The concept of Profiles for OSI, and the structure of the International Standardized Profiles that document them, are defined in ISO/IEC TR 10000-1. Such Profiles are divided into a number of different classes and sub-classes. Two of these classes contain sub-classes comprising functions of the Virtual Terminal Basic Class Service and Protocol specified in the base standards ISO 9040 and ISO 9041. These are the Application Profiles (A-Profiles) and the Interchange Format and Representation Profiles (F-Profiles).
The relationship between A-Profiles and F-Profiles is described in 7.3.2 of ISO/IEC TR 10000-1 and is as follows. Application Layer base standards require, implicitly or explicitly, the stru cture of information carried or referenced by them to be specified for each instance of communication. It is the purpose of F-Profiles to specify such information structures. Particular functional requirements may then be met by the combination of an A-Profile with one or more F-Profiles.
Establishment of a VT-association involves the selection by negotiation of a particular Virtual Terminal Environment profile (VTE-profile), and of particular values for any arguments of that VTE-profile. The VTE-profile specification, and possibly al so the values of certain VTE-profile arguments, may in turn reference the definitions of VT control object types and assignment types. These VTE-profiles, control object types and assignment types are therefore Information Objects that require explicit reference within the VT protocol.
Particular instances of these Information Objects are fully defined within the base standards, but the base standards also provide for further instances to be defined by registration. Each registered instance constitutes an F-Profile within the framewor k of ISO/IEC TR 10000.
The Virtual Terminal Basic Class Service and Protocol may be used to realize a wide range of distinct functions. Particular fun ctions may be realized through the selection of appropriate VT functional units, F-Profiles and other VTE-profile argument values. The specification of the selection required to realize a particu lar function and to promote interoperability constitutes a Virtual Terminal A-Profile within the framework of ISO/IEC TR 10000.
The three International Registers of VT information structures and the specifications of VT Application Profiles are each published as a separate multi-part ISP as follows:
- ISO/IEC ISP 11184 is the Register of VTE-profiles;
- ISO/IEC ISP 11185 is the Register of control object type definitions;
- ISO/IEC ISP 11186 is the Register of assignment-type definitions;
- ISO/IEC ISP 11187 contains the specifications of VT Application Profiles.
This part of ISO/IEC ISP 11187 is applicable to environments in which a terminal population requires access to application packages running on a variety of computers. It may be used where the connection between the terminal and the computer that hosts the application package is local, is made across a Local or Wide Area Network, or is made across a concatenation of such networks.
This part of ISO/IEC ISP 11187 contains the specification of the A-mode Generalized Telnet Application Profile. Virtual Terminal implementations that operate in accordance with this A-profile provide powerful general-purpose terminal capabilities which are suitable in particular for TELNET emulation. This A-profile specifies a mode of operation of, and a selection of options for use with, the A-mode Generalized Telnet VTE-profile FVT115. These are together designed to provide versatility and to promote interoperability between Virtual Terminal implementations which support that VTE-profile.
This part of ISO/IEC ISP 11187 also specifies a Profile ICS proforma for the A-mode Generalized Telnet Application Profile specified herein in compliance with the relevant requirements, and in accordance with the relevant guidance, given in ISO/IEC [DIS] 9646-7. The supplier of an implementation which is claimed to conform to ISO/IEC ISP 11187-5 is required to complete a copy of the Profile ICS proforma as specified in 5.2 and is required to provide the information necessary to identify both the supplier and the implementation.
1.2 Position within the Taxonomy
The taxonomy of International Standardized Profiles for OSI is laid down in ISO/IEC TR 10000-2. Within the classification scheme of this taxonomy, the OSI Profiles specified in this International Standardized Profile are in the Virtual Terminal sub-class of the class of Application Profiles.
A Profile within this subclass has a Profile identifier of the form AVTab, where ab is a structured numerical identifier that identifies the position of the Profile within two levels of subdivision of the subclass. The value of a is a single digit but b is an integer that is not necessarily a single digit.
In principle the ISO Virtual Terminal model allows for multiple classes of operation, although at the time of publication of this International Standardized Profile only the Basic Class has been defined. The value of the identifier component a distinguishes between the permitted modes of operation of the Virtu al Terminal Service as follows:
a = 1 for Basic Class A-mode (asynchronous mode);
a = 2 for Basic Class S-mode (synchronous mode).
Values greater than 2 are reserved for future developments.
ISO/IEC ISP 11187 contains the specifications of the Profiles wit h identifiers of the form AVT1b and AVT2b. The component b distinguishes between different Application Profiles that make use of the same mode of operation.
This part of ISO/IEC ISP 11187 contains the specification of the Application Profile with the Profile identifier:
AVT16 - A-mode Generalized Telnet Application Profile.