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Distributed Computing Systems, 1997., Proceedings of the Sixth IEEE Computer Society Workshop on Future Trends of

Date 31-31 Oct. 1997

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  • Proceedings of the Sixth IEEE Computer Society Workshop on Future Trends of Distributed Computing Systems

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    Freely Available from IEEE
  • Author index

    Page(s): 345 - 346
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    Freely Available from IEEE
  • Future trends in Internet security

    Page(s): 216 - 217
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    The Internet is, by far, one of the most significant achievements in recent history. When it was designed and started as Arpanet in the 1970s, the Internet was never intended to be secure or open for commercial use. In the 1980s, the Internet was structured to accommodate 43 billion potential network addresses. It afforded roughly one address for every person on earth. Yet today, with more than 50 million users on-line, the address space is getting short. The solution, yet to be implemented and deployed, is the Internet Protocol v6 (IPv6), or IP next generation IPng. IPv6 will offer better security and performance and will allow a wide range (up to 3×1038) of nodes. Nodes will include almost any device anyone can imagine; even sensors, doors, and cars will have IP addresses so they can be controlled from afar. The Internet seems to be the infrastructure for the global village but without security, not only e-commerce is in danger, but also human lives could be at stake. The paper discusses future trends in Internet security and government regulations View full abstract»

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  • Performance evaluation of scheduling algorithm in a real-time distributed transactional system

    Page(s): 290 - 295
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    In a real-time distributed transactional system, transactions which should be scheduled to be executed on different servers. To schedule these transactions the circulating multisequencer algorithm has been considered to obtain a global view of the system. A mathematical model is developed to obtain the average stay time of a transaction within the system, when no transaction misses its deadline. This model introduces the bulk arrival M/G/I station with K classes of customers, where bulks are considered according to FIFO discipline and customers (actions) are scheduled according to EDF within a group. The validity of the model has been proved by simulation View full abstract»

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  • Profiles and protocols for the Internet Public-Key Infrastructure

    Page(s): 220 - 224
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    The purpose of the paper is to discuss the ongoing standardization activities within the Internet community with respect to public key infrastructures based on the X.509 authentication framework. In particular, this paper describes the status of the Internet Public Key Infrastructure which is being addressed within the IETF PKIX working group. This paper introduces the concept of a PKI in general and specifically discusses the purpose and status of the following PKIX work areas: X.509 certificate and CRL profile; operational protocols; certificate management protocols; certificate policy and certification practices framework; time stamp protocols; and notrary protocols View full abstract»

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  • An efficient causal order algorithm for message delivery in distributed system

    Page(s): 270 - 275
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    Though causal order of message delivery simplifies the design and development of distributed applications, the overhead of enforcing it is not negligible. A causal order algorithm which does not send any redundant information is efficient in the sense of communication overhead. The authors characterize and classify redundant information into four categories: information regarding just delivered, already delivered, just replaced, and already replaced messages. They propose an efficient causal order algorithm which prevents propagation of this redundant information. Their algorithm sends less control information needed to ensure causal order than other existing algorithms. Since the algorithm's communication overhead increases relatively slowly as the number of processes increases, it shows good scalability. The potential of the algorithm is shown by simulation View full abstract»

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  • Scheduling for distributed computing

    Page(s): 284 - 289
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    A typical model for distributed computing is to have a main program thread that runs on one processor. This thread spawns a number of tasks from time-to-time. When tasks are spawned, they are sent to other processors for completion and the main thread waits till the results of all task are received from the remote processors. This is the typical fork join paradigm. This paradigm results in an interesting scheduling problem that is studied in the paper. Several heuristics are proposed for various variants of this scheduling problem View full abstract»

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  • A scheduling algorithm for aperiodic groups of tasks in distributed real-time systems and its holistic analysis

    Page(s): 296 - 301
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    The paper deals with the problem of scheduling aperiodic groups of tasks in distributed systems. It proposes two contributions, namely: (i) a distributed scheduling algorithm to be included, together with a set of aperiodic servers to deal with the processor utilisation and the network bandwidth local to the system nodes, in a distributed aperiodic server, and (ii) an extensive analysis of the behaviour of the proposed scheduling algorithm by applying an holistic approach. The sensitivity of the response time of the algorithm to the parameters involved is also studied View full abstract»

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  • Scalable security in an unimaginably large Internet

    Page(s): 225 - 226
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    The Internet is predicted to become unimaginably large in the coming decades. Not only will it grow in the number; but also in the diversity, of the connected devices. This paper briefly looks at how the security challenges presented by such growth differ from those of today, and some possible directions to meet those challenges View full abstract»

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  • A distributed simulation based monitoring

    Page(s): 72 - 77
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    MSS, a computer-based monitoring system with integrated cooperative objects is proposed. MSS uses an object-based framework to interface with the user to guide a specific system evolution. MSS espouses a blackboard architecture and runs according a cooperating objects model. To achieve monitoring tasks, MSS selects the appropriate technique(s) within a set of a high performance algorithms. From the user viewpoint, MSS has been developed as a control assistant featuring different levels of interactivity, a hierarchical design style and fully embedded algorithmic tools. Virtually, MSS is able to design a monitoring board for any dynamic system View full abstract»

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  • Replicating objects using the CORBA Event Service?

