What Does Network-to-Network Interface Mean?
A network-to-network interface (NNI) is a physical interface that connects two or more networks and defines inter signaling and management processes. It enables the linking of networks using signaling, Internet Protocol (IP) or Asynchronous Transfer Mode (ATM) networks.
A network-to-network interface is also known as a network node interface (NNI).
Techopedia Explains Network-to-Network Interface
A NNI is used to provide the interconnection between two or more service providers or connecting service providers with an organizational network. It usually connects two or more P routers, which are used in Generalized Multiprotocol Label Switching (GMPLS) or signaling based networks. NNI can be implemented in several different modes and vary according to scenario. If using GMPLS, the connection can be created using a back-to-back and Exterior Border Gateway Protocol (EGBP) based NNI connection mode. NNI also provides linking services for full mixed and mesh network environments.