Network Switches - What Every AV Professional Ought To Know

 

Ok so we all know by now that AV signal transmission is, more and more (whether we like or not) migrating onto the IP network. Which in turn also means that point-to-multipoint communications are becoming increasingly prevalent on every network where AV type traffic (such as IPTV) is used. So, it therefore becomes important to understand how multicasting will impact your business.

The Network Switch is the Infrastructure

What we’re really referring to here, the essential ingredient of all this, is of course the network switch. The real-time demands of applications such as voice and video, not to mention the bandwidth requirements, especially high-volume, high-bandwidth video can easily strain a poorly designed network to its limits.

But let’s just define what we mean by real-time traffic here. In professional AV, media content (such as IPTV for example) is streamed across the network with the principle requirement being that it be delivered to the desired endpoint with very low latency (sometimes less than 1ms.) But that’s not all. In many cases it also has to do this while synchronizing multiple channels and then also having to deal with peripheral AV applications such as USB connections, any IR and RS 232 information, for control, as well as audio….to name a few. All this information has to arrive on time, and in sequence.

This is in stark contrast to consumer type streaming where if a user clicks on a YouTube or social platform link for example, they access a highly compressed video file that can arrive even after a number of seconds, and also does not need to synchronize with anything else. The time it took to arrive from the video host’s server is of comparatively small consequence – and the fact that it is usually buffered and stored for even up to a few seconds before playout has minimal impact on the user experience.

IPTV’s Special Needs

So it goes without saying that for applications such as IPTV, whether residential or ProAV, the demands placed on the network switches will be far greater than in consumer type network environments. To add to this, many larger AV installations are looking to integrate into the main corporate network. After all…isn’t this one of the driving factors of placing signals such as audio or video on IP?  One network to carry everything, data, voice, video…..so only one infrastructure to maintain?

So the big question then becomes - do you need a special switch that is able to handle all these requirements, and is able to satisfy the needs of AV networking?

The answer is a simple, no.

Switches have come a long way since the days of legacy network  equipment such hubs, repeaters and early generation switches.  Technological developments have brought major performance enhancements to switches, not to mention the introduction of protocols such as IGMP which are designed to optimise high-bandwith traffic such as video across networks. This is all standard issue stuff – or should be on any managed switch worth its salt – and should be available in most (if not all) switches provided by almost all vendors these days.

The standard, multicast capabilities of modern switches are more than adequate to handle video bandwidths in most cases, whether this is a compressed video solution over a 1Gb network or an uncompressed solution over 10Gb networks - the principles remain the same. In most case the enablement of multicasting on the switch is a minor configuration addition. Typically it takes the form of enabling parameters such as IGMP Snooping, Multicast FastLeave (or Immediate Leave) IGMP Querier and perhaps filtering for unregistered multicasts. That’s about it. A few tick boxes on a fully managed switch with a web interface, or a few commands via CLI. Some manufacturers even offer these necessary configuration parameters set as default ‘out-of-the-box’. Depending on the video encoding equipment, some of these parameters may not even be needed.

Everything You Need Is Already There

So don’t get confused when you hear that ‘special’ switches are needed for AV distribution. Yes, the bandwidth demands are greater, and the real-time nature of the streams differ from the standard data traffic, (which is why we enable the parameters as mentioned above) but there’s nothing ‘special’ about that, not in terms of what a modern switch should be able to handle. Ultimately, to the switch they’re just data packets, and the network handles them just as any other packet – only it has the tools and mechanisms (such as multicast functionality) to take care of it optimally. And as previously mentioned, for some models, the switch itself just works ‘off the shelf’ with no configuration necessary at all, it’s been pre-configured for multicast

It’s also worth mentioning that there are technologies available such as AVB (Audio Video Bridge) that certain switch models support that are designed to accommodate and distribute ProAV type traffic more easily, but only a comparatively small number of switch vendors support it, and even then it’s usually limited to only certain switch models. In any event, as explained earlier, standard multicast functionality is available more widely  and is more than adequate to support AV transport in a properly designed network.

So don’t be fooled. The ability to transport high-bandwidth professional quality video and audio, even at uncompressed 4K resolutions together with any other AV related signals such USB or IR in a synchronized, timely manner inherently exists in the (vast) majority of managed switches these days.

And don’t let anyone else tell you otherwise.