Default: {}                  Values: Set of osi or nsp

    Note: On the DECnet/OSI for Digital UNIX V1.0
          products the default was tp4 rather than osi.

    This command sets the order in which transports are selected when
    establishing a connection. The default order is to try OSI, then
    NSP. The command takes a set as input. Valid items in the set are
    SESSION CONTROL TRANSPORT SERVICE entity names.

    Examples:

    set session control -
      transport precedence {}  ! By default OSI is preferred over NSP.

    set session control -
      transport precedence {nsp,osi} ! Prefers NSP over OSI.