HP-UX SNAplus2 R7 General Information

Introducing SNAplus2
SNAplus2 Resources
NOF applications administer SNAplus2 configuration and management resources.
Applications that use CSV
Applications use Common Service Verb (CSV) verbs to provide utility functions such as character translation
and application trace control.
The APIs for APPC, CPI-C, LUA, and CSV are included both on SNAplus2 servers and on HP-UX and Windows
clients. HLLAPI, Java CPI-C, NOF and MS APIs are only available on HP-UX systems (both servers and clients).
Many third-party Windows emulation programs supported by SNAplus2 include HLLAPI support.
For more information, see Section 2.2.4,
Client/Server Support.
On HP-UX systems, applications using the SNAplus2 APIs can be compiled and linked to run in either 32–bit mode
or 64–bit mode.
2.2.3 SNAplus2 Passthrough Services
Passthrough services support communication between a host and computers on a LAN, making it possible to reduce
the number of communication links to the host and simplify configuration. In addition, the TN server feature can
provide access to TN3270 users in a TCP/IP network.
Dependent LU Requester
Normally, a dependent LU session requires a direct communications link to the host computer. If many nodes
(including a host node) are connected together in an APPN network, some of them might not have a direct connection
to the host, but only an indirect connection through another node; it is not possible to establish dependent LU sessions
to the host from these indirectly connected nodes.
Dependent LU requester (DLUR) is an APPN feature designed to overcome this limitation. DLUR on an APPN
node (such as a node running SNAplus2) works in conjunction with dependent LU server (DLUS) at the host, to
route sessions from dependent LUs on the DLUR node across the APPN network to the DLUS host. The route
to the host can span multiple nodes, and can take advantage of APPN’s network management, dynamic resource
location, and route calculation facilities. DLUR must be available on the node where the LUs are located, and
DLUS must be available on the host node, but there is no need for DLUR to be available on any intermediate nodes
in the session route.
If the SNAplus2 DLUR node is a network node, it can also provide DLUR facilities for dependent LUs on
downstream computers connected to the SNAplus2 node. These LUs can use DLUR on the SNAplus2 node to
access the host across the network, in the same way as for LUs internal to the node.
PU Concentration
Normally, a dependent LU session requires a direct communications link to the host computer. However, a node
running SNAplus2 that has a direct communications link to the host can also provide PU concentration facilities to
LUs on downstream computers, enabling them to access the host over the communications link from the SNAplus2
node.
The downstream computer must contain an SNA PU type 2.0 or 2.1 to support dependent LUs at the host. For
example, it could be another computer running SNAplus2 in a stand-alone configuration.
An example of a node providing PU concentration is shown in Figure 2–1, PU Concentration Linking Multiple
Downstream Workstations to a Host Computer.
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