Defining the Physical Unit (PU)

Figure 1 shows an example of a Physical Unit List after definitions have been made. Later in the dialog, panels come into play which are special to a certain link type, for example the IBM® token ring.

Two physical units are defined at link 035. Notice, by the way, how the dialog has assigned a link name of 'L0350001' according to its own naming convention which is laid out in Naming Convention.

Figure 1. Physical Unit List
 COM$COM1       HARDWARE CONFIGURATION: PHYSICAL UNIT LIST

 LIST OF PU AT A LEASED SDLC LINK

 Link Address: 035        Link Name: L0350001

 OPTIONS: 3 = SELECT FOR FURTHER PROCESSING     5 = DELETE PHYSICAL UNIT

       OPT               SDLC       CONTROLLER
                       ADDRESS         TYPE
        _              C1           3274 31C
        _              C2           4700
        _
        _
        _
        _
        _
        _


 PF1=HELP     2=REDISPLAY  3=END                  5=PROCESS    6=ADD PU

To start your physical unit definition, press PF6 for ADD PU.

The PU definition comprises the following parameters. With each parameter, the link types are shown to which the parameter applies.
  1. Subsystem Group (applies to: all link types)
    In the Hardware Configuration: Subsystem Group panel, you are asked to select one of the following two:
    • Display and Printer System, or
    • Intelligent System

    Below, in Figure 2 and Figure 3, you find two lists of devices for each subsystem group.

  2. Physical Unit (applies to: all link types)

    Indicate the device number/model of the physical unit.

    You will have to select from one of two selection sets, depending on the 'subsystem group' you had specified before.

    For subsystem group 'Display and Printer System', the selection set is the one shown in Figure 2.

    For subsystem group 'Intelligent System', the selection set is the one shown in Figure 3.

    Figure 2. Display and Printer System - Physical Unit Selection
     COM$MDL            HARDWARE CONFIGURATION: DISPLAY/PRINTER CU

 SELECT A PRODUCT, ENTER ITS NUMBER  AND PRESS ENTER

    1  PC (standalone)
    2  PC Gateway
    3  Displaywriter
    4  8775 Display Terminal
    5  5550 Display System (Single Station)
    6  3820 Printer

       3270-Information-Display-System:
    7  ... 3274 Model 21C                   12  ... 3276 Model 12
    8  ... 3274 Model 31C                   13  ... 3276 Model 13
    9  ... 3274 Model 41C                   14  ... 3276 Model 14
   10  ... 3274 Model 51C
   11  ... 3274 Model 61C                   15  ... 3174 Model xxR
                                            16  ... 3174 xxR with TR gateway



 PF1=HELP       2=REDISPLAY  3=END


 ==>
    Figure 3. Intelligent System - Physical Unit Selection
     COM$INTL       HARDWARE CONFIGURATION: INTELLIGENT SYSTEM

 SELECT A PRODUCT, ENTER ITS NUMBER, AND PRESS ENTER

   1  Personal Computer (with APPC)    10  3680 Programmable Store System
   2  Scanmaster                       11  3770 Data Communic. System
   3  Series/1                         12  4700 Finance Communic. System
   4  System/34                        13  5280 Distributed Data System
   5  System/36                        14  5520 Administrative System
   6  System/38                        15  6670 Information Distributor
   7  3630 Plant Communic. System      16  8100 Information System
   8  3650 Retail Store System
   9  3660 Supermarket System




 PF1=HELP    2=REDISPLAY  3=END

 ==>

  3. SDLC Station Address (applies to: all link types except SDLC Token-Ring and NTRI)

    Specify two hexadecimal characters for the physical unit's station address. The address must be unique for each physical unit attached to the link. The valid range is X'01' through X'FE'.

    You establish this address during the customization of the control unit. Consult the relevant device publication for guidance in assigning this value.

    You can define up to eight physical units to a leased link. Switched links attach one physical unit at a time (the one that dialed in), but you can of course define any number of physical units.

  4. Identification Block (applies to: all switched link types, SDLC Token-Ring, NTRI)

    This is the (binary) block number. For certain control units, z/VSE automatically generates this block number. If the number is not known, the dialog requests that you specify the number.

    The Identification Block is a 12-bit number (specified in hexadecimal notation - xxx). Check the appropriate device component description publication to determine the id block number for the given device.

