HP HP-UX SNAplus2, Administration Manual, Page: 40 / 398

40 Chapter 1
SNA Terms and Concepts
Basic SNA Concepts
As shown in Figure 1-3, “Communication between Transaction Programs
and Logical Units,” information is exchanged between TPs and LUs to
enable one node to communicate with another. Although the TPs appear
to be communicating directly, the LUs on each node are the
intermediaries in every exchange.
Figure 1-3 Communication between Transaction Programs and Logical
Units
SNA defines two types of conversations: basic and mapped. These two
types of conversations use different methods to indicate the length of
transmitted or received data packages to be passed between SNAplus2
and the TP.
• In a basic conversation, data must be formatted by the TP as logical
records before being presented to the
SEND
function.