Layered Protocols: IP Layers, interfaces, and protocols in the Internet model.
Purpose of Layered Models mask the heterogeneity of systems provide convenient programming abstraction
Layered Protocols: OSI TvS 2.2 Layers, interfaces, and protocols in the OSI model.
Middleware Protocols An adapted reference model for networked communication. TvS 2.6
Purpose of Middleware ‘Middleware is primarily a set of programming abstractions developed to facilitate the development of complex distributed systems.’ – Gustavo Alonso
Middleware provides… protocols to support general-purpose services to more specific applications, e.g. authentication protocols authorization protocols distributed commit protocols distributed locking protocols high-level communication protocols ^remote procedure calls (RPC) ^remote method invocation (RMI)
Middleware 1-22 TvS 1.24 General structure of a distributed system as middleware.
Middleware and Openness In an open middleware-based distributed system, the protocols used by each middleware layer should be the same, as well as the interfaces they offer to applications. 1.23 TvS 1.25
Sources: Middleware Adapted from Introduction to Distributed Systems: Slides for CSCI 3171 Lectures by E. W. Grundke References: [TvS] A. Tanenbaum and M. van Steen Distributed Systems: Principles and Paradigms, Prentice-Hall (2002) http://www.prenhall.com/divisions/esm/app/author_tanenbaum/custom/dist_sys_1e/ [CDK] G. Coulouris, J. Dollimore and T. Kindberg Distributed System: Concepts and Design, Addison-Wesley (2001) http://www.cdk3.net/ig/beida/ [ISO] International Organization for Standardization/ International Electrotechnical Commission Standard ISO/IEC 7498-1: Information Technology — Open Systems Interconnection — Basic Reference Model: The Basic Model (Second ed., corrected and reprinted 1996-06-15) Reference number ISO/IEC 7498-1:1994(E) http://standards.iso.org/ittf/PubliclyAvailableStandards/s020269_ISO_IEC_7498- 1_1994(E).zip
Sources: Web Services Gustavo Alonso, Fabio Casati, and Harumi Kuno. Web Services: Concepts Architectures and Applications (Springer-Verlag, 2004) Slides from.http://www.inf.ethz.ch/~alonso/WebServicesBook Gustavo Alonso and Cesare Pautasso. Graduate course given at the University of Lappeenranta,Finland. August 9–13, 2004. http://www.inf.ethz.ch/personal/alonso/Web-book/Lappeenranta-graduate-course.zip