User–network interface
In telecommunications, a User Network Interface (UNI) is a demarcation point between the responsibility of the service provider and the responsibility of the subscriber. This is distinct from a Network to Network Interface (NNI) that defines a similar interface between provider networks.
Specifications defining a UNI
Metro Ethernet Forum
The Metro Ethernet Forum's Metro Ethernet Network UNI specification defines a bidirectional Ethernet reference point for Ethernet service delivery.
Optical Internetworking Forum
The Optical Internetworking Forum defines a UNI software interface for user systems to request a network connection from an ASON/GMPLS control plane.