AES67, Networked Audio, and the Impulse Towards Interoperability 1

Sponsored by Audinate hile the core principles of common, this has been less of an issue. WIP-based networking have But in broadcast and live, where a been in existence for much longer greater variety of products is likely to be thanks to their early adoption in required to work together seamlessly, the IT world, it is only in the last 15 there has been a more obvious need years that they have begun to be for interoperability. As well as removing deployed extensively in professional any lingering doubt on the part of the audio applications such as fixed end-user that product A will work with install, live sound and broadcast. product B and so on, despite which With each passing year, Audio over IP networking technologies are being used, (AoIP) and its ability to deliver fast and there has also been a growing awareness flexible networked audio over existing that proven interoperability would help infrastructures has resonated more encourage the overall move towards IP. strongly with customers seeking to work efficiently and cost-effectively. Published in 2013 after several years in development, the AES67 standard The result has been a gradual expansion is a response to these issues and is of the variety and availability of networked designed to provide a guaranteed level audio technologies and solutions. of interoperability between existing AoIP Developed in the 1990s but still prevalent technologies. Dante and Ravenna both today, CobraNet and EtherSound now offer compatibility with the standard. were the trailblazers for digital audio In 2016, it is increasingly evident that networking. More recently, the practicality AES67 is contributing usefully to the PART I of audio over IP networking has in many accelerating adoption of IP-based audio. CONTEXT cases outpaced the marketing efforts of the AVB manufacturers. Technologies AES67 is not a networking solution built on IP have taken center stage since in and of itself, but rather a group they are able to operate over existing of interoperability specifications for networked infrastructures and therefore connecting the lower level media streams do not require substantial investment to and therefore has many limitations when be realized. it comes to implementation in complex 2 networked environments. Some existing In particular, Audinate’s Dante is now AoIP solutions already provide a level of by some distance the world’s fastest functionality and features that is above growing media networking technology. To the transport layers and beyond those a lesser extent, ALC NetworX’s Ravenna of AES67 – and is also likely to surpass has also achieved traction, although those offered by future prospective primarily in broadcast to the present time. related standards.

Inevitably given the existence of multiple In addition to outlining the strengths and protocols, one result of the last decade’s limitations of AES67, this White Paper worth of development has been the will consider the future of standards more creation of ‘islands’ of products that generally in pro-audio as one or two support the use of one or more AoIP established media technologies continue technology. In fixed install, where one to grow their market presence.  protocol-based solutions are more

AES67, NETWORKED AUDIO, AND THE IMPULSE TOWARDS INTEROPERABILITY hereas the pricing and their widely-reported January 2015 paper, Wavailability of dedicated ‘The Death of Analogue and the Rise of switches has undoubtedly slowed Audio Networking’. the adoption of AVB-based solutions, and the rather limited But as the take-up of individual networked interoperability between various audio technologies has accelerated, so AVB implementations, the rise has uncertainty about whether they can of IP-centric networked audio be used together successfully in complex has progressed largely without integrated environments. It is within this interruption for more than a decade context that the AES began to work on now. The ability for end-users to deploy an interoperability standard for existing AoIP via existing IT infrastructures IP audio technologies towards the end has an obvious positive implication for of 2010, with publication of AES67 end-users in terms of set-up costs and eventually taking place in September subsequent support and maintenance. 2013. Simultaneously, there has been a gradual awakening – particularly within Shortly after the standard was published, the broadcast community – of AoIP’s its promotion began in earnest, as potential to enable faster and more underlined by the creation of the Media efficient delivery and production of audio Networking Alliance (MNA) to encourage in OB facilities and broadcast centers, as the adoption of AES67. Speaking to SVG well as the opportunities it can provide for Europe at the AES Convention in 2015, monetized content-sharing. MNA Marketing Working Group chair Will PART II Hoult placed AES67 in the context of the Fixed installation has been another general acceptance of AoIP: THE OBJECTIVES notable beneficiary, especially for AND BENEFITS venues such as conference centers and “We see many different implementations OF AES67 entertainment complexes where flexible of [AoIP], but essentially what the distribution of audio between different customer wants to be able to do is take rooms and external facilities is increasingly product A and connect it to product essential. With Dante, in particular, B – whether those products are using achieving sustained market growth, AoIP Dante, Ravenna or whatever – and know has now moved emphatically from “the that they are going to work together. 3 invention stage to be big enough to create That factor has really helped to drive the ecosystems”, as RH Consulting wrote in conversation about AES67.”

