Questions About Axia, Livewire+ and AES67

I hear you’ve renamed Livewire to Livewire+™. What does this mean?

You probably know that the Telos Alliance has been involved in designing the architecture of AoIP interoperability since the very beginning (even when some folks claimed it wouldn’t even work!).

First, we promoted interoperability using the standard IP networking technologies built into Livewire, beginning in 2003. Then we became sustaining members of the X.192 project committee, which wrote the AES67 standard ratified by the AESSC in September, 2013. By December 2013, we had already implemented AES67 in our Axia xNode audio interfaces.

But we didn’t just stop there. We’ve continued to fully integrate AES67 into Livewire+, in order to give Axia clients the best possible experience. Not only that: we’ve structured Livewire+ so that it can be extended to comply with future standards.

This represents a huge leap forward — so much so that Livewire technology has evolved to become Livewire+.

I heard that Livewire+ is actually the basis for AES67. Is that true?

As part of the X.192 working group, Axia and the Telos Alliance worked with other companies to help define the standard. During this process, we made available, at no charge, parts of our own patented technology to help speed development of the standard.

Does that mean that Livewire+ actually is AES67?

Not exactly! What it does mean is that much of Livewire+ is the basis for AES67. You might say that AES67 has Livewire+ in its DNA.

So what does the “plus” in Livewire+ mean, exactly?

It means three things.

  1. Livewire+ is completely AES67-compliant. Compliant means that Livewire+ fully complies with all parts of the AES67 standard.
  2. Livewire+ is future-proof, because it’s extensible. Future standards (such as might come from the AES X.210 group) can be included once ratified; Livewire+ can never become obsolete.
  3. Choosing Livewire+ means you don’t have to wait for interoperability. Livewire+ represents the world’s largest grouping of AoIP technology partners – over 80 software and hardware manufacturers and integrators whose products work together, with integrated audio, source discovery, logic control and data — right now, without the need to wait for additional standards.

You say Livewire+ is “AES67-compliant”. Other companies say their gear is “AES-67 compatible.” What’s the difference?

The difference is subtle, but important — compliant is not the same as compatible! “Compliant” means that Livewire+ fully complies with all parts of the AES67 standard. It’s baked-in, if you will.

“Compatible”, on the other hand, means that someone’s proprietary tech can co-exist with the AES67 standard. In essence, compatibility is like two different people sharing one body: the proprietary tech is patched with add-on code to get by, but doesn’t fully comply with all aspects of the standard.

What does the AES67 standard contain?

According to Mark Yonge, AES Standards Manager:

“This standard defines an interoperability mode for transport of high-performance audio over networks based on the Internet Protocol. For the purposes of the standard, high-performance audio refers to audio with full bandwidth and low noise. These requirements imply linear PCM coding with a sampling frequency of 44,1 kHz and higher and resolution of 16 bits and higher. High performance also implies a low-latency capability compatible with live sound applications. The standard considers latency performance of 10 milliseconds or less. This standard provides comprehensive interoperability recommendations in the areas of synchronization, media clock identification, network transport, encoding and streaming, session description and connection management.”


If AES67 does all this, why does Livewire+ exist?

Good question! The AES67 specification is a good start toward interoperability, but is actually a subset of the many functions that Livewire+ performs today. When we developed Livewire back in the early 2000s, we had to synthesize the critical links between networking technologies, because a full standard didn't exist yet — and earlier networked audio systems lacked critical functionality. We developed a way to make GPIO logic “ride along” with the audio streams, and a way for available sources to “advertise” their availability to all the networked devices that operators might want to use.

We also recruited partner companies whose products are respected and widely-used in the radio industry. Then we shared our technology with them, so that station engineers could connect as many audio devices as possible directly to their audio network. Not only is native connectivity an elegant solution, it reduces total system costs by removing the need for those extra I/O devices.

Ten years later, the industry finally adopted a standard for AoIP audio transport in AES67. The goal is for every studio audio device to eventually click together with CAT-5 and share audio. But along with that shared audio, there’s a whole world of other functionality that broadcasters expect — like device start/stop functions, monitor mutes, on-air tallies, the ability to control peripherals from the console, the ability to know when an audio source is live and ready for air, the ability for playout systems to control fader on/off functions and more. Those are functions that AES67 alone doesn’t provide for,  but Livewire+ does. And now that the first AES67 devices are appearing in the marketplace, broadcasters have quickly found that they also need to support those additional capabilities in order to provide an integrated control experience for the user — otherwise they’re no better than AES3 streams, with serial GPI cables running alongside.

