waashk/acm huggingface dataset:
analysis of a 3d toroidal network for a shared memory architecture  this paper describes a synchronized network model suitable for the horizon architecture. the model is defined in terms of a topology and routing policy. a three dimensional toroidal topology is investigated for its multiple redundant paths, memory locality and simplicity in both routing and construction. the routing policy is based on a desperation routing scheme in which it is not guaranteed that a message will make progress on a given network cycle. this scheme requires no complex deadlock avoidance algorithms or node to node flow control, allowing a very simple and efficient implementation. design considerations and preliminary performance results are discussed.  f. pittelli d. smitley
service specification and protocol construction for the transport layer  in a computer network, the transport layer uses the service offered by the network layer and in turn offers its users the transport service of reliable connection management and data transfer. we provide a formal specification of the transport service in terms of an event-driven system and safety and progress properties. we construct three verified transport protocols that offer the transport service. the first transport protocol assumes a perfect network service, the second assumes loss-only network service, and the third assumes loss, reordering and duplication network service.  our transport service specifications are very realistic. each user can be closed, listening, active opening, passive opening, open, or closing. a local incarnation number uniquely identifies every active opening and listening duration. users can issue requests for connection, listening, closing, data send, etc. the transport layer issues indications for successful or unsuccessful connection, closing, data reception, etc. a connection is established only if one user requested the connection and the other was listening, or both requested the connection. a user receives data only from the appropriate incarnation of the distant user, and receives it insequence, without loss or duplication. progress properties ensure that every outstanding user request is eventually responded to by an appropriate transport indication.  our protocols are constructed by stepwise refinement of the transport service. the construction method automatically generates a verification that the protocols satisfy the transport service. one distinctive feature of our protocol construction is that the events and verification of the data transfer function is directly obtained from any one of the numerous verified single- incarnation data transfer protocols already presented in the literature.  s. l. murphy a. u. shankar
comparative performance evaluation of cache-coherent numa and coma architectures  two interesting variations of large-scale shared-memory machines that have recently emerged are cache-coherent non- uniform-memory-access machines (cc- numa) and cache-only memory architectures (coma). they both have distributed main memory and use directory-based cache coherence. unlike cc- numa, however, coma machines automatically migrate and replicate data at the main-memory level in cache-line sized chunks. this paper compares the performance of these two classes of machines. we first present a qualitative model that shows that the relative performance is primarily determined by two factors: the relative magnitude of capacity misses versus coherence misses, and the granularity of data partitions in the application. we then present quantitative results using simulation studies for eight parallel applications (including all six applications from the splash benchmark suite). we show that coma's potential for performance improvement is limited to applications where data accesses by different processors are finely interleaved in memory space and, in addition, where capacity misses dominate over coherence misses. in other situations, for example where coherence misses dominate, coma can actually perform worse than cc-numa due to increased miss latencies caused by its hierarchical directories. finally, we propose a new architectural alternative, called coma-f, that combines the advantages of both cc-numa and coma.  per stenström truman joe anoop gupta
link layer retransmission schemes for circuit-mode data over the cdma physical channel  in the last few years, wide-area data services over north american digital (tdma and cdma) cellular networks have been standardized. the standards were developed under three primary constraints: (i) compatibility with existing land-line standards and systems, (ii) compatibility with existing cellular physical layer standards that are optimized for voice, and (iii) market demands for quick solutions. in particular, the is-95 cdma air interface standard permits multiplexing of primary traffic (e.g., voice or circuit data) and secondary traffic (e.g., packet data) or in-band signaling within the same physical layer burst. in this paper, we describe two radio link protocols for circuit-mode data over is-95. the first protocol, protocol s, relies on a single level of recovery and uses a flexible segmentation and recovery (fsar) sublayer to efficiently pack data frames into multiplexed physical layer bursts. we next describe protocol t, that consists of two levels of recovery. protocol t has been standardized for cdma circuit-mode data as is-99 (telecommunications industry association, 1994). we provide performance comparisons of the two protocols in terms of throughput, delay and recovery from fades. we find that the complexity of the two level recovery mechanism can buy higher throughput through the reduced retransmission data unit size. however, the choice of tcp (and its associated congestion control mechanism) as the upper layer of recovery on the link layer, leads to long fade recovery times for protocol t. the two approaches also have significant differences with respect to procedures and performance at handoff and connection establishment.  mooi choo chuah bharat doshi subra dravida richard ejzak sanjiv nanda
