bluuebunny/crossref_metadata_2025_split huggingface dataset:
An analysis of Memnet—an experiment in high-speed shared-memory local networking
Authors: Delp G. , Sethi A. , Farber D. 
Published: October 2004

Memnet is a shared-memory local area network under development at the University of Delaware that provides close coupling to the processors of a physically distributed multiprocessor system. The Memnet local network appears as memory in the physical address space of each processor (host) on the network.
This paper describes an analysis of the Memnet system performed to predict the possible performance levels attainable by a Memnet system. One objective of this analysis is to provide analytic results demonstrating the intrinsic soundness of the Memnet architecture. This is in support of the intuitive arguments of the shared-memory network model over the I/O modeled local network schemes. Another function of this analysis has been to provide design feedback for the choice of values for parameters such as page size.
The analysis results indicate that the Memnet approach to networking should significantly speed communication compared to alternative networking schemes.
Due to space limitations, the details of the analysis have not been included. The full text is available as TR-88-6-1 from: Department of Electrical Engineering, University of Delaware, Newark DE, 19716.
A multicast transport protocol
Authors: Crowcroft J. , Paliwoda K. 
Published: October 2004

This paper presents the design of a reliable multicast transport protocol. The aim of the protocol is to provide a service equivalent to a sequence of reliable sequential unicasts between a client and a number of servers, whilst using the broadcast nature of some networks to reduce both the number of packets transmitted and the overall time needed to collect replies.
The service interface of the protocol offers several types of service, ranging from the collection of a single reply from any one of a set of servers to the collection of all replies from all known servers. The messages may be of effectively arbitrary size, and the number of servers may be quite large. To support this service over real networks, special flow control mechanisms are used to avoid multiple replies overrunning the client. Reliable delivery is ensured using timeouts and a distributed acknowledgement scheme. The protocol is implemented over a network layer which support multicast destination addressing and packet delivery. The behaviour of the protocol over both LANs and LANs interconnected by WAN lines is discussed. We also include some notions for possible future support from network interface hardware.
A high performance broadcast file transfer protocol
Authors: Daka J. S. J. , Waters A. J. 
Published: October 2004

This paper describes a broadcast bulk file transfer protocol and presents its performance characteristics. The protocol is for bulk file distribution over a single satellite channel. The transmitting site and multiple receiver sites share channel access time to send data and acknowledgements.
The protocol performance characteristics are investigated using a simulation model that includes modelling of the uplink and downlink error processes at both the transmitter and receivers. The results obtained show that this protocol offers efficient reliable bulk file transfer to multiple receivers using a single satellite channel.
Researches in network development of JUNET
Authors: Murai J. , Kato A. 
Published: October 2004

JUNET was developed in order to provide a testing environment for studies of computer networking and distributed processing by connecting a large number of computers and by providing actual services for the users. Research interests in development of the network have been focused on resource name managing, Japanese character handling and communication technologies.
For the name managements, the hierarchical domain concept is employed to construct a name space for the network, and a mechanism for text message exchange is implemented using the concept. An environment for text message exchange using Japanese characters is achieved as results of general discussions to handle 16-bit Kanji codes in computers. Efficient data transmissions with the high speed modems are achieved by a new UUCP protocol and the dial-up IP link mechanism developed with a tty driver which provides host-to-modem flow control mechanism.
As the result of researches described above, JUNET currently connects various types of organizations relating computer science which are 87 organizations with more than 250 computers in number. It connects universities and major research laboratories in Japan, and the protocols currently used are TCP/IP over leased lines as well as dial-up lines, and UUCP over dial-up lines. The services such as electronic mail and network news have been provided since the network was started, and special technologies for Japanese character handling, name servers, and multimedia mail supports have been developed.
In this paper, the current status of JUNET and its research results in development of the network are described.
A verified connection management protocol for the transport layer
Authors: Murphy S. L. , Shankar A. U. 
Published: October 2004

