miniDSP Ltd, Hong Kong /
/ Features and specifications subject to change without prior notice
7
1.2
A
BOUT
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 groundwork for unparalleled
guaranteed media streaming over Ethernet networks. The overall concept of AVB is actually rather simple. In
brief, the three core protocols specify:
1.
Timing and synchronization
2.
Bandwidth allocation through the Stream Reservation Protocol (SRP)
3.
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 Stream Reservation Protocol (SRP).
These are the key terms used for AVB streaming:
Audio Video Bridging (AVB)
General descriptive for a group of protocols providing audio/ video streaming, timing,
synchronization, Quality of service (QoS) , control and discovery.
AVB Endpoint
A device capable of transmitting and/ or receiving audio streams using the P1722/P1733
transport protocol.
Talker
An AVB endpoint transmitting audio to the network (source).
Listener
An AVB endpoint receiving audio from the network (sink/destination).
Talker/Listener
An AVB endpoint that is both transmitting and receiving.
Precision Time Protocol (PTP)
The protocol that allows devices on the network to get a notion of global time in order to
synchronize with each other. PTP components 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.
Stream ID
Unique 64-bit stream identifier used by AVB transport protocols to identify streams.
