Push video on demand is so-named because the provider "pushes" the content out to the viewer's set-top box without the viewer having requested the content. This technique is used by several broadcasters on systems that lack the connectivity and bandwidth to provide true "streaming" video on demand. Push VOD is also used by broadcasters that want to optimize their video streaming infrastructures by pre-loading the most popular contents to the consumers' set-top device. If the consumer requests one of these films, it is already loaded on her or his DVR. A push VOD system uses a personal video recorder (PVR) to store a selection of content, often transmitted in spare capacity overnight or all day long at low bandwidth. Users can watch the downloaded content at the time they desire, immediately and without any buffering issues. Push VOD depends on the viewer recording content so choices can be limited.