In Broadcast - December 2013 - 74

I N T E R N A T I O N A L

WWW.INBROADCAST.COM | ISSUE 26 - DECEMBER 2013

N E W S

InAUDIO

Audio Over Ethernet
By Mikael Vest
Sales Director of
NTP Technology

R

outing audio within broadcast
facilities, as well as contributing
and distributing audio nationwide
and globally, has gone through
many cycles in the past 25 years.
Audio routing is now ﬁrmly in the
network age. Given the capacity of
Ethernet networks today, and the
quality of the network components
and Layer 3 IP services, Gigabit
Ethernet backbone for real-time
audio is a reality.
For radio and television
broadcasters, audio routing on
Gigabit IP Layer 3 networks enables
a more ﬂexible audio infrastructure
than conventional central routing
solutions and full use can be made
of advanced routing control and IP
based clock distribution using the
IEEE 1588 Precision Time Protocol.
In most cases this also saves on
the cost of the installation related to

74

cable and ﬁbre infrastructure.
Most broadcast facilities still rely
on time-division multiplexed digital
matrices. But they also face the
challenge that this technology is
limited by the need for physical input/
output lines, dark ﬁbre connections
and the capacity of the TDM engine.
These factors can make expansion
and reconﬁguration complicated or,
in some cases, impossible.
Alongside the development of
centrally installed broadcast audio
matrices, the distribution of digital
audio content was made easier by
the introduction of the Synchronous
Digital Hierarchy telecommunication
protocol during the 1990s, allowing
audio to be delivered over E1 or
T1 circuits. With the emergence of
efﬁcient lossless coding algorithms,
ISDN lines became widely used
for handling digital audio in a very
ﬂexible manner.
In TV environments audio is
also often embedded with the SDI
video signal, reducing the need for
separate audio distribution. With
this technology, the routing and
audio distribution systems are
designed as a central router with

Audio routing on Gigabit IP Layer 3 networks enables a much more
ﬂexible audio infrastructure

dedicated digital links and inputs/
outputs connecting larger structures.
The need for individual control
and conﬁguration of the various
elements is quite comprehensive.
Given the use of the internet ,
audio contribution using SIP codec
and Voice-over-IP technologies
often eliminates the need for ISDN
lines. However the solutions up to
now have used a point-to-point
star-based network approach or
convention Layer 2 based Ethernet
connections in order to provide a
complete routing solution.
With the inherent structure of
Layer3 IP Ethernet, local and wide
area networks, but not the internet,

will perfectly serve the purpose of
being the backbone of an audio
router even with channel count of
thousands of channels, enabling
audio to be passed between all
I/O nodes of the network in a very
ﬂexible manner.
With the NTP Technology IP audio
routing solution, a complete routing
control and audio interfacing system
can be established that can deliver
high quality full-bit-rate digital
audio at low-latency. This NTP
IP Audio solution is powered by
Dante which is based on common
network standards including AVB.
Enjoy the Ethernet age of digital
audio routing!

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