“We see many different implementations of [AoIP], but essentially what the customer wants to be able to do is take product A and connect it to product B – whether those products are using Dante, Ravenna or whatever – and know that they are going to work together. That factor has really helped to drive the conversation about AES67.” – Will Hoult Product Manager, Focusrite/RedNet The desire to provide this level of As will be highlighted in the next assurance was undoubtedly a primary section, AES67 excludes a host of impetus behind the entire AES67 features that can be said to contribute project. But the standards team and its to the creation of a comprehensive supporters have also been assisted by networked audio environment. But for the ability to provide concise outlines of its ability to guarantee a certain level of AES67. In summary, its interoperability interoperability, AES67 has resonated features cover the following areas: with pro-audio vendors and integrators alike. Dante and Ravenna, as well as Synchronization: whereby the Livewire and Q-LAN, are all now able mechanism for a common clock system to deliver AES67 compatibility, and at is defined. AES 2015 in New York a large-scale public demo featured no fewer than 22 Media Clocks: whereby the media networked audio devices. clocks that have to be supported are defined, as is the way in which they relate Devised to highlight the benefits of to the common clock system. AoIP interoperability, the showcase featured all four of the above-mentioned Transportation: providing a description technologies, with products from for the way in which media data is Genelec, Lawo, Merging, Yamaha, ALC transported across the network. NetworX, Archwave, Digigram, Focusrite, PART II Meinberg, QSC, Solid State Logic, THE OBJECTIVES Encoding and Streaming: providing Telos/Axia and Telos/Linear Acoustic AND BENEFITS a description for the way in which audio is all residing on the same networked OF AES67 digitised and formatted into the sequence infrastructure.  of packets comprising a stream.

Streaming Description: this specifies the information that is necessary for 4 connection management, including network address mechanisms, encoding formats and origination details.

Connection Management: in other words, the procedure and protocols used to establish a media stream connection between the sender and one or more receivers.

AES67, NETWORKED AUDIO, AND THE IMPULSE TOWARDS INTEROPERABILITY he basic interoperability Chris Ware – as well as: Darryl Bryans, Tguaranteed by AES67 has made Product Line Manager, DSP, Bose it a ‘hot topic’ in pro-audio for the Corporation; Trent Wagner, Senior past few years. But increasingly Product Manager, Symetrix; and Ethan there is an awareness that AES67 Wetzell, Platform Strategist, Bosch should not be misconstrued as a Communications Systems. panacea for all ills. Above all, it should not be regarded as an audio networking Above all others, the main limitation of solution in and of itself, given that it is AES67 cited by those interviewed for concerned primarily with transportation this White Paper is that the standard’s and is therefore lacking multiple other scope is more or less entirely restricted key components required to competently to basic audio transportation only. For implement an IP audio network. example, it does not prescribe control or device management requirements. The limitations of AES67 were Bryans remarks: examined in some depth during several recent extended conversations with “What we have with AES67 is leading audio technology developers essentially a very low level compatibility and consultants. These included two standard. It allows for the sharing principal members of the R&D team of audio around disparate systems. at Dante developer Audinate – CTO There is no control, there is no device PART III Aidan Williams and VP of Engineering management or discovery.” THE LIMITATIONS - AND STRENGTHS - OF AES67 What is included in the AES67 Specification

INCLUDED NOT INCLUDED 5

Synchronization No Discovery

Media Clocks No Control Mechanism

Transportation No Stream Description

Encoding and Streaming No Device Management

Streaming Description

Connection Management This observation underlines the fact that There is no prescribed control any ‘pure’ comparisons between AES67 mechanism. and existing AoIP technologies are bound to be bogus. Wetzell outlines the There is no prescribed means of substantial difference that exists between distributing a description of the stream: this the specification of AES67 and existing is required for successful point-to-point AoIP solutions, such as Dante: transmission and point-to-point unicast transmission. “It should not be regarded as an ‘apples to apples’ comparison. To put it in audio There is no prescribed method of terms, comparing AES67 to a fully device management. architected solution like Dante or Ravenna is a bit like comparing a raw frame woofer As a bridging method between existing to a two-way loudspeaker system; they AoIP technologies, AES67 has undoubted share characteristics, of course, but they value. But for the reasons cited above, it are not at all the same thing.” cannot and will supplant the likes of Dante. While further standards efforts may fill So whilst AES67 means that it is possible in some of the other gaps, the reality is to put a compliant device onto any that existing solutions are already able to participating network, it does not contain deliver feature-sets that are unlikely to be many of the other elements required for surpassed in the medium- to long-term successful networked audio, namely: future.  PART III THE LIMITATIONS - There is no single, prescribed AND STRENGTHS - discovery mechanism (several options are listed in the standard, OF AES67 but no single approach is mandatory). 6 “Comparing AES67 to a fully architected solution like Dante or Ravenna is a bit like comparing a raw frame woofer to a two-way loudspeaker system; they share characteristics, of course, but they are not at all the same thing.” - Ethan Wetzell Platform Strategist Bosch Communications Systems

