Why AVB?
First of all, what is AVB?
Audio Video Bridging (AVB for short) is an umbrella of new and augmented IEEE standards to provide for time synchronized delivery of audio and video media through networks, and assure that it gets there (Quality of Service, or QoS). With respect to Ethernet, it is the answer to question of “Why can’t I get my audio and video reliably, synchronized, and with low latency over a network?”
What does AVB provide?
- Inherent time-synchronization of endpoints: real-time, low latency delivery of media as well as enabling time-sensitive control applications
- Reservation-based bandwidth management ensures QoS for media traffic
- Supports an arbitrary number of media clock domains
- Supports a heterogeneous network for media, control, and legacy traffic: existing non-media, non-time critical protocols such as TCP-IP, UDP, FTP, HTTP (web traffic), etc.
- Future extensibility for any isochronous data: audio, video, telemetry, etc.
Why will this work?
So it sounds too good to be true. There have been promises before (see below regarding the Historical Perspective), but there are key differences as to why will AVB work where others have failed.
- Open standards
- Audio and Video
- Supported by silicon – ground up!
- Broad applicability to multiple markets
Similar to why Ethernet has succeeded in being the ubiquitous networking media, AVB is an augmentation of the ubiquitous, open standards which are supported by a plethora of manufacturers. The IEEE (Institute of Electronics and Electrical Engineers) is the organization which defined “legacy” Ethernet defines the standards which multiple manufacturers can implement. NOTE: with the advent of AVB, non-timing critical, non-media data is termed ‘legacy’. AVB is an augmentation and evolution of these open standards which have broad market appeal and multi-vendor implementations.
Additionally, our world is becoming richer, and richer with audio and video (AV) content. AVB has been built from the “ground up” with provisions for support of both audio and video. Thus it is designed with content rich, high definition media in mind.
As alluded to previously, there are a number of significant silicon manufacturers involved in the AVB revolution. With such manufacturers (which previous proprietary attempts could not garner), the necessary fundamental changes to Ethernet would are possible. Likewise, the number of manufacturers who are involved providing AVB solutions yields multiple solutions to manufacturers, which allows for the appropriate selection of solution (one size doesn’t fit all) and design options as well as field of “coopertition” which lowers pricing. NOTE: “coopertition” is a manufactured term comprised of ‘cooperation’ and ‘competition’ whereby competitive entities work together (cooperate) to generate larger and new markets in which they can participate (and compete).
Also, AVB has a VERY broad appeal to multiple markets. This increases volume, which decreases prices, which grows the potential applications for the technology, which further yields more markets and higher volumes. Primary markets include professional applications, automotive, and high volume consumer markets. Previous protocols were conceived and driven from within small niche markets (typically professional), which simply did not have the broad appeal, and thus were not able to achieve mass penetration / adoption.
A historical perspective
There have been a number of proprietary protocols. Examples in professional audio include CobraNet, EtherSound, and Dante. All of these attempted to utilize some portions of Ethernet for audio distribution. These proprietary protocols were only available from the originating company, thus this “sole source” lead to higher cost solutions (often with per channel royalty business models), and limited adoption (due both the limited implementations and the aforementioned cost barriers).
In the past, proprietary attempts tried to work around the shortcomings of Ethernet. When Ethernet was conceived it was developed for the purpose of transferring data, but not in a deterministic or time sensitive manner.
Ask a better question
Those involved with AVB chose to ask a better question: “Why try to work around the issues of Ethernet, why don’t we ‘change’ Ethernet!?” Many of those asking this “better question” were the low level silicon manufactures who make the chips which form the fundamental building blocks of today’s ubiquitous Ethernet networking structure are built. Thus work began, which was originally called “Residential Ethernet” as a workgroup within 802.3 (the physical definition specifications for Ethernet). Fortunately it was realized that high quality, synchronized audio and video with bandwidth reservation to assure delivery would have MUCH broader application than within just the residential space. Thus the work was moved to the 802.1 portion of the Ethernet specification, and the Audio Video Bridging workgroup was born.
Just the beginning
The majority of work to date focuses on wired Ethernet, but work is underway to support wireless Ethernet (augmentation to IEEE 802.11) as well as other shared access networks (media over coax or power lines). As mentioned above, there are broad range of markets which can benefit from AVB. A number of these markets, specifically Consumer, desire other physical media for distribution. Stay tuned, the AVB revolution is just beginning.