for example, integrate production signals like program feeds.
For handling connections over
large distances, say, between a production facility and a remote studio,
VoIP connections are a good solution. Session Initiated Protocol (
SIP)-based technology supports the EBU
Tech 3347 standard, which allows for
connections to remote systems and
integrates them into a single infrastructure. The only downside to using VoIP technology is that it does not
provide real-time communication.
However, broadcast applications are
more concerned with connectivity
rather than minimal latency (perhaps
a few tens of milliseconds) that may
occur with VoIP.
for non-AVB traffic. This allows AVB
devices to share the same cabling
and infrastructure with non-AVB
devices like network monitoring or
A protocol for device discovery,
enumeration, connection management and control is currently undergoing the final phase of standardization and is due to be released soon.
eliminates the need for dedicated
cabling for intercoms, thereby reducing cabling costs.
Despite the potential for overall
increased network complexity, the
time required to set up communication networks will be reduced because only one network needs to be
installed. Furthermore, AVB offers
the possibility to use hardware from
The IEEE 1722.1 protocol will allow for
easy integration of AVB into a broadcast
workflow and facilitate interoperability
between different manufacturers’ devices.
A current intercom trend is to leverage the same technology used to
deliver content for communication.
Audio/video bridging (AVB) is an
Ethernet-based technology that allows the use of a single infrastructure
to transport multiple types of signals
over the same network backbone.
AVB permits both data communication and content audio to travel over
an AVB-compliant network.
AVB makes use of several IEEE standards, including: IEEE 802.1AS: Timing and Synchronization for Time-Sensitive Applications (gPTP); IEEE
802.1Qat: Stream Reservation Protocol (SRP); IEEE 802.1Qav: Forwarding and Queuing for Time-Sensitive
Streams (FQTSS); and IEEE 802.1BA:
Audio Video Bridging Systems.
A key component in these standards is IEEE 802.1Qat, which provides a mechanism for bandwidth
reservation. Contrary to common
QoS schemes, 802.201Qat provides
a reliable mechanism of reserving
bandwidth for each audio or video
stream. (See Figure 1.)
Any potential for network overload is avoided through bandwidth
management, which means denying
streams that might exceed network
capacity. It is also possible to reserve
a portion of the available bandwidth
Switch (Ethernet AVB)
1...... 8 1
There are four major applications for AVB in intercom:
Figure 1. This shows a block diagram of an AVB-based network. In addition to providing
full intercom features, the network can intermix multiple vendors, control a range of non-intercom equipment and protect program content channels via IEEE 802.1Qat.
This protocol, IEEE 1722.1, will allow for easy integration of AVB into
a broadcast workflow and facilitate
interoperability between devices of
This capability means new options
for intercom and infrastructure de-
sign. The flexibility will permit con-
trol panels to be added at any point
in the system just by connecting them
to an Ethernet port. AVB effectively
multiple manufacturers together on a