Communications Server for AIX

IBM Communications Server for AIX enables your pSeries computer to communicate with System/370, System/390 and AS/400 hosts and other personal computers. The Communications Server gateway allows applications to run, unchanged, over both SNA and TCP/IP communication networks.

Every data communications network consists of a number of linked elements, or nodes. The nodes are connected both physically and logically. Communications Server for AIX enables nodes that have been attached physically to recognize each other, and to be linked logically. It keeps track of the location of each node that is part of the network and implements communication between them.

A single network node is made up of one or more network accessible units (NAUs). An NAU can be a physical unit (PU), such as a piece of hardware, or a logical unit (LU), such as a terminal session. A single node can include multiple NAUs, both PUs and LUs. A single PU can support multiple LUs.

Communications Server for AIX requires that each NAU is configured. The configuration specifies:

Configuring Communications Server for AIX

You must configure Communications Server for the host connection and for each of the LUs that will be used for 3270 emulation. If the configuration has already been done for a host connection, you need configure only the LUs.

Configuring Communications Server consists of defining resource information in a configuration file. You can do this using any of the following:

If you are installing Blueworx Voice Response for the first time, it is suggested that you use xsnaadmin to create the initial configuration.

If you are migrating from a DirectTalk system that used Version 6.1 or earlier of Communications Server for AIX, or SNA Server/6000, or SNA Services/6000, you can use the exportsna utility before you remove that level of SNA. The exportsna utility creates an ASCII file of the previous configuration files so they can be migrated and imported to Communications Server Version 6 using the snamig utility.

No migration is required if you are upgrading from a DirectTalk system that used Version 5 of Communications Server for AIX, because Communications Server for AIX Version 6 can use your existing configuration information without change.

For more information on this, see the Communications Server for AIX: Migration Guide.

The configuration tasks you need to perform depends on your network configuration and whether you are sending 3270 data streams over SNA or over TCP/IP. Use the information provided in: to identify the information you need, then use the instructions provided in either Defining a link station using SNA or Defining a link station using TCP/IP to configure Communications Server.
Configuring LU 2 sessions:
  • The local LU address, as specified in the LU 2 configuration, is the LU DAF address. The address is normally assigned by automatic configuration; if you need to change it, it should correspond to the LOCADDR field in the LU configuration record on VTAM. This should be different for each LU which is defined on the PU, with addresses 0 and 1 reserved for SSCP-PU sessions.
  • The SSCP field is a 12-digit hexadecimal number specifying the SSCP. The first two digits are always 05. The low-order 10 digits contain the SSCP ID. The default configuration allows any SSCP ID; if you need to restrict it, select Advanced from the LU Type 0-3 dialog.
  • For VTAM Version 3 and above, the network name and LU name need to be specified in the LU 2 configuration; these are not generated automatically during quick configuration. The network name should match the NETID field in the VTAM ATCSTRnn member. The LU name should be the name assigned on the LU macro in the VTAM definition.
Configuring an SDLC RS-232 host l link station:
  • Depending on the type of modem used for the connection, the network type can be either switched or non-switched. If the line is connected by a dedicated leased line, the connection is non-switched. If the connection is made by a dial-up modem, the connection uses the standard switched network.
  • In the SDLC Link Station dialog, the Poll address field gives the polling address for the PU. It is specified in the VTAM configuration for the PU in the ADDR field.
  • For switched connections, set the Local Node ID field to the value specified for the PU in the VTAM configuration. The IDBLK field specifies the first three digits and the IDNUM field specifies the last five digits. This number is in hexadecimal format.
Configuring a token-ring link station:
  • The remote link address is the address, on the token ring, used by the 3745 or 3174 terminal controller for this link station. This value must match the controller value, or no communication can take place. The field is a 12-digit hexadecimal value. For 3745 connections, this is specified in the LOCADD field of the LINE statement.
  • In the Port dialog, the Token Ring Card field identifies the token ring adapter that will be used. With Communications Server for AIX, the number of link stations that could be defined on one token ring card was limited by whether they were calling or listen link stations. This restriction does not apply to Communications Server; however, if you are using multiple links per adapter, careful configuration is necessary.
  • For 3174 connections, the Window Size field in the LLC2 Port Parameters dialog should be less than the W value specified in 3174 customization question 941. To see the LLC2 Port Parameters dialog, select Advanced from the port's Token Ring SAP dialog.
  • For 3174 connections, the maximum I-FIELD size should match the F value specified in 3174 customization question 941. To change it, type the following command: 
    snaadmin define_tr_port

    Then change the max_rcv_btu_size and max_send_btu_size fields.

