Centralised Vs Decentralised

In the IP-CCTV world there are two main concepts to consider before deciding which product to buy.  Generally, the two platforms are called:

• Centralised
• Decentralised

What is the difference?

The above image (click to enlarge) shows the two platform types available.  In a "Standard IP" camera solution, all the intelligence lies in the Network Recorder (or server).  This is where all of the event management, configuration, alarm management, storage management etc takes place.  It generally requires a big, powerful server to run on (which is fundamentally expensive).

In a "Decentralised" solution, the intelligence has moved from a central point (the NVR) to the camera itself - the big advantage this has, is that there is no central point of failure, if the network dies the cameras record to themselves (on an internal memory card).

Basically, even though both systems run on the same internal infrastructure the location of the management intelligence is the big difference between centralised and decentralised.

More Detail

In a Centralised system, you would generally require:

• Cameras
• Lenses
• Video Management Software (Recording Software)
• PC / Server
• External Storage
• External Housings (weatherproof)
• Network

That is a fair old list of bits for a CCTV Network, especially if there is only going to be a few cameras.

The Decentralised system doesn't need as much:

• Cameras
• Lenses
• Storage
• Network
• Low End PC (dependant on the number of cameras)

Surprised? With the image processing, management, video processing and external weatherproof housing intelligence within the camera itself, all that is really needed is a connection to the network, and a simple PC with an Internet Browser.

On the flip side, the centralised system requires at least the central management software (generally on a server) where the video processing is performed.  Lose this server, there is no video to look at.  Additionally, there is a delay between the event being recorded, and the event being searchable.

Costs

This is the big question for choosing between centralised and decentralised.  Fundamentally, the cost differences aren't that great - high end IP Cameras will set you back a fair amount of cash, however offset that cost against the on-going software subscription per camera license and annual maintenance for a centralised system the costs between the two start to get a lot bigger.

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