This thesis discusses the problems of the conventional ISO 9646 methodology for OSI conformance testing, and proposes a new methodology based on trace analysis. In the proposed methodology, a trace analyzer is used to determine whether the observed behavior of the implementation under test is valid or invalid. This simplifies test cases dramatically, since they now need only specify the expected behavior of the IUT; unexpected behavior is checked by the trace analyzer. Test suites become correspondingly smaller. Because of this reduction in size and complexity, errors in test suites can be found and corrected far more easily. As a result, the reliability and the usefulness of the conformance testing process are greatly enhanced. In order to apply the proposed methodology, trace analyzers are needed. Existing trace analyzers are examined, and found to be unsuitable for OSI conformance testing. A family of new trace analysis algorithms is presented and proved. To verify the feasibility of the proposed methodology, and to demonstrate its benefits, it is applied to a particular protocol, the LAPB protocol specified by ISO 7776. The design and implementation of a trace analyzer for LAPB are described. The conventional ISO 8882-2 test suite for LAPB, when rewritten to specify only the expected behavior of the IUT, is found to be more than an order of magnitude smaller. / Science, Faculty of / Computer Science, Department of / Graduate

This thesis addresses two major issues in protocol conformance testing: test sequence generation and test result analysis. For test sequence generation, a new approach based on the constraint satisfaction problem (CSP) techniques, which is widely used in the AI community, is presented. This method constructs a unique test sequence for a given FSM by using an initial test sequence, such as a transition tour or an UIO test sequence, and incrementally generating a set of test subsequences which together represent the constraints imposed on the overall structure of the FSM. The new method not only generates test sequence with fault coverage which is at least as good as the one provided by the existing methods, but also allows the implementation under test (IUT) to have a larger number of states than that in the specification. In addition, the new method also lends itself naturally to both test result analysis and fault coverage measurement. For test result analysis, the CSP method uses the observed sequence as the initial sequence, constructs all fault models which satisfy the initial sequence and introduces additional subsequences to pinpoint the IUT fault model. In addition, a second method for test result analysis is proposed, which is originated from a model of diagnostic reasoning from first principle, another well-known AI techniques which produces all minimal diagnoses by considering the overall consistency of the system together with the observation. Unlike the first method, the second method does not require the computation of all fault models explicitly, and hence is considered to be more suitable for large systems. To our knowledge, the proposed methods in this thesis represent the first attempt in applying AI techniques to the problem of protocol test sequence generation and analysis. / Science, Faculty of / Computer Science, Department of / Graduate

The Open Systems Interconnection Passive Monitor (OSI-PM), which is based on the principles of the OSI-Reference Model (OSI-RM), provides a framework for the development of multi-layer passive monitoring and testing. It adopts the same seven-layer architecture of the OSI-RM and provides the capability of selectively displaying, capturing, and analyzing the protocol events on single or multiple connections for any subset or all of the seven layers. Different from conventional monitors, the OSI-PM is able to detect protocol violation as they occur in addition to the monitoring functions. The current OSI-PM is able to monitor and test up to the transport layer of the OSI-RM. This thesis discusses the design, prototype implementation and testing of the OSI-PM. / Science, Faculty of / Computer Science, Department of / Graduate

As communications protocols are becoming more complex and sophisticated, developing a test system that has the ability to provide a controlled environment for comprehensive protocol testing is essential to achieve a "real open system". This thesis advocates the need for a multi-party test method as currently identified by ISO, and discusses two important aspects of protocol testing: Conformance and Interoperability. They are complementary to each other and are necessary to ensure the conformity and interoperability of a protocol implementation. The proposed ferry clip based test architecture is presented. Both the concepts and design principles employed to achieve a flexible and generalized test system and the specific components which comprise the Ferry Clip based Test System are described. The test system is general and flexible not only with respect to the test configurations and test methods but also with respect to the protocol to be tested, the system under test, and the underlying communication system. Applications of the ferry clip approach to multi-party conformance and interoperability testing are discussed, followed by an example of MHS conformance testing which demonstrates the applicability of the ferry clip approach to multi-party testing. / Science, Faculty of / Computer Science, Department of / Graduate

No description available.