a comprehensive approach to signaling, transmission, and traffic management for wireless atm networks we propose and evaluate a signaling and transmission algorithmic system for wireless digital networks, in conjunction with a traffic monitoring algorithm (tma) for dynamic capacity allocation in multimedia atm environments. the deployed signaling protocol is stable, and two transmission techniques are compared: a framed time-domain based (ftdb) technique and a framed cdma (fcdma) technique. the overall signaling/transmission/traffic monitoring proposed system has powerful performance characteristics, while the tma-ftdb combination is superior to the tma-fcdma combination in environments where message lengths are relatively short and the speed of the transmission lines is relatively low. we also evaluate a system deploying the ethernet protocol as a signaling protocol, instead. in the presence of relatively tight admission delay constraints in signaling, the latter is significantly inferior to our proposed signaling technique. as the above admission delay constraints diminish, the ethernet protocol breaks down, while our proposed signaling technique maintains its high performance characteristics. anthony burrell p. papantoni-kazakos
performance improvements for iso transport  the nbs protocol performance laboratory is developing enhanced protocol mechanisms for osi class 4 transport that will improve the throughput efficiency achieved on a satellite channel. a selective acknowledgement mechanism has been shown to improve throughput efficiency by as much as 34%. several alternative expedited data mechanisms have demonstrated throughput efficiency improvements as great as 38%. most of the protocol mechanism enhancements considered require only minor changes to the international standard osi transport protocol.  richard colella robert aronoff kevin mills
analysis of an algorithm for distributed recognition and accountability  computer and network systems are vulnerable to attacks. abandoning the existing huge infrastructure of possibly-insecure computer and network systems is impossible, and replacing them by totally secure systems may not be feasible or cost effective. a common element in many attacks is that a single user will often attempt to intrude upon multiple resources throughout a network. detecting the attack can become significantly easier by compiling and integrating evidence of such intrusion attempts across the network rather than attempting to assess the situation from the vantage point of only a single host. to solve this problem, we suggest an approach for distributed recognition and accountability (dra), which consists of algorithms which "process", at a central location, distributed and asynchronous "reports" generated by computers (or a subset thereof) throughout the network. our highest-priority objectives are to observe ways by which an individual moves around in a network of computers, including changing user names to possibly hide his/her true identity, and to associate all activities of multiple instances of the same individual to the same networkwide user. we present the dra algorithm and a sketch of its proof under an initial set of simplifying albeit realistic assumptions. later, we relax these assumptions to accommodate pragmatic aspects such as missing or delayed "reports", clock skew, tampered "reports", etc. we believe that such algorithms will have widespread applications in the future, particularly in intrusion-detection systems.  calvin ko deborah a. frincke terrance goan todd heberlein karl levitt biswanath mukherjee christopher wee
the cedar system and an initial performance study  in this paper, we give an overview of the cedar multiprocessor and present recent performance results. these include the performance of some computational kernels and the perfect benchmarks. we also present a methodology for judging parallel system performance and apply this methodology to cedar, cray ymp-8, and thinking machines cm-5.  d. kuck e. davidson d. lawrie a. sameh c. q. zhu a. veidenbaum j. konicek p. yew k. gallivan w. jalby h. wijshoff r. bramley u. m. yang p. emrath d. padua r. eigenmann j. hoeflinger g. jaxon z. li t. murphy j. andrews
architecture and protocols of stella: a european experiment on satellite interconnection of local area networks  stella (satellite transmission experiment linking laboratories) is a european wide-band data transmission experiment. stella makes use of the european orbital test satellite (ots) which provides a 2 mb/s broadcast data transmission channel. the first phase of the stella project (stella/i) is summarized. the more important design characteristics of an improved version (stella/ii) of stella/i are emphasized. collaboration between stella/ii and universe projects in the framework of cost-11bis is then outlined.  n. celandroni e. ferro l. lenzini b. m. segal k. s. olofsson
dynamic qos allocation for multimedia ad hoc wireless networks  in this paper, we propose an approach to support qos for multimedia applications in ad hoc wireless network. an ad hoc network is a collection of mobile stations forming a temporary network without the aid of any centralized coordinator and is different from cellular networks which require fixed base stations interconnected by a wired backbone. it is useful for some special situations, such as battlefield communications and disaster recovery. the approach we provide uses csma/ca medium access protocol and additional reservation and control mechanisms to guarantee quality of service in ad hoc network system. the reson we choose csma protocol instead of other mac protocols is that it is used in most of currently wireless lan productions. via qos routing information and reservation scheme, network resources are dynamically allocated to individual multimedia application connections.  hsiao-kuang wu pei-hung chuang
