Improving Transport Stream Protection

When an idea is good in principle but doesn't quite work as well as it should in practice, there's a strong case for a re-think, writes Simen Frostad, Chairman of Bridge Technologies.

The test and monitoring sector is as reliant on standards as most other parts of the media industry, but support for an industry standard does not necessarily guarantee that a monitoring system gets the best job done, or even that the actual performance of the system implements the standard effectively.

The core standard in digital media transport stream monitoring is ETR290 (ETSI TR 101 290), which measures MPEG interoperability. This standard is a necessary component of a monitoring strategy, but it's not the only requirement for effective operational monitoring. ETR290 is also a complex standard to understand and calibrate correctly in practice, and where there is complexity and a lack of understanding, results usually suffer. In the hard-pressed world of digital media operations, in-depth expertise is in short supply and if the many threshold settings required for ETR290 testing are not set up correctly, the quality of the monitoring data is lowered, potentially to the point of undermining trust in the system's output. Inaccurate and inappropriate calibration can lead to a blizzard of alarms for insignificant conditions, and conversely, no alarms for conditions that really do require action. The position is complicated further by the lack of direct correlation between individual phenomena tested for by ETR290, and actual service-affecting problems; instead it is often the cumulative effect of otherwise insignificant errors that causes a problem.

Because ETR290 is difficult to set up, and because transport stream integrity is not the only criterion for guaranteeing that the subscriber gets a good service, a better solution would be one that assists operational staff in making the most of ETR290, and one that provides testing for critical service components that are outside the scope of the standard.

With Gold TS Protection, Bridge Technologies has made transport-stream testing based on ETR290 far easier to use and more effective, and added effective testing for important elements of a digital media service that ETR290 doesn't touch: such as the conditional access system (CAS), the electronic program guide (EPG), subtitles, and language track assignment. As well as reducing the chaff of false alarms that a poor calibration of ETR290 test creates, the technology takes the load off operational staff by providing very effective isolation and explanation of genuinely significant errors when they occur.

When significant faults arise, efficient analysis and diagnosis is crucial to a quick resolution of the problem and the maintenance of good service levels. But many monitoring systems tend to present a large volume of analysis data which requires high levels of concentration and expertise to sift through in order to find possible causes of the error. Tracing and resolving problems is made even harder when the test criteria set during calibration were imprecise and incomplete.

Gold TS Protection overcomes this problem by creating a reference from the correctly-calibrated and functioning service that includes all the service's key criteria for successful performance – including but not limited to those based on ETR290. From that point on, all the criteria are continually analysed and compared with the reference. Any deviation from the reference is instantly flagged for attention, and rapid fault-identification is made easy for the user by a clear presentation of the error condition, with the deviation from the reference values automatically highlighted, side by side with the correct values in the reference. The clarity of the display helps the operator focus instantly on the cause of the error, without having to wade through tables of data.

Using this reference-comparison analysis of the stream dramatically accelerates the time-to-resolve errors – typically by a factor of 10-15. In operational terms, this means that maintenance staff can monitor effectively larger numbers of streams, because they spend less time setting up the calibration, and less time tracing and resolving errors.

Gold TS Reference puts the ETR290 standard into the context of commercial operations and makes the best possible use of it. Rather than a box-ticking exercise, compliance with the standard becomes part of an effective monitoring strategy that delivers real protection for the service quality of digital media services.

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