    Page(s): 14 - 19
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    The Common Object Request Broker Architecture (CORBA) is becoming a standard for distributed application middleware, but no support is currently provided to handle object replication. In this paper, we discuss the relevance of using the Object Management Group's Event Service for replicating objects in a CORBA environment and compare it to other approaches View full abstract»

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  • Available fail-safe systems

    Page(s): 176 - 182
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    Continuity of service and cost-effectiveness are adding new challenges to life critical systems over and above the underlying safety concerns. The introduction of redundant components is a necessary condition for increasing the overall system availability with respect to physical component failures. Here we consider redundancy by means of replicating fail-safe components in a distributed real-time system for railway applications. In such a system, some functions cannot tolerate even a brief service interruption. These functions have to be replicated using active redundancy, and their outputs must be consolidated with the goal that the failure of one component has no effect on the delivered service. We formally investigate conditions for preserving safety properties of fail-safe components when replicating them using active redundancy. We focus our analysis on duplex computers with two fail-safe units. Given some safety constraints, we show that inconsistency of replicated units can lead to safety degradation even if each replicated component (taken individually) satisfies the given safety constraints. Two solutions are studied: masking and detection of state or context inconsistency. The former leads to requirements on the output consolidation function and the latter to requirements on the redundancy management mechanisms View full abstract»

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  • A temporal model for fault-tolerant parallel programs

    Page(s): 304 - 309
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    The authors present the technical issues of a temporal model for fault-tolerant parallel programs. They present successively the formal aspects of this temporal model, and an algorithm that they have developed to detect errors in parallel programs running on a parallel architecture with shared memory. A simple example is given to illustrate the model and the algorithm View full abstract»

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  • Cooperative concurrency control on the Web

    Page(s): 118 - 123
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    Sharing of data in collaborative environments requires mechanisms that ensure the consistency of data in spite of concurrency and failures. This is traditionally handled by transactions or extended transaction mechanisms. The World Wide Web, although originally designed as an information storage and retrieval system, is being extended to serve as a vehicle for collaboration. However, the proposed extensions mainly address the basic issues such as file formats and up- and downloading of files. We are developing a configurable set of services for handling concurrency, recovery and collaboration that can be integrated into different system environments. We show an approach to use them for supporting cooperative work on the Web. In particular, the design and implementation of a cooperative concurrency control mechanism for the Web is presented View full abstract»

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  • Temporal firewalls in large distributed real-time systems

    Page(s): 310 - 315
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    The complexity of large distributed real-time systems can be reduced by partitioning the system into a set of almost autonomous subsystems that are connected by stable control-free interfaces called temporal firewalls. A temporal firewall provides an understandable abstraction of the subsystem behind the firewall, confines the impact of most changes to the encapsulated subsystem, and limits the potential of error propagation. The paper describes the stable properties of temporal firewalls and discusses where, in a large distributed real-time architecture, temporal firewalls should be placed. The final section investigates some possibilities of how to renegotiate the static properties of temporal firewalls in case the controlled object changes it behavior substantially View full abstract»

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  • Cryptographic key recovery

    Page(s): 34 - 37
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    Internet/intranet security has witnessed an explosive and exciting growth in the past two years. Under the surface of excitement lies a mine of technical and commercial challenges. Without solving these challenges, secure systems will not reach their expected potential. Security can be achieved via encryption. Encryption uses “keys” to encrypt and decrypt the information. Without having the cryptographic key, the enciphered information will never be converted into its original text. In case of key loss or damage or forgetting the key password, there should be a mechanism to recover the cryptographic keys and decipher the encrypted information. This paper describes a key recovery mechanism to facilitate the recovery of encryption keys and encrypted data. The mechanism does not require keys to be escrowed. It is based on adding an extra small field-the Key Recovery Entry (KRE)-to a message or file being transmitted. This mechanism facilitates key recovery both for session keys in symmetric cryptographic systems and private keys in asymmetric cryptographic systems without any need to escrow any key information. The author makes the differentiation between key escrow and key recovery View full abstract»

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  • Intrusion ripple analysis in distributed information systems

    Page(s): 28 - 33
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    Security is a very important aspect of distributed computing systems, especially in distributed information environments involving wide-area networks, such as internets. This paper addresses how a security breach, such as intrusion, propagates through a distributed or networked information system. In particular, the issue of how an intrusion, once it occurrs, propagates through a distributed system is addressed. Our approach has a strong resemblance to ripple effect analysis, which had been extensively studied in the area of software maintenance View full abstract»

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  • Entry consistency versus lazy release consistency in DSM systems: analytical comparison and a new hybrid solution

