waashk/acm huggingface dataset:
a dominating set model for broadcast in all-port wormhole-routed 2d mesh networks  a new model for broadcast in wormhole-routed networks is proposed. the model uses and extends the concept of dominating sets in order to systematically develop efficient broadcast algorithms for all-port wormhole-routed systems, in which each node can simultaneously transmit messages on different outgoing channels. in this paper, two broadcast algorithms for two-dimensional (2d) mesh networks are presented. in the first approach, the source node uses a multicast algorithm to deliver the message to a set of dominating nodes, which can subsequently deliver the message to all other nodes in the network in a single message-passing step. this algorithm requires at most [log2n] steps, where n is the total number of nodes in the network, although in many cases only [log2n] 1 steps are needed. the second algorithm, called the d-node algorithm, reduces the number of steps by using multiple levels of dominating nodes in a recursive manner. for square meshes containing n=22(k+2) nodes, k≥0, the d-node algorithm requires at most k+4 steps. similar upper bounds are shown to hold for meshes of other sizes and shapes. for specific source nodes and mesh shapes, the number of steps is shown to equal the theoretical lower bound of [log5n]. a simulation study confirms the advantage of the d-node algorithm, under various system parameters and conditions, over other broadcast algorithms.  yih-jia tsai philip k. mckinley
prediction of transport protocol performance through simulation  a five-layer simulation model of osi protocols is described and applied to predict transport performance on a local area network (lan). emphasis is placed on time-critical applications typical of a small, flexible manufacturing system. the results predict that, with current technology, osi protocols can provide 1.5 mbps throughput, one-way delays between 6 and 10 ms, and response times between 15 and 25 ms. the results also indicate that csma/cd is a reasonable access method for time-critical applications on small, factory lans, if loads of less than 40% are anticipated. for loads between 40% and 70%, a token passing access method provides better performance for time- critical applications.  k mills m wheatley s heatley
performance analysis of local communication loops  the communication loops analyzed here provide an economical way of attaching many different terminals to a ibm 4331 host processor which may be several kilometers away.  as a first step of the investigation protocol overhead is derived. it consists of request and transmission headers and the associated acknowledgements as defined by the system network architecture. additional overhead is due to the physical layer protocols of the synchronous data link control including lower level confirmation frames.  the next step is to describe the performance characteristics of the loop attachment hardware, primarily consisting of the external loop station adapters for local and teleprocessing connections and the loop adapter processor.  kuno m. roehr horst sadlowski
an evaluation framework for multicast ordering protocols  a new framework for evaluating multicast ordering protocols is presented. it allows to compare solutions to the problem of ordering multicast messages in an identical way at all receiving sites when multiple senders operate concurrently. a new type of delay measure called synchronization delay forms the basis for this framework. it filters out network-dependent factors and accounts precisely for the excess delay that user messages suffer in order to achieve the ordering property. the usefulness of the evaluation framework is demonstrated by applying it to three protocols covered in the literature. as an example their delay behavior is analyzed for low-traffic environments. the evaluation results allow a user to choose the most suitable protocol for his application.  erwin mayer
a case for packet switching in high-performance wide-area networks  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.  z. haas d. r. cheriton
simulation-based performance evaluation of routing protocols for mobile ad hoc networks  in this paper we evaluate several routing protocols for mobile, wireless, ad hoc networks via packet - level simulations. the ad hoc networks are multi - hop wireless networks with dynamically changing network connectivity owing to mobility. the protocol suite includes several routing protocols specifically designed for ad hoc routing, as well as more traditional protocols, such as link state and distance vector, used for dynamic networks. performance is evaluated with respect to fraction of packets delivered, end - to - end delay, and routing load for a given traffic and mobility model. both small 30 nodes and medium sized 60 nodes networks are used. it is observed that the new generation of on - demand routing protocols use much lower routing load, especially with small number of peer - to - peer conversations. however, the traditional link state and distance vector protocols provide, in general, better packet delivery and end - to - end delay performance.  samir r. das robert castañeda jiangtao yan
cp/m development system (abstract only)  one of the most useful tools for a microcomputer laboratory is a development system for the implementation of a variety of microcomputers. such a development system has been implemented for both 8 and 16 bit microprocessors such as the 8085, 8086, 68000, etc. the system incorporates not only the cross assemblers needed but common memory which can be downloaded from the cp/m system and can be tri-stated between the microcomputer in use and the cp/m system.  kenneth cooper jeffrey smith
