A large number of errors in digital systems are due to the presence of transient faults. This is especially true of microprocessor-based systems working in a radiation environment that experience transient faults due to single event upsets. These upsets cause a temporary change in the state of the system without any permanent damage. Because of their random and non-recurring nature, transient faults are difficult to detect and isolate, hence they become a source of major concern, especially in critical real-time application areas. Concurrent detection of these errors is necessary for real-time operation. Most existing fault tolerance schemes either use redundancy to mask effects of transient faults or monitor the system for abnormal operations and then perform recovery operation. Although very effective, redundancy schemes incur substantial overhead that makes them unsuitable for small systems. Most monitoring schemes, on the other hand, only detect control flow errors. A new approach called Concurrent Processor Monitoring for on-line detection of transient faults is proposed that attempts to achieve high error coverage with small error detection latency. The concept of the execution profile of an instruction is defined and is used for detecting control flow and execution errors. To implement this scheme, a watchdog processor is designed for monitoring operation of the main processor. The effectiveness of this technique is demonstrated through computer simulations. / Ph. D.

"Distributed systems are clusters of computers working together on one task. The sharing of information across different architectures, and the timely and efficient use of the network resources for communication among computers are some of the problems involved in the implementation of a distributed system. In the case of a low latency system, the network utilization and the responsiveness of the communication mechanism are even more critical. This thesis introduces a new approach for the distribution of messages to computers in the system, in which, the Common Object Request Broker Architecture (CORBA) is used in conjunction with IP multicast to implement a fault-tolerant, low latency distributed system. Fault tolerance is achieved by replication of the current state of the system across several hosts. An update of the current state is initiated by a client application that contacts one of the state object replicas. The new information needs to be distributed to all the members of the distributed system (the object replicas). This state update is accomplished by using a two-phase commit protocol, which is implemented using a binary tree structure along with IP multicast to reduce the amount of network utilization, distribute the computation load associated with state propagation, and to achieve faster communication among the members of the distributed system. The use of IP multicast enhances the speed of message distribution, while the two-phase commit protocol encapsulates IP multicast to produce a reliable multicast service that is suitable for fault tolerant, distributed low latency applications. The binary tree structure, finally, is essential for the load sharing of the state commit response collection processing. "

Intrusion Detection & Countermeasure Systems (IDCS) and architectures commonly used in commercial, as well as research environments, suffer from a number of problems that limit their effectiveness. The most common shortcoming of current IDCSs is their inability to tolerate failures. These failures can occur naturally, such as hardware or software failures, or can be the result of attackers attempting to compromise the IDCS itself. Currently, the WPI System Security Laboratory at Worcester Polytechnic Institute is developing a Secure Architecture and Fault-Resilient Engine (S.A.F.E.), a system capable of tolerating failures. This system makes use of solutions to the Byzantine General's Problem, developed earlier by Lamport and others. Byzantine Agreement Protocols will be used to achieve consensus about which nodes have been compromised or failed, with a series of synchronized, secure rounds of message exchanges. Once a consensus has been reached, the offending nodes can be isolated and countermeasure actions can be initiated by the system. We consider the necessary and sufficient conditions for the application of Byzantine Agreement Protocols to the intrusion detection problem. Further, a first implementation of this algorithm will be embedded in the Distributed Trust Manager (DTM) module of S.A.F.E. The DTM is the key module responsible for assuring trust amongst the members of the system. Finally, we will evaluate the DTM, as a standalone unit, to ensure that it performs correctly.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND AERO / Bibliography: leaves B1-B6. / by Michael Roy Mantz. / M.S.

