ZyXEL Communications XGS1930-38 User Manual page 142

Table 64 Advanced Application > Spanning Tree Protocol > Status: MSTP (continued)
LABEL DESCRIPTION
Forwarding Delay This is the time (in seconds) the root switch will wait before changing states (that is, listening to
(second) learning to forwarding).
Cost to Bridge This is the path cost from the root port on this Switch to the root switch.
Port ID This is the priority and number of the port on the Switch through which this Switch must
communicate with the root of the Spanning Tree.
Configuration This field displays the configuration name for this MST region.
Name
Revision Number This field displays the revision number for this MST region.
Configuration A configuration digest is generated from the VLAN-MSTI mapping information.
Digest
This field displays the 16-octet signature that is included in an MSTP BPDU. This field displays the
digest when MSTP is activated on the system.
Topology This is the number of times the spanning tree has been reconfigured.
Changed Times
Time Since Last This is the time since the spanning tree was last reconfigured.
Change
Instance These fields display the MSTI to VLAN mapping. In other words, which VLANs run on each
spanning tree instance.
Instance This field displays the MSTI ID.
VLAN This field displays which VLANs are mapped to an MSTI.
MSTI Select the MST instance settings you want to view.
Bridge Root refers to the base of the MST instance. Our Bridge is this switch. This Switch may also be
the root bridge.
Bridge ID This is the unique identifier for this bridge, consisting of bridge priority plus MAC address. This ID
is the same for Root and Our Bridge if the Switch is the root switch.
Internal Cost This is the path cost from the root port in this MST instance to the regional root switch.
Port ID This is the priority and number of the port on the Switch through which this Switch must
communicate with the root of the MST instance.
Port This field displays the number of the port on the Switch.
Port State This field displays the port state in STP.
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Port Role This field displays the role of the port in STP.
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Chapter 13 Spanning Tree Protocol
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.
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.
XGS1930 Series User's Guide
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