User`s guide

Configuring Spanning Tree
Configuring Multiple Spanning Tree
Page 118
The MSTP Interface Settings Page contains the following fields:
• Instance ID — Lists the MSTP instances configured on the device. The possible field range is 1-16.
• Interface — Displays the specific interface for this page’s MSTP setting. The possible field values are:
– Port of Unit — Specifies the port for which the MSTP settings are displayed.
– Trunk — Specifies the trunk for which the MSTP settings are displayed.
• STP Port State — Indicates if STP is enabled on the port. The possible field values are:
– Enabled — Indicates that STP is enabled on the port.
– Disabled — Indicates that STP is disabled on the port.
• Port State — Indicates whether the port is enabled for the specific instance. The possible field values are:
– Forwarding — Indicates that the port forwards packets.
– Discarding — Indicates that the port discards packets.
– Disabled — Indicates that STP is disabled on the port.
– N/A — Indicates that the port is not available for STP; for example, if the port belongs to a trunk.
• Type — Indicates whether the port is a Boundary or Master port. The possible field values are:
– Boundary — Indicates that the 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.
– Internal — Indicates the port provides connectivity within the same region.
• 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 trunk 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 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.
• Interface Priority (0-240,in steps of 16) — Indicates the priority value of the port connected to the selected
port for the specified instance. A lower priority increases the probability of connecting to a root port. The
possible field values are 0-240, in multiples of 16. The default value is 128.
• Path Cost (1-200,000,000) — Indicates the port contribution to the Spanning Tree instance. The field range
is 1-200,000,000.
– Use Default — Defines the default path cost as the Path Cost field setting.
• 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.
• Forward Transitions — Indicates the number of times the Trunk State has changed from a Forwarding state
to a Blocking state.
• Remain Hops — Indicates the hops remaining in the region before the BPDU is discarded.