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Chapter 10: Configuring Spanning Tree
Defining Interface Settings
SGE2000/SGE2000P Gigabit Ethernet Switch Reference Guide
Chapter
10
optimizes the STP protocol convergence. STP convergence can take 30-60 seconds in large
networks.
•
Root Guard
— Prevents devices outside the network core from being assigned the spanning tree
root.
•
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:
–
Disabled
— Indicates that STP is currently disabled on the port. The port forwards traffic
while learning MAC addresses.
–
Blocking
— Indicates that the port is currently blocked and cannot forward traffic or learn
MAC addresses. Blocking is displayed when Classic STP is enabled.
–
Listening
— Indicates that the port is in Listening mode. The port cannot forward traffic nor
can it learn MAC addresses.
–
Learning
— Indicates that the port is in Learning mode. The port cannot forward traffic,
however it can learn new MAC addresses.
–
Forwarding
— Indicates that the port is in Forwarding mode. The port can forward traffic
and learn new MAC addresses.
•
Port Role
— Displays 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 switch.
–
Designated
— The port or LAG through which the designated switch is attached to the
LAN.
–
Alternate
— Provides an alternate path to the root switch 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
— The port is not participating in the Spanning Tree.
•
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 being rerouted.
•
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 provided in
increments of 16.
•
Designated Bridge ID
— Indicates the bridge priority and the MAC Address of the designated
bridge.
•
Designated Port ID
— Indicates the selected port’s priority and interface.
