HP-UX SNAplus2 General Information (October 1998)

Chapter 1 15
SNA Networking
Components of a Subarea Network
Components of a Subarea Network
A simple subarea network includes the following components.
Node
A node is a component or a computer that participates
in an SNA network. SNA defines different node types
for different roles in the network.
Host
A host is a mainframe computer compatible with the
original IBM System/370. A host is a type 5 node.
Front-End Processor (FEP)
An FEP (also known as a “communication controller”)
is a separate processor attached to the host, to manage
the host's communications with other computers. An
FEP is a type 4 node.
Communications Link
Users are often on a separate site from the host, so the
two sites need to be connected by a communications
link.
Terminal controller
At the remote end of the communications link is a
terminal controller, which controls the use of the link
and routes data to the terminals. The best-known IBM
terminal controllers are the 3174 and 3274, but a
computer running SNAplus2 can act as a terminal
controller. A terminal controller is a type 2.1 node.
Terminals
Users work at terminals to submit work to the host or
run host applications. The best-known IBM terminal is
the 3270.
Printers
Printers such as the IBM 3278 can also be attached to
the terminal controller. They can receive output from
the host.