Definition of Terms

Definitions, notation, abbreviation and terminology used in this book are consistent with the terminology and principles established by ISO for Open Systems interconnection.

The OSI reference model is based on a number of 'abstract' descriptions. In our implementation model, these abstract descriptions are refined to define the precise context they take as they apply to this implementation architecture.

Facility

To evade the question of whether an operation is implemented as a function or a preprocessor macro, the word facility is used. What is of interest is the facility's interface description. Most of the facilities are described as if they were functions. But when efficiency justifies the equivalent may be implemented as macro. With this understanding, 'facility' and 'function' are used interchangeably.

Module

Typically a set of related facilities and data abstractions are combined into a module. The facility is typically realized by a link module (e.g. a library) and a declaration module. The correct way to use a facility is to have, at the beginning of the user program, a preprocessor #include command to include the relevant facility declarations.

Open C Environment

OCE is a set of architectural guide lines, conventions and a well defined platform interface that can ease portable implementation of OSI software.

Open C Platform

OCP is a collection of modules that provide the basic facilities expected by lower layers. The interface to these facilities is described in this book.

Open C Layer

An OCL is an implementation of an OSI layer that adheres to the architecture of Open C Environment.

Service Provider

A module responsible for providing some well defined set of services through a well defined set of interfaces.

Service User

A module that uses the services of a service provider.

Primitive

A facility expressing an interaction between a service user and a service provider.

Parameter

A facility argument to a primitive.

Primitive Action

A facility invocation into the service provider module. Primitive actions are provided in the service provider module and invoked by the service user. Primitive action is the collective name for requests and responses.

Primitive Event

A facility invocation outside of the service provider module. Typically in the service user module. Primitive events are provided in the service user module and invoked by the service provider. Primitive event is the collective name for indications and confirmations. The set of primitive events to be used are communicated to the service provider during the creation of the service access point.

Request

A primitive issued by the service user to express a request for a service from the service provider.

Indication

A primitive issued by the service provider to indicate that a request has been issued by the service user at the peer service access point or to communicate a local event to the service user.

Response

A primitive issued by the service user in response to some indication previously invoked by the service provider.

Confirm

A primitive issued by the service provider in response to some response previously issued by the service user.

Service Access Point

A service access point (SAP) is defined as the interface between a service user and a service provider. Each SAP is identified by the service provider through a SAP-Address-Selector.

Connection End Point

An (N) connection is an association established by the (N) layer between two or more (N+1) entities for the transfer of data. An (N) connection end point (CEP) is a terminator at one end of an (N) connection within an (N)-SAP. An (N) connection end point identifier (CEP-ID) is a unique representation of a CEP within the scope of the (N) service

sequence-of

Borrowed from ASN.1. sequence-of type: A structured type, defined by referencing a single existing type; each value in the new type is an ordered list of zero, one or more values of existing type.

set-of

Borrowed from ASN.1. set-of type: A structured type, defined by referencing a single existing type; each value in the new type is an unordered list of zero, one or more values of the existing type.