HP 3000 Manuals

Using SNA IMF Pass Thru

Structure of SNA IMF 

SNA IMF works with the SNA link product on the HP 3000.  Figure 1-2
illustrates the components of SNA IMF on the HP 3000 and their
relationship to the IBM host.


          Figure 1-2.  SNA IMF Components and the IBM Host 

SNA IMF Product 

SNA IMF is a software product that implements the upper three layers of
SNA: the Data Flow Control, Presentation Services, and Application
layers.  In other documents you may see SNA IMF referred to as an SNA 
Service.  An SNA Service is an HP data communications software product,
like SNA IMF, SNA NRJE, or LU 6.2 API, which runs on top of the SNA link
product.

SNA IMF stores data in the form of an internal screen image.  The
internal screen imagecontains the location and attributes of all the
fields on the screen.  It also contains any information that has been
entered into the fields.  Whenever an application or end user on the HP
3000 enters data to be transmitted to the IBM host, or whenever the IBM
host sends data to the HP 3000, SNA IMF modifies the internal screen
image.

SNA Link Products 

Hewlett-Packard offers three SNA link products:  SNA Link/V, SNA/SDLC
Link/XL, and SNA/X.25 Link/XL. SNA link products are bundled software and
hardware products that permit a logical and physical connection from an
HP 3000 into an SNA network.  An SNA link product has two parts:

   1.  SNA Transport(software)

   2.  INP(MPE V hardware) or PSI(MPE XL hardware)

SNA Link/V has a third component:  Node Management Services(software).
On MPE XL, Node Management Services is part of the Fundamental Operating
System (FOS)and is not bundled with SNA/SDLC Link/XL or SNA/X.25 Link/XL.
The FOS is a collection of MPE programs, utilities, and subsystems
bundled together for one price and supplied on a Master Installation Tape
(MIT).


NOTE  In this manual, the term SNA link product is used when the
      information being given is true for all three SNA link products.
      The terms SNA Link/V, SNA/SDLC Link/XL, and SNA/X.25 Link/XL are
      used when a distinction between the SNA link products is necessary.


SNA Transportemulates an SNA Type 2 node.  Through the Path Controland
Transmission Control layers, it coordinates the communication sessions
within the SNA network.

The hardware portion of the SNA link product is the INP (Intelligent 
Network Processor) card on MPE V, or the PSI (Programmable Serial 
Interface) card on MPE XL.The INP or PSI card implements the Physical
Control and Data Link Control layersof SNA. It uses the SDLC protocolto
control transmission over the communications line.

Node Management Services (NMS)is used by all the SNA Services (like SNA
IMF and SNA NRJE) installed on the HP 3000.  NMS handles configuration,
link and node level startupand shutdown, logging, tracing, and diagnostic
functions.

In both Pass Thru mode and programmatic mode, SNA IMF intrinsics call SNA
link intrinsics whenever data is sent to or received from the host.  SNA
IMF and the SNA link product together implement all architectural layers
of SNA.

A separate INP or PSI card is required for each communications line from
the HP 3000 to an IBM host.  With multiple INP or PSI cards, you can
connect the HP 3000 to multiple IBM hosts, or you can run multiple
communications lines to a single IBM host. 

The same INP or PSI can be used by multiple SNA Services.

The PSI card can also be used to run Network Services (NS). The same PSI
card can be used for both NS and SNA communications, but NS and SNA
cannot be run concurrently on the same PSI card.


NOTE  The SNA link products are not supported as separate products
      independent of the SNA Services.  Therefore, you must order and use
      SNA link products only with SNA Services.

MPE/iX 5.0 Documentation