Among the plethora of solutions to the Business-to-Business interoperability problem, no other solution has obtained as much attention asWeb Services Technology (WST), which allows entities to exchange data regardless of their underlying platforms. WST also allows services to be composed in order to provide high quality customer service over the web. In order to perform transactions across different service providers, standard protocols need to be supported by participating providers. Many useful protocols are coming into the market, but are often ambiguously specified by protocol designers and not fully verified. Furthermore, even if the specifications are reasonably clear, programmers often make subtle assumptions, possibly leading to errors that are hard to detect and locate, especially when the number of participating entities is dynamic. Consequently, these can lead to interoperability problems among implementations of the same protocol and high software maintenance costs. To address these issues, a hierarchical automata-based framework is proposed to model the functional aspects of Web Services (WS) protocols that also assists in verifying their correctness. The modelling formalism has a sound mathematical foundation and aims to reconcile desirable features while still maintaining syntactic and semantic simplicity. The properties to be verified are specified using a pattern system and/or 'observer' states, which have been adapted for WS protocols. In particular, always in a positive observer state implies proper termination and partial functional correctness while reachability of a negative observer state signifies deadlock and/or violation of a safety property. Verification itself is handled by automatic translation of the model and its properties into a model-checker's input code and interpretation of the output produced by the model-checker. A test-bed is proposed to check the conformance of a protocol implementation to its specification It helps in locating errors in the implementations of WS protocols especially where the number of participating entities is dynamic. Conformance checking is achieved by capturing sequences of exchanged messages of the actual implementations and checking them against the formal specification. Experience using the framework is also described and illustrated using two non-trivial WS protocols, namely WS-BusinessActivity and WS-AtomicTransaction.

Among the plethora of solutions to the Business-to-Business interoperability problem, no other solution has obtained as much attention asWeb Services Technology (WST), which allows entities to exchange data regardless of their underlying platforms. WST also allows services to be composed in order to provide high quality customer service over the web. In order to perform transactions across different service providers, standard protocols need to be supported by participating providers. Many useful protocols are coming into the market, but are often ambiguously specified by protocol designers and not fully verified. Furthermore, even if the specifications are reasonably clear, programmers often make subtle assumptions, possibly leading to errors that are hard to detect and locate, especially when the number of participating entities is dynamic. Consequently, these can lead to interoperability problems among implementations of the same protocol and high software maintenance costs. To address these issues, a hierarchical automata-based framework is proposed to model the functional aspects of Web Services (WS) protocols that also assists in verifying their correctness. The modelling formalism has a sound mathematical foundation and aims to reconcile desirable features while still maintaining syntactic and semantic simplicity. The properties to be verified are specified using a pattern system and/or 'observer' states, which have been adapted for WS protocols. In particular, always in a positive observer state implies proper termination and partial functional correctness while reachability of a negative observer state signifies deadlock and/or violation of a safety property. Verification itself is handled by automatic translation of the model and its properties into a model-checker's input code and interpretation of the output produced by the model-checker. A test-bed is proposed to check the conformance of a protocol implementation to its specification It helps in locating errors in the implementations of WS protocols especially where the number of participating entities is dynamic. Conformance checking is achieved by capturing sequences of exchanged messages of the actual implementations and checking them against the formal specification. Experience using the framework is also described and illustrated using two non-trivial WS protocols, namely WS-BusinessActivity and WS-AtomicTransaction.

Business transactions (a.k.a., business conversations) are series of message exchanges that occur between software applications coordinating to achieve a business objective. Web service has been proven to be a promising technology in supporting business transactions. Business transaction can either be long-running or short-lived. A transaction whether in a database or web service paradigm consists of an “all-or-nothing” property. A transaction could either succeed or fail. Web Service Atomic Transactions (WS-AT) is a specification that currently supports Two-Phase Commit (2PC) protocol in a short-lived transaction. WS-AT is developed by OASIS–a standards development organization. However, not all business process scenarios require a 2PC, in that case, just a One-Phase Commit (1PC) would be sufficient. But unfortunately, WS-AT currently does not support 1PC optimization. The ideal scenario where 1PC can be used instead of 2PC is when there is only a single participant. Short-lived transactions involving only one participant can commit without requiring initial “prepare” phase. Thus, there is no overhead to check whether the participant is prepared to either commit or rollback. This research focuses on designing a mechanism that can add 1PC support in WS-AT. The technical implementation of this mechanism is developed by using JBoss Transaction API. As a part of this thesis, 1PC mechanism for a single participant scenario was implemented. This mechanism optimizes the web service transaction process in terms of overhead and performance in terms of execution time. The technical implementation solution for 1PC mechanism was evaluated using three different business process scenarios in a controlled experiment as a presence or absence test. Evaluation results show that 1PC mechanism has a lower mean for execution time and performed significantly better than 2PC mechanism. Based on the contributions made by this thesis, we recommend OASIS to consider including 1PC mechanism as a part of the WS-AT specification.