by Patrick Lam Sze Fan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1997. / Includes bibliographical references (leaves 163-[170]). / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- Fault-tolerant CUM LAUDE NET --- p.7 / Chapter 2.1 --- Overview of CUM LAUDE NET --- p.7 / Chapter 2.2 --- Network architecture of CUM LAUDE NET --- p.8 / Chapter 2.3 --- Design of Router-node --- p.10 / Chapter 2.3.1 --- Architecture of the Router-node --- p.10 / Chapter 2.3.2 --- Buffers Arrangement of the Router-node --- p.12 / Chapter 2.3.3 --- Buffer transmission policies --- p.13 / Chapter 2.4 --- Protocols of CUM LAUDE NET --- p.14 / Chapter 2.5 --- Frame Format of CUM LAUDE NET --- p.15 / Chapter 2.6 --- Fault-tolerant (FT) and Auto-healing (AH) algorithms --- p.16 / Chapter 2.6.1 --- Overview of the algorithms --- p.16 / Chapter 2.6.2 --- Network Failure Scenarios --- p.18 / Chapter 2.6.3 --- Design and Implementation of the Fault Tolerant Algorithm --- p.19 / Chapter 2.6.4 --- Design and Implementation of the Auto Healing Algorithm --- p.26 / Chapter 2.6.5 --- Network Management Signals and Restoration Times --- p.27 / Chapter 2.6.6 --- Comparison of fault-tolerance features of other networks with the CUM LAUDE NET --- p.31 / Chapter 2.7 --- Chapter Summary --- p.31 / Chapter 3 --- Overview of the Asynchronous Transfer Mode (ATM) --- p.33 / Chapter 3.1 --- Introduction --- p.33 / Chapter 3.2 --- ATM Network Interfaces --- p.34 / Chapter 3.3 --- ATM Virtual Connections --- p.35 / Chapter 3.4 --- ATM Cell Format --- p.36 / Chapter 3.5 --- ATM Address Formats --- p.36 / Chapter 3.6 --- ATM Protocol Reference Model --- p.38 / Chapter 3.6.1 --- The ATM Layer --- p.39 / Chapter 3.6.2 --- The ATM Adaptation Layer --- p.39 / Chapter 3.7 --- ATM Signalling --- p.44 / Chapter 3.7.1 --- ATM Signalling Messages and Call Setup Procedures --- p.45 / Chapter 3.8 --- Interim Local Management Interface (ILMI) --- p.47 / Chapter 4 --- Issues of Connectionless Gateway --- p.49 / Chapter 4.1 --- Introduction --- p.49 / Chapter 4.2 --- The Issues --- p.50 / Chapter 4.3 --- ATM Internetworking --- p.51 / Chapter 4.3.1 --- LAN Emulation --- p.52 / Chapter 4.3.2 --- IP over ATM --- p.53 / Chapter 4.3.3 --- Comparing IP over ATM and LAN Emulation --- p.59 / Chapter 4.4 --- Connection Management --- p.61 / Chapter 4.4.1 --- The Indirect Approach --- p.62 / Chapter 4.4.2 --- The Direct Approach --- p.63 / Chapter 4.4.3 --- Comparing the two approaches --- p.64 / Chapter 4.5 --- Protocol Conversion --- p.65 / Chapter 4.5.1 --- Selection of Protocol Converter --- p.68 / Chapter 4.6 --- Packet Forwarding Modes --- p.68 / Chapter 4.7 --- Bandwidth Assignment --- p.70 / Chapter 4.7.1 --- Bandwidth Reservation --- p.71 / Chapter 4.7.2 --- Fast Bandwidth