A protocol developed by IBM as the second generation of Systems Network Architecture (SNA).
Advanced Peer-to-Peer Networking (APPN) is an extension of SNA that was developed
APPN provides a mechanism for peer-to-peer networking and session establishment between any two logical units (LUs) on an SNA network. APPN provides greater distributed network control than legacy SNA by isolating the effects of single-point failures. It supports the dynamic exchange of information about network topology to facilitate connection, reconfiguration, and route selection. APPN also supports the dynamic definition and automated registration of network resources.