performance interactions between p-http and tcp implementations this document describes several performance problems resulting from interactions between implementations of persistent-http (p-http) and tcp. two of these problems tie p-http performance to tcp delayed-acknowledgments, thus adding up to 200ms to each p-http transaction. a third results in multiple slow-starts per tcp connection. unresolved, these problems result in p-http transactions which are 14 times slower than standard http and 20 times slower than potential p-http over a 10 mb/s ethernet. we describe each problem and potential solutions. after implementing our solutions to two of the problems, we observe that p-http performs better than http on a local ethernet. although we observed these problems in specific implementations of http and tcp (apache-1.1b4 and sunos 4.1.3, respectively), we believe that these problems occur more widely. john heidemann
the distributed double-loop computer network (ddlcn)  this paper presents the design of the distributed double-loop computer network (ddlcn), which is a local-area distributed computing system that interconnects midi, mini and micro computers using a fault-tolerant double-loop network. several new features and novel concepts have been incorporated into the design of its subsystems, viz., the reliable communication network, the programming/operating system (p/os), and the distributed loop data base system (dldbs). the interface design is unique in that it employs tri-state control logic and bit-sliced processing, thereby enabling the network to become dynamically reconfigurable and fault tolerant with respect to communication link failure as well as component failure in the interface. three classes of multi-destination communication protocols, each providing a different degree of reliability, have been incorporated into the network to facilitate efficient and reliable exchanges of messages.  the p/os is distinguished from other similar research efforts in that its ultimate goal is to support not only communication and cooperation among autonomous, distributed processes running at various nodes, but also to support convenient and correct resource sharing through program generation (semi-automatic programming) for application and systems programmers. a new concurrency control mechanism for dldbs has been developed, which uses distributed control without global locking and is deadlock free. in addition to being simple to implement and having good performance (high throughput and low delay), the mechanism is also robust with respect to failure of both communication links and hosts.  ming t. liu sandra a. mamrak jayshree ramanathan
adaptive filters in multiuser (mu) cdma detection  the primary purpose of this work is to provide a perspective on adaptive code- division multiple- access (cdma) mu receivers that have been proposed for future digital wireless systems. adaptive receivers can potentially adapt to unknown and time-varying environmental parameters such as the number of users, their received powers, spreading codes and time-delays. two adaptive receiver architectures are primarily considered -- one in which the sampled received signal is filtered, and can be used in both the uplink (i.e., at the base station) and downlink (i.e., at the mobile handset), and another in which the spreading codes of users are filtered (assuming knowledge of users' codes and its timing at the receiver) for use in the uplink. relevant issues such as training-based and blind implementations of the adaptive receiver are discussed, as well as (transient) convergence rates and estimation noise in steady-state.  teng joon lim sumit roy
flexible network support for mobile hosts  fueled by the large number of powerful light-weight portable computers, the expanding availability of wireless networks, and the popularity of the internet, there is an increasing demand to connect portable computers to the internet at any time and in any place. however, the dynamic nature of a mobile host's connectivity and its use of multiple network interfaces require more flexible network support than has typically been available for stationary workstations.  this paper introduces two flow-oriented mechanisms, in the context of mobile ip [25], to ensure a mobile host's robust and efficient communication with other hosts in a changing environment. one mechanism supports multiple packet delivery methods (such as regular ip or mobile ip) and adaptively selects the most appropriate one to use according to the characteristics of each traffic flow. the other mechanism enables a mobile host to make use of multiple network interfaces simultaneously and to control the selection of the most desirable network interfaces for both outgoing and incoming packets for different traffic flows. we demonstrate the usefulness of these two network layer mechanisms and describe their implementation and performance.  xinhua zhao claude castelluccia mary baker
on the performance of loosely coupled multiprocessors  a processing element (pe) essentially consists of a processor and a memory module. a loosely coupled multiprocessor is comprised of a set of such pes interconnected through an interconnection network (in). the design of the in is crucial to an efficient communication beween the pes. this paper presents approximate evaluations of two loosely coupled architectures, each having three types of ins, namely: shared bus, crossbar and a class of multistage interconnection networks (mins) called omega network. probability of acceptance (pa) of a message is considered as a measure of the performance. for a high rate of internal requests, it is shown that an omega network performs close to a crossbar while reducing the the cost of interconnection to a large extent.  laxmi n. bhuyan
