IBM Advanced Peer-to-Peer Networking (APPN) is an extension to the

Systems Network Architecture Systems Network Architecture (SNA) is IBM's proprietary computer network, networking architecture, created in 1974. It is a complete protocol stack for interconnecting computers and their resources. SNA describes formats and protocols but, in its ...

(SNA) "that allows large and small computers to communicate as peers across local and wide-area networks."

Goals and features

The goals of APPN were: * Provide effective routing for SNA traffic * Allow sessions to be established without the involvement of a central computer * Reduce the requirements to predict resource use * Provide prioritization within SNA traffic * Support both legacy and APPN traffic To meet these goals it includes features such as these: * distributed network control * dynamic exchange of network topology information to foster ease of connection, reconfiguration, and route selection * dynamic definition of network resources * automated resource registration and directory lookup.

History

APPN was defined around 1986, and was meant to complement

IBM International Business Machines Corporation (using the trademark IBM), nicknamed Big Blue, is an American Multinational corporation, multinational technology company headquartered in Armonk, New York, and present in over 175 countries. It is ...

's Systems Network Architecture. It was designed as a simplification, but it turned out to be significantly complex, in particular in migration situations. APPN was originally meant to be a "

DECNET DECnet is a suite of network protocols created by Digital Equipment Corporation. Originally released in 1975 in order to connect two PDP-11 minicomputers, it evolved into one of the first peer-to-peer network architectures, thus transforming DEC ...

killer", but DEC actually died before APPN was completed. APPN has been largely superseded by

TCP/IP The Internet protocol suite, commonly known as TCP/IP, is a framework for organizing the communication protocols used in the Internet and similar computer networks according to functional criteria. The foundational protocols in the suite are ...

(Internet). APPN evolved to include a more efficient data routing layer which was called High Performance Routing (HPR). HPR was made available across a range of enterprise corporation networking products in the late 1990s, but today is typically used only within IBM's z/OS environments as a replacement for legacy SNA networks. It seems to be still widely used within UDP tunnels, this technology is known as

Enterprise Extender IBM Enterprise Extender (EE) is a standard internet transport protocol for IBM Systems Network Architecture (SNA) High Performance Routing traffic over IP. Enterprise Extender is analogous to, but independent of, Transmission Control Protocol ( ...

. APPN should not be confused with the similarly named APPC (Advanced Program-to-Program Communication). APPN manages communication between machines, including routing, and operates at the transport and network layers. By contrast, APPC manages communication between programs, operating at the application and presentation layers. APPN has nothing to do with peer-to-peer file sharing software such as

Bittorrent BitTorrent is a Protocol (computing), communication protocol for peer-to-peer file sharing (P2P), which enables users to distribute data and electronic files over the Internet in a Decentralised system, decentralized manner. The protocol is d ...

emule eMule is a Free software, free peer-to-peer file sharing application for Microsoft Windows. Started in May 2002 as an alternative to eDonkey2000, eMule connects to both the eDonkey network and the Kad network. The distinguishing features of eM ...

. The designation peer-to-peer in the case of APPN refers to its independence from a central point of control, similar to the way that a

FireWire IEEE 1394 is an interface standard for a serial bus for high-speed communications and isochronous real-time data transfer. It was developed in the late 1980s and early 1990s by Apple in cooperation with a number of companies, primarily Sony a ...

PC connection allows a video camera to talk directly to a disk drive on the FireWire network.

Components

An APPN network can be composed of up to five types of nodes: In VTAM, APPN nodes are defined as PU 2.1.

Device support

APPN is supported on a variety of IBM and non-IBM "intelligent" devices and software. It is available on mainframes, AS/400, System/36,

OS/2 OS/2 is a Proprietary software, proprietary computer operating system for x86 and PowerPC based personal computers. It was created and initially developed jointly by IBM and Microsoft, under the leadership of IBM software designer Ed Iacobucci, ...

via Communications Server, Cisco equipment, and Microsoft Host Integration Services (HIS) for Windows.

References

{{Reflist Advanced Peer-to-Peer Networking Network protocols Advanced Peer-to-Peer Networking