PWR-DSP3
User Manual
Page 10 of 27
Copyrights DSP4YOU ltd
2.4.3
Audio Video Bridging (AVB)
AVB defines a group of network protocols for the distribution of time synchronized and low latency Audio & Video
streams over IEEE802 networks. By leveraging a combination of existing 802 network technologies along with
standards specifically designed for the purpose, AVB technology lays the ground work for un-paralleled guaranteed
media streaming over Ethernet networks. The overall concept of AVB is actually rather simple. Without getting into
too much detail, the three core protocols specify:
-
Timing and synchronization
-
Bandwidth allocation through the Stream Reservation Protocol (SRP)
-
Traffic shaping to ensure that low priority Ethernet traffic does not interfere with AVB traffic
Engineered from the ground up for media streaming applications, AVB has a definitive edge over legacy Ethernet
technology in the sense that it allows bandwidth allocation and priority rules based on timing. Unlike similar audio
over IP (AOIP) technology, AVB will dynamically assign and defend bandwidth allocation for AVB streaming thanks to
the concept of Stream Reservation Protocol (SRP).
Terminology for AVB streaming goes as follow:
o
Audio Video Bridging (AVB):
General descriptive for a group of protocols providing audio/ video streaming,
timing, synchronization, Quality of service (QoS) , control and discovery.
o
AVB Endpoint
: AVB powered device, capable of transmitting and/ or receiving audio streams using P1722/
P1733 transport protocol.
o
Talker:
AVB endpoint transmitting audio to the network. (Source)
o
Listener:
AVB endpoint receiving audio from the network. (Sink/ Destination)
o
Talker/Listener:
AVB endpoint that is both transmitting and receiving. All AVB endpoints used on Dana series
are by default Talker/Listener devices.
o
Precision Time Protocol (PTP):
Allows devices on the network to get a notion of global time in the effort to
synchronize with each other. PTP component in each AVB module can act as a Grand Master (providing
clock) or as a slave (receiving clock). Once a grand master negotiates and is selected as a sync source, all
units will synchronize to it.
o
Streams:
General term describing packetization of one or multiple audio/ video channels over the network.
Stream can be unicast or multicast. For the time being, the AVB module only supports unicast streaming.
Future revisions will provide additional features.
o
Stream ID
: Unique 64-bit stream identifier used by AVB transport protocols to identify streams.
This feature is optional and may be opted out at the time of ordering. It can be enabled at a later time using a
unique license key, valid for a single unit. You can contact our
Sales team
for more information on how to purchase
the license key.
Important note: Until ratification of 1722.1 standard allowing universal discovery and control of AVB devices, only
DSP4YOU products will be recognized in the AVB Streamer interface. A future firmware upgrade with the ability to
discover and control other AVB devices will be released as soon as 1722.1 standard is ratified.
In the mean time, It basically means that AVB streams can only be built among AVB devices of DSP4YOU (e.g. Dana
server, Eline, Epower). Please check
www.dsp4you.com
for more information about our AVB products.