When the subject of edge recording arises, many people think of SD cards and a need to restrict local site video transport to manage bandwidth. While both do play a part in edge storage, the approach can also use dedicated archiving devices and deliver enhanced topologies. Benchmark considers the argument for such an approach.
Historically, video archiving has used a centralised approach, and this was adopted because of the limitations of analogue systems. It wasn’t a case of centralised recording being the best approach, nor that engineers sat down, analysed all the options, selected centralised archiving as the best solution and then built recorders to do just that.
If anything, centralised archiving was adopted because it presented the solution with the most acceptable compromises. Using a single VCR with multiplexer, and later a DVR, was never the first choice of manufacturers, installers and integrators, or end users. However, at the time, it delivered an affordable solution with an acceptable amount of missed video.
Because analogue cameras require a dedicated connection for the video signal, this meant that every device needed a separate coaxial cable, and each cable needed to be brought back to the central archiving point. This restriction in terms of topology was unavoidable, but in reality it severly impacted upon system design flexibility and installation time.
There was no option to avoid this limited topology, because it was forced onto installers due to limitations in the technology at that time. The only other option involved duplication of devices, which made such systems not financially viable.
A smarter option?
If engineers were to sit down today and design a general approach to video surveillance installation, the odds are that they would not consider a centralised approach. In reality, the topologies for such an archiving model involve much duplication and are far more labour-intensive than they need to be. Once the additional time is factored in, they are also not cost-effective, nor are they superior in terms of performance of reliability. So why is centralised recording still prominent?
It could be argued that ‘force of habit’ plays a strong part in the decisions of many installers and integrators, but such thinking actually does a disservice to many forward-thinking engineers. If anything, the manufacturers have tended to replicate the topologies of the analogue era, and are now changing their approach in response to demands from the installation and integration sectors. Also, an awareness of the costs of installing a surveillance system mean that engineers are embracing an edge approach. Many understand that selecting two lower capacity recorders can be cheaper than a single high capacity unit when the additional cabling to a single centralised unit is factored in. Recording at the edge saves on duplicated cabling, it allows better control over image quality, and it removes issues with a single point of failure!
The biggest argument for edge recording is that a high degree of flexibility can be introduced when dealing with topologies. If, for example, a site deploys cameras in clusters, the cabling can be simplified and costs saved.
If a cluster is made up of four cameras, a centralised approach will require four dedicated cables to be brought back to the recorder. Dependent upon site layout, this could be labour-intensive and time consuming, and includes a fair degree of duplication in work. By archiving video at the edge, via a wide range of devices, a single cable may be required for transmission of video to an operator.
Modern solutions may even be able to dispense with this using mobile communications devices and alternative streaming technologies.
Often, if a low resolution stream is used for monitoring purposes, it may be possible to use redundant cabling from other systems or existing infrastructure. With network-based systems, cables can also be shared between numerous camera clusters.
It can be argued that such an approach introduces duplication in equipment, and it does. However, the savings in terms of reducing on-site time plus the enhanced reliability and performance of the overall system counters that.
A more flexible topology using edge recording can also benefit installers and integrators when it comes to system expansions and upgrades. By being able to add devices and capacity at any part of the system reduces costs and can alleviate disruption for the user while works are carried out. Also, where a user wants to introduce an element of business intelligence, for example, it becomes a simpler task to handle diverse video devices separately.
Wider range of options
Some people – and they include manufacturers, system evangelists (both for new and old technologies) and surveillance experts – are too quick to think of edge recording as a camera with an SD card. Whilst such an approach can work well, and is often underestimated in terms of capacity and flexibility, edge recording is far more varied and allows for a wide range of solutions to meet the operational requirements of sites.
When considering edge recording, it is best to think it terms of a distributed archiving model, rather than limiting yourself to recording at the camera. Options for edge recording can include NVRs and DVRs, servers, NAS and SAN devices, HDDs and SSDs, media cards, etc..
There is no ‘one size fits all’ solution, and where relevant installers and integrators can utilise a variety of archiving options dependent upon the number of cameras, archiving requirements and operational needs. Flexibility is the key benefit of edge recording, and this allows cost savings to be made without cutting corners!
Consideration should also be given to how recordings will be accessed and managed. Providers of VMS understand the benefits of edge recording, and as a result are adding functionality which provides a seamless degree of management across a variety of recording devices and media.
Edge recording is not just a method of reducing bandwidth loads on networks, as is commonly claimed. It will help achieve this, but also offers a much wider degree of benefits. Indeed, the approach is so flexible that it’s worth investigating the motives of those who belittle its potential!
The distributed archiving model makes sense, and is increasingly being recognised by manufacturers. For installers and integrators who embrace it, increased profits will follow.