AV devices often appear to sprout wires from every orifice, so it’s easy to imagine that they’re already ‘networked’. But cabling two devices together – a so-called point-to-point or circuit-switched connection – isn’t really networking. In fact, one of the joys of true networking is a reduction in all those sprouting wires.
“Networked AV allows many different services – audio, video, lighting control and more – to use the same infrastructure cables,” explains Genio Kronauer, electronics director at L-Acoustics. “So instead of plugging dozens of different cables into your device, you use one for all communications, control and content.”
Operating on the same network means every device speaks the same languages, such as Ethernet and IP. “As compared to traditional, circuit-switched solutions like HDBaseT, networked video leverages low-cost, commodity Ethernet switches and can even be incorporated into existing network infrastructure,” says Rob Carter, technology manager for digital media at Crestron. “When video is on the network you don’t have to deal with ‘inputs’ or ‘outputs’ on your switch. It’s all just Ethernet. This allows for flexible designs that can scale as big as your network.”
“Anything people used to do with a switcher they now want to do via the network switch,” says Michael Crisci, business development manager for AV over IP (AVoIP) at Atlona. “We’ve moved from audio over IP and video over IP to AVoIP. And now we’re seeing control over IP and USB over IP take shape. With support peripherals including cameras and keyboards now being networked too, we’re inching closer to everything over IP.”
Networked AV can be very versatile. “Traditional video matrixes are locked into a set number of inputs and outputs, but video matrixed over IP allows for any number of inputs and outputs to be matrixed simultaneously,” says Nathan Lane, product manager at Control4. “Adding just one more of either doesn’t require swapping out expensive hardware. Integrators can just add one new endpoint for the whole system to access.”
AV networking is becoming commonplace. “Most equipment can now be networked, to either deliver content, control devices or manage AV systems centrally,” says Eliot Fulton-Langley, solutions architect at integrator, CDEC. “Many customers are either already fully networked, moving over elements of their systems, or looking to implement networked AV in the near future. Control systems have utilised networks for some time to monitor, control and update remote equipment via a central management suite, such as Extron GVE or Crestron Fusion.”
Almost any AV device or application can benefit from being networked, as long as the scale justifies it. “HDBaseT still makes a lot of sense for small, cost-sensitive spaces that just need simple signal extension or light switching,” says Carter. “But for pretty much every other application in which you might have considered HDBaseT, it’s worth taking a close look at networked AV.”
“Any distribution of audio or video content is worth considering over the network, and the cost of AVoIP end points is already competitive compared with traditional technologies such as HDBaseT or analogue cabling,” agrees Stuart Leader, director of integrated solutions at Polar. “From a control viewpoint it’s worth networking and monitoring everything that you’ll need to manage and control remotely.”
In fact control can be the most rewarding aspect of AV to put on the network, argues Fulton-Langley. “It’s low bandwidth and allows for central management, firmware and updates. This can range from a full system to a collection of screens, such as Clevertouch MDM, or to centrally manage a number of like devices such as Kramer VSM.”
Among specific applications, security is often a trailblazer. “Where we might want to add one or two streaming cameras to a network, security professionals may want to have hundreds of cameras,” says Paul Streffon, training manager at tvONE. “These use the same streaming protocols and have the same bandwidth issues, so after that our small AV systems aren’t a big problem.”
Collaboration is ripe for networking. “Networked AV easily scales from small rooms to larger presentation spaces, boardrooms and classrooms,” says Carter. “You can then tie all these rooms together to create overflow rooms or company-wide ‘town hall’ meetings. Networked AV also lends itself to digital signage, where you might have only a few sources but lots of displays.”
“IPTV and signage are prime examples of solutions which are ideal for a network, as users can send TV, media and content over the network and control it so that it’s viewed at the right time, by the right people,” adds Mark Stanborough, sales manager at Cabletime.
Lane reckons the first application integrators should consider networking is audio. “There are many possible applications for networked audio that can fit into many different locations, including paging, huddle rooms, conference rooms, campus audio, live venues and recording studios.”
Nearly all organisations already have Ethernet-based IP networks for their IT, and theoretically AV traffic could simply be piggy-backed on to these.
“With proper planning, networked AV can be fully integrated with existing IT infrastructure,” says Lukas Duda, an integrated network solutions specialist at AVMI. “Full integration enables scalability and flexibility alongside effective support and management capability, at a local and remote level.”
That’s the theory, anyway. “In reality every case is different and there are times when keeping the media and data traffic separate is more appropriate,” Duda admits.