AES67, NETWORKED AUDIO, AND THE IMPULSE TOWARDS INTEROPERABILITY he value of basic standards but it stands to reason that there will Tin supporting an industry as it be more scope for debate as one goes moves from one distinct phase of higher up the stack. Of course, this development to another is well- also allows vendors to differentiate their established at this point. But they networking solutions, and therefore always need to be viewed in a broader establish a credible commercial profile context, as Wetzell points out: for their offerings.

“Standards can be used together or Nonetheless, despite the standard’s individually within a given solution. limitations, Audinate was quick to This provides a great opportunity for recognize the value of AES67 in

“If you have a Dante-based network everything works fine, and that is easy to achieve as there are now so many Dante- supporting products available.” – Trent Wagner Senior Product Manager at Symetrix

PART IV manufacturers to build solutions that are encouraging the adoption of IP-based interoperable but still add value in unique audio, and thus signaled its intention to GOING BEYOND ways. When you think about it, this is support AES67 networking. This was STANDARDS what the IT world has known for ages. A delivered via a firmware update to OEM network switch is an implementation that partners in the closing months of 2015. supports a huge number of standards With Dante, it is therefore possible to while also providing for interoperability. operate as part of multi-AoIP networks I can certainly get some unique stuff if and ‘pure’ Dante network configurations. I build my IT infrastructure around one manufacturer, but if I mix and match At the time of writing, Dante has 7 switch vendors things still work and I can recorded in excess of 300 vendor choose features based on the product partners and 800 Dante-enabled benefits to me as a user. There is no products. At this point the ecosystem need for this to be a win or lose situation has assumed its own significant for anybody.” momentum and as such specifiers and end-users preferring to work in a Dante- Gaining agreement on basic features only environment are spoilt for choice at is fundamental to the progress of any the product level. standards project coming to fruition, Dante’s ability to provide high channel monitoring, packet error reporting, and counts, superlative audio quality, and bandwidth usage statistics. ease of installation have been well- documented elsewhere. But what is “If you have a Dante-based network worth reiterating in this context is Dante’s everything works fine, and that is easy support for flexible signal routing and to achieve as there are now so many system configuration, via the Dante Dante-supporting products available,” Controller software application that is says Wagner. purpose-designed to manage devices on a network. As a result, setting up a The comprehensive feature-sets of Dante network is typically just a matter solutions such as Dante underline why, of plugging devices into an Ethernet for many consultants and specifiers, switch and connecting a computer to AES67 is not a priority concern. When the network. All Dante devices are there is a solution whose ecosystem automatically discovered and displayed in supports extensive, multi-vendor-based Dante Controller. system designs, it can make both practical and economic sense to remain There are also long-term benefits for within that one ecosystem for a given the health of the network thanks to configuration. And as the RH Consulting the inclusion of a suite of diagnostic report, and many other recent analyses tools within Dante Controller. Among published in the pro-audio trade press, other advantages, this suite enables indicate quite overwhelmingly, that visibility into the network health status solution now – and for the foreseeable PART IV through features such as device latency future – is set to be Dante.  GOING BEYOND monitoring, active clock health STANDARDS

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AES67, NETWORKED AUDIO, AND THE IMPULSE TOWARDS INTEROPERABILITY lthough by no means One of the great strengths of pro- Acomprehensive, the degree of audio since its real emergence in the discussion – if not actual product- immediate post-war period has been a level implementation at this stage friendly competition between vendors – pertaining to AES67 indicates that and technology developers that has standards will continue to play a role frequently had the effect of pushing R&D in IP-based audio networking. For to new heights. If anything, this looks the late adopters, in particular, they may set to accelerate in the networked audio help smooth the passage into a realm era as solutions providers work to deliver of operation that is certain to determine features that ensure users can benefit audio workflows for the coming decades. from every possible advantage of fully integrated IP-based infrastructures.  But it is the features offered above and beyond the provisions of a standard that really help people to build AV systems – and thus different specifications will invariably appeal to different users, working in contrasting environments and applications.

PART V CONCLUSION: PUSHING R&D TO NEW HEIGHTS

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