A Network Video Recorder is a device for storing digital CCTV images on an IP network. (For contrast, see DVR). The NVR is therefore a networked computing device and benefits from this in such aspects as location (which is independent of camera or control room location), security and network access and functionality. In this last respect, NVRs can be written to and read from simultaneously thus allowing the viewing and analysis of one stream of video whilst another stream is being written. Commonly equipped with hot-swappable additional storage, NVRs are easily scalable and their contents can be subject to the back-up, recover and disaster recovery regimes that already exist on the IT network that they share.