On balance, separation seems to be the approach recommended by integrators and vendors most of the time. This can involve installing a brand new physical network, but a popular compromise is to set up a separate virtual network (VLAN) using the same physical infrastructure as the main IT traffic.
“Regardless of whether AV uses a standalone network or is converged on to an existing one, the bottom line is that it belongs to IT,” says Zach Snook, audio products manager at Biamp. “Generally, IT would prefer that everything is on the same network, but with various levels of separation on the data being transferred. Media can be isolated in a variety of ways such as VLANing, prioritising network traffic based on the media type, and dealing with traffic situations involving technologies, such as multicasting.”
According to Lane the most common issue on converged networks is traffic priority, meaning that proper quality of service must be configured throughout the network. “Multicast video requires a proper implementation of IGMP snooping. While this is widely available, not every switch supports the same features and some don’t truly use IGMP correctly.”
The bandwidth of the existing network can be a deciding factor. Control functions tend to use minimal bandwidth and audio is often relatively easy to accommodate, but video can be very bandwidth-hungry. “Uncompressed video can run alongside IT traffic on a 10Gb network, but if you only have a 1Gb network then choose your AVoIP vendor carefully,” advises Rob Muddiman, EMEA sales director at ZeeVee. “Some solutions take up to 800-900Mb of bandwidth, so there may not be much left for your IT traffic.”
Uncompressed 4K video can gobble up to 10Gb. Compression using an H.264, H.265 or JPEG2000 encoder/decoder can significantly reduce this, although the video quality will be affected. Multicasting technology, which enables many viewers to tap into a single video stream, can also significantly reduce bandwidth usage.
As well as being greedy, AV content tends to be more time-critical than IT content. Nobody much minds if an email takes a few extra seconds to arrive, but stop-start or pixellated video and teleconferences where participants’ lips and voices are out of sync can be beyond irritating.
One solution is AVB (Audio Video Bridging), an IT standard that combines the audio, video and control elements of AV signals and ensures they all make it through the network unscathed.
“AVB-enabled switches, for example, will allow network managers to reserve bandwidth for video and audio, and this is dynamic, so if video isn’t being transmitted the bandwidth can be used in other ways,” says Leader.
Connecting devices together at scale inevitably raises questions of compatibility and interoperability. Industry bodies such as AIMS, the Avnu Alliance and the SDVoE Alliance are working hard to create interoperable standards, and some standards are already widely accepted.
The audio networking standard Dante is a shining example, according to Leader. “A device can transmit over Dante and then be received with another brand of Dante receiver with true interoperability.”
However, the view from the sharp end is that across the whole range of AV networking, reliable interoperability may still be some way off. “We stick with single platforms per project,” says Andi Allan, senior design engineer at integrator, Reflex. “Interoperability is limited and makes the job harder to design, install, commission and maintain.”
“The recommendation should always be to use one brand for encoder/decoder pairs,” agrees Chris Sulej, commercial director of Aurora distributor, Crystalised. “While some may be interoperable, sometimes when a problem occurs you have two manufacturers stating that their device works with a hundred others. They’ll both be correct, but for some reason they won’t work together. Good luck trying to figure out why?”
The relative novelty of full-on AV networking means that skills are often in short supply – not just within end user organisations but across the AV industry as a whole. Many vendors offer training on their own kit and a number of courses are worth considering: Streffon recommends the Networked AV Systems (NAVS) course taught by AVIXA, while Crisci suggests taking a CCNA (Cisco Certified Network Association) course.
But often what AV professionals really need to understand is psychology rather than technology.
“It’s not necessarily essential for an AV integrator to be an expert in network configuration, and actually that can cause problems,” says Allan. “The customer will very often have network staff who don’t want a third party coming in and telling them to change their network. The key skill is interpersonal: being able to gently convince a network manager that the proposed system won’t threaten their existing network traffic and can be properly managed and controlled.”
“AV managers need to ‘speak’ networking rather than ‘do’ networking,” agrees Streffon. “In a coax world AV managers had complete control, but in a networked world they need to learn to share and hence negotiate the access that they need to deliver an effective service. This means learning how to talk to network managers and develop an insight into their mindset. While an AV team might well be willing to ‘suck it and see’, corporate network managers are understandably much more risk averse.
“AV teams also often fail to appreciate the siloed structure of large corporate IT departments. They may seek to implement a service that provides video to the desktop, synchs with users’ calendars and is accessible on meeting room screens, without appreciating that each of these IT elements is managed by a different individual. My recommendation is to take the network manager for a coffee and have a chat about what you’re trying to accomplish.”