Reservation --- p.72 / Chapter 4.7.3 --- Bandwidth Advertising --- p.72 / Chapter 4.7.4 --- Bandwidth Advertising with Cell Drop Detection --- p.73 / Chapter 4.7.5 --- Bandwidth Allocation on Source Demand --- p.73 / Chapter 4.7.6 --- The Common Problems --- p.74 / Chapter 5 --- Design and Implementation of the Connectionless Gateway --- p.77 / Chapter 5.1 --- Introduction --- p.77 / Chapter 5.1.1 --- Functions Definition of Connectionless Gateway --- p.79 / Chapter 5.2 --- Hardware Architecture of the Connectionless Gateway --- p.79 / Chapter 5.2.1 --- Imposed Limitations --- p.82 / Chapter 5.3 --- Software Architecture of the Connectionless Gateway --- p.83 / Chapter 5.3.1 --- TCP/IP Internals --- p.84 / Chapter 5.3.2 --- ATM on Linux --- p.85 / Chapter 5.4 --- Network Architecture --- p.88 / Chapter 5.4.1 --- IP Addresses Assignment --- p.90 / Chapter 5.5 --- Internal Structure of Connectionless Gateway --- p.90 / Chapter 5.5.1 --- Protocol Stacks of the Gateway --- p.90 / Chapter 5.5.2 --- Gateway Operation by Example --- p.93 / Chapter 5.5.3 --- Routing Table Maintenance --- p.97 / Chapter 5.6 --- Additional Features --- p.105 / Chapter 5.6.1 --- Priority Output Queues System --- p.105 / Chapter 5.6.2 --- Gateway Performance Monitor --- p.112 / Chapter 5.7 --- Setup an Operational ATM LAN --- p.117 / Chapter 5.7.1 --- SVC Connections --- p.117 / Chapter 5.7.2 --- PVC Connections --- p.119 / Chapter 5.8 --- Application of the Connectionless Gateway --- p.120 / Chapter 6 --- Performance Measurement of the Connectionless Gateway --- p.121 / Chapter 6.1 --- Introduction --- p.121 / Chapter 6.2 --- Experimental Setup --- p.121 / Chapter 6.3 --- Measurement Tools of the Experiments --- p.123 / Chapter 6.4 --- Descriptions of the Experiments --- p.124 / Chapter 6.4.1 --- Log Files --- p.125 / Chapter 6.5 --- UDP Control Rate Test --- p.126 / Chapter 6.5.1 --- Results and analysis of the UDP Control Rate Test --- p.127 / Chapter 6.6 --- UDP Maximum Rate Test --- p.138 / Chapter 6.6.1 --- Results and analysis of the UDP Maximum Rate Test --- p.138 / Chapter 6.7 --- TCP Maximum Rate Test --- p.140 / Chapter 6.7.1 --- Results and analysis of the TCP Maximum Rate Test --- p.140 / Chapter 6.8 --- Request/Response Test --- p.144 / Chapter 6.8.1 --- Results and analysis of the Request/Response Test --- p.144 / Chapter 6.9 --- Priority Queue System Verification Test --- p.149 / Chapter 6.9.1 --- Results and analysis of the Priority Queue System Verifi- cation Test --- p.150 / Chapter 6.10 --- Other Observations --- p.153 / Chapter 6.11 --- Solutions to Improve the Performance --- p.154 / Chapter 6.12 --- Future Development --- p.157 / Chapter 7 --- Conclusion --- p.158 / Bibliography --- p.163 / A List of Publications --- p.171

