TWAMP measurements

This test uses two-way Active Measurement Protocol (TWAMP) for measuring two-way (and in part also one-way) loss and delay. Both full TWAMP and TWAMP Light are supported. Full TWAMP includes the TWAMP control protocol, which performs a handshake between initiator and reflector, while TWAMP Light does not require the control protocol.

Prerequisites

To perform TWAMP measurements, you need to install at least one Netrounds Test Agent and have one or several TWAMP enabled devices in your network.

For guidance on how to deploy a new Test Agent, see our quick start guides in the Netrounds Test Agents section. The procedure is different depending on what kind of hardware you have available. For enabling TWAMP on your equipment, please consult the documentation from your equipment vendor.

A further prerequisite is that you have configured TWAMP reflectors in Netrounds.

Then create a new test or monitoring, and fill in the mandatory parameters as shown below. 

Parameters

General (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 (seconds): 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

  • Senders: Test Agents that are going to act as TWAMP senders.
  • Reflectors: A list of TWAMP reflectors with their host names and port numbers.
  • Rate (Mbit/s): The rate at which the senders will send frames. The value is calculated based on packet rate and frame size. Min: 0.01 Mbit/s. Max: 10000 Mbit/s. No default.
  • Time sync: Indicates whether the sender and reflector have synchronized clocks. When this option is enabled, the sender Test Agent is able to measure one-way delay and delay variation. 

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 by Netrounds. Min: 0%. Max: 100%. Default: 0%.
  • Delay (ms): Delay threshold for triggering an errored second. If the delay between server and reflector exceeds this value during one second, an ES will be indicated by Netrounds. Min: 1 ms. Max: 5000 ms. No default.
  • Delay variation (ms): Delay variation (jitter) threshold for triggering an errored second. If the delay variation between server and reflector exceeds this value during one second, an ES will be indicated by Netrounds. Min: 1 ms. Max: 5000 ms. No default.

Thresholds for severely errored seconds (SES)          

  • Loss (%): Packet loss threshold for triggering a severely errored second. Min: 0. No default.
  • Delay (ms): Delay threshold for triggering a severely errored second. Min: 0. No default.
  • Delay variation (ms): Delay variation threshold for triggering a severely errored second. Min: 0. No default.

Advanced

  • Frame size (bytes): Size of Layer 2 frame for the stream. Min: 87 bytes. Max: 9018 bytes. Default: 1518 bytes.
  • DSCP: The Differentiated Services Code Point (DSCP) or IP Precedence to be used in IP packet headers. The available choices are listed in the drop-down box. Default: "0 / IPP 0".
  • VLAN priority (PCP): Priority bits in VLAN header. Min: 0. Max: 7. 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 the senders sent TWAMP packets.
  • Min round-trip delay (ms): Minimum round-trip delay measured.
  • Average round-trip delay (ms): Average round-trip delay.
  • Max round-trip delay (ms): Maximum round-trip delay.
  • Round-trip DV (ms): Round-trip delay variation.
  • Far-end loss (%): Far-end loss.
  • Far-end misorders: Far-end misorders.
  • Min far-end delay (ms): Minimum one-way far-end delay.
  • Average far-end delay (ms): Average one-way far-end delay.
  • Max far-end delay (ms): Maximum one-way far-end delay.
  • Far-end DV (ms): Far-end delay variation.
  • Near-end loss (%): Near-end packet loss.
  • Near-end misorders: Near-end misorders.
  • Min near-end delay (ms): Minimum one-way near-end delay.
  • Average near-end delay (ms): Average one-way near-end delay.
  • Max near-end delay (ms): Maximum one-way near-end delay.
  • Near-end DV (ms): Near-end delay variation.
  • ES (%): Aggregated errored second (ES) percentage, taking into account all types of error.
  • ES delay (%): Accumulated errored second percentage for two-way delay.
  • ES delay variation (%): Accumulated 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 for the test or monitoring: equal to (100 – ES) %.
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