Many applications distributed over networked computers share common needs. In this chapter we identify four of these, discuss why these needs arise and what facilities are needed to address them, and introduce standard services and protocols designed to meet these requirements.
The issues we introduce in this chapter are the need to establish a context for communication between separated processes, the need to execute instructions on a remote system, the need for reliable transfer of large data volumes, and the need to coordinate components of a distributed application to avoid inconsistencies of state in shared data.
Each section of this chapter begins by considering a problem inherent in distributed application development. Description of the oOSI service and protocol designed to address the problem follows. Tables of parameters for service primitives of these OSI common service elements appear in a separate section at the end of the chapter. This placement provides easy access to them as needed throughout the chapter and convenient reference for later use.