Specification and implementation of computer network protocols

A reliable and effective computer network can only be achieved by adopting efficient and error-free communication protocols. Therefore, the protocol designer should produce an unambiguous specification meeting these requirements. Techniques for producing protocol specifications have been the subject of intense interest over the last few years. This is partly due to the advent of an international standard for networking. A variety of methods have been employed, some of which are described in detail in this thesis. [Continues.

Applying Formal Methods to Networking: Theory, Techniques and Applications

Despite its great importance, modern network infrastructure is remarkable for the lack of rigor in its engineering. The Internet which began as a research experiment was never designed to handle the users and applications it hosts today. The lack of formalization of the Internet architecture meant limited abstractions and modularity, especially for the control and management planes, thus requiring for every new need a new protocol built from scratch. This led to an unwieldy ossified Internet architecture resistant to any attempts at formal verification, and an Internet culture where expediency and pragmatism are favored over formal correctness. Fortunately, recent work in the space of clean slate Internet design---especially, the software defined networking (SDN) paradigm---offers the Internet community another chance to develop the right kind of architecture and abstractions. This has also led to a great resurgence in interest of applying formal methods to specification, verification, and synthesis of networking protocols and applications. In this paper, we present a self-contained tutorial of the formidable amount of work that has been done in formal methods, and present a survey of its applications to networking.Comment: 30 pages, submitted to IEEE Communications Surveys and Tutorial

Model Driven Communication Protocol Engineering and Simulation based Performance Analysis using UML 2.0

The automated functional and performance analysis of communication systems specified with some Formal Description Technique has long been the goal of telecommunication engineers. In the past SDL and Petri nets have been the most popular FDTs for the purpose. With the growth in popularity of UML the most obvious question to ask is whether one can translate one or more UML diagrams describing a system to a performance model. Until the advent of UML 2.0, that has been an impossible task since the semantics were not clear. Even though the UML semantics are still not clear for the purpose, with UML 2.0 now released and using ITU recommendation Z.109, we describe in this dissertation a methodology and tool called proSPEX (protocol Software Performance Engineering using XMI), for the design and performance analysis of communication protocols specified with UML. Our first consideration in the development of our methodology was to identify the roles of UML 2.0 diagrams in the performance modelling process. In addition, questions regarding the specification of non-functional duration contraints, or temporal aspects, were considered. We developed a semantic time model with which a lack of means of specifying communication delay and processing times in the language are addressed. Environmental characteristics such as channel bandwidth and buffer space can be specified and realistic assumptions are made regarding time and signal transfer. With proSPEX we aimed to integrate a commercial UML 2.0 model editing tool and a discrete-event simulation library. Such an approach has been advocated as being necessary in order to develop a closer integration of performance engineering with formal design and implementation methodologies. In order to realize the integration we firstly identified a suitable simulation library and then extended the library with features required to represent high-level SDL abstractions, such as extended finite state machines (EFSM) and signal addressing. In implementing proSPEX we filtered the XML output of our editor and used text templates for code generation. The filtering of the XML output and the need to extend our simulation library with EFSM abstractions was found to be significant implementation challenges. Lastly, in order to to illustrate the utility of proSPEX we conducted a performance analysis case-study in which the efficient short remote operations (ESRO) protocol is used in a wireless e-commerce scenario

A design model for Open Distributed Processing systems

This paper proposes design concepts that allow the conception, understanding and development of complex technical structures for open distributed systems. The proposed concepts are related to, and partially motivated by, the present work on Open Distributed Processing (ODP). As opposed to the current ODP approach, the concepts are aimed at supporting a design trajectory with several, related abstraction levels. Simple examples are used to illustrate the proposed concepts

Analytical performance evaluation of concurrent communicating systems using SLD and stochastic Petri nets

Bibliography: leaves 113-117.In this thesis, the performance analysis of SDL with a new type of stochastic Petri net is described. This new net is called SDL-net. The Concurrent Communicating System is described, and the need for qualitative and quantitative analysis of such systems is motivated. Formal methods are demonstrated which can be used to represent such Concurrent Communicating Systems. The Specification and Description Language (SDL) is shown in the context of Concurrent Communicating Systems and the software development cycle is described for SDL systems. Correctness and performance of SDL are discussed and it is shown how the semantics of time for performance can be introduced into SDL by adding external information, by extending the SDL syntax or by using compiler directives. In this thesis only external information is added

SPEAR II - The Security Protocol Engineering and Analysis Resource

Multi-dimensional security protocol engineering is effective in creating cryptographic protocols since it encompasses a variety of analysis techniques, thereby providing a higher security confidence than individual approaches. SPEAR, the Security Protocol Engineering and Analysis Resource, was a protocol engineering tool which focused on cryptographic protocols, with the specific aims of enabling secure and efficient protocol designs and support for the production process of implementing security protocols. The SPEAR II tool is a continuation of the highly successful SPEAR project and aims to build on the foundation laid by SPEAR. SPEAR II provides more advanced multidimensional support than SPEAR, enabling protocol specification via a graphical user interface, automated security analysis that applies a number of well-known analysis methods, performance reporting and evaluation, meta-execution and automated code generation

A graphical representation for the formal description technique Estelle

Includes bibliographical references.This dissertation concerns the specification and description of complex communicating systems using Formal Description Techniques. Specifically, we propose a standard graphical representation for the Formal Description Technique Estelle and present a prototype editor based on this representation. Together they integrate the new graphical representation with existing Estelle textual tools to create a powerful graphical design technique for Estelle. The perennial popularity of graphical techniques, combined with recent advances in computer graphics hardware and software which enable their effective application in a computing environment, provide a double impetus for the development of a graphical representation for Estelle. Most importantly, a graphical technique is more easily read and understood by humans, and can better describe the complex structure and inter-relationships of components of concurrent communicating systems. Modern graphical technology also presents a number of opportunities, separate from the specification method, such as hyperlinking, multiple windows and hiding of detail, which enrich the graphical technique. The prototype editor makes use of these opportunities to provide the protocol engineer with an advanced interface which actively supports the protocol design process to improve the quality of design. The editor also implements translations between the graphical representation and the standard Estelle textual representation, on the one hand allowing the graphical interpretation to be applied to existing textual specifications, and on the other, the application of existing text-based processing tools to a graphical specification description