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Audio Video Bridging (AVB)

Audio Video Bridging (AVB) is a a suite of IEEE technical standards intended to allow the low latency, time-synchronised transfer of audio and video data across standard IT Ethernet networks. It is a 'Layer 2' AoIP protocol, defined under the IEEE 802 standards. The AVnu Alliance certifies consumer and professional AVB equipment to ensure inter-operability. 

In essence, the AVB standard reserves for audio/video data traffic a certain amount of data bandwidth on a standard Ethernet network, and precise synchronisation of that data at the receiver is achieved using a 'generalised precision time protocol' (gPTP) which is also defined as part of the IEEE 802 standards.

In theory, AVB traffic can coexist within a standard IT network, although AVB-capable switches are required to reserve the necessary bandwidth and to ensure data synchronisation. Data is transmitted as a multicast (one sender, multiple listeners) within defined timeslots to avoid collisions. It is also categorised for priority with Class A (professional) traffic having a guaranteed latency of 2ms, whereas Class B (consumer) traffic has a guaranteed latency of 50ms.  

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