Y.1731 delay measurement (ETH-DM)

With Y.1731 ETH-DM (Dual-ended delay measurement) you can send traffic from a Netrounds Test Agent towards a Y.1731 ETH-DM capable device. Frame delay and frame delay variation measurements are collected by sending periodic frames with ETH-DM information to the peer MEP and receiving frames with ETH-DM information from the peer MEP during a proactive measurement session and/or diagnostic interval. Each MEP may perform frame delay and frame delay variation measurement.

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.

Unicast ETH-DM is an on-demand or proactive CFM function that can be used to measure frame delay and frame delay variation between a pair of peer MEPs.

Prerequisites

To run a Y.1731 measurement you need to have at least one Netrounds Test Agent installed as well as one or several Y.1731-enabled devices in your network. See our quick start guides in the Netrounds Test Agents section for guidance on how to deploy a new Test Agent. Regarding enabling of Y.1731 on your equipment, consult your equipment vendor.

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

Then create a new test or monitoring and fill in the mandatory parameters below:

Parameters

Tests only

  • Duration (seconds): The duration of this test step in seconds. Min: 30 s. Max: 604800 s. Default: 60 s.
  • Fail threshold (seconds): The maximum number of errored seconds (ES) that may occur without triggering a fail for this test step. Default: 0.
  • Wait for ready: Time to wait before starting the test. The purpose of inserting a wait is to allow all Test Agents time to come online and acquire good time sync. Min: 1 min. Max: 24 hours. Default: "Don't wait", i.e. zero wait time.

General

  • Clients: Test Agents to act as initiating MEPs.
  • MEPs (MAC addresses): A list of reflector MEPs containing MAC addresses.  
  • Rate (Mbit/s): The rate at which the clients will send frames in Mbit/s.
  • Rate (packets/s): The rate at which the clients will send frames in packets/s. Min: 2 packets/s. Max: 1,000,000 packets/s.
  • Frame size (bytes): Layer 2 Ethernet frame size in bytes (definition). 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)

  • Delay (ms): One-way delay threshold for triggering errored seconds. If the delay between server and clients exceeds this value during one second, an ES will be indicated by Netrounds. No default.
  • Delay variation (ms): Delay variation (jitter) threshold for triggering errored seconds. If the delay variation between server and clients exceeds this value during one second, an ES will be indicated by Netrounds. No default. 

Thresholds for severely errored seconds (SES)

  • Delay (ms): One-way delay threshold for triggering severely errored seconds. If the delay between server and clients exceeds this value during one second, an SES will be indicated by Netrounds. No default.
  • Delay variation (ms): Delay variation (jitter) threshold for triggering severely errored seconds. If the delay variation between server and clients exceeds this value during one second, an SES will be indicated by Netrounds. No default.

Advanced

  • VLAN priority (PCP): Specifies which Priority Code Point to use in the VLAN header. Default: 0.
  • Delayed start (s): (Tests only) Time by which to delay the start of the test within a test step. Default: 0 s.

SLA thresholds (monitorings only)

  • SLA Good: Threshold for good fulfillment of service level agreement. Default: 99.95%.
  • SLA Acceptable: Threshold for acceptable fulfillment of service level agreement. Default: 99.5%.

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.
  • Min delay near (ms): Minimum one-way delay, near end.
  • Average delay near (ms): Average one-way delay, near end.
  • Max delay near (ms): Maximum one-way delay, near end.
  • Delay variation near (ms): Delay variation, near end.
  • Min delay far (ms): Minimum one-way delay, far end.
  • Average delay far (ms): Average one-way delay, far end.
  • Max delay far (ms): Maximum one-way delay, far end.
  • Delay variation far (ms): Delay variation, far end.
  • ES (%): Aggregated errored second (ES) percentage, taking into account all types of error.
  • 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 seconds percentage.
  • SLA: Service level agreement fulfillment for the test or monitoring: equal to (100 – ES) %.
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