In NAF 4, UAF, and DoDAF 2, a Needline is a relationship between OperationalPerformers that specifies they have a need to communicate with one another. A Needline is directional, and carries OperationalExchanges.
Note The UAF metamodel (on which NAF 4 is built) does not implicitly mention Needline; however the concept has been added to System Architect to correctly implement the DoDAF 2, NAF 3.1, and MODAF 1.2 domain metamodels on which UAF is built. In System Architect, the definition is named Needline (UAFx) – the ‘x’ representing a value-added extension to the UAF spec.