NOW! 12-13 - Telos

AXIA | NETWORKING | TECHNOLOGY ARTICLE
96
EVOLUTION
AoIP IN BROADCAST ENGINEERING
This year we celebrate a decade since the irst public demonstration
of AoIP. Does that seem too long a time? It’s not — although
oficially revealed a year later in 2003, Livewire actually
debuted at NAB in 2002. Sitting hidden inside Telos display furniture,
it was secretly powering the demo of our SmartSurface
mixing console. So it seems appropriate that we look back on
how AoIP began and evolved, see where it has taken us today,
and maybe take a peek into the future.
PRO AUDIO OVER IP? THAT’S CRAZY! OR IS IT?
By the late 1990’s, data networking was already present in
everyday activities. There was a good selection of reasonably
priced networking devices and cabling materials on the market,
and connecting a basic ofice data network was a relatively
easy, almost plug-and-play task, thanks to the huge effort that
the computer and data networking industry had been making
for many years.
Radio broadcast facilities were no exception — on the ofice
side, at least. But in the studio? Racks of tremendously expensive
special-purpose equipment, and tons of cabling could still
be found there. The equipment at the heart of broadcast radio
was, back then, far behind that of the data networking industry.
In October, 2000, Steve Church visited the Real-Time Systems
laboratory at the University of Latvia, bringing with him an
extremely interesting document: a technical outline of a
completely new approach to building audio infrastructure
for a modern radio broadcast facility, based on using standard
Ethernet/IP-based protocols and off-the-shelf data
network equipment.
Two major misconceptions stood in the way of introducing
modern data network technologies into broadcast applications;
namely that Ethernet = Internet, and that PC Platform =
MS Windows. In reality, Ethernet is capable of delivering huge
bandwidth at excellent performance and very reasonable cost
— switched-duplex Ethernet links do not suffer from the problems
that are so common on the Internet. And x86 hardware
was a universal high-performance processing device that could
support sub-microsecond timing resolution. The OS was what
slowed things down, not the hardware.
Understanding these two fundamental facts allowed Telos to
start one of the most ambitious R&D projects the radio broadcast
industry has ever seen. Its successful implementation in
just a few years opened the doors to a major technical breakthrough
in many broadcast facilities all over the world.
The work started in October of 2000, at the University of
Latvia, and the beginning was rather academic. A team of
highly skilled software and data networking experts started
examining various performance aspects of the Linux operating
system and switched Ethernet. Many hours of tricky experiments
produced CPU/OS and Ethernet throughput estimates,
multicast and QoS behavior test reports, network packet latency
distribution graphs at different conditions, and more.
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