What is a de-centralized IP CCTV network system and where it can be applied ?

Midway between centralized (fully) and decentralized (fully) deployment topology, lies the decentralized topology. In centralized system, their in ONE storage area for all N cameras in the system. In Distributed system, their are N storage areas for all N cameras in the system. In decentralized their are M storage areas for N cameras where 1 < M < N. The main motivation for doing this is when the network is highly unreliable (speed varies based on other factors) AND/OR hard/expensive/impossible to build. Very large systems like City Surveillance, Country surveillance etc will use such designs AND if multiple on-premise centralized setups (buildings) are linked to a common control room, then this larger system becomes a decentralized setup.

For eg, a villa layout wants to cover all roads and intersections and junctions. It can deploy a pole at each junction/intersection and at some midway point cameras to cover all roads running away from it. Since its not possible to network each and every pole in a retrofit manner with Fiber or copper cabling, it is not feasible to provide a wired networking and wireless may have bandwidth constraints. There the ideal choice is to locate small recorders on the camera pole itself , with UPS unit in weather proof housing and use wideband modem connectivity like 4G-LTE /5G to hook up to a centralized location, where surveillance video can be viewed. Similarly many apartment complexes may have multiple buildings each with a lobby and secure place to have local, manned surveillance command center, with each building coming up at different time of year/decade making a decentralized setup a logical way forward to start installing the system. Once the project is 100% completed a reliable backbone IP network can be built and the decentralized setup can be converted to a fully centralized setup or linked together to a bigger command center. Analog CCTV integrators typically follow this approach because that is what they are comfortable and experienced with [the NVR and TV is always an arm's throw distance away from the camera ;-))]. And also because they are generally ignorant about privacy and recording device safety.

We assume above that power can be supplied in such distributed setups. If not off-grid solar (or on-grid in case of large outages) is the only option, further adding to the costs & complexity.

- Suman Kumar Luthra @ APRC-P3 Telecom Sub-Committee