Having spoken to lots of people with all levels of familiarity with Audio over IP (AoIP), a question most people seem to want to know the answer to is what is the difference between the competing technologies? I am going to try to help with a series of articles highlighting the principal alternatives and trying to explain the similarities and differences between them. To begin this series I’m going to start with RAVENNA.

RAVENNA was introduced in 2010 and was envisaged as a platform-independent content exchange technology. It comes from a broadcast background where it has been very successful, largely because it has been designed to meet specific needs while adhering to some guiding principles. The most significant of these are:

• It is based on existing standards - i.e. it uses currently available technology. In terms of hardware and data standards RAVENNA aims to meet its desired performance using currently established network standards.
• It is non-proprietary - i.e. it is not protected under a restrictive license and it is based on standards which are in the public domain.

When trying to see where RAVENNA sits in the AoIP landscape it can be helpful to see RAVENNA as being similar to Dante but an open standard, whereas Dante is proprietary.

RAVENNA is a layer 3 (IP-based) solution based on existing standards. It can operate on most existing network infrastructures, it offers full bit transparency with all media formats (i.e. it can pass uncompressed audio), with low latency and full network redundancy support and most importantly it is open. So what does open mean? In this context it means:

• Based on technology which is publicly available - no proprietary “black box” design.
• Uses standard Protocols - proven technology, widely supported.
• Designed to work on existing networks - no new network equipment required
• No proprietary licensing policy - no “cost per channel”, it suits all performance needs.

Looking at the AoIP landscape you’ll notice there are fewer products supporting RAVENNA than some of the alternatives. This is because it takes time for manufacturers to implement open standards - it’s quicker to implement proprietary hardware. However access to the developer resources is open too - there are freely available RAVENNA framework documents for manufacturers looking to develop for RAVENNA and over time more manufacturers will bring products currently in development to market.

It’s inevitable that in any discussion of RAVENNA AES67 will be mentioned because of the various AoIP technologies, AES67 is most closely related to RAVENNA. When looking at RAVENNA, it’s worth bearing in mind that all of the AES67 principles and protocols exist within RAVENNA, but RAVENNA is more comprehensive than just AES67. It includes more functionality and covers data formats which are not included in AES67. 

There are some significant names in the list of currently available RAVENNA products, including Merging’s Hapi and Horus which have already been reviewed by James. Then there is Neumann, who have their DMI-8 digital mic system and there are various I/O boxes serving the broadcast sector which could just as easily be used in a music or post setting. With the Genelec 8430A IP SAM studio monitors now available the whole signal chain from microphone to speaker can now be covered in RAVENNA.

RAVENNA is definitely one to watch as, while it hasn’t been the fastest to market, its combination of a pragmatic approach to the use of existing standards and infrastructure, combined with its open status and its close relationship to AES67 make it a very robust technology.

If you are curious about the name, apparently RAVENNA was named after the Italian town of the same name where the poet Dante died…