session directories and scalable internet multicast address allocation a multicast session directory is a mechanism by which users can discover the existence of multicast sessions. in the mbone, session announcements have also served as multicast address reservations - a dual purpose that is efficient, but which may cause some side-affects as session directories scale.in this paper we examine the scaling of multicast address allocation when it is performed by such a multicast session directory. despite our best efforts to make such an approach scale, this analysis ultimately reveals significant scaling problems, and suggests a new approach to multicast address allocation in the internet environment. mark handley
an associative/parallel processor for partial match retrieval using superimposed codes  this paper presents the design and implementation of special hardware for effective use of the method of superimposed codes. it is shown that the method of superimposed codes is particularly well suited to easy design and implementation of fast and modular hardware. the implementation has shown that a performance gain of two orders of magnitude over conventional software implementations is obtained by using the special hardware. this makes the method of superimposed codes extremely attractive for data base system requiring partial match retrieval. we also demonstrate that the associative memory design is easily adaptable to large scale integration which would make such an approach very cost effective and lead to even further gains in performance.  sudhir r. ahuja charles s. roberts
nifdy: a low overhead, high throughput network interface in this paper we present nifdy, a network interface that uses admission control to reduce congestion and ensures that packets are received by a processor in the order in which they were sent, even if the underlying network delivers the packets out of order. the basic idea behind nifdy is that each processor is allowed to have at most one outstanding packet to any other processor unless the destination processor has granted the sender the right to send multiple unacknowledged packets. further, there is a low upper limit on the number of outstanding packets to all processors.we present results from simulations of a variety of networks (meshes, tori, butterflies, and fat trees) and traffic patterns to verify nifdy's efficacy. our simulations show that nifdy increases throughput and decreases overhead. the utility of nifdy increases as a network's bisection bandwidth decreases. when combined with the increased payload allowed by in- order delivery nifdy increases total bandwidth delivered for all networks. the resources needed to implement nifdy are small and constant with respect to network size. timothy callahan seth copen goldstein
mocha: a quality adaptive multimedia proxy cache for internet streaming  multimedia proxy caching is a client-oriented solution for large- scale delivery of high quality streams over heterogeneous networks such as the internet. existing solutions for multimedia proxy caching are unable to adjust quality of cached streams. thus these solutions either can not maximize delivered quality or exhibit poor caching efficiency. this paper presents the design and implementation ofmocha, a quality adaptive multimedia proxy cache for layered encoded streams. the main contribution of mocha is its ability to adjust quality of cached streams based on their popularity and on the available bandwidth between proxy and interested clients. thus mocha can significantly improve caching efficiency without compromising delivered quality. to perform quality adaptive caching, mocha implementsfine-grained replacementandfine-grained prefetchingmechanisms. we describe our prototype implementation of mocha on top of squid and address various design challenges such as managing partially cached streams. finally, we validate our implementation and present some of our preliminary results.  reza rejaie jussi kangasharju
local networking by ring, ethernet, broadband, and pabx - perspectives from the field  the advocates of various approaches to local networking have largely emerged from the ranks of research and development organizations, and have thus mostly described the prospective advantages of their preferred technologies. often, in the field, the dominating concerns turn out to be different from the ones anticipated by the developers. this panel session will bring together four representatives of organizations that have each chosen different local network technologies, developed them, placed products in the field, and gained some practical experience.  jerome h. saltzer
the performance potential of multiple functional unit processors  in this paper, we look at the interaction of pipelining and multiple functional units in single processor machines. when implementing a high performance machine, a number of hardware techniques maybe used to improve the performance of the final system. our goal is to gain an understanding of how each of these techniques contribute to performance improvement. as a basis for our studies we use a cray-like processor model and the issue rate (instructions per clock cycle) as the performance measure. we then systematically augment this base, non-pipelined, machine with more and more hardware features and evaluate the performance impact of each feature. we find, for example, that in non-vector machines, pipelining multiple function units does not provide significant performance improvements. dataflow limits are then derived for our benchmark programs to determine the performance potential of each benchmark. in addition, other limits are computed which apply more realistic constraints on a computation. based on these more realistic limits, we determine it is worthwhile to investigate the performance improvements that can be achieved from issuing multiple instructions each clock cycle. several hardware approaches are evaluated for issuing multiple instructions each clock cycle.  a. r. pleszkun g. s. sohi
