AV over IP – The Perfect Fit for AV Distribution

What is AV over IP anyway?

Well, as the name implies, AV over IP simply means using an IP network (in many cases this could just mean a network switch) as the transport mechanism for the sending and receiving of AV signals and data (audio, video, management traffic) between AV devices. This is a departure from the traditional AV distribution model of using the separate, distinct and proprietary infrastructure of a matrix switch.

Just as millions of IP devices (known as hosts) connected to networks around the world are able to send and receive data to each other over an IP network, AV over IP simply means that IP aware AV devices such as encoders and decoders are able to do exactly the same thing.

Being regular IP hosts they connect to each other using the same standards and protocols to distribute and receive encoded video and audio signals across the network. That means that any type of signal requiring switching, be it audio, video, KVM etc, is treated as just another IP stream and so can be routed dynamically to the intended recipient right across the same AV system. And all this using widely adopted, standards based technologies rather than specific vendor defined proprietary options is, simply, one of the biggest plus’s in anyone’s book for adopting AV over IP.

IP Network Environment

In the examples shown here, the data rate required is dependent on whether the AV over IP devices are compressing the video and audio signals prior to transmitting them over the network. Uncompressed video will need a higher data rate, but will deliver virtually no pixel loss and very low latency. Compressed video will consume less bandwidth, but will experience some pixel loss and have higher latency. Ethernet provides transmission rates of 1000Mbps and 10000Mbps. The faster the data rate, the more ‘transparent’ the network.

Ethernet is by far the most common link-level transport system for AV over IP but the transport mechanism is in itself secondary. The real intelligence lies in collection of protocols that run above it, commonly known as TCP/IP. This set of protocols accommodates different kinds of data for different kinds of applications. For example, File Transfer Protocol (FTP) supports local and remote file transfers between hosts, Simple Mail Transfer Protocol (SMTP) supports e-mail, Hypertext Transfer Protocol (HTTP) supports web applications. Of all the protocols in the TCP/IP suite, UDP and IP are the most important to AV over IP.

Switches make the AV over IP network

In the early days of Ethernet, hubs were used to connect hosts and devices to the network, but these indiscriminately broadcast packets (or more accurately, frames) to all hosts. Then switches were introduced, and these more efficient network appliances only pass packets to their intended destinations. This means that traffic – even high bandwidth traffic such as uncompressed video – can flow between hosts without clogging up precious network resources.

Intelligent switches also make it possible to virtually segment the network up using Virtual Local Area Networks, or VLANs. Although Ethernet itself by definition is not deterministic, thoughtful planning of your network can create areas or zones of determinism. Using intelligent switches to partition devices on a virtual or even physical network segments can provide enough governance for all but the most demanding applications, and this includes uncompressed AV over IP.