We specify and verify a connection management protocol for use between entities connected by channels that can lose, reorder, and duplicate messages. The protocol is symmetric. Each entity is in one of the following states: closed, listen, open, active opening, passive opening, or closing. The first three are stable states to be exited only by user request, while the last three are transient states. Each entity maintains a local incarnation number at all times, and a remote incarnation number only when opening, open, and closing. Our protocol employs the 3-way handshake used in TCP and ISO Transport Protocol (Class 4).
We verify the safety property that when an entity is open, its remote incarnation number matches the remote entity's local incarnation number. This ensures that data messages from past connection instances are not delivered to the user. We verify the following progress properties: an actively opening entity will eventually establish a connection, provided that the remote entity is willing to communicate or is itself actively opening; the states of active opening, passive opening, and closing are transient; if the entities remain closed, the channels will eventually become empty, assuming messages have a maximum lifetime.
This protocol specification can be immediately combined with the data transfer protocol specifications presented in [SHAN1, SHAN2, SHAN3] to provide a transport layer protocol with the functions of connection management and two-way data transfer. The verifications too can be immediately combined to provide a hierarchical verification of the multi-function protocol. The specifications and verifications can be combined because the connection management and data transfer protocols are images of the multi-function protocol. This illustrates the power of protocol projections in constructing multi-function protocols.
Extensions to communicating sequential processes to allow protocol performance specification
Authors: Zic J. J. 
Published: October 2004

Formalisms based on Hoare's Communicating Sequential Processes (CSP) and Milner's Calculus of Communicating Systems (CCS) for verifying protocols are currently being used by the International Standard Organisation (ISO). However, these models need to be extended if protocol performance specification and verification is to be done, as neither of these models have timing information (other than sequencing) nor a way of specifying controlled loss of information.
This paper presents two extensions to Hoare's CSP that are felt by the author to provide suitable mechanisms for specifying protocol performance. Firstly, the effects of introducing time into CSP are presented, based on the work done by Reed and Roscoe. Secondly, the traces model is modified by associating probabilities with event sequences.
Finally, some example specifications are given using these two extensions.
Laboratory for emulation and study of integrated and coordinated media communication
Authors: Ludwig L. F. , Dunn D. F. 
Published: October 2004

In future telecommunications networks, understanding the issues of user-network control, Customer Premise Equipment (CPE) technologies, services and user applications is as important as the classical network problems of channel structure, switching, and transmission. This paper discusses a Bell Communications Research facility, the Integrated Media Architecture Laboratory (IMAL), designed to flexibly emulate a wide range of current and future network and CPE environments with a focus on multiple media communications. IMAL combines off-the-shelf technologies to create an easily clonable emulation environment for studying, planning, demonstrating, and checking the feasibility of integrated media communications.
The IMAL project has assembled workstations which feature speech-synthesis/sampled-audio/telephony capabilities, local 1 MIP computation capacity, and a high-resolution color display integrating text/graphics/image/video under an expanded X Window display management system. (X Windows is an emerging windowing standard to provide high performance device-independent graphics.) The workstations may be augmented as needed by local image digitizers, video cameras, and color image printers producing paper and viewgraph hardcopies. Also, the workstations are interconnected with switches permitting access to one another as well as shared databases, temporary storage, intelligence, and information processing/conversion resources. Communications services are implemented under a distributed, real-time service primitive control scheme. This multiple-media service primitives scheme employs a threaded/dataflow-type architecture to support user-defined, network-defined, and vendor-defined services while including a wealth of flexible features for the study of network architecture, protocol, network management, and billing functions.
Telescience and advanced technologies
Authors: Leiner B. M. 
Published: October 2004

Space Station and its associated laboratories, coupled with the availability of new computing and communications technologies, have the potential of significantly enhancing scientific research. Telescience involves the interaction of scientific researchers and equipment on earth with on-board personnel and equipment as well as with other researchers, remote ground-based resources, mission control personnel, and space station developers. To assure that this potential is met, scientists and managers associated with the Space Station project must gain significant experience with the use of these technologies for scientific research, and this experience must be fed into the development process for Space Station.
In this talk, a pilot program is described that is attempting to address this problem. University researchers are conducting rapid prototyping testbeds employing new telescience technologies and ideas. These testbeds are specific research experiments within the scientific discipline areas that will use Space Station laboratories. The experiments are being carried out in a coordinated manner to allow the critical questions to be answered by groups of scientists working with technologists in a rapid prototyping testbed environment.
The rapid prototyping testbeds are not like a typical testbed. Rather than being used to evaluate and integrate systems on the way to deployment, the rapid prototyping testbeds constitute a Technology Evaluation Environment (TEE), allowing users to interact with advanced technologies in the conduct of scientific research in order to develop the required base of experience to permit development and evaluation of requirements and specifications.
Resource management scheme in distributed environments
Authors: Nakamura O. , Saito N. 
Published: October 2004

