waashk/acm huggingface dataset:
an ipc protocol and its hardware realization for a high-speed distributed multicomputer system  multicomputer systems with distributed control form an architecture that simultaneously satisfies such design goals as high performance through parallel operation of vlsi processors, modular extensibility, fault tolerance, and system software simplication. the nodes of the system may be locally concentrated or spatially dispersed as a local network. applications range from data base-oriented transactional systems to "number crunching." the system is service-oriented; that is, it appears to the user as one computer on which parallel processing takes place in the form of cooperating processes. cooperation is regulated by the unique interprocess communication (ipc) protocol presented in this paper. the high-level protocol is based on the computer/producer model and satisfies all requirements for such a distributed multicomputer system. it is demonstrated that the protocol lends itself toward a straightforward mechanization by dedicated hardware consisting of a cooperation handler, an address transformation and memory guard unit, and bus connection logic. these special hardware resources, assisted by a "local operating system", form the supervisor of a node. nodes are connected by a high-speed bus (280m bit/sec). programming aspects as implied by the ipc protocol are also described.  w. k. giloi p. behr
enhanced privacy and authentication for the global system for mobile communications  the global system for mobile communications (gsm) is widely recognized as the modern digital mobile network architecture. increasing market demands point toward the relevancy of security-related issues in communications. the security requirements of mobile communications for the mobile users include: (1) the authentication of the mobile user and visitor location register/home location register; (2) the data confidentiality between mobile station and visitor location register, and the data confidentiality between visitor location register and visitor location register/home location register (vlr/hlr); (3) the location privacy of mobile user. however, gsm does not provide enough security functions to meet these requirements. we propose three improved methods to enhance the security, to reduce the storage space, to eliminate the sensitive information stored in vlr, and consequently to improve the performance of the system. proposed methods include an improved authentication protocol for the mobile station, a data confidentiality protocol, and a location privacy protocol. the merit of the proposed methods is to improve but not to alter the existing architecture of the system. furthermore, this study also performs computational and capacity analyses to evaluate the original gsm system and proposed approaches on a comparative basis.  chii-hwa lee min-shiang hwang wei-pang yang
multicast atm switches: survey and performance evaluation computer networks are undergoing a remarkable transformation. the widespread use of optical fiber to transmit data has made tremendous increases in network bandwidth. furthermore, greater cpu power, increasing disk capacity, and support for digital audio and video are creating demand for a new class of network services. for example, video-on-demand, distant learning, distant diagnosis, video conferences, and many others applications have popped up one after another in recent years. many of these services have one thing in common. they all require that the same piece of data be sent to multiple recipients. even in traditional networks, this operation, called multicasting, can not be handled easily and cheaply. when scaled up to high speed atm-based networks, the situation could be worse. multiple streams of data travel around atm networks. each tries to send to many different destinations simultaneously. therefore, designing economical atm network switches which can support multicasting operations easily is very important in the future generation high speed networks. in the past twelve years or so, many designs for multicasting atm switches are proposed. it seems about time to do a historical survey. it is hoped that by learning from the wisdom of the previous authors, new spark or angle can be found and exploited to design new multicasting atm switches. without easy and inexpensive multicasting, all the exciting services may become unaffordable. this will in turn lead to the diminishing of customer bases and finally will hinder the full-scale deployment of high speed networks. ming-huang guo ruay-shiung chang
mobile atm buffer capacity analysis  this paper extends a stochastic theory for buffer fill distribution for multiple "on" and "off" sources to a mobile environment. queue fill distribution is described by a set of differential equations assuming sources alternate asynchronously between exponentially distributed periods in "on" and "off" states. this paper includes the probabilities that mobile sources have links to a given queue. the sources represent mobile user nodes, and the queue represents the capacity of a switch. this paper presents a method of analysis which uses mobile parameters such as speed, call rates per unit area, cell area, and call duration and determines queue fill distribution at the atmcell level. the analytic results are compared with simulation results.  stephen f. bush joseph b. evans victor frost
a proposal of an atm wireless access system for tetherless multimedia services  this paper proposes an atm wireless access system for tetherless multimedia services. the proposed system is intended to provide atm-based high-speed transmission capability for tetherless multimedia services by wireless media in private lan/wan environments as well as public environments. to enable high-speed transmission, this paper proposes the utilization of the shf band taking advantage of its wide frequency spectrum availability. however, the propagation feature of the shf band limits the wireless terminal mobility in the proposed system compared with current cellular phone systems. this paper discusses the concept and system architecture of the proposed atm wireless access system, including its atm transport based on atm/tdma conversion using a time stamp scheme.  masahiro umehira akira hashimoto hideaki matsue masamitsu nakura
