IBM Communication Controller Migration Guide

© Copyright IBM Corp. 2002, 2005, 2006 427

Glossary

ACF. A group of IBM licensed programs,

principally VTAM, TCAM, NCP, and SSP, that

use the concepts of Systems Network

Architecture (SNA), including distribution of

function and resource sharing.

ACF/NCP. See NCP.

ACF/VTAM See VTAM.

ACP/TPF. See TPF.

Advanced Communications

Function.

See ACF.

Advanced Peer-to-Peer Networking. See

APPN.

Advanced Program-to-Program

Communication.

See APPC.

API. A software interface that enables

applications to communicate with each other.

An API is the set of programming language

constructs or statements that can be coded

in an application program to obtain the

specific functions and services provided by

an underlying operating system or service

program.

APPC. An advanced SNA API whose base

function is to provide application programs

with commands that coordinate and control

the sending and receiving of data among

networked devices. Some systems

implement optional APPC functions, such as

commands controlling database commits and

synchpointing or “waking up” a partner

program across a network to enable

communication. LU 6.2 is an implementation

of APPC, and although not exactly technically

correct, the terms APPC and LU 6.2 are

nearly always used synonymously.

APPN. An extension to SNA featuring:

򐂰 More distributed network control that

avoids critical hierarchical dependencies,

thereby isolating the effects of single

points of failure

򐂰 Dynamic exchange of network topology

information to foster ease of connection,

reconfiguration, and adaptive route

selection

򐂰 Dynamic definition of network resources

򐂰 Automated resource registration and

directory lookup

APPN extends the LU 6.2 peer orientation for

user services to network control and can

support multiple LU types, including LU 2

(see DLUR), LU 3, and LU 6.2.

asynchronous. Pertaining to two or more

processes that do not depend upon the

occurrence of specific events such as

common timing signals. Without regular time

relationship.

asynchronous communication. A method

of communication supported by the operating

system that allows an exchange of data with

a remote device, using either a start-stop line

or an X.25 line. Some common names for

asynchronous transmission devices include:

async Ascii, TTY, TWX, WTTY, IBM

3151,IBM 3767, and various Digital

Equipment Corporation devices such as DEC

VT100.