The user interface for distributed computing environment needs several kinds of transparency for resources which are distributed on many sites connected to the network. Access transparency and location transparency are general concept for distributed resources.
In distributed environment, there are many resources of the same functions in various sites. For example, cashed resources which are complete duplicated resources exist on many sites in order to realize high performance.
In this paper, the resource management scheme in the distributed environment is described. The sophisticated semantics transparency which is a general scheme for manipulating duplicated resources in distributed environment is provided. The specification language for the environment which provides semantics transparency is also discussed.
A case for packet switching in high-performance wide-area networks
Authors: Haas Z. , Cheriton D. R. 
Published: October 2004

The large capacity of optical fibers suggests that circuit-switching may become a more attractive switching method in future communication networks. We show, however, that under some reasonable assumptions the delays associated with circuit-switching make the technique inferior to packet-switching in a high-performance, distributed environment. A network design that demonstrates the feasibility of packet-switching in high-performance environment is also presented.
This work was sponsored in part by the Defense Advanced Research Projects Agency under contract N00039-86-K-0431, by the Digital Equipment Corporation, by ATT Information Systems and by Bell Northern Research.
More on selecting sequence numbers
Authors: Dalal Yogen K. 
Published: October 2004

This note serves to supplement and extend the ideas and issues raised in [TO74]. Tomlinson examines the problem of establishing a connection (association), and being able to detect delayed packets of an old incarnation of a connection, when it is being opened and closed in quick succesion, or when the connection breaks owing to some crash and is restarted later. No protocol can guarantee reliability of communication given certain types of crashes [SU74], [BE74]. This last issue is out of the scope of this note.
First the problem of establishing and closing a connection is further examined and the claim that a three way exchange is sufficient for single message transfer in [TO74] (even under conditions of a correctly functioning system) is refuted. Next the mechanism for implementing the “clock-driven” initial sequence number choice is examined in detail showing how various parameters interact, and the algorithms neccessary in order that it work. Finally alternative schemes to replace “resynchronization” are considered and the tradeoffs shown.
Formalisms for interprocess communication
Authors: Cerf Vinton 
Published: October 2004

The literature is rich in examples of a variety of interprocess communication methods, some of which can be considered simple line control procedures (half duplex, full duplex, polled, etc.) and others which are more elaborate and deal with reordering, duplicate detection, stochastic delays, and so on.
Among the most poorly worked out areas of interprocess communication is a formal representation which permits proofs to be made of correct behavior under all circumstances. Some necessary conditions for correct behavior have been proposed in the papers in this Proceedings.
Comprehensive scheduling controls for Ada tasking
Authors: Elrad T. 
Published: October 2004

One of the functions for which Ada needs more expressive power is scheduling control. Scheduling controls provide a mechanism for comprehensive scheduling.
In order to evaluate any concurrent language for its ability to control a multi-events environment, we need to have a general set for classifying all possible controls. Such a classification can exploit the expressive power of any concurrent language, and thus be used to provide us with a priori knowledge regarding the capacity of the language to be used for a specific application. It will also enable us to suggest the best environment for the application at hand. Evaluating Ada against these control capacities will provide us with a scientific approach to the issue of forming an integrated design of comprehensive scheduling controls for Ada.
Performance analysis of an access method suitable for the integration of voice and data
Authors: Behr J. P. , Killat U. 
Published: October 2004

This contribution describes a new type of an integrated system's architecture which reconciles the diverging needs of both, stream traffic of 64 kbit/s and bursty traffic of low and high data rates.
The total capacity of a unidirectional bus is subdivided into a high-speed channel and a certain number of time slots for stream traffic.
The capacity of the high-speed channel can dynamically be adjusted according to the amount of time slots required for stream traffic. Due to the dynamic creation and deletion of time slots, the subsystem for 64-kbit/s channels is almost blocking-free.
The same mechanism is used to control access to the high-speed channel, and to determine the fraction of the total capacity dedicated to the high-speed channel.
The performance of the proposed access mechanism has been investigated by means of system modelling and simulation. The results show that besides its ability to accommodate 64-kbit/s channels it compares quite favourably with other LAN concepts like CSMA/CD.
Some critical considerations on the ISO/OSI RM from a network implementation point of view
Authors: Popescu-Zeletin R. 
Published: October 2004

