
Master Port — Indicates the port is a master port. A Master port
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provides connectivity from a MSTP region to the outlying CIST root.
Port Priority — Priority value of the port. The priority value influences
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the port choice when a bridge has two ports connected in a loop. The
priority range is between 0-240. The priority value is determined in
increments of 16.
Path Cost — Indicates the port contribution to the root path cost. The
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path cost is adjusted to a higher or lower value, and is used to forward
traffic when a path is re-routed.
Port State — Displays the current STP state of a port. If enabled, the
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port state determines what forwarding action is taken on traffic.
Possible port states are:
Forwarding — Indicates that the port forwards traffic while
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learning MAC addresses.
Designated Cost — Indicates the cost of the port participating in the
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STP topology. Ports with a lower cost are less likely to be blocked if
STP detects loops.
Defining Multiple STP Instance Settings 237