Level 0 systems need to exchange data or services, but cannot directly interoperate. The lack of direct, electronic connectivity may rest solely on differing security or access control policies.
Procedures – system has locally established procedures governing access control. A user must access the system directly to share information with other systems.
Applications –functionally independent in most isolated systems. The resulting data is important but the ability to consistently manipulate that data does not come into play.
Infrastructure – primarily independent between systems. Most information exchange is by physical access. At most an isolated system can exchange data by common physical media such as disks or tapes.
Data – private data models