Chapter 13 Spanning Tree Protocol
GS1915 Series User’s Guide
143
13.3 Configure Rapid Spanning Tree Protocol
Use this screen to configure RSTP settings, see
for more information on RSTP.
Click
RSTP
in the
Advanced Application
>
Spanning Tree Protocol
screen.
Port
This field displays the number of the port on the Switch.
Port State
This field displays the port state in STP.
•
Discarding
– The port does not forward or process received frames or learn MAC
addresses, but still listens for BPDUs.
•
Learning
– The port learns MAC addresses and processes BPDUs, but does NOT forward
frames yet.
•
Forwarding
– The port is operating normally. It learns MAC addresses, processes BPDUs
and forwards received frames.
Port Role
This field displays the role of the port in STP.
•
Root
– A forwarding port on a non-root bridge, which has the lowest path cost and is the
best port from the non-root bridge to the root bridge. A root bridge does NOT have a root
port.
•
Designated
– A forwarding port on the designated bridge for each connected LAN
segment. A designated bridge has the lowest path cost to the root bridge among the
bridges connected to the LAN segment. All the ports on a root bridge (root switch) are
designated ports.
•
Alternate
– A blocked port, which has a best alternate path to the root bridge. This path is
different from using the root port. The port moves to the forwarding state when the
designated port for the LAN segment fails.
•
Backup
– A blocked port, which has a backup or redundant path to a LAN segment
where a designated port is already connected when a switch has two links to the same
LAN segment.
•
Disabled
– Not strictly part of STP. The port can be disabled manually.
Designated Bridge
ID
This field displays the identifier of the designated bridge to which this port belongs when the
port is a designated port. Otherwise, it displays the identifier of the designated bridge for the
LAN segment to which this port is connected.
Designated Port ID
This field displays the priority and number of the bridge port (on the designated bridge),
through which the designated bridge transmits the stored configuration messages.
Designated Cost
This field displays the path cost to the LAN segment to which the port is connected when the
port is a designated port. Otherwise, it displays the path cost to the root bridge from the
designated port for the LAN segment to which this port is connected.
Table 63 Advanced Application > Spanning Tree Protocol (continued)
LABEL
DESCRIPTION