  • For switched connections, set the Local Node ID field to the value specified for the PU in the VTAM configuration. The IDBLK field specifies the first three digits and the IDNUM field specifies the last five digits. This number is in hexadecimal format.
Configuring a DLUR link station:
  • The Enterprise Extender (EEDLC) feature of Communications Server for AIX is used to send 3270 data streams over an IP network. Enterprise Extender uses a Dependent Logical Unit Requester (DLUR) to connect to the host machine via a Dependent Logical Unit Server (DLUS) using an APPC session. The 3270 dependent control sessions flow over this pipe.
  • In the DLUR PU window, the DLUR PU and DLUS PU names are eight character alphanumeric strings. The DLUS PU name should be preceded by the APPN network name using the form XXXXXXXX.YYYYYYYY
  • The linkstation name is the name of the DLUR connection, not the IP link station itself.

Defining a link station using SNA

Use the command xsnaadmin to define the link station and LU 2 sessions required. In the following procedure, a token ring connection is used as an example.

For more detailed information on configuring Communications Server for AIX, see the Communications Server for AIX: Administration Guide.

Start

  1. Log on to AIX as root.
  2. Configure the node: Type the following command and press Enter. 
    xsnaadmin

    The system displays the Motif CS/AIX Nodewindow.

  3. Click Services —> Configure Node Parameters.
  4. In the Node Parameters window, specify the Control Point name, then click OK.

    The node box changes from Unconfigured to Inactive.

  5. Define a port: Click New.
  6. Click Port Using Token Ring Card, then click OK.
  7. Define a link station: Click New.
  8. Click Link Station to Port portname, then click OK.

    The Token Ring Link Station window appears.

  9. In the Token Ring Link Station window, select On Node Startup for Activation, then specify the Local Node ID (XID) and the MAC address.
  10. Define the LUs: Click New.
  11. Click LU for 3270 Display to Link Station linkstationname, then click OK.

    The LU Type 0-3 window appears.

  12. Specify the LU name and select either single LU or a range of LUs and specify a range of numbers.

When you have completed the configuration, start Communications Server for AIX using the procedure in Starting Communications Server and the link stations manually.

Defining a link station using TCP/IP

Use the command xsnaadmin to define the link station and LU 2 sessions required.

For more detailed information on configuring Communications Server for AIX, see the Communications Server for AIX: Administration Guide.

Start

  1. Log on to AIX as root.
  2. Configure the node: Type the following command and press Enter. 
    xsnaadmin

    The system displays the Motif CS/AIX Node window.

  3. Click Services —> Configure Node Parameters.
  4. In the Node Parameters window, specify the Control Point name, then click OK.

    The node box changes from Unconfigured to Inactive.

  5. Define a port: Click New.
  6. Click Enterprise Extender (HPR/IP), then click OK.
  7. Define a link station: Click New.
  8. Click Link Station to Port portname, then click OK.

    The IP Link Station window appears.

  9. In the IP Link Station window, select On Node Startup for Activation, then specify the Remote IP hostname.
  10. Define the DLUR PU: Click New.
  11. Click DLUR PU, then click OK.

    The DLUR PU window appears.

  12. In the DLUR PU window, specify a name for the DLUR PU and the name and PU ID for the DLUS.

    Optionally, select Initially Active and Retry Contacting DLUS Indefinitely.

  13. Define the LUs: Click New.
  14. Click LU for 3270 Display to Link Station linkstationname, then click OK.

    The LU Type 0-3 window appears.

  15. Specify the LU name and select either single LU or a range of LUs and specify a range of numbers.
  16. Click Advanced
  17. Click LU use and select CS/AIX V4.2 LU1-3.
  18. Type the fully qualified partner LU name and click OK.
  19. Click OK again.

When you have completed the configuration, start Communications Server for AIX using the procedure in Starting Communications Server and the link stations manually.

Parent topic: Connecting to a 3270 mainframe