LevelOne GSW-4876 User Manual

Page 252

HAPTER

| 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.

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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.

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Bridge Instance – The Bridge instance - CIST, MST1, ...

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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.)

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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.)

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Topology Change Count – The number of times the Spanning Tree

has been reconfigured (during a one-second interval).

CIST Ports & Aggregations State

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Port – Port Identifier.

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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.

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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.

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State – Displays the current state of this port in the Spanning Tree:

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Blocking – Port receives STA configuration messages, but does not

forward packets.

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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.

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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.