APPC lets two partner programs communicate through a defined protocol. The interface to the protocol mechanisms on each side is called a logical unit (LU). To allow program-to-program communication, these LUs must be of type 6.2 (LU6.2). APPC protocols are more complex to implement than other protocols. However, the APPC protocols provide better performance and reliability, and they should be considered as preferred protocol for use with TSM. This particularly applies when TSM supports LAN server clients such as OS/2 LAN servers or Novell NetWare servers.
TSM implements Independent LUs. SNA PU type 2.1 support is required in VTAM, the SNA gateway, and in Tivoli Storage Manager client communications software. In an MVS environment, PU 2.1 support is provided as a combination of communications gateway software and VTAM levels.
For the supported communications gateways, the requirements are the following:
PU 2.1 support requires the following software levels:
PU 2.1 support requires the following software levels:
PU 2.1 support requires the following software levels:
OR
Your VTAM system administrator or systems programmer defines a new application to VTAM through the use of an access control block (ACB). An ACB defined for TSM, when added to the VTAM configuration, provides an application ID which the client references when it wants to connect to the TSM server. When the TSM application ID is referenced, a logon procedure is begun which ultimately tells the server where to look for the TSM client.
You define the ACB in the VTAM APPL statement. The following is an example of the APPL statement that the VTAM systems programmer should add to your VTAM configuration:
+--------------------------------------------------------------------------------+ |TIVSM VBUILD TYPE=APPL | |DSMSERV1 APPL ACBNAME=DSMSERV1,EAS=30,AUTH=(ACQ,PASS,VPACE), X | | HAVAIL=YES,APPC=YES,PARSESS=YES,SONSCIP=YES, X | | VPACING=5,MODETAB=ISTINCLM,DLOGMOD=#BATCH, | +--------------------------------------------------------------------------------+
DSMSERV1 is the application ID (applid) that the TSM client references when it wants to connect to the server. The way in which the client references this name is discussed later in this installation guide where we cover client connectivity. If you are installing the OS/2 client and you prefer to review that section now, you can find it in Configuring the OS/2 Client for APPC Using Communication Manager/2. If you are installing the Novell NetWare client and you prefer to review that section now, you can find it in Configuring Novell NetWare Client for APPC Using NetWare Requester.
When the client references the application ID for the TSM server (DSMSERV1), the MODETAB=ISTINCLM and DLOGMOD=#BATCH parameters reference a logon mode definition which establishes the connection and the characteristics of the session. These characteristics include the maximum number of sessions allowed, the maximum number of conversations allowed, and other control information. MODETAB references the table in which the logon mode definition entry is found. In this example, the table referenced is the IBM supplied VTAM default table (ISTINCLM). DLOGMOD references the table entry itself which is the logon mode definition #BATCH. We recommend that you use the #BATCH mode entry in the VTAM default logon mode table (ISTINCLM) initially to establish the APPC connection. Depending on your VTAM level, this mode might not be pre-defined in the default logon mode table. You should verify this with your VTAM system programmer. If this mode is needed, add it to the default logon mode table as shown below:
+--------------------------------------------------------------------------------+ | TITLE '#BATCH' | |#BATCH MODEENT LOGMODE=#BATCH, X | | ENCR=B'0000',SSNDPAC=8, X | | SRCVPAC=8,PSNDPAC=8 | +--------------------------------------------------------------------------------+
After you have the APPC connection established and would like to create a new mode for performance tuning, you can create it in your current logon mode table, compile, and then link-edit the member into the VTAM library.
In VTAM, a response unit (RU) is a message unit that acknowledges a request. Since the RU size is negotiated between VTAM and the workstations, you do not have to specify a size in the #BATCH logon mode definition. However, if you specify a size, it should be at least 4K.
Each workstation connected to the network must be represented on the network as physical unit (PU). A PU can have one or more logical units (LUs). However, only one LU on a PU can be an independent LU. An independent LU can activate a session directly with the server LU without asking for services from the VTAM system services control point (SSCP). A dependent LU, however, must request services from the SSCP in order to activate a session with server LU. The LU provides the end user application with the ability to access and communicate with server.
The PUs and their associated LUs for the TSM clients are defined and linked together through a VTAM switched major node definition. A switched major node is the major building block of VTAM through which all the PUs and LUs for a given application such as TSM are linked together so that they can communicate with the server. The APPC connection for an TSM client must be made through an independent LU.
You define a switched major node through the VTAM build statement (VBUILD). The following VBUILD statement (Figure 11) defines the PUs and LUs for three workstations. F13833B0, F13833C0, F13833D0 are the independent LUs. Based on your TSM client configuration, you must define a similar VBUILD statement.
* SWITCHED MAJOR NODE * * VBUILD TYPE=SWNET,MAXGRP=1, X MAXNO=1 * F13833B PU ADDR=C5, X IDBLK=05D,IDNUM=F333B, X ISTATUS=ACTIVE, X PUTYPE=2,MAXOUT=8,MAXDATA=4105,MAXPATH=1, X VPACING=8,PACING=8,DISCNT=NO, X USSTAB=USSSNAM,SSCPFM=USSSCS, X MODETAB=MTD1SERH,DLOGMOD=QUERY X F13833B0 LU LOCADDR=0,MODETAB=ISTINCLM,DLOGMOD=#BATCH, X VPACING=8,PACING=8 F13833B1 LU LOCADDR=2 F13833B2 LU LOCADDR=3 F13833B3 LU LOCADDR=4 F13833B4 LU LOCADDR=5 F13833B5 LU LOCADDR=6,MODETAB=WI3820,PACING=0,VPACING=0, X DLOGMOD=IBM3820T * F13833C PU ADDR=C5, X IDBLK=05D,IDNUM=F333C, X ISTATUS=ACTIVE, X PUTYPE=2,MAXOUT=8,MAXDATA=4105,MAXPATH=1, X VPACING=8,PACING=8,DISCNT=NO, X USSTAB=USSSNAM,SSCPFM=USSSCS, X MODETAB=MTD1SERH,DLOGMOD=QUERY X F13833C0 LU LOCADDR=0,MODETAB=ISTINCLM,DLOGMOD=#BATCH, X VPACING=8,PACING=8 * F13833D PU ADDR=C5, X IDBLK=05D,IDNUM=F333D, X ISTATUS=ACTIVE, X PUTYPE=2,MAXOUT=8,MAXDATA=4105,MAXPATH=1, X VPACING=8,PACING=8,DISCNT=NO, X USSTAB=USSSNAM,SSCPFM=USSSCS, X MODETAB=MTD1SERH,DLOGMOD=QUERY X F13833D0 LU LOCADDR=0,MODETAB=ISTINCLM,DLOGMOD=#BATCH, X VPACING=8,PACING=8 |
Enter the ACBNAME (DSMSERV1) from VTAM APPL statement in the server options file's LUNAME option. Refer to The VTAM APPL Statement. The entry takes the following format:
+--------------------------------------------------------------------------------+ |luname dsmserv1 | +--------------------------------------------------------------------------------+
The ACBNAME identifies the TSM server to VTAM as the application to which the client can connect.