LevelOne GSW-4876 - Manual (Page 252)

C HAPTER 5 | Monitoring the Switch
Displaying Information on the Spanning Tree
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◆ Topology Flag – The current state of the Topology Change Notification
flag (TCN) for this bridge instance.
◆ Topology Change Last – Time since the Spanning Tree was last
reconfigured.
STP Detailed Bridge Status – Click on a bridge instance under the MSTI
field to display detailed information on the selected entry. The following
additional information is displayed.
◆ Bridge Instance – The Bridge instance - CIST, MST1, ...
◆ Regional Root – The Bridge ID of the currently elected regional root
bridge, inside the MSTP region of this bridge. (This parameter only
applies to the CIST instance.)
◆ Internal Root Cost – The Regional Root Path Cost. For the Regional
Root Bridge this is zero. For all other CIST instances in the same MSTP
region, it is the sum of the Internal Port Path Costs on the least cost
path to the Internal Root Bridge. (This parameter only applies to the
CIST instance.)
◆ Topology Change Count – The number of times the Spanning Tree
has been reconfigured (during a one-second interval).
CIST Ports & Aggregations State
◆ Port – Port Identifier.
◆ Port ID – The port identifier as used by the RSTP protocol. This
consists of the priority part and the logical port index of the bridge port.
◆ Role – Roles are assigned according to whether the port is part of the
active topology connecting 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.
◆ State – Displays the current state of this port in the Spanning Tree:
■
Blocking – 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.
◆ Path Cost – The contribution of this port to the path cost of paths
towards the spanning tree root which include this port. This will either
be a value computed from the Auto setting, or any explicitly configured
value.