by Arion Ko Kin Wa. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1997. / Includes bibliographical references (leaves 101-[106]). / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Overview --- p.1 / Chapter 1.2 --- Service Survivability Planning --- p.2 / Chapter 1.3 --- Categories of Outages --- p.3 / Chapter 1.4 --- Goals of Restoration --- p.4 / Chapter 1.5 --- Technology Impacts on Network Survivability --- p.5 / Chapter 1.6 --- Performance Models and Measures in Quantifying Network Sur- vivability --- p.6 / Chapter 1.7 --- Organization of Thesis --- p.6 / Chapter 2 --- Design and Implementation of A Survivable High-Speed Mul- timedia Network --- p.8 / Chapter 2.1 --- An Overview of CUM LAUDE NET --- p.8 / Chapter 2.2 --- The Network Architecture --- p.9 / Chapter 2.2.1 --- Architectural Overview --- p.9 / Chapter 2.2.2 --- Router-Node Design --- p.11 / Chapter 2.2.3 --- Buffer Allocation --- p.12 / Chapter 2.2.4 --- Buffer Transmission Priority --- p.14 / Chapter 2.2.5 --- Congestion Control --- p.15 / Chapter 2.3 --- Protocols --- p.16 / Chapter 2.3.1 --- Design Overview --- p.16 / Chapter 2.3.2 --- ACTA - The MAC Protocol --- p.17 / Chapter 2.3.3 --- Protocol Layering --- p.18 / Chapter 2.3.4 --- "Segment, Datagram and Packet Format" --- p.20 / Chapter 2.3.5 --- Fast Packet Routing --- p.22 / Chapter 2.3.6 --- Local Host NIU --- p.24 / Chapter 2.4 --- The Network Restoration Strategy --- p.25 / Chapter 2.4.1 --- The Dual-Ring Model and Assumptions --- p.26 / Chapter 2.4.2 --- Scenarios of Network Failure and Remedies --- p.26 / Chapter 2.4.3 --- Distributed Fault-Tolerant Algorithm --- p.26 / Chapter 2.4.4 --- Distributed Auto-Healing Algorithm --- p.28 / Chapter 2.4.5 --- The Network Management Signals --- p.31 / Chapter 2.5 --- Performance Evaluation --- p.32 / Chapter 2.5.1 --- Restoration Time --- p.32 / Chapter 2.5.2 --- Reliability Measures --- p.34 / Chapter 2.5.3 --- Network Availability During Restoration --- p.41 / Chapter 2.6 --- The Prototype --- p.42 / Chapter 2.7 --- Technical Problems Encountered --- p.45 / Chapter 2.8 --- Chapter Summary and Future Development --- p.46 / Chapter 3 --- A Simple Experimental Network Management Software - NET- MAN --- p.48 / Chapter 3.1 --- Introduction to NETMAN --- p.48 / Chapter 3.2 --- Network Management Basics --- p.49 / Chapter 3.2.1 --- The Level of Management Protocols --- p.49 / Chapter 3.2.2 --- Architecture Model --- p.51 / Chapter 3.2.3 --- TCP/IP Network Management Protocol Architecture --- p.53 / Chapter 3.2.4 --- A Standard Network Management Protocol On Internet - SNMP --- p.54 / Chapter 3.2.5 --- A Standard For Managed Information --- p.55 / Chapter 3.3 --- The CUM LAUDE Network Management Protocol Suite (CNMPS) --- p.56 / Chapter 3.3.1 --- The Architecture --- p.53 / Chapter 3.3.2 --- Goals of the CNMPS --- p.59 / Chapter 3.4 --- Highlights of NETMAN --- p.61 / Chapter 3.5 --- Functional Descriptions of NETMAN --- p.63 / Chapter 3.5.1 --- Topology Menu --- p.64 / Chapter 3.5.2 --- Fault Manager Menu --- p.65 / Chapter 3.5.3 --- Performance Meter Menu --- p.65 / Chapter 3.5.4 --- Gateway Utility Menu --- p.67 / Chapter 3.5.5 --- Tools Menu --- p.67 / Chapter 3.5.6 --- Help Menu --- p.68 / Chapter 3.6 --- Chapter Summary --- p.68 / Chapter 4 --- A Local Map Based (LMB) Self-Healing Scheme for Arbitrary Topology Networks --- p.70 / Chapter 4.1 --- Introduction --- p.79 / Chapter 4.2 --- An Overview of Existing DCS-Based Restoration Algorithms --- p.72 / Chapter 4.3 --- The Network Model and Assumptions --- p.74 / Chapter 4.4 --- Basics of the LMB Scheme --- p.75 / Chapter 4.4.1 --- Restoration Concepts --- p.75 / Chapter 4.4.2 --- Terminology --- p.76 / Chapter 4.4.3 --- Algorithm Parameters --- p.77 / Chapter 4.5 --- Performance Assessments --- p.78 / Chapter 4.6 --- The LMB Network Restoration Scheme --- p.80 / Chapter 4.6.1 --- Initialization - Local Map Building --- p.80 / Chapter 4.6.2 --- The LMB Restoration Messages Set --- p.81 / Chapter 4.6.3 --- Phase I - Local Map Update Phase --- p.81 / Chapter 4.6.4 --- Phase II - Update Acknowledgment Phase --- p.82 / Chapter 4.6.5 --- Phase III - Restoration and Confirmation Phase --- p.83 / Chapter 4.6.6 --- Phase IV - Cancellation Phase --- p.83 / Chapter 4.6.7 --- Re-Initialization --- p.84 / Chapter 4.6.8 --- Path Route Monitoring --- p.84 / Chapter 4.7 --- Performance Evaluation --- p.84 / Chapter 4.7.1 --- The Testbeds --- p.84 / Chapter 4.7.2 --- Simulation Results --- p.86 / Chapter 4.7.3 --- Storage Requirements --- p.89 / Chapter 4.8 --- The LMB Scheme on ATM and SONET environment --- p.92 / Chapter 4.9 --- Future Work --- p.94 / Chapter 4.10 --- Chapter Summary --- p.94 / Chapter 5 --- Conclusion and Future Work --- p.96 / Chapter 5.1 --- Conclusion --- p.95 / Chapter 5.2 --- Future Work --- p.99 / Bibliography --- p.101 / Chapter A --- Derivation of Communicative Probability --- p.107 / Chapter B --- List of Publications --- p.110

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND AERONAUTICS. / Bibliography: p. 235-239. / by Jere Schenck Meserole, Jr. / Ph.D.

[No Abstract]

Thesis (M.Phil.)--City University of Hong Kong, 2006. / "Submitted to Department of Electronic Engineering in partial fulfillment of the requirements for the degree of Master of Philosophy" Includes bibliographical references (leaves 88-92)

Thesis (Ph. D.)--University of Oregon, 2001. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 124-127). Also available for download via the World Wide Web; free to University of Oregon users.