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Monitoring Spanning Tree Protocols on Switches

Purpose

Note:

This topic applies only to the J-Web Application package.

Use the monitoring feature to view status and information about the spanning-tree protocol parameters on your EX Series switch.

Action

To display spanning-tree protocol parameter details in the J-Web interface, select Monitor > Switching > STP.

To display spanning-tree protocol parameter details in the CLI, enter the following commands:

  • show spanning-tree interface

  • show spanning-tree bridge

Meaning

Table 1 summarizes the spanning-tree protocol parameters.

Table 1: Summary of Spanning Tree Protocols Output Fields
Field Values

Bridge Parameters

Routing instance name

Note:

The option is supported only on EX4300 switches.

Displays bridge information for the specified routing instance.

Context ID

An internally generated identifier.

Enabled Protocol

Spanning-tree protocol type enabled.

Root ID

Bridge ID of the elected spanning-tree root bridge.

The bridge ID consists of a configurable bridge priority and the MAC address of the bridge.

Root cost

Calculated cost to reach the root bridge from the bridge where the command is entered.

Root port

Interface that is the current elected root port for this bridge.

Bridge ID

Locally configured bridge ID.

Hello time

The time for which the bridge interface remains in the listening or learning state.

Forward delay

The time for which the bridge interface remains in the listening or learning state before transitioning to the forwarding state.

Extended System ID

The system ID.

Inter Instance ID

An internally generated instance identifier.

Maximum age

Maximum age of received bridge protocol data units (BPDUs).

Number of topology changes

Total number of spanning-tree protocol topology changes detected since the switch last booted.

Time since last topology change

Note:

This option is supported only on EX4300 switches.

Number of seconds elapsed since the last topology change.

Spanning Tree Interface Details

Interface Name

Interface configured to participate in the spanning-tree protocol instance.

Port ID

Logical interface identifier configured to participate in the spanning-tree protocol instance.

Designated Port ID

Port ID of the designated port for the LAN segment to which the interface is attached.

Designated Bridge ID

ID of the designated bridge to which the interface is attached.

Port Cost

Configured cost for the interface.

Port State

Spanning-tree protocol port state:

  • Forwarding (FWD)

  • Blocking (BLK)

  • Listening

  • Learning

  • Disabled

Role

MSTP or RSTP port role, Designated (DESG), backup (BKUP), alternate (ALT), or root.

Spanning Tree Statistics of Interface

Interface

Interface for which statistics is being displayed.

BPDUs Sent

Total number of BPDUs sent.

BPDUs Received

Total number of BPDUs received.

Next BPDU Transmission

Number of seconds until the next BPDU is scheduled to be sent.