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NE40E V800R010C10SPC500 Feature Description - System Monitor 01

This is NE40E V800R010C10SPC500 Feature Description - System Monitor
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Huawei uses machine translation combined with human proofreading to translate this document to different languages in order to help you better understand the content of this document. Note: Even the most advanced machine translation cannot match the quality of professional translators. Huawei shall not bear any responsibility for translation accuracy and it is recommended that you refer to the English document (a link for which has been provided).
Principles

Principles

Related Concepts

TWAMP Light has two measurement modes: on-demand, and proactive measurement.

  • On-demand measurement works in a specified period after being started. It can be performed once or periodically in the specified period.
  • Proactive measurement works continuously after being started to collect statistics.

Principles of TWAMP Light

A TWAMP Light service must be established before TWAMP Light is implemented.

  1. Establishing a TWAMP Light service

    Figure 8-4 Establishing a TWAMP Light service

    The Controller and Responder are deployed as shown in Figure 8-4.

    1. The Control-Client on the Controller creates a TWAMP Light test session, and the Controller is specified as the Session-Sender.
    2. The Responder is specified as the Session-Reflector.
    3. The Session-Sender on the Controller starts the test session, and the Controller sends TWAMP-Test packets to the Responder based on the configured packet sending rate and packet template.
    4. The Responder responds to the TWAMP test packets.
  2. Collecting performance statistics

    TWAMP Light defines two types of TWAMP-Test packets: Test-request packets and Test-response packets.
    • Test-request packets are sent from the Controller to the Responder.
    • Test-response packets are replied by the Responder to the Controller.
    Figure 8-5 TWAMP Light implementation

    In Figure 8-5, TWAMP-Test packets function as probes and carry the IP address and UDP port number that are predefined for the test session between the Controller and Responder. The Controller sends a TWAMP-Test packet to the Responder, and the Responder replies to it. The Controller collects TWAMP statistics as follows:

    1. The Controller collects statistics about the two-way delay, jitter, and packet loss rate based on the sequence numbers and timestamps carried in TWAMP-Test packets.

      Delay

      The delay is calculated based on timestamps. The Controller sends a probe carrying a sending timestamp t1, and the Responder replies with a response probe carrying a receiving timestamp t1' and a responding timestamp t2'. After receiving the response probe, the Controller records the receiving timestamp t2. The delay during a single period is calculated based on the four timestamps.

      Delay1 = t2 - t1- ( t2' - t1')

      Jitter

      The jitter is calculated based on two consecutive delays.

      Based on the preceding delay formula, the following delay can be calculated as follows: Delay2 = t4 - t3 - ( t4' - t3')

      Jitter = | Delay2 — Delay1 |

      Packet Loss Rate

      The packet loss rate is calculated based on the sequence numbers (starting from 0) carried in probes. The Controller sends a probe with a sequence number, and the Responder replies with a response probe with the same sequence number. Each time the Controller sends a probe or the Responder replies with a response probe, the sequence number increases by 1. The packet loss rate is calculated based on the two rows of sequence numbers.

      Packet loss rate = |Number of sent packets-Number of received packets|/Number of sent packets

    2. The Controller collects performance statistics based on TWAMP-Test packets and reports the statistics to the NMS. The NMS provides performance statistics for users.

      In different measurement modes, the controller reports statistics to the NMS as follows:
      • On-demand measurement: reports statistics to the NMS using MIBs.
      • Proactive measurement: reports statistics to the NMS using Performance Monitoring (PM).
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Updated: 2019-01-03

Document ID: EDOC1100055050

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