Configuring Spanning Tree
Configuring Multiple Spanning Tree
Page 144
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.