    Workstations use special communication programs which make the specification of a special id block number mandatory. For some commonly used programs the id block number is the following:
    • 017 IBM Workstation 3270 Emulation Program Version 3
    • 049 IBM 3270-Workstation or 3270-Workstation/G Communication Program with PS/55
    • 050 APPC Workstation
    • 05D IBM OS/2 Extended Edition
    • 05D IBM Communication Manager/2
    • 05E IBM Workstation Program
    • 061 IBM Personal Communication/3270
  5. Identification Number (applies to: all switched link types, SDLC Token-Ring, NTRI)

    This is a 20-bit identification number (specified in hexadecimal notation - xxxxx) which is required to identify the physical unit. You may regard it as some kind of password.

    The number can either be freely chosen according to a scheme that you developed for your installation. Or, you may use the device's serial number. You get the serial number from the component description publication for the device, or from the person who planned the device's installation.

    For a type 2.1 peripheral node on a switched line, in addition to or in place of the preceding parameters, Identification Block and Identification Number, you may supply a control point name (CPNAME) value:

  6. Control Point Name (applies to: all switched link types, SDLC Token-Ring, NTRI)

    This is the control point (CP) name of a type 2.1 peripheral node. It is valid only for type 2.1 nodes that have a control point name.

    The name consists of 1 to 8 characters. The first character must be alphabetic or @, #, $.

  7. X.25 Packet-Switched Parameters (applies to: SDLC X.25 SVC)
    When defining a physical unit attached at one or more Switched Virtual Circuits (SVCs), you must specify some or all of the following X.25-unique parameters.
    • DIAL OUT - indicates whether the host (= VTAM) can call the control unit (= physical unit). Note that DIAL OUT relates to host and physical unit. Compare this with the CALL DIRECTION parameter when defining the link (=SVC). The latter specifies in which direction(s) the transmission through the link (SVC) may flow. In other words, when the host calls the control unit over an SVC, the call can travel only via an outgoing or via a two-way SVC.

      The following four parameters appear on a separate panel.

    • DIAL NUMBER - is the calling address of the physical unit (not of the port). The number is between one and fifteen digits long. Your common carrier assigns the number when you subscribe to the network.
    • CUG INDEX - is the identifier of a closed user group (CUG). CUG is an X.25 optional user facility. Provided you have subscribed to this facility, specify the CUG index if the physical unit is a member of more than one closed user group.
    • RPOA NUMBER - is the identifier of a recognized private operating agency (RPOA). RPOA selection is an X.25 optional user facility. It applies to connections which span several networks. Provided you have subscribed to this facility, specify the RPOA number to indicate which route through the networks should be taken.
    • REVERSE CHARGING - indicates whether the physical unit will be charged for the call (reverse charging).
  8. SDLC Token-Ring Parameters (applies to SDLC Token-Ring)

    When defining a physical unit that is attached via a token-ring link, you must specify some or all of the following token-ring related parameters. In doing this, bear in mind that VTAM treats this physical unit like an SDLC-switched station. As a result, the Interactive Interface dialog will generate a switched major node definition, plus a PU definition statement for each physical unit in the switched major node. The Hardware Configuration dialog cannot, at this switched major node, define physical units other than those at the token ring.

    The Interactive Interface suggests some values, either system-provided defaults or values which you had specified before. Please refer to the following two figures.

    The kind of data to be entered varies slightly depending on the type of token-ring attachment: integrated token-ring adapter (TRA) versus NCP/Token-Ring interconnection (NTRI).

    Integrated Token-Ring Adapter:

    Figure 4. Describing the PU at the Integrated TRA
     COM$TRA3       HARDWARE CONFIGURATION: PU IDENTIFICATION

 Enter the required data and press ENTER.

 LAN ADDRESS/1 ........  4000         First 4 hex digits of the MAC address
 LAN ADDRESS/2 ........  ________     Last 8 hex digits of the MAC address
 IDBLK PARAMETER.......  017          Block number assigned to the specific
                                      device
 IDNUM PARAMETER.......  _____        Identification number assigned to the
                                      station being defined
 CPNAME................  ________     Control point (CP) name of a type 2.1
                                      peripheral node
 CALL DIRECTION........  3            1-in, 2-out, 3-inout

Token ring specific information (optional, not needed for 3172 or OSA)
 SIZE, STEP............  2      1      Dynamic window process
 TIMER, COUNT..........  10     1      Acknowledgement process
 TIMER, COUNT..........  20     2      Connected state
 TIMER, COUNT..........  50     1      Connection process
 TIMER.................  20            Inactivity timer

 PF1=HELP       2=REDISPLAY  3=END

 ==>
    • LAN ADDRESS - is the address of the physical unit (the station) on the token ring, the so-called medium access control (MAC) address.

      The address consists of 12 hexadecimal digits. You specify the address in two parts: the first 4 digits and then the right-most 8 digits.

