VMS Help SET, HOST, /LAT, Parameter  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 service-name

    Specifies the name of the service to which you want your terminal
    connected. A service is a resource on the LAN. A service often
    consists of all of the resources of a computer system. Other
    examples of services are a file storage system and an application
    program running on a computer system. A computer system that
    offers one or more services is called a service node.

    If several service nodes offer the same service, and you do not
    specify the /NODE=node-name qualifier, your terminal connects to
    the service node that is the least busy.

    To display a list of services on your LAN, use the LAT Control
    Program (LATCP) SHOW SERVICES command. Refer to the OpenVMS
    System Management Utilities Reference Manual.