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Example: Configuring Internal Fabric OAM Monitoring

This example shows how to configure the internal fabric Operation, Administration, Maintenance (OAM) monitoring feature on the QFabric system, including the fabric maintenance association (FMA) and flow specifications for unicast Ethernet traffic.

Internal fabric monitoring enables you to validate the flow path of protocol data units (PDUs) across a given VLAN on the QFabric system using the ping operation.

Internal fabric monitoring is useful for fault detection on the QFabric system. For example, if a PDU reaches a destination that is not part of the VLAN configuration, the ping operation displays the exception on the console at runtime.


This example uses the following hardware and software components:

  • One QFabric system with the following components:

    • A Director group (two Director devices)

    • Two QFabric system Interconnect devices

    • Node devices, including:

      • One Node device (Node-81) configured in a default network Node group (NNW-NG-0)

      • One Node device (Node-80) in an autogenerated server Node group (SNG-80)

      • Two Node devices (Node-83 and Node-84) configured in a redundant server Node group (RSNG-8384)

  • Junos OS Release 12.2 or later

Before you configure the FMA, first configure a VLAN in which the internal fabric OAM monitoring occurs. You can usually configure a VLAN by specifying a VLAN ID or VLAN name. However, in the case of the VLAN used for internal fabric OAM monitoring, you must specify a VLAN name (not a VLAN ID). The FMA configuration requires a VLAN name and not a VLAN ID.

If you have already configured a VLAN ID for the VLAN, you must delete the VLAN ID from the associated interfaces and then add a VLAN name.


On a QFabric system, enabling internal fabric OAM monitoring requires that you configure an FMA and a flow specification.

  • The FMA associates a particular VLAN with a set of source and destination interfaces called fabric maintenance endpoints (FMEPs) that are used for tracing the data path between the endpoints. Configuration of the VLAN name is mandatory when you configure an FMA.

  • A flow specification is used to determine the contents of a packet that is used for a particular operation. For example, an Ethernet type flow specification describes the contents of a pure Layer 2 packet, whereas an Ethernet IPv4 type flow specification describes an Ethernet IPv4 packet.


This example uses the following topology:

  • The QFabric system Node devices are connected to the Interconnect devices.

  • Node device Node-80 is configured in the server Node group SNG-80.

  • Node devices Node-83 and Node-84 are configured in a redundant server Node group RSNG-8384.

  • The device with the unicast flow source IP address is connected to Node-80.

  • The device with the unicast flow destination IP addresses is connected to Node-84.

Table 1 maps the association of the fabric OAM elements configured in this example.

Table 1: Fabric OAM Configuration Elements





Flow Specifications





  • flowspec1

  • flowspec2





  • flowspec1

  • flowspec2


CLI Quick Configuration

To quickly configure this example, copy the following commands, paste them in a text file, remove any line breaks, change any details necessary to match your network configuration, and then copy and paste the commands into the CLI at the [edit] hierarchy level.


Step-by-Step Procedure

To configure internal fabric OAM monitoring:

  1. Configure a name and ID for the VLAN.

  2. Assign a set of interfaces to the VLAN.

  3. Define the FMA and associate it with a VLAN name.

  4. Configure FMEPs for the FMA.

  5. Configure two IPv4 flow specifications for unicast traffic from FMEP 1 to FMEP 2.


Display the results of the configuration.


Confirm that the configuration is working properly.

Verifying Configuration of Fabric OAM Interfaces


Verify that the interfaces are associated with the FMA.


Display the fabric OAM interfaces.


Interfaces Node-84:xe-0/0/22.0 and Node-80:xe-0/0/22.0 are associated with the FMA, FMEP, and VLAN as configured.

Interfaces that are not configured for fabric OAM monitoring (NW-NG-0:NULL, RSNG-8384:NULL, SNG-60:NULL, and SNG-80:NULL) display an asterisk (*) in the VLAN column, and the default FMA and FMEP names in the Fabric-Maintenance Association and MEP Name columns.

Verifying Configuration of the Fabric OAM Flow Specification


Verify the configuration of the flow specifications.


Display the fabric OAM flow specification configuration.


The output shows that flow specifications were configured as the user intended.

Verifying Operation of the Unicast ping Command


Verify that the fabric OAM unicast ping command works.


Issue the ping fabric unicast-flow command.


The fabric OAM unicast ping request from the source Node device (Node-80) to the destination Node device (Node-84) has been successful.