The paper outlines the conceptual and practical aspects encountered in the design and implementation of a heterogeneous computer network based on the standardization output.
We discuss the feasability of the reference model and its related standards from a design, implementation and operational point of view focussing on the adopted solutions and their rationales.
Communication primitives supporting the execution of atomic actions at remote sites
Authors: Rothermel Kurt 
Published: October 2004

A request manager is described that provides a set of communication primitives supporting the cooperation between processes requesting service and processes providing service. These communication primitives allow the initiation and termination of atomic actions at remote sites. They also maintain recoverable action state tables, which can be used to recall uncompleted actions during restart recovery. The presented request manager is a good foundation on which to develop application oriented high-level primitives as well as language level primitives.
Besides a detailed description of the services offered by the request manager, the paper develops a request management protocol that, no matter what happens, insures the atomic property of actions. Evaluation nets, which are a modified form of Petri nets, are applied to describe this protocol.
Some issues in protocol implementation testing
Authors: Cerny E. 
Published: October 2004

Communication between various makes of communication equipment and across international boundaries is becoming easier due to the continuing development of international standards on communication protocols, such as those defined by ISO for Open Systems Interworking (OSI). Although the agreement to use standard protocols by the various parties involved is the first necessary step towards OSI, it is not sufficient without assuring that the protocols be correctly implemented in the communication equipment.
The assessment of the adherence of a communication protocol implementation to its specification relies on testing as its main tool. The development of the tests and their application (the architecture of the test system) have properties and constraints which make them different from those currently created for testing hardware and software systems.
In the remainder of the presentation, these constraints and problems as related to the successful development of a protocol test system will be reviewed. They will be separated into those aspects which pertain more to the form of the test support system (the system architecture), and to those which influence the selection of effective test interaction sequences. This division is slightly arbitrary, for some of the issues have effect on both of the above components of the test system.
A lazy buddy system bounded by two coalescing delays
Authors: Barkley R. , Lee T. 
Published: October 2004

The watermark-based lazy buddy system for dynamic memory management uses lazy coalescing rules controlled by watermark parameters to achieve low operational costs. The correctness of the watermark-based lazy buddy system is shown by defining a space of legal states called the lazy space and proving that the watermark-based lazy coalescing rules always keep the memory state within that space. In this paper we describe a different lazy coalescing policy, called the DELAY-2 algorithm, that focuses directly on keeping the memory state within the lazy space. The resulting implementation is simpler, and experimental data shows it to be up to 12% faster than the watermark-based buddy system and about 33% faster than the standard buddy system. Inexpensive operations make the DELAY-2 algorithm attractive as a memory manager for an operating system.
The watermark-based lazy buddy policy offers fine control over the coalescing policy of the buddy system. However, applications such as the UNIX System kernel memory manager do not need such fine control. For these applications, the DELAY-2 buddy system provides an efficient memory manager with low operational costs and low request blocking probability. In the DELAY-2 buddy system, the worst-case time for a free operation is bounded by two coalescing delays per class, and when all blocks are returned to the system, the system memory is coalesced back to its original state. This ensures that the memory space can be completely shared.
Analysis of transaction management performance
Authors: Duchamp D. 
Published: October 2004

There is currently much interest in incorporating transactions into both operating systems and general-purpose programming languages. This paper provides a detailed examination of the design and performance of the transaction manager of the Camelot system. Camelot is a transaction facility that provides a rich model of transactions intended to support a wide variety of general-purpose applications. The transaction manager's principal function is to execute the protocols that ensure atomicity.
The conclusions of this study are: a simple optimization to two-phase commit reduces logging activity of distributed transactions; non-blocking commit is practical for some applications; multithreaded design improves throughput provided that log batching is used; multi-casting reduces the variance of distributed commit protocols in a LAN environment; and the performance of transaction mechanisms such as Camelot depend heavily upon kernel performance.
X-NET: a dual bus fiber-optic LAN using active switches
Authors: Kamal A. E. , Abeysundara B. W. 
Published: October 2004

X-Net is a new local area network based on the dual, unidirectional bus topology. Stations are connected to two fiber-optic busses using active switches. At light load, X-Net behaves as a random access scheme. With increasing load, transmissions are done in an orderly manner, arranged into cycles.
The main advantage of X-Net is its superior channel utilization and delay performance, compared to other bus schemes. The packet delay is bounded at all loads. Performance is shown to be satisfactory over a wide range of a values, where a is the ratio of end-to-end medium propagation delay to the packet transmission time. Therefore, X-Net is a suitable candidate for operation at high speeds.