heterogeneous computer architecture  this paper reviews computer architecture as it has progressed from the stand- alone computer to the computer system to computer networks. the degree of success of an architecture can be measured by the number of different implementations made of it. an architecture is ultimately limiting in some way, thereby spawning specialized units, called algorithm boxes, or special- purpose computers. the author takes the view that this is a beneficial trend, but one that needs architectural guidance. an architecture is valuable if designers can build, and programmers can use, the resulting system. the paper reviews current trends that might be described as the development of computer architecture by "default". the particular case of local computer networks is discussed.  james e. thornton
quality adaptation for congestion controlled video playback over the internet streaming audio and video applications are becoming increasingly popular on the internet, and the lack of effective congestion control in such applications is now a cause for significant concern. the problem is one of adapting the compression without requiring video-servers to re-encode the data, and fitting the resulting stream into the rapidly varying available bandwidth. at the same time, rapid fluctuations in quality will be disturbing to the users and should be avoided.in this paper we present a mechanism for using layered video in the context of unicast congestion control. this quality adaptation mechanism adds and drops layers of the video stream to perform long-term coarse-grain adaptation, while using a tcp-friendly congestion control mechanism to react to congestion on very short timescales. the mismatches between the two timescales are absorbed using buffering at the receiver. we present an efficient-scheme for the distribution of buffering among the active layers. our scheme allows the server to trade short-term improvement for long-term smoothing of quality. we discuss the issues involved in implementing and tuning such a mechanism, and present our simulation results. reza rejaie mark handley deborah estrin
distributed orthogonal factorization  we describe several algorithms for computing the orthogonal factorization on distributed memory multiprocessors. one of the algorithms is based on givens rotations, two others employ column householder transformations but with different communication schemes: broadcast and pipelined ring. a fourth algorithm is a hybrid; it uses househlolder transformations and givens rotations in separate phases. we present expressions for the arithmetic and communication complexity of each algorithm. the algorithms were implemented on an ipsc-286 and the observed times agree well with our analyses.  a. pothen p. raghavan
analysis of the autonomous system network topology mapping the internet is a major challenge for network researchers. it is the key to building a successful modeling tool able to generate realistic graphs for use in networking simulations. in this paper we provide a detailed analysis of the inter-domain topology of the internet. the collected data and the resulting analysis began in november 1997 and cover a period of two and a half years. we give results concerning major topology properties (nodes and edges number, average degree and distance, routing policy, etc.) and main distributions (degree, distance, etc.). we also present many results about the trees of this network. the evolution of these properties is reviewed and major trends are highlighted. we propose some empirical laws that match this current evolution. four new power-laws concerning the number of shortest paths between node pairs and the tree size distribution are provided with their detailed validation. damien magoni jean jacques pansiot
atm network: goals and challenges  asynchronous transfer mode (atm) can provide both circuit and packet-switching services with the same protocol, and this integration of circuit and packet- switching services can be beneficial in many ways. four major benefits of the atm technique are considered here: scalability, statistical multiplexing, traffic integration, and network simplicity. in the course of achieving those benefits, atm makes compromises. in this article we assess the benefits and ensuing penalties of these compromises and put them into perspective.  b. g. kim p. wang
replication requirements in mobile environments replication is extremely important in mobile environments because nomadic users require local copies of important data. however, today's replication systems are not "mobile-ready". instead of improving the mobile user's environment, the replication system actually hinders mobility and complicates mobile operation. designed for stationary environments, the replication services do not and cannot provide mobile users with the capabilities they require. replication in mobile environments requires fundamentally different solutions than those previously proposed, because nomadicity presents a fundamentally new and different computing paradigm. here we outline the requirements that mobility places on the replication service, and briefly describe roam, a system designed to meet those requirements. david ratner peter reiher gerald j. popek geoffrey h. kuenning
on the measured behaviour of a x.25 packet switching subnetwork  the aim of this paper is to present some measurements on the performance of a x.25 packet switching subnetwork and of a typical x.25 dte-dce interface. the communication parameters considered are the window size of the link layer flow control, the length and contents of the packets and the internode distance. the collected measurements on the x.25 subnetwork are compared with others obtained through different versions of dte connected to the same subnetwork. some considerations are presented about the time spent by the packets inside the dte and consequently about the efficiency of the dte version used in these experiments.  alberto faro gaetano messina franco martinucci