microcellular handoff using fuzzy techniques  in order to manage the high call density expected in future cellular systems, microcell must be used. the size of the microcell will cause a dramatic increase in the number of handoffs. in addition, the small size of the microcell will require handoff algorithms to respond faster than those in today's systems. the problems are further exacerbated by the corner effect phenomenon which causes the signal level to drop by 20--30 db in 10--20 m. thus, in order to maintain reliable communication in a microcellular system new and better handoff algorithms must be developed. the use of hysteresis and averaging window in classical handoff techniques reduces unnecessary handoffs, but causes delays which may result in the calls being dropped. a fuzzy based handoff algorithm is proposed in this paper as a solution to this problem. the performance of fuzzy based handoff algorithm was also compared to that obtained using the classical handoff algorithms.  george edwards ravi sankar
design methodology of a 200mhz superscalar microprocessor: sh-4  a new design methodology focusing on high speed operation and short design time is described for the sh-4 200mhz superscalar microprocessor. random test generation, logic emulation, and formal verification are applied to logic verification for shortening design time. delay budgeting, forward/back annotation, and clock design are key features for timing driven design.  toshihiro hattori yusuke nitta mitsuho seki susumu narita kunio uchiyama tsuyoshi takahashi ryuichi satomura
concepts of the system/370 vector architecture  this paper discusses the performance, complexity and system-integration considerations that shaped the system/370 vector architecture [1, 9]. the architecture is intended for compatible systems providing a range of price and performance. the paper reviews the reasons for choosing a register-oriented architecture with compound instructions over storage-to-storage operations and vector- instruction chaining. then it discusses the role of cache in stride-n storage accessing, and describes some new facilities introduced for control- program purposes.  b. moore a. padegs r. smith w. buchholz
experience with adaptive mobile applications in odyssey  in this paper, we present our experience with application-aware adaptation in the context of odyssey, a platform for mobile data access. we describe three applications that we have modified to run on odyssey --- a video player, a web browser, and a speech recognition system. our experience indicates that it is relatively simple to incorporate applications into odyssey, and that application source code is not always essential. although our applications were built without knowledge of each other, odyssey is able to run them concurrently without interference. however, our experience also exposes important areas of future work. specifically, it reveals the difficulty of balancing agility with stability in adaptation, and emphasizes the need for controlled exposure of internal odyssey state to users.  b. d. noble m. satyanarayanan
deriving traffic demands for operational ip networks: methodology and experience  engineering a large ip backbone network without an accurate network-wide view of the traffic demands is challenging. shifts in user behavior, changes in routing policies, and failures of network elements can result in significant (and sudden) fluctuations in load. in this paper, we present a model of traffic demands to support traffic engineering and performance debugging of large internet service provider networks. by defining a traffic demand as a volume of load originating from an ingress link and destined to a set of egress links, we can capture and predict how routing affects the traffic traveling between domains. to infer the traffic demands, we propose a measurement methodology that combines flow-level measurements collected at all ingress links with reachability information about all egress links. we discuss how to cope with situations where practical considerations limit the amount and quality of the necessary data. specifically, we show how to infer interdomain traffic demands using measurements collected at a smaller number of edge links-the peering links connecting the neighboring providers. we report on our experiences in deriving the traffic demands in the at&amp;t; ip backbone, by collecting, validating, and joining very large and diverse sets of usage, configuration, and routing data over extended periods of time. the paper concludes with a preliminary analysis of the observed dynamics of the traffic demands and a discussion of the practical implications for traffic engineering.  anja feldmann albert greenberg carsten lund nick reingold jennifer rexford fred true
a trace-based evaluation of adaptive error correction for a wireless local area network  wireless transmissions are highly susceptible to noise and interference. as a result, the error characteristics of a wireless link may vary widely depending on environmental factors such as location of the communicating systems and activity of competing radiation sources, making error control a difficult task. in this paper we evaluate error control strategies for a wireless lan. based on low-level packet traces of wavelan, we first show that forward error correction (fec) is effective in recovering from bit corruptions and that packet length adjustment can reduce packet truncation. however, as expected, fixed error control policies can perform very poorly, because they either introduce too much overhead in "good" environments or are not aggressive enough in "bad" environments. we address this problem through adaptive error control, i.e., error control policies that adapt the degree of fec redundancy and the packet size to the environment. the effectiveness of adaptive error control depends on the characteristics of the error environment, e.g., the type of errors and the frequency with which the error environment changes. our evaluation shows that adaptive error control can improve throughput consistently across a wide range of wireless lan error environments. the reason for this effectiveness is that changes in the error environemtn are often caused by human mobility-related events such as the motion of a cordless phone, which take place over seconds, while adaptation protocols can respond in tens of milliseconds. evaluating adaptive error control in a wireless environments is challenging because repeatable experiments are difficult: the wireless environment cannot easily be isolated and the adaptation process itself changes the environment, which may make trace-based evaluation difficult. we introduce a trace-based evaluation methodology that deals appropriately with changes in packet content and size.  david a. eckhardt peter steenkiste
credit-based flow control for atm networks: credit update protocol, adaptive credit allocation and statistical multiplexing  this paper presents three new results concerning credit-based flow control for atm networks: (1) a simple and robust credit update protocol (cup) suited for relatively inexpensive hardware/software implementation; (2) automatic adaptation of credit buffer allocation for virtual circuits (vcs) sharing the same buffer pool; (3) use of credit-based flow control to improve the effectiveness of statistical multiplexing in minimizing switch memory. these results have been substantiated by analysis, simulation and implementation.  h. t. kung trevor blackwell alan chapman
simd machines: do they have a significant future? i volunteered to write this report during the simd panel session held on 2/9/95 at frontiers '95. all panelists cooperated by sending me their transparency masters. a draft report was prepared based on these transparency masters, position statements published in the frontiers '95 proceedings on pp. 466-469, and my own notes. the draft was e-mailed on 3/17/95 to the panel organizer/moderator and the panelists for their comments. this final version of the report is based on comments and markups received through 3/31/95. i have drawn from the panelists' ideas freely, using quotation marks only when including their statements verbatim.the panel consisted of both academic and industry experts in the field of massively parallel systems (see the table below). all but tim bridges, who is currently involved in a large-scale software development project for the maspar mp-2 simd architecture, have built working simd machines. the vast practical experience of the panel was quite evident in the insightful presentations and interactions. it is indeed a privilege for me to have worked on this report. behrooz parhami
a processor architecture for horizon  horizon is a scalable shared- memory multiple instruction stream - multiple data stream (mimd) computer architecture independently under study at the supercomputing research center (src) and tera computer company. it is composed of a few hundred identical scalar processors and a comparable number of memories, sparsely embedded in a three-dimensional nearest-neighbor network. each processor has a horizontal instruction set that can issue up to three floating point operations per cycle without resorting to vector operations. processors will each be capable of performing several hundred million floating point operations per second (flops) in order to achieve an overall system performance target of 100 billion (1011) flops.  this paper describes the architecture of the processor in the horizon system. in the fashion of the denelcor hep, the processor maintains a variable number of single instruction stream - single data stream (sisd) processes, which are called instruction streams. memory latency introduced by the large shared memory is hidden by switching context (instruction stream) each machine cycle. the processor functional units are pipelined to achieve high computational throughput rates; however, pipeline dependencies are hidden from user code. hardware mechanisms manage the resources to guarantee anonymity and independence of instruction streams.  m. r. thistle b. j. smith
the architecture of the universe network  the universe network is composed of a number of local area networks at various sites in the u. k., joined by high capacity data links. apart from one token ring, all of the local area networks are cambridge rings; the high capacity data links are provided by a 1 mbit/s satellite broadcast channel. the universe project encompasses both the design and implementation of the network, and a program of experiments which make use of the network. one of the notable features of the network is that a host's view of communication over the network is no different from communication over a single ring; no internet protocol is used.  ian m leslie roger m needham john w burren graham c adams
