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Configuring Ethernet Loopback for RFC 2544-Based Benchmarking Tests

Ethernet loopback is a feature that you can use for verifying the connectivity and identifying or isolating faults in a network.

On ACX Series routers, Ethernet loopback is supported on the egress user-to-network interfaces (UNIs) direction for a bridge family configuration. In ACX Series routers, Ethernet loopback is configured on the logical interfaces. The Ethernet loopback feature can be used in performance measurements where packets are looped back to the measuring device for testing various services.

Figure 1: Testing End-to-End Service in Ethernet Loopback ModeTesting End-to-End Service in Ethernet Loopback Mode

Figure 1 shows a scenario where UNI-B interface is configured in Ethernet loopback mode in the egress direction. The packets received on the network-to-network interface (NNI) of the ACX Series router are forwarded to the UNI-B interface and looped back at the UNI-B interface after the source and destination MAC addresses are swapped. This is a use case for testing an end-to-end service.

You can use the following optional parameters to identify an egress traffic flow for Ethernet loopback:

  • Source MAC address

  • Destination MAC address

  • Source IPv4 address

  • Destination IPv4 address

  • VLAN

  • VLAN .1p priority

  • EtherType

  • Test iterator duration

While performing RFC2544 benchmarking tests, configure Ethernet loopback as the test mode on a logical interface by including the Ethernet-loopback CLI statement at the [edit services rpm rfc2544-benchmarking] hierarchy level.

If you configure Ethernet loopback on logical interfaces without configuring any of the optional parameters, then any unknown unicast traffic in the same bridge domain also gets looped back and does not get forwarded to other logical interfaces while the test is being performed.

When an RFC2544 benchmarking test is being performed, if the test-iterator-duration parameter is not configured, then Ethernet loopback continues until the test is completed or terminated.


When performing RFC2544 benchmarking tests, you can configure the test in initiator, reflector, or loopback mode. You cannot perform the RFC2544 benchmarking tests in a combination of these test modes.

The following is a sample Ethernet loopback configuration: