CICS Transaction Gateway V5 The WebSphere ... - IBM Redbooks

2.1 Introduction to APPC
18 CICS Transaction Gateway V5
If two systems are to communicate successfully, they must use a common set of
rules that both understand. A communications protocol is a set of rules that
defines, for example, a set of standard requests and responses, and the order in
which they can be sent.
LU TYPE 6.2 (LU 6.2) is a Systems Network Architecture (SNA) protocol that
supports both system-to-system communication and system-to-device
communication. LU 6.2 is also known as advanced program-to-program
communications (APPC).
CICS TG V5.0
LU6.2
LU6.2/SNA
Figure 2-1 CICS client-server connections
Communications
Server
VTAM
z/OS
APPC
connection
CICS TS V2.2
region
For all connected client systems, CICS requires both a CONNECTION and
SESSIONS definition. The CONNECTION definition identifies the remote
system, and one or more SESSIONS definitions are associated with this
CONNECTION to define the properties of the sessions.