      If you do not enter the first 4 digits, VTAM's default value of 4000 will be used.

      The last 8 digits are determined as follows:
      1. You either use the burnt-in number in the token-ring adapter card. The number is also known as universally administered address.
      2. Or you override this number when you customize the token-ring adapter card. On a workstation, this is accomplished by an Emulation Program. For an IBM 3174 control unit, it is done via microcode customization. This number is also known as locally administered address.
    • IDBLK and IDNUM and/or CPNAME - they are part of any SDLC-switched station definition. Please refer to items 4 through 6 above.
    • CALL DIRECTION - specifies whether the stations, or VTAM®, or both, can initiate calls over this line.

      If the line is to be used only for incoming calls, enter 1. If the line is to be used only for outgoing calls (VTAM is to call the physical unit), enter 2. If the line is to be used for both incoming and outgoing calls, enter 3.

    • SIZE, STEP - specifies the send window size and the window step.

      The send window is the maximum number of sequentially numbered I-LPDUs (Information-Logical Link Level Protocol Data Units) that the link station may have outstanding at any time. Valid numbers are 1 through 127.

      Window step is the number of sequentially numbered I-LPDUs that a link station must receive before increasing the local window. Valid numbers are 1 through SIZE. A value of 0 means that the send window is static, and dynamic windowing cannot take place.

    • Acknowledgment TIMER, COUNT - specifies the acknowledgment delay timer and the number of data units received prior to sending an acknowledgment. If either the timer expires or the count is reached, then an acknowledgment is sent.

      The TIMER value is expressed in tenths of seconds. The valid range is 0 - 255. A value of 0, however, means that the timer is disabled.

      Valid values for COUNT are 0 through 127.

      If either TIMER or COUNT is specified as 0, then the other must be specified as 0.

    • Connection TIMER, COUNT - the TIMER specifies the time period to elapse before a retry is attempted during connection or disconnection of a link station. The timer value is expressed in tenths of seconds, in the range 0 through 255.

      COUNT specifies the number of times to retry a transmission during connection or disconnection of a link station. The valid range is an integer from 0 through 255. A value of 0 means no retry.

      When the number of retries has been reached and the TIMER has elapsed for each retry, the link station is considered to be in an inoperative condition.

    • Connected state TIMER, COUNT - the TIMER specifies the time period to elapse before a transmission retry is attempted, at a time when the station is connected. The timer value is expressed in tenths of seconds, in the range 0 through 255.

      COUNT specifies the number of times to retry a transmission. The valid range is an integer from 0 through 255. A value of 0 means no retry.

      When the number of retries has been reached and the TIMER has elapsed for each retry, the link station is considered to be in an inoperative condition.

    • Inactivity TIMER - specifies the time period to elapse before a link station is considered to be inactive.

      The timer is expressed in tenths of seconds. The valid range is 0 - 255. If 0 is specified, then the timer is disabled.

    NCP/Token-Ring Interconnection (NTRI):

    Figure 5. Describing the PU at the Token-Ring (NTRI Attachment)
     COM$TRA4          HARDWARE CONFIGURATION: PU IDENTIFICATION

 Enter the required data and press ENTER.


 LAN ADDRESS/1................4000        First part of the LAN address
                                          (cannot be modified)

 LAN ADDRESS/2............... ________    Second part of the LAN address.  The
                                          entry will be ignored for CALL
                                          DIRECTION = 1.
 IDBLK PARAMETER............. 017         Block number assigned to the specific
                                          device

 IDNUM PARAMETER............. _____       Identification number assigned to the
                                          station being defined
 CPNAME...................... ________    Control point (CP) name of a type 2.1
                                          peripheral node.

 BACKUP TIC.................. ____        Enter the relative line number of
                                          your backup TIC.  The entry will be
                                          ignored for CALL DIRECTION = 1.
 CALL DIRECTION...............3           1=in,  2=out,  3=inout
 PF1=HELP       2=REDISPLAY  3=END

    Except for BACKUP TIC, the parameters have the same meaning as in the case of an integrated TRA. Please refer to the explanations on the preceding pages.

    LAN ADDRESS/2 is optional and will be ignored (no PATH statement generated) for call direction 1.
    • BACKUP TIC - is the relative line number of the backup token-ring interface coupler (TIC), if there is any. The backup TIC provides for higher availability: if one coupler breaks down the other takes over.

      The dialog does not check, rather assumes that the TIC has been defined correctly (in the Hardware Configuration: Define NCP Line panel; see Figure 1).

      The specification of a backup TIC here leads to a second PATH statement in the VTAM switched major node definition. It is therefore only meaningful for call directions 2 and 3.