reworking the rpc paradigm for mobile clients  remote procedure call (rpc) is a popular paradigmfor designing distributed applications. the existing rpc implementations, however, do not allow special treatment of mobile hosts and wireless links; which can be a cause of degraded performance and service disruptions in the presence of disconnections, moves and wireless errors. in addition, future information oriented and location aware mobile applications will also need the ability to dynamically bind mobile clients to local information servers. current rpc implementations do not support dynamic binding of mobile clients to servers. in this paper we explore an alternate approach for implementing remote procedure calls that is based on a client- agent-server orindirect model. we describe an rpc implementation based on this approach, called m-rpc, which provides a clean way for mobile wireless clients to access existing rpc services on the wired network via their mobility support routers (msrs). m-rpc adds to the rpc layer on the mobile clients such useful features as dynamic binding, support for disconnected operation and call retries from the msr.  ajay v. bakre b. r. badrinath
probability of heavy traffic period in third generation cdma mobile communication  the paper considers a problem of deriving the multidimensional distribution of a segment of a long-range dependent traffic in the third generation mobile communication network. an exact expression for the probability is found when a self-similar process from [8] models the traffic. the probability of heavy- traffic period, the outage probability, and the level-crossing probability are found. it is shown that the level crossing probability depends on the average call length only. further, this probability for traffic with dependent samples is lower than for traffic with independent samples. also, it is shown that there is a linear dependence between the average heavy traffic interval and the average call length.  b. s. tsybakov
an end-to-end approach to host mobility  we present the design and implementation of an end-to-end architecture for internet host mobility using dynamic updates to the domain name system (dns) to track host location. existing tcp connections are retained using secure and efficient connection migration, enabling established connections to seamlessly negotiate a change in endpoint ip addresses without the need for a third party. our architecture is secure---name updates are effected via the secure dns update protocol, while tcp connection migration uses a novel set of migrate options---and provides a pure end-system alternative to routing-based approaches such as mobile ip.  mobile ip was designed under the principle that fixed internet hosts and applications were to remain unmodified and only the underlying ip substrate should change. our architecture requires no changes to the unicast ip substrate, instead modifying transport protocols and applications at the end hosts. we argue that this is not a hindrance to deployment; rather, in a significant number of cases, it allows for an easier deployment path than mobile ip, while simultaneously giving better performance. we compare and contrast the strengths of end-to-end and network- layer mobility schemes, and argue that end-to-end schemes are better suited to many common mobile applications. our performance experiments show that hand- off times are governed by tcp migrate latencies, and are on the order of a round-trip time of the communicating peers.  alex c. snoeren hari balakrishnan
decoupled access/execute computer architectures  an architecture for improving computer performance is presented and discussed. the main feature of the architecture is a high degree of decoupling between operand access and execution. this results in an implementation which has two separate instruction streams that communicate via queues. a similar architecture has been previously proposed for array processors, but in that context the software is called on to do most of the coordination and synchronization between the instruction streams. this paper emphasizes implementation features that remove this burden from the programmer. performance comparisons with a conventional scalar architecture are given, and these show that considerable performance gains are possible.  single instruction stream versions, both physical and conceptual, are discussed with the primary goal of minimizing the differences with conventional architectures. this would allow known compilation and programming techniques to be used. finally, the problem of deadlock in such a system is discussed, and one possible solution is given.  james e. smith
a comparison of layering and stream replication video multicast schemes  the heterogeneity of the internet's transmission resources and end sys tem capability makes it difficult to agree on acceptable traffic characteristics among the multiple receivers of a multicast video stream. three basic approaches have been proposed to deal with this problem: 1) multicasting of replicated video streams at different rates, 2) multicasting the video encoded in cumulative layers, and 3) multicasting the video encoded in non-cumulative layers. even though there is a common belief that the layering approach is better than the replicated stream approach, there has been no studies that compare these schemes. this paper is devoted to such a systematic comparison. our starting point is an observation (substantiated by results in the literature) that a bandwidth penalty is incurred by encoding a video stream in layers. we argue that a fair comparison of these schemes needs to take into account this penalty as well as the specifics of the encoding used in each scheme, protocol complexity, and the topological placement of the video source and the receivers relative to each other. our results show that the believed superiority of layered multicast transmission relative to stream replication is not as clear cut as is widely believed and that there are indeed scenarios where replication is the preferred approach.  taehyun kim mostafa h. ammar