IEEE 1722 Layer 2 AVB transport protocol

This protocol basically handles the packetising of the AV data into a standard 1722 Ethernet frame. It also shoulders the responsibility of passing down the 1722 AVB packet to the driver for it to transmit over the Ethernet.

This protocol is implemented as part of the talker application, which does the following: Reads raw audio/video data from a file Packetises the same data into a standard AVB Ethernet frame Delivers the AVB Ethernet frame to the lower layer driver for its transmission This application has also undergone significant modifications, which involve reading data directly from the AV devices and streaming it to the listener application. The main purpose of this is to extract the raw data and play it in real-time over the loudspeaker/headphones, or when using an ALSA sub-system.

We are currently experimenting with an AVB set-up that involves AVB endpoints (talker/listener) designed and developed by XMOS and an AVB Ethernet switch from DSP4U. Initially, our set-up included only one talker and one listener, with support from the first three AVB protocols, but now the AVB stack has evolved and is mature enough to handle multiple AVB devices in an AVB network. We will discuss the AVDECC, MAAP and IEEE 1722 layer 2 transport protocols in the next article about multiple AVB devices in an AVB network.

But before we do that, here’s some food for thought. Can you think of another domain where this technology can penetrate? What will an entire AVB network set up using Ethernet LAN cables look like? Quite clumsy, right! So what’s next? An AVB wireless chip?