3Com 3CRUS2475 - Page 240

240 CHAPTER 11: CONFIGURING SPANNING TREE
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
provides connectivity from a MSTP region to the outlying CIST root.
■ Role — Indicates the port role assigned by the STP algorithm to
provide to STP paths. The possible field values are:
■ Root — Provides the lowest cost path to forward packets to the
root device.
■ Designated — Indicates the port or LAG through which the
designated device is attached to the LAN.
■ Alternate — Provides an alternate path to the root device from the
root interface.
■ 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.
■ Disabled — Indicates the port is not participating in the Spanning
Tree.
■ Mode — Indicates the STP mode by which STP is enabled on the
device. The possible field values are:
■ Classic STP — Classic STP is enabled on the device. This is the
default value.
■ Rapid STP — Rapid STP is enabled on the device.
■ Multiple STP — Multiple STP is enabled on the device.
■ Interface Priority — Defines the interface priority for the specified
instance. The field range is 0-240. The default value is 128.
■ Path Cost — Indicates the port contribution to the Spanning Tree
instance. The range should always be 1-200,000,000.
■ Designated Bridge ID — Displays the ID of the bridge that connects
the link or shared LAN to the root.
■ Designated Port ID — Displays the ID of the port on the designated
bridge that connects the link or the shared LAN to the root.
■ Designated Cost — Indicates that the default path cost is assigned
according to the method selected on the Spanning Tree Global
Settings page.