Monitoring IP streams
Nov 1, 2008 12:00 PM, By Richard Chernock
The technology requires new tools and unique diagnostic procedures.
Figure 2. Basic DTV carriage auditing
Select image to enlarge.
Internal monitoring schemes
The primary goal of monitoring is to catch errors before they cause noticeable degradation to or disruption of viewers' service. Thus, operators must make sure they are monitoring video streams at key points in their infrastructures. Ideally, every stream sent out to viewers should be actively monitored all of the time. As A/78 or SCTE-142 is increasingly built into monitoring equipment, and as that equipment evolves to handle a much larger volume of video flows at a reasonable cost, operators can benefit from implementing monitoring systems at multiple points.
On one end of the spectrum, broadcasters and service providers can use single-point verification for reference purposes, as in the simplified cable system illustrated in Figure 1 on page 18. Any type of plant benefits from more extensive monitoring, which allows the operator to identify errors as soon as they arise and helps engineering staff to localize problems quickly and resolve them before they compromise viewer services. By placing sufficient monitoring equipment throughout the plant to allow for a reasonable level of localization, the operator can realize good troubleshooting capabilities at a moderate cost.
At the other end of the spectrum, facilities seeking to establish maximum monitoring in a highly localized environment can place monitoring equipment “behind” every component that might impact the transport stream.
Monitoring external streams
While monitoring DTV transport streams within a broadcast or cable plant is indispensable to proactive maintenance of high-quality service, monitoring outgoing and incoming streams is valuable in DTV carriage auditing. Because most television viewers receive a broadcaster's service through a cable provider or other downstream infrastructure, auditing plays an important role in ensuring the sustained integrity of programming. Figure 2 demonstrates the concept of carriage auditing in action.
The quality of the broadcaster's service, including its video quality, as delivered through a cable plant or satellite operator can be significantly affected by decisions made by the downstream operator with respect to rate shaping, metadata accuracy, etc. Cost-effective stream-monitoring systems provide monitoring, measurement and even recording of DTV streams to ensure their integrity, reliability and compliance with standards.
The data delivered through the stream monitor facilitates rapid identification of issues and their origin, simplifying troubleshooting and serving as a basis for negotiating service-level agreements between broadcasters and cable, telco and IPTV providers. A standards-based monitoring model not only enhances quality of service, but also supports a stronger business model for all partners.
Richard Chernock is the chief technology officer at Triveni Digital.
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