LATCP$HELP.HLB  —  CREATE  LINK
    Creates the LAT data links, which are connections to LAN devices,
    such as Ethernet or FDDI (fiber distributed data interconnect)
    controllers, that you want your node to use. You must have OPER
    privilege to use this command.

    Format

      CREATE LINK  link-name

1  –  Parameter 

 link-name

    Specifies a name for a LAT data link. A link name can have up to
    16 ASCII characters. The characters allowed are as follows:

    o  Alphanumeric characters: A-Z, a-z, 0-9

    o  A subset of the international character set: ASCII codes 192-
       253

    o  Punctuation characters: dollar sign ($), hyphen (-), period
       (.), and
       underscore (_)

    You can create a maximum of eight links on your local node.
    Use the SHOW LINK command for a list of the link names that are
    defined for your node.

2  –  Qualifiers

2.1    /DECNET 

       /DECNET
       /NODECNET

    Directs LAT protocol to use the DECnet data link address (
    /DECNET) or the hardware address (/NODECNET) when starting the
    LAN controller. If you do not specify the /DECNET or /NODECNET
    qualifier, the default is that the LAT protocol will use the
    DECnet data link address.

    Note that if you enter the CREATE LINK command with the /DECNET
    qualifier and receive an error message indicating a "bad
    parameter value," it means the SCSSYSTEMID system parameter is
    set to an illegal value. To change the value of this parameter,
    use the following formula:

    (1024 * a) + n

    In the formula, a is the DECnet area and n is the DECnet computer
    number. If the value is outside the range of 1025 to 65535, the
    LAT protocol cannot start.

    When you use the /NODECNET qualifier, the LAN device driver code
    determines which address to use. For example:

    o  If SCSSYSTEMID is set to 0 but DECnet is already running on an
       Ethernet controller, the LAN device code allows LAT to use the
       same address as DECnet (AA-00-04-00-xx-xx).

    o  If SCSSYSTEMID is set to 0 and DECnet is not running, the 08-
       00-2B-xx-xx-xx address is used (a different address format is
       used if your LAN controller is supplied by a vendor other than
       Digital).

    o  If the setting for SCSSYSTEMID is the same as the DECnet node
       number and DECnet is not running, the LAN device code forces
       LAT to use the AA-00-04-00-xx-xx address.

    If DECnet is configured on the system (or if the system is part
    of a cluster), SCSSYSTEMID may contain a nonzero value. This
    is a problem only when the system has 2 or more LAN controllers
    connected to the same logical LAN.

    For example, if your system has an FDDI controller and an
    Ethernet controller, your site may be configured so that the
    FDDI ring attached to the FDDI controller and the Ethernet
    segment attached to the Ethernet controller are bridged by a
    10/100 LAN bridge (FDDI-to-Ethernet). In this configuration, it
    is impossible to run LAT over both controllers.

    In such a configuration, you must run LAT and DECnet over the
    same controller if SCSSYSTEMID is not 0. If you fail to do so,
    DECnet starts first, which in turn causes the LAT startup on
    the other controller to fail. This failure occurs because LAT
    startup tries to use the AA-00-04-00-xx-xx address (the DECnet
    LAN address) but is prevented from doing so by the data link
    layer. The LAT startup fails because DECnet is already using
    this address on a different controller. (In a single logical
    LAN, all data link addresses must be unique. In this setup,
    both controllers try to use the same address, which is then not
    unique.)

    The following command (which creates the LAT link) also fails
    because the LAN driver tries to use the address based on
    SCSSYSTEMID:

    LATCP> CREATE LINK LAT$LINK_2 /NODECNET

    If SCSSYSTEMID is set to 0, configuring LAT and DECnet on
    different controllers is possible. However, in a cluster
    environment, SCSSYSTEMID cannot be set to 0.

2.2    /DEVICE 

       /DEVICE=device-name

    Specifies the LAN controller device name for a LAT data link (for
    example, XEB0:). Only one LAT data link can be associated with a
    LAN controller. If you enter the CREATE LINK command without the
    /DEVICE qualifier, LATCP attempts to find an available controller
    by using a list of possible LAT data link device names. Digital
    advises that you specify a default device name by defining the
    LAT$DEVICE logical name.

2.3    /LOG 

       /LOG
       /NOLOG

    Specifies whether LATCP displays a message confirming that
    the link was created. If you do not specify the /LOG or /NOLOG
    qualifier, the default is that no message will be displayed.

2.4    /STATE 

       /STATE=option

    Specifies whether the link will be available for use. STATE can
    have two options:

    ON    Specifies that the created link will be available for use
          with the LAT protocol running.
    OFF   Specifies that the created link will not be available for
          use.

    If you do not specify the /STATE=option qualifier, the default is
    that the created link will be available for use (ON).

3  –  Example 

  LATCP> CREATE LINK NETWORK_A /DEVICE=XEB0: /STATE=ON

      The CREATE LINK command in this example creates an Ethernet
      link named NETWORK_A. It specifies the Ethernet controller
      device XEB0 for that link. The link will be available for use.
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