waashk/acm huggingface dataset:
analysis of a local-area wireless network  to understand better how users take advantage of wireless networks, we examine a twelve-week trace of a building-wide local-area wireless network. we analyze the network for overall user behavior (when and how intensively people use the network and how much they move around), overall network traffic and load characteristics (observed throughput and symmetry of incoming and outgoing traffic), and traffic characteristics from a user point of view (observed mix of applications and number of hosts connected to by users).  amongst other results, we find that users are divided into distinct location- based sub- communities, each with its own movement, activity, and usage characteristics. most users exploit the network for web-surfing, session- oriented activities and chat-oriented activities. the high number of chat- oriented activities shows that many users take advantage of the mobile network for synchronous communication with others. in addition to these user-specific results, we find that peak throughput is usually caused by a single user and application. also, while incoming traffic dominates outgoing traffic overall, the opposite tends to be true during periods of peak throughput, implying that significant asymmetry in network capacity could be undesirable for our users.  while these results are only valid for this local- area wireless network and user community, we believe that similar environments may exhibit similar behavior and trends. we hope that our observations will contribute to a growing understanding of mobile user behavior.  diane tang mary baker
on the stability of the ethernet  we consider the stochastic behavior of binary exponential backoff, a probabilistic algorithm for regulating transmissions on a multiple access channel. ethernet, a local area network, is built upon this algorithm. the fundamental theoretical issue is stability: does the backlog of packets awaiting transmission remain bounded in time, provided the rates of new packet arrivals are small enough?  we present a realistic model of n ≥ 2 stations communicating over the channel. our main result is to establish that the algorithm is stable if the sum of the arrival rates is sufficiently small. we report detailed results on which rates lead to stability when n = 2 stations share the channel. in passing we derive several other results bearing on the efficiency of the conflict resolution process. lastly, we report results from a simulation study, which, in particular, indicate alternative retransmission strategies can significantly improve performance.  j goodman a g greenberg n madras p march
the satellite transmission protocol of the universe project  the universe network uses a broadcast satellite channel to connect local area networks into a high speed wide area network. the satellite channel is scheduled using a packet tdma scheme. time allocation is controlled by one site acting as master, but is based on indications received from each participating site about its own requirements. the tdma scheduling is thus based not on circuits or the requirements of individual packets, but on a picture of the distributed requirements of the network as a whole. the paper describes the protocol currently implemented on the universe network and looks forward to a more general way of applying this technique.  a. gillian waters christopher j. adams
the atm physical layer  in this article, we present an overview of the physical layer specification of the emerging asynchronous transfer mode (atm) networks. these specifications concern the complete details of how to ship 53-byte atm cells from point a to point b over a physical medium on a local area network (wan). while the task of defining the interfaces and line coding of the transceivers over different physical media is ongoing, the primary underlying theme has been the leveraging of existing standards and practices to the maximum extent possible.  sailes k. rao mehdi hatamian
ask digital demodulation scheme for noise immune infrared data communication  a high performance architecture is proposed for the ask (amplitude shift keying) digital demodulation, which is dedicated to the noise immune wireless infrared data communication. in this architecture, an infrared subcarrier detected by a photodetector is digitized into ttl interface level pulses, and the digitized subcarrier is demodulated by a 1-bit digital demodulator. to improve the noise immunity against fluorescent lamps, the optical noises from the lamps are analyzed and the behavior of an ask infrared communication link is modeled under these noises. on the basis of this model, a digital demodulator is synthesized by means of a high level synthesis tool, aiming at implementing an algorithm of discriminating the subcarrier from optical noises. a part of experimental results shows that the ask receiver realized with the use of this digital demodulator can achieve an error free infrared link even under the intense noises from fluorescent lamps.  hiroshi uno keiji kumatani hiroyuki okuhata isao shirakawa toru chiba
multicast support for mobile-ip with the hierarchical local registration approach  the mobile-ip (m-ip) protocol allows ip hosts to move between different networks without the need to tear down established sessions. the mobile-ip systems supporting local registration were introduced to reduce the frequency by which home registration with the remotely located home agent is needed. providing an efficient system that support ip multicast, in an environment where the multicast group members frequently change their locations, is a challenge for systems providing mobility support. the local registration introduces its own additional challenges that prevent the direct application of the approaches proposed in the ietf standard to support multicast on mobile-ip. in this work we will propose an architecture that supports ip multicast in this environment. three flavours of the architecture are described while presenting the corresponding features. the proposed schemes take advantage of the inherent characteristics of the local registration to enhance the efficiency of the multicast support. performance aspects such as multicast datagram delay, delivery cost and robustness are analyzed, then simulation results are used to describe the performance of the different approaches under various conditions.  h. omar t. saadawi m. lee
on estimating end-to-end network path properties the more information about current network conditions available to a transport protocol, the more efficiently it can use the network to transfer its data. in networks such as the internet, the transport protocol must often form its own estimates of network properties based on measurements performed by the connection endpoints. we consider two basic transport estimation problems: determining the setting of the retransmission timer (rto) for a reliable protocol, and estimating the bandwidth available to a connection as it begins. we look at both of these problems in the context of tcp, using a large tcp measurement set [pax97b] for trace-driven simulations. for rto estimation, we evaluate a number of different algorithms, finding that the performance of the estimators is dominated by their minimum values, and to a lesser extent, the timer granularity, while being virtually unaffected by how often round-trip time measurements are made or the settings of the parameters in the exponentially- weighted moving average estimators commonly used. for bandwidth estimation, we explore techniques previously sketched in the literature [hoe96, ad98] and find that in practice they perform less well than anticipated. we then develop a receiver-side algorithm that performs significantly better. mark allman