SNAX/APN Application Programming Manual

The SNALU Interface
SNAX/APN Application Programming Manual—420111-001
4-12
SNALU Application Initiates Session with Remote
SLU
filename
identifies a remote LU by the fully qualified name assigned to it through SCF
configuration.
filenum
supplies a variable which returns a file number that uniquely identifies this opening.
flags
specifies certain file-system characteristics.
A single file name can be used to access several remote LUs, provided it has one session
at a time. However, a Tandem application usually accesses several different remote LUs
at a time and participates in concurrent LU-LU sessions with them. In such cases, a
remote LU is created for each of the sessions during SCF configuration. These remote
LUs have different file names given them by the ADD LU command. At session
establishment, the Tandem application must open each of these remote LUs, using its
particular file name. The number of remote LUs opened must equal the number of
concurrent sessions you want to establish.
SNALU Application Initiates Session with Remote SLU
When the SNALU application is the PLU, it can initiate a session with an SLU as
follows:
1. The application opens the remote LU (OPEN call).
2. The application formats a BIND request, sends it to the SLU, and waits for a
response (WRITEREAD call). A positive response indicates successful initiation.
This is called PLU Acquire mode. For illustrations of situations in which PLU Acquire
is used, see Appendix C, Logic Flows and Internal Formats When Using SNALU
.
The detailed format of the BIND request is available in the IBM Systems Network
Architecture: Format and Protocol Reference: Architectural Logic manual. The
applicability and use of individual parameters varies from one device to another. When
you are constructing a BIND image for use with a particular device, the component
description manual for the device provides you with explicit guidelines.
An application can set the PLU name in the BIND request. If the PLU name is not
included in the BIND request, the LOCALSNANAME of the SNALU LU will be used
instead. The PLU name in the BIND request must be unique in the network.
If the application specifies the SLU name in the BIND request, the SLU name must
match the SNANAME configured for the SNALU LU, if one is configured. Otherwise,
the BIND request will be rejected.
If the application omits the SLU name from the BIND request, the SNANAME
configured for the SNALU LU will be used as the SLU name sent in the BIND request.
However, if no SNANAME is configured for the SNALU LU, the BIND request will be
rejected.