AES67 is the newest kid on the networking block, but can it really bring the kind
of uniformity to the marketplace that is claimed on its behalf? David Davies finds
out – and previews the forthcoming AES-X210 standard.

“In standards work it is comparatively rare, but AES67 is one of those happy
occasions where we have the “right thing at the right time’.’
– Mark Yonge, Standards Manager, AES

AVB, Dante, Ravenna… the new additions to the pro-audio networking
landscape have arrived thick and fast over the past few years. But now the
picture is set for yet another shake-up with the introduction – and rapid
adoption – of a new Audio Engineering Society (AES) protocol suite known as
AES67.

Spearheaded by the AVnu Alliance, the AVB (Audio/Video Bridging) networking
technology has picked up support from some of the biggest names in the AV
industry since 2009 – Avid, Harman and Yamaha, to name just three. Over the
past 12 months, however, there has been a sense of fading momentum around
the project, with the Layer 2 IP transport-based technology’s requirement for
dedicated switches arguably not being satisfied with sufficient quantity of
available (and, more to the point, cost-efficient) product.

Simultaneously, the outlook for Layer 3 IP networking solutions that can use
existing switches has brightened considerably. One of the great strengths of the
AVB initiative was its reinforcement by official standards; but now the Layer 3
camp is strengthening its case with AES67 set to bring clarity to a market
featuring Layer 3-capable solution such as ALC NetworX’s Ravenna and
Audinate’s Dante.

But we are getting ahead of ourselves: first things first, what is exactly is
AES67? In development for at least two years before publication last
September, AES67, a due-process standard published by the AES, is a Layer 3
protocol suite designed to allow interoperability between various existing IP-
based audio networking systems.

Contained within the suite are interoperability recommendations for professional
quality audio networking in the areas of synchronisation, media clock
identification, network transport, encoding and streaming, and session
description. It offers, in essence, a meeting point between different solutions
and should therefore not be perceived as a comprehensive media distribution
system in the same fashion as AVB.
v
“A diffuse market’

AES standards manager Mark Yonge recalls that the project commenced with a
highly defined objective: “We didn’t want to invent anything new; the objective
was interoperability, and this involved all kinds of parameters such as defining
packet time, which determines network latency, and whether you are going to
be using PCM encoding or something else. Fairly simple issues on the surface of
it, but vital if you are going to achieve interoperability between different
solutions.’

“Fairly simple’ its aims might be, but in an audio over IP scene that Yonge rightly
describes as remaining “highly diffuse’, the through-line provided by AES67
looks appealing on both marketing and end-user fronts. Therefore there was a
raft of significant announcements during and after this year’s ISE exhibition in
Amsterdam. In a move that Audinate’s CEO, Lee Ellison, described as “wholly
logical’, the company confirmed that its evermore ubiquitous media networking
solution, Dante, will accommodate AES67 by adding a Layer 3 RTP (Real-time
Transport Protocol) option to its existing Layer 3 UDP (User Datagram Protocol)
transport.

This decision has significant ramifications for current systems, such as Bosch’s
OMNEO media networking architecture, which is based on Dante. “Bosch OMNEO
will integrate the Dante AES67 support, and will thereafter be interoperable with
AES67 equipment,’ says Jeff Berryman, Senior Scientist with Bosch
Communications Systems, who describes AES67 as a “sensible, usable package’
that has “..contributed greatly to clarification of the relationship between media
transport protocols and discovery/name-service protocols…

ALC NetworX, meanwhile, says that its Ravenna solution – which has proven to
be a huge hit in the broadcasting sector with support from the likes of Lawo,
Genelec, Innovason and Neumann – not only already satisfies the requirements
of AES67, but actually exceeds them. “Since AES67, targeting interoperability,
defines just a minimum set of requirements, Ravenna exceeds AES67 in terms of
supported payload formats, packet data rates, achievable synchronisation
precision and functionality required for a satisfying experience, [such as]
advertisement and discovery and stream redundancy support,’ says Andreas
Hildebrand, Senior Product Manager, ALC NetworX.

Kevin Gross is founder of AVA Networks, which provides consulting services to
users and manufacturers of media networked systems, and also played a
decisive role in initiating the entire AES67 project. Looking ahead, he predicts
that: “..by this time next year enough devices will have AES67 capability that the
benefits of interoperability will be clear. It appears that the first place this will be
making a significant difference is with European broadcasters who have built IP
networks in their studios and in some cases nationwide which are designed to
handle live audio contribution and distribution.’

The next standard

With QSC expressing its intention to support the standard, Telos Alliance
already shipping the AES67-compatible Telos Axia Audio xNode AoIP interface,
and a major “plugfest’ on course for October, momentum behind AES67 seems
unlikely to slow any time soon.

But already the attention of the AES standards group is beginning to switch to
the next piece of the networking puzzle – the network control-oriented AES-
X210.

The new standard, currently in its development phase, will be based around the
Open Control Architecture (OCA) specification, which provides architecture for
controlling devices on a media network. Berryman, who is task group leader for
AES-X210, puts the project in context: “AES67 answers the question: “How can I
get audio from device A to device B?’ X210’s standard will answer the question:
“How can I tell devices what to do with the audio once they have it?’’
OCA was developed by the OCA Alliance and given to the AES for
standardisation in 2013. It is expected that AES-X210’s standard (which will
have a publication name of the form “AESnn’) will be published later this year.
“With AES67 in charge of transporting signals, and X210’s standard in charge of
controlling devices, the industry will have a complete media networking
standards suite. As companies adopt these standards, true multi-manufacturer
media networking will become a reality for all,’ says Berryman.

“Sense of urgency’

Although the official introduction of AES-X210 is still some way off, as Yonge
remarks: “Where the AES used to spend 10 years developing new standards,
it’s now more like two years or less. The ability to collaborate over the internet
has definitely helped to increase the pace, but so has a sense of urgency
[around networking]. We have lots of technology but there hasn’t been much
interoperability, which is desperately needed. That feeling of urgency has been
very useful in getting things done.’

Reflecting on a 10-year period characterised by numerous contrasting solutions
and considerable confusion at an end-user level, one is not exactly
overwhelmed by an air of urgency. But with AVB no longer regarded as
necessarily being the panacea for all networking ills, and more and more
permanent and non-permanent applications the target of full networking, the
need for a path through the maze of available solutions is more pressing than
ever before. Early indications suggest that AES67 and AES-X210 could be at
least part of that path, but as ever, only time will tell.