HP-UX SNAplus2 General Information (October 1998)

Chapter 1 17
SNA Networking
Components of a Subarea Network
Subarea SNA Node Components
This section describes the logical SNA components in a subarea network.
The host node contains the following elements:
SSCP
The host node contains a system services control point
(SSCP) that is responsible for managing network
resources. Its jobs include activating and deactivating
sessions between host and remote components.
The SSCP also provides an interface to network
operators at the host system, who can inspect and
control resources in the network.
Logical Units (LUs)
The host node also contains LUs. On the host, each LU
provides an access point to the network for an
application.
Communication sessions are maintained between host
LUs and the LUs on remote devices, to enable remote
end-users to communicate with host-based
applications.
At the remote end of the communications link, the node in the terminal
controller contains the following logical elements to help control
communications with the resources on the host:
Physical Units (PUs)
The PU type 2 manages the data link to the host.
Logical Units
The node contains LUs that provide access points to
the network for end users and terminal applications.
Communication sessions are maintained between these
LUs and the LUs on the host.
LUs in subarea networks are dependent LUs; they depend on the
support of the SSCP on the host. Before two dependent LUs can
establish and use a session, the SSCP must establish a session with the
PU on the remote node (the SSCP-PU session). The SSCP uses this
session to control and monitor resources on the remote node.