estimating the multiplicities of conflicts to speed their resolution in multiple access channels  new, improved algorithms are proposed for regulating access to a multiple- access channel, a common channel shared by many geographically distributed computing stations. a conflict of multiplicity n occurs when n stations transmit simultaneously to the channel. as a result, all stations receive feedback indicating whether n is 0, 1, or ≥2\. if n = 1, the transmission succeeds; whereas if n ≥ 2, all the transmissions fail. algorithms are presented and analyzed that allow the conflicting stations to compute a stochastic estimate n* of n, cooperatively, at small cost, as a function of the feedback elicited during its execution. an algorithm to resolve a conflict among two or more stations controls the retransmissions of the conflicting stations so that each eventually transmits singly to the channel. combining one of our estimation algorithms with a tree algorithm (of capetanakis, hayes, and tsybakov and mikhailov) then leads to a hybrid algorithm for conflict resolution. several efficient combinations are possible, the most efficient of which resolves conflicts about 20 percent faster on average than any of the comparable algorithms reported to date.  albert g. greenberg philippe flajolet richard e. ladner
seamless - a latency-tolerant risc-based multiprocessor architecture (abstract)  the seamless parallel system being developed at the university of iowa ece department provides a method for providing latency tolerance in physically- distributed memory systems utilizing "off- the-shelf" risc cpu's without incurring the overhead of multithreading. seamless encompasses an evolutionary new programming model emphasizing data locality that views communication as data movement rather than message passing i/o. a hardware locality manager is added to each processing element to perform this data movement concurrently with computation.  samuel a. fineberg thomas l. casavant brent h. pease
building reliable mobile-aware applications using the rover toolkit  this paper discusses extensions to the rover toolkit for constructing reliable mobile-aware applications. the extensions improve upon the existing failure model, which addresses client or communication failures and guarantees reliable message delivery from clients to server, but does not address server failures (e.g., the loss of an incoming message due to server failure) (joseph et al., 1997). due to the unpredictable, intermittent communication connectivity typically found in mobile client environments, it is inappropriate to make clients responsible for guaranteeing request completion at servers. the extensions discussed in this paper provide both system- and language-level support for reliable operation in the form of stable logging of each message received by a server, per-application stable variables, programmer-supplied failure recovery procedures, server process failure detection, and automatic server process restart. the design and implementation of fault-tolerance support is optimized for high performance in the normal case (network connectivity provided by a high latency, low bandwidth, wireless link): measurements show a best-case overhead of less than 7% for a reliable null rpc over wired and cellular dialup links. experimental results from both micro-benchmarks and applications, such as the rover web browser proxy, show that support for reliable operation can be provided at an overhead of only a few percent of execution time during normal operation.  anthony d. joseph m. frans kaashoek
multiple crossbar network integrated supercomputing framework  at los alamos national laboratory, site of one of the world's most powerful scientific supercomputing facilities, a prototype network for an environment that links supercomputers and workstations is being developed. driven by a need to provide graphics data at movie rates across a network from a supercomputer to a scientific workstation, the network is called the multiple crossbar network (mcn). it is intended to be a coarsely-grained, loosely- coupled, general-purpose multicomputer framework that will vastly increase the speed at which supercomputers communicate with each other in large networks. the components of the network are described, as well as work done in collaboration with vendors who are interested in providing commercial products.  r. hoebelheinrich r. thomsen
wireless architecture for access to remote services (wiars) (poster session)  our research involves the creation of a plug and play environment where different devices and services can be made to function together effortlessly. currently the connection of any entity to another entity, through a network, needs prior setup and configuration. we aim to design an architecture, which requires minimal setup processes or none, for easy access to remote services using the wireless application protocol (wap) and jini.  amisha thakkar bina ramamurthy
a turnable protocol for symmetric surveillance in distributed systems  in distributed systems surveillance protocols are used for monitoring the status of remote sites. a remote site is regarded as being available as long as messages are received from this site, otherwise it is regarded as being unavailable. if a site becomes unavailable, this will be reported to other sites and recovery actions can be initiated. using an example it will be shown that in certain cases it is necessary, that whenever some site s1 detects the unavailability of some other site s2, within a fixed amount of time s2 must also have detected an unavailability of s1. unfortunately, this cannot be guaranteed by existing surveillance protocols. another problem with existing protocols is, that remote sites are usually reported as being unavailable after being timed out only once, i.e. the loss of just one message might cause complete systems to back out.  two versions of a protocol for so-called symmetric surveillance are presented. both guarantee, that if s1 detects the unavailability of s2 at time t0, then s2 (provided that s2 has not crashed) will become aware of this fact at t1 such that [t1 - t0] < Δ. this property is of special interest for handling network partitionings. additionally, one of the versions is tunable, i.e. it can be specified, how many timeouts may occur before a site is regarded as being unavailable.  b walter