ZyXEL Communications XS1920 Series, Руководство пользователя

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Chapter 13 Spanning Tree Protocol
XS1920 Series User’s Guide
132
13.6 Configure Multiple Spanning Tree Protocol
To configure MSTP, click MSTP in the Advanced Application > Spanning Tree Protocol screen.
See Multiple STP on page 123 for more information on MSTP.
Port State This field displays the port state in STP.
• Discarding - The port does not forward/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/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 segament to which this port is connected.
Table 54
Advanced Application > Spanning Tree Protocol > Status: MRSTP (continued)
LABEL DESCRIPTION