In IBM® networks, Systems Network Architecture (SNA) is the layered logical structure, formats, protocols, and operational sequences that are used for transmitting information units through networks. SNA also controls the configuration and operation of networks.
APPC, APPN, and HPR are some examples of the protocols included within SNA. They can be used to connect the iSeries™ server with other IBM systems, or non-IBM systems, to connect remote controllers, and to maintain a high level of security on your system.