ESSENTIAL CEDIA

DESIGNING TIMING-AWARE NETWORKS - A WIN FOR AV

David Meyer, CEDIA Technical Knowledge Manager, examines the increasing importance of timing in networks.

Designing distributed AV systems is a core competency for CEDIA integrators. Like many other subsystems, distributed AV continues to increasingly utilise the IP network. Networking is highly matured and will inevitably be a core part of any home system because it unifies the cabling and communications, and has been proven robust. There are many things to consider, but the network requirements intrinsic to any networked AV system design underpins overall compatibility and performance.

Networking standards are composed of hundreds of documents from organisations like the Institute of Electrical and Electronics Engineers (IEEE) and the Internet Engineering Task Force (IETF). We can credit their efforts over many years to evolve the technologies that afford us the high reliability and low latency we take for granted today. That said, most of today’s home networking applications are still primarily concerned with ensuring the integrity of delivered data, not necessarily with its timing – knowing precisely when data will arrive at its destination.

If there’s one thing AV streams increasingly have in common, it’s the need for synchronisation. Whether it’s for syncing picture and sound, or multiple channels or zones of audio, it’s necessary to build timely delivery into any distribution system. When that system is on the network, the timing capability needs of the network must also be considered and understood. Sometimes the demands might be for real-time applications for delivery within a few milliseconds, with timing accuracy counted in mere microseconds. In other cases, it might not matter so much if there’s some modest delay, provided it is known and can be reliably predicted and synchronised according to expectations.

Whatever the case, applications for timingaware networks are growing. Some network AV distribution systems already use a combination of standards-based protocols and proprietary technologies to achieve synchronisation over the network. Leading examples in audio distribution include Audio-Video Bridging (AVB) and Dante Audio, respectively. Meanwhile, standards are evolving to broadly transition networks to become inherently timing-aware and deterministic, namely with the IEEE’s Time Sensitive Networking (TSN) standards.

This is what CEDIA’s Designing TimingAware Networks for AV white paper is all about. It explores the basis, scope, and direction of synchronous and deterministic networks in the home. It examines what it all means and how the main standards interrelate, with insight into system design and implementation requirements that are key to achieving predictable and reliable performance. What it is not is a guide to choosing a networked AV system, such as Dante Audio, AVB, or one of the plethora of AV-over-IP systems – that is a matter for manufacturers and integrators alike. However, knowing the fundamentals of when and how to design a timing-aware network on which to install such a system means that whichever is used, it can be optimised for best performance. And that’s a win all around.

To download CEDIA’s Designing TimingAware Networks for AV white paper for free as a CEDIA member, visit cedia.net/whitepapers.