No, to my understanding, this is not about networking DVRs within a home (which IMO is ethically a great idea but legally perhaps questionable because it threatens revenue of MPAA and etc.).
This is about letting video providers record one copy of a show on a central hard disk for all subscribers, and playing it on demand, just like video on demand. Depending on the implementation, this can only let subscribers see what they specifically ask to record in advance, or it could actually let subscribers "rewind" tv up to, say, 48 hours or even 7 days, only limited by central storage capacity of their provider.
Sky Angel does something like this with their "Faith" package of channels. They have a constantly running recording of each channel at the central SA* server, and this allows subscribers to rewind on demand up to the last 48 hours of programming.
Cablevision and other video providers would like to be able to successfully claim that recording one copy on a central server can be legally no different from having each subscriber separately record their own copy of a given program. This could allow video providers to offer substantially cheaper DVR services, and perhaps even allow Tru2way compliant devices to have DVR features even if the device itself has no hard drive and/or no native DVR capability. Because as far as the TV or the cable box is concerned, network DVR requires only the same functionailty allowing video on demand.
