HP-UX SNAplus2 General Information (October 1998)

16 Chapter 1
SNA Networking
Components of a Subarea Network
A diagram of a subarea network looks like an inverted tree, as shown in
Figure 1-1, “SNA Subarea Network.”
Figure 1-1 SNA Subarea Network
The root of the tree (at the top of the diagram) is the host computer that
controls the network. The branches are the communications links. The
leaves (at the bottom of the diagram) are the terminals or printers
attached to the network and accessed by users.
The traditional subarea SNA setup described here enables users to
access the resources of a single host system. The terminals provide only
simple data entry and display functions to and from the terminal
controller. The terminal controller is responsible for handling SNA
communications between the terminals and the host.
The terminal controller and its terminals can be replaced by an SNA
product, such as SNAplus2. From the host's point of view, SNAplus2
appears as a terminal controller. However, it provides the users with
additional functions, such as the ability to access more than one host
system and facilities for customizing screen displays. In addition,
SNAplus2 runs on HP-UX computers that can also be used for other
tasks not related to SNA (unlike the terminal controller, which is used
solely for communications with the host).