Choosing names for the local subsystem

You define the names for the local subsystem and its VTAM® password to Db2 by using the installation panels, or by using the change log inventory utility.

Procedure

Choose the following names for the local Db2 subsystem:
  • A unique name by which the other systems in the network can recognize your subsystem. The name can have 1–16 characters and is called the location name. (Db2 Connect refers to this as the target database name.) Make sure that the local location name is different from the name of every other system in the network, no matter where it is physically located.

    You must share the location name with the other systems that need to send SQL requests to this one.

    The location name should not change even if the network changes. Therefore, tightly control the allocation of location names. To ensure uniqueness, you use an IBM-registered SNA NETID as the first six bytes of your location name. If location names are not unique, you have to change many programs and tables if your network is later joined with another network using the same location name.

    The IBM® recommendation for the NETID is the following format:

    • The first two bytes are the country code as defined in ISO standard ISO 3166. These codes include the uppercase letters A through Z.
    • The next four bytes are the enterprise code of the registering enterprise. This might already be registered with IBM as your SNA NETID. The enterprise code can include the uppercase letters A through Z, the numbers 0 through 9, and the underscore character (_).

    To register your SNA NETID, see your IBM representative.

  • A name by which VTAM can recognize the local subsystem. It must be either a unique name or, in some cases, a generic name.
    • The unique name must be unique within the network of connected systems, can have 1–8 characters, and is called the LU name. The LU name and the location name of a subsystem can be identical, but this is not recommended; LU names are unique only within a network, and networks can change. You must share the LU name with any system that requests data from your local subsystem. Later, you enter this name in the VTAM APPL statement.
    • If the z/OS® system on which Db2 is running is part of an z/OS sysplex, you can use a generic 8-character name to represent a group of VTAM LU names. The generic name might be useful if your network is in a transitional period, and you want to use generic names to reference network nodes.

      Specify the generic LU name in the field Db2 GENERIC LUNAME on installation panel DSNTIPR. Use column GENERIC of SYSIBM.LUNAMES to indicate that you want to use the generic LU name for CNOS processing and SQL requests to a particular server.

  • Server location aliases. You can use the Change Log Inventory utility to define up to eight aliases for a location. Applications can use these alias names to refer to the local Db2 subsystem or data sharing group.

    Aliases are most useful in a data sharing environment in which two or more Db2 subsystems are migrated to a single data sharing group. In this case, you can define the old location for each subsystem as an alias for the location name of the group. Remote applications that refer to the old location names do not need to change.

    Use the Print Log Map utility to print all location alias names that are defined for a Db2 subsystem.

    You can set up multiple server location aliases as locations on the z/OS requester to restrict which members an application will use when accessing a data sharing group. The z/OS requester must be using the IPLIST or LULIST table to route connections to the data sharing group.