DVB-C MPEG

Netrounds Test Agents can receive one or several DVB-C channels, measuring MPEG TS parameters in compliance with ETSI TR 101 290 (Measurement guidelines for DVB systems). When you start a DVB-C test or monitoring, the Test Agents will tune to the frequency of the selected channels, then start monitoring them continuously.

By using the DVB-C testing feature, you will quickly get a view of DVB-C channel quality at the points where you have connected the Test Agents. Using multiple Test Agents lets you monitor quality in different parts of your network. Netrounds will measure and highlight MPEG loss, PCR jitter, rate, and any general problems with the stream.

Note that Netrounds does not decrypt any of the MPEG streams; its quality measurements are based on the unencrypted MPEG headers only.

Setting up a test or monitoring

First decide upon your network topology, then follow the steps below.

To run DVB-C/MPEG measurements you need to have at least one Netrounds Test Agent installed. If you haven't already done the installation, consult our quick start guides for various types of Test Agents in the section Netrounds Test Agents.

To be able to monitor DVB-C channels, the Test Agent must be equipped with a special DVB-C USB device (dongle). Install this dongle if you haven't already.

Also make sure that you have prepared Netrounds with your DVB-C channel list.

Then create a new DVB-C MPEG 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

  • Receivers: Specify the DVB-C USB dongles you want to use in the test or monitoring. The devices are identified as "Test_Agent_name:dongle_serial_number".
  • Channels: Select the DVB-C channels that should be monitored from the preset channel list. Only those channels that have the same frequency, symbol rate, FEC and modulation can be selected at a time.

Thresholds for errored seconds (ES)              

  • MPEG loss: Maximum tolerated MPEG packet loss (CC errors) per second. Default: 2 packets per second.
  • Jitter: Maximum tolerated jitter (delay variation) in the received streams. Default: 50 ms.

Advanced

  • 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): The bit rate of the MPEG program stream.
  • Transport rate (Mbit/s): The bit rate of the MPEG transport stream (MPEG-TS), that is, the rate of the MPEG stream including the overhead from the header of the Transport Stream packet.
  • MPEG loss: MPEG packet loss, calculated from the Continuity_count_error counter in the MPEG stream.
  • PCR jitter (ms): The jitter (delay variation) of the received MPEG stream. Calculated from the timestamps in the Program Clock Reference (PCR) field transmitted in the adaption layer of the MPEG transport stream.
  • RTP jitter, loss, misorders: If the stream contains RTP headers, Netrounds will calculate RTP jitter, loss, and misorders, which are basically the same as the corresponding metrics for IP. Whether or not the stream contains RTP headers depends on the encoder at the head-end.
  • PAT errors: A Program Allocation Table (PAT) should be received every half-second on a multicast group according to the standards. If a PAT is not received within that interval, a PAT error is triggered.
  • PMT errors: A Program Map Table (PMT) should be received every half-second on a program according to the standards. If a PMT is not received within that interval, a PMT error is triggered.
  • PID errors: On regular audio/video streams, a frame should be received every 5 seconds according to the standards. If no frame is received for 5 seconds, one PID error is generated for each further second that elapses from that point.
  • ES MPEG loss: Number of errored seconds triggered by MPEG loss exceeding the MPEG loss threshold during one second.
  • ES jitter: Number of errored seconds triggered by PCR jitter or RTP jitter exceeding the Jitter threshold.
  • ES invalid stream: An aggregate of PAT, PMT, and PID errors. If any of these types of error is encountered during a second, it is marked as an Invalid stream errored second.
  • ES total: Aggregated errored second percentage, taking into account all types of error.
  • SLA: Service level agreement fulfillment for the test or monitoring: equal to (100 – ES total) %.
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