HP-UX SNAplus2 R7 General Information

Introducing SNAplus2
SNAplus2 Resources
if there is no direct connection between them, because the communications path can be established through
the intermediate nodes.
If all the end nodes and network nodes are connected to the same Enterprise Extender (HPR/IP), FDDI, token
ring or Ethernet network, there is a direct communications path between all nodes, so that in theory any two
nodes can communicate directly. Such a network is referred to as a shared-access transport facility (SATF).
However, to enable direct communications between two nodes, you need to define link stations between every
pair of nodes; this results in a very large number of link station definitions if you want to enable any two
nodes on the SATF to communicate directly.
APPN enables you to set up this type of configuration without having to define each link station explicitly,
by defining a connection network that represents the SATF. For each node on the SATF, you define one or
more ports used to access the connection network. Instead of defining a link station to each remote node, you
specify the name of a virtual routing node (VRN) as part of the port definition. You can think of the VRN
as an imaginary node that represents all the other nodes on the SATF. All nodes on the connection network
use the same VRN name.
When two nodes on the SATF need to communicate, and both have a port defined with the same VRN name,
APPN can dynamically establish a direct connection between them; no additional configuration is necessary.
Because the connection is direct and does not need to go through any intermediate nodes, using a connection
network reduces traffic on the LAN and improves performance.
Logical units
An LU is the node’s point of contact with a user program (3270 emulation program, RJE workstation, APPC
TP, CPI-C, or LUA application). LUs are divided into the following categories:
• LU types 0–3 (sometimes referred to as “old LUs”) are used to communicate with hosts using 3270
emulation, RJE, or LUA.
• LU type 6.2 is used to communicate with either hosts or peer computers using APPC or CPI-C.
Type 0–3 LUs are referred to as “dependent LUs.” They can support only one user session at a time. The
user session is controlled by the host program. Type 6.2 LUs can also be dependent LUs, if they are used to
communicate with host computers that use older versions of SNA host software.
Type 6.2 LUs that are used to communicate with peer computers, or with newer SNA software on host com-
puters, are referred to as “independent LUs.” They can support multiple user sessions simultaneously.
SNAplus2 supports the following type 0–3 LUs:
Display
Display LUs support 3270 display sessions, with the models representing different screen sizes:
• Model 2 - 80 x 24
• Model 3 - 80 x 32
• Model 4 - 80 x 43
• Model 5 - 132 x 27
Printer
Printer LUs support printer sessions:
• 3270 printer
• SCS printer
RJE
RJE model LUs support RJE workstations.
Unrestricted
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