    Page(s): 78 - 83
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    Entry consistency (EC), implemented in Midway, and lazy release consistency (LRC), implemented in TreadMarks, are two promising relaxed memory consistency models which tend to minimize communication costs. This is an important goal of software-based distributed shared memory (DSM) solutions built on workstation networks. While Midway uses a fine-grain update-based coherence protocol, TreadMarks implements an invalidation-based protocol with virtual memory page as the granularity unit. Instead of transferring the whole page on a page fault, TreadMarks transfers diffs-lists of modifications to the page during a critical section. According to a previous comparative study of EC and LRC neither is unconditionally better than the other and the performance advantages depend highly on the application. This paper examines the performance/complexity trade-offs of EC and LRC, based on a model that includes storage overhead, as well as the communication and computation costs. A proposal for a new hybrid of LRC and EC is also presented View full abstract»

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  • Portable memory

    Page(s): 162 - 167
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    Migrating applications is necessary to provide fault tolerance in a distributed environment. In this paper, we present a new design that enables the heterogeneous migration of a general class of applications. Our approach can handle applications that use pointers. Our design is tailored for the C programming language, but can be adapted for other languages. We chose the C language because it is more difficult to handle than other languages, especially its pointer operations View full abstract»

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  • Distributed transaction processing as a reliability concept for mobile agents

    Page(s): 59 - 64
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    Mobile agents offer a new possibility for the development of applications in distributed systems and are no longer a theoretical issue since different architectures for their implementations have been proposed. With the increasing market of electronic commerce it becomes an interesting idea to use autonomous mobile agents for electronic business transactions. Being involved in money transactions, supplementary security features for mobile agent systems have to be ensured. We present an architecture for a mobile agent system which offers fault tolerance for the whole agent system at a high level. This architecture additionally guarantees security for the host as well as security for the agent. To handle these issues for mobile agents we use various encryption mechanisms and we apply a novel method for mobile agent systems by using distributed transactions in our architecture. Due to this security architecture an agent will be enabled to carry out money transactions View full abstract»

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  • Multi-criterion coherence protocol for distributed shared memory

    Page(s): 202 - 207
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    We present a coherence protocol, which supports three different consistency models of distributed shared data: sequential consistency, causal consistency and PRAM consistency. The protocol is dedicated to an asynchronous reliable distributed computing system. It allows one to update the replicas of variables in distributed shared memory according to consistency criteria which are attributes of write operations View full abstract»

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  • Consensus: the big misunderstanding [distributed fault tolerant systems]

    Page(s): 183 - 188
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    The paper aims at clarifying some misunderstandings about the consensus problem. These misunderstandings prevent consensus from being considered as it should be, i.e., a fundamental paradigm in the context of fault-tolerant distributed systems, not only from a theoretical point of view, but also from a practical point of view. Six frequent misunderstandings are discussed View full abstract»

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  • A software platform for secure applications based on CORBA

    Page(s): 22 - 27
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    Shows an architecture for providing security services in a CORBA-based environment. We design it to follow the CORBA security specification and implement a prototype using a commercial product. The platform provides common security mechanisms such as authentication and access control for CORBA-based applications. It also has the security context management function, which is responsible for protecting the message contents. Applications can be established using the secure service interfaces on this platform. Therefore, this architecture gives us a base to deploy secure applications. This platform supports many secure characteristics, which are described in the specification, and it also provides a connection to external security services. We can deploy it in the information infrastructure View full abstract»

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  • The universality of a class of (2log2N-1)-stage interconnection networks

    Page(s): 92 - 97
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    The performance of a highly-parallel multiprocessor system depends heavily on the efficiency of its interconnection network. We focus on an N×N, (2log2N-1)-stage interconnection network. A concatenated (2log2N-1)-stage interconnection network (denoted by (Δ⊕Δ')) is a combination of two, cube-type networks with the rightmost stage of Δ and the left most stage of Δ' overlapped. Despite the better performance, (2log2N-1)-stage networks have not been studied enough to explore all the important topological properties. We study the topological structure of (Δ⊕Δ') and then state, formulate and prove a very important property, the interstage correlation. Interstage correlation is the relationship between output line bits of the left network SEs and input line bits of the right network SEs in (Δ⊕Δ'). Interstage correlation can be used as the criteria of classification for (2log2N-1)-stage networks. Until now, research in this field was focused only on the class of Benes-equivalent networks. This class is just a small subset of a set of all possible interconnection networks. We formulate interstage correlation such that it can be used to classify many possible (2log2N-1)-stage networks and discuss their topological equivalence View full abstract»

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  • A solution to atomic commitment based on an extended consensus protocol

    Page(s): 98 - 103
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    Chandra and Toueg (1996) have proposed a new approach to overcome the impossibility of deterministically reaching consensus in asynchronous systems subject to crash failures. They augment the asynchronous model with unreliable failure detectors. We present an extension of an algorithm that they proposed to solve consensus using □S failure detectors. We argue that this extension is a simple and efficient building block which can be used to solve various agreement problems. We consider a particular agreement problem, namely the non-blocking atomic commitment problem and we show the advantages of our solution by comparing it to other classical approaches View full abstract»

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