Y.1731 Ethernet loopback (ETH-LB)

This task lets you send traffic from a Test Agent towards a Y.1731 ETH-LB capable device and have the traffic reflected back to the Test Agent, which measures two-way delay, loss, and delay variation (jitter). ETH-LB can be used for the following applications:

  • Verifying bidirectional connectivity between a MEP and a MIP or between two MEPs.

  • Performing a bidirectional in-service or out-of-service diagnostics test between a pair of peer MEPs. This includes verifying bandwidth throughput and detecting bit errors.

../../_images/y1731-lb.png

Y.1731 is a Layer 2 protocol, and Layer 2 connectivity is therefore required between the Test Agent and the device you are testing towards.

This task works with both IPv4 and IPv6.

Prerequisites

To run a Y.1731 ETH-LB measurement you need to have at least one Test Agent installed as well as one or several Y.1731-enabled devices in your network. See the installation guides found here for instructions on how to deploy a new Test Agent. Regarding enabling of Y.1731 on your devices, consult your equipment vendor.

You also need to prepare a Y.1731 MEP list in Paragon Active Assurance, as explained on this page.

Then add an ETH-LB task to your test or monitor and fill in the mandatory parameters below:

Parameters

See the common parameters page for the following:

  • Parameters that are set on the test step level: Duration, Fail threshold, and Wait for ready.

  • SLA thresholds for monitors: SLA Good and SLA Acceptable.

  • Advanced settings common to all test tasks: Delayed start.

General

  • Clients: Test Agent interfaces that will act as initiating MEPs.

  • MEPs (MAC addresses): List of reflector MEPs containing MAC addresses.

  • Rate (Mbit/s): Rate at which clients will send frames in Mbit/s.

  • Rate (packets/s): Rate at which the clients will send frames in packets/s.

    Min: 2 packets/s. Max: 1,000,000 packets/s.

  • Frame size (bytes): Size of Layer 2 Ethernet frame.

    See this page. Min: 64 bytes. Max: 9018 bytes. Default: 1518 bytes.

Once Frame size is defined, changing one Rate parameter will cause the other to adjust automatically to agree with it.

Thresholds for errored seconds (ES)

  • Loss (%): Packet loss threshold for triggering an errored second.

    If the loss exceeds this value during one second, an ES will be indicated. Min: 0%. Default: 0%.

  • Delay (ms): Two-way delay threshold for triggering an errored second.

    If the delay between server and clients exceeds this value during one second, an ES will be indicated. Min: 1 ms. No default.

  • Delay variation (ms): Jitter threshold for triggering an errored second.

    If the jitter (delay variation) between server and clients exceeds this value during one second, an ES will be indicated. Min: 1 ms. No default.

Thresholds for severely errored seconds (SES)

  • Loss (%): Packet loss threshold for triggering a severely errored second. If the loss exceeds this value during one second, an SES will be indicated. Min: 0%. No default.

  • Delay (ms): Two-way delay threshold for triggering a severely errored second. If the delay between server and clients exceeds this value during one second, an SES will be indicated. Min: 1 ms. No default.

  • Delay variation (ms): Delay variation (jitter) threshold for triggering a severely errored second. If the delay variation between server and clients exceeds this value during one second, an SES will be indicated. Min: 1 ms. No default.

Advanced

  • VLAN priority (PCP): Priority Code Point to use in the VLAN header.

    See this page. Default: 0.

Result metrics

  • Rate (Mbit/s): Actual rate at which clients sent Y.1731 frames.

  • Sent (packets): Number of sent packets.

  • Received (packets): Number of received packets.

  • Lost (packets): Number of lost packets.

  • Loss (%): Packet loss ratio.

  • Misorder (packets): Number of misordered packets.

  • Min delay (ms): Minimum two-way delay.

  • Average delay (ms): Average two-way delay.

  • Max delay (ms): Maximum two-way delay.

  • Delay variation (ms): Delay variation (jitter).

  • ES (%): Aggregated errored second (ES) percentage, taking into account all types of error.

  • ES loss (%): Errored second percentage for packet loss.

  • ES delay (%): Errored second percentage for delay.

  • ES delay variation (%): Errored second percentage for delay variation.

  • SES (%): Aggregated severely errored second (SES) percentage, taking into account all types of error.

  • Unavailable seconds (%): Unavailable second (UAS) percentage.

  • SLA: Service level agreement fulfillment: equal to (100 – ES) %.