With Livewire+, you can have your cake and eat it, too. Over 5,500 Livewire+ powered consoles and 60,000 devices are in use around the world daily. Livewire+ provides audio with integrated control and discovery right now. And, because Livewire+ is extensible, broadcasters using it can enjoy its rich control architecture and integration with over 80 partner products, exchange audio with AES67 devices, and be assured that when an AES standard for control is ratified, it will be part of Livewire+ as well. Livewire, the original AoIP technology for broadcast is still on the leading edge, and is the most successful by a wide margin.

Does Livewire+ still work with RAVENNA?

Yes. Axia and RAVENNA have been partners for several years, both working together to define the AES67 standard. Going forward, standards-based Livewire+ will continue to be backward-compatible with the RAVENNA protocol.

The Telos Alliance and ALCNetworX were a big part of the X.192 project. Isn’t AES67 just a synthesis of those two systems?

Not at all. The X.192 Task Group consisted of over 100 members from a wide variety of equipment manufacturers — including some who are direct competitors. It wasn’t a “rubber-stamp” project! AES67 is the result of 3 years of collaboration by these many contributors, ensuring use of the best ideas, no matter where they originated.

You say that Axia introduced AoIP to broadcast in 2002, and you’ve got 5,500 studios on-air. So why is AES67 even needed?

When Steve Church, Greg Shay and their team were developing Livewire, they had to invent tech that didn’t exist before. One critical piece of tech was network clock sync. Problem was, the Ethernet standard in place at the time had no criteria for high-precision time-synched audio.

Why is this so critical? As Telos Alliance Chief Science Officer Greg Shay explained in his excellent paper “Taking the ‘Sting’ Out of Evolving Digital Audio Networks” (presented at NAB 2013): “Accurate timebase recovery is directly related to, and essential for, low latency (low delay) of the audio going over the network.”

In other words, if you want networked, real-time, broadcast quality audio without jitter and delay, you’ve got to have all network devices synchronized to a network master clock. So we invented the first distributed high-precision clocking system for Ethernet, and debuted it in Livewire.

Although Axia has always been happy to share our tech with software and hardware manufacturers, other, open methods of Ethernet clock sync emerged, one of which became the IEEE-1588 synchronization standard — which is an integral part of AES67.

I need new studios. Should I wait to purchase equipment until all the manufacturers adopt AES67?

Not unless you’re prepared to wait quite a while. Implementing a new standard always takes time, as manufacturers adapt existing products, design new ones, and release software updates.

In the meantime, Livewire+, with over 5,500 studios on-the-air worldwide, is working today, and has a roadmap for future compatibility of existing hardware. This assurance means that the studio you build with Livewire+ today will be compatible with future AES standards for AoIP — your studio gear can’t become obsolete.

What changes, if any, will be required for my existing Livewire network to support AES67?

Compliance with AES67 is a part of the latest software present in Axia analog, AES/EBU, microphone and mixed-signal xNode AoIP interfaces, and Linear Acoustic SDI xNode devices. If you have these products already, simply download the update packages and apply them using a standard Web browser and PC, or use Axia iProbe software to “push” the update to your devices en masse. After this update, you’ll be able to generate and consume native AES67 streams.

And of course, the Telos Alliance plans to implement AES67 capability within more products going forward — your assurance that studios built with Livewire+ are future-proof.

Will I need to change my Ethernet switches to work with Livewire+ and AES67?

No! Livewire+ and AES67 coexist on the same switch fabric.

What are the advantages of specifying Partner equipment that works with Livewire+, versus gear that supports AES67 alone?

The whole idea of AES67 is to open up more equipment choices when you buy. The AES67 standard enables equipment from a variety of manufacturers to exchange “agnostic” audio streams without fuss. However, the AES67 specification provides interoperability standards for audio only not forcontrol or data exchange. Nor does AES67 equipment have the ability to automatically discover available audio, and present it to the operator for use. Most engineers agree that these abilities are a big part of the AoIP advantage. So, if control and source advertising is important to you, choosing equipment with Livewire+ capability will definitely be to your advantage.

At this moment, our engineering team is reviewing the final specification to determine just that.

In many cases, a software update might be all that’s needed. Applying software updates to Axia products is generally a painless process — simply download the update packages and apply them using a standard Web browser and PC, or use Axia iProbe software to “push” the update to your devices en masse.

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