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Spanning Tree Algorithm Configuration
118
NXA-ENET24 - Software Management Guide
Displaying Interface Settings
The STP Port Information and STP Trunk Information pages display the current status of ports and trunks in
the Spanning Tree.
Command Attributes
Note: The following attributes are read-only and cannot be changed:
• Spanning Tree: Shows if STA has been enabled on this interface.
•STA Status: Displays current state of this port within the Spanning Tree:
• Discarding - Port receives STA configuration messages, but does not forward
packets.
• Learning - Port has transmitted configuration messages for an interval set by the
Forward Delay parameter without receiving contradictory information. Port
address table is cleared, and the port begins learning addresses.
• Forwarding - Port forwards packets, and continues learning addresses.
The rules defining port status are:
• A port on a network segment with no other STA compliant bridging device is always
forwarding.
• If two ports of a switch are connected to the same segment and there is no other
STA device attached to this segment, the port with the smaller ID forwards packets
and the other is discarding.
• All ports are discarding when the switch is booted, then some of them change state
to learning, and then to forwarding.
• Forward Transitions: The number of times this port has changed from the Learning state to the Forward-
ing state.
• Designated Cost: The cost for a packet to travel from this port to the root in the current Spanning Tree
configuration. The slower the media, the higher the cost.
• Designated Bridge: The bridge priority and MAC address of the device through which this port must com-
municate to reach the root of the Spanning Tree.
• Designated Port: The port priority and number of the port on the designated bridging device through
which this switch must communicate with the root of the Spanning Tree.
• Oper Link Type: The operational point-to-point status of the LAN segment attached to this interface.
This parameter is determined by manual configuration or by auto-detection, as
described for Admin Link Type in STA Port Configuration on page 120.
• Oper Edge Port: This parameter is initialized to the setting for Admin Edge Port in STA Port Configu-
ration on page 120 (i.e., true or false), but will be set to false if a BPDU is received,
indicating that another bridge is attached to this port.
•Port Role: Roles are assigned according to whether the port is part of the active topology con-
necting the bridge to the root bridge (i.e., root port), connecting a LAN through the
bridge to the root bridge (i.e., designated port), or is an alternate or backup port that
may provide connectivity if other bridges, bridge ports, or LANs fail or are removed.