secure audit logs to support computer forensics  in many real-world applications, sensitive information must be kept it log files on an untrusted machine. in the event that an attacker captures this machine, we would like to guarantee that he will gain little or no information from the log files and to limit his ability to corrupt the log files. we describe a computationally cheap method for making all log entries generated prior to the logging machine's compromise impossible for the attacker to read, and also impossible to modify or destroy undetectably.  bruce schneier john kelsey
equal resource sharing scheduling for pcs data services  for high speed mobile communication applications, the data rate can be increased by using multiple channels (or time slots) instead of one channel. to reduce the high blocking rate of multiple channels assignment, flexible resource allocation strategies have been proposed. this paper proposes the equal resource sharing allocation scheme (ersa scheme) for flexible resource allocation. the ersa scheme dynamically averages the allocated resource to the call requests based on the number of calls in a base station. the scheme accommodates the maximum number of requests while providing acceptable quality to the admitted requests. we developed an analytic model to investigate the performance of ersa, and conducted simulation experiments to validate the analytic model. we define satisfaction indication si as the performance measurement of the resource allocation algorithm. the experiment results indicate that the ersa scheme outperforms other resource allocation algorithms proposed in our previous study.  jeu-yih jeng yi-bing lin
boosting the performance of hybrid snooping cache protocols previous studies of bus-based shared-memory multiprocessors have shown hybrid write- invalidate/write-update snooping protocols to be incapable of providing consistent performance improvements over write-invalidate protocols. in this paper, we analyze the deficiencies of hybrid snooping protocols under release consistency, and show how these deficiencies can be dramatically reduced by using write caches and read snarfing.our performance evaluation is based on program-driven simulation and a set of five scientific applications with different sharing behaviors including migratory sharing as well us producer- consumer sharing. we show that a hybrid protocol, extended with write caches as well as read snarfing, manages to reduce the number of coherence misses by between 83% and 95% as compared to a write-invalidate protocol for all five applications in this study. in addition, the number of bus transactions is reduced by between 36% and 60% for four of the applications and by 9% for the fifth application. because of the small implementation cost of the hybrid protocol and the two extensions, we believe that this combination is an effective approach to boost the performance of bus-based multiprocessors. fredrik dahlgren
the application of token rings to local networks of personal computers  it is the thesis of this short note that a network which operates by passing a control token sequentially around a loop, much like that of the distributed computing system [farb 73, farb 75] is appropriate for at least two forthcoming kinds of local personal computer networks. high end personal scientific computers will probably require very high bandwidth (50 mhz) local networks, a requirement well suited for a token type ring network. at the other end of the spectrum, a low bandwidth (300 baud) network for low cost home or business personal computers may be established that use the conventional phone system and a variation of the token ring for arbitration.  r. l. gordon
performance of cached dram organizations in vector supercomputers  drams containing cache memory are studied in the context of vector supercomputers. in particular, we consider systems where processors have no internal data caches and memory reference streams are generated by vector instructions. for this application, we expect that cached drams can provide high bandwidth at relatively low cost.  we study both drams with a single, long cache line and with smaller, multiple cache lines. memory interleaving schemes that increase data locality are proposed and studied. the interleaving schemes are also shown to lead to non- uniform bank accesses, i.e. hot banks. this suggest there is an important optimization problem involving methods that increase locality to improve performance, but not so much that hot banks diminish performance. we show that for uniprocessor systems, both types of cached drams work well with the proposed interleave methods. for multiprogrammed multiprocessors, the multiple cache line drams work better.  w.-c. hsu j. e. smith
transmission-efficient routing in wireless networks using link-state information the efficiency with which the routing protocol of a multihop packet-radio network uses transmission bandwidth is critical to the ability of the network nodes to conserve energy. we present and verify the source-tree adaptive routing (star) protocol, which we show through simulation experiments to be far more efficient than both table-driven and on-demand routing protocols proposed for wireless networks in the recent past. a router in star communicates to its neighbors the parameters of its source routing tree, which consists of each link that the router needs to reach every destination. to conserve transmission bandwidth and energy, a router transmits changes to its source routing tree only when the router detects new destinations, the possibility of looping, or the possibility of node failures or network partitions. simulation results show that star is an order of magnitude more efficient than any topology-broadcast protocol proposed to date and depending on the scenario is up to six times more efficient than the dynamic source routing (dsr) protocol, which has been shown to be one of the best performing on-demand routing protocols. j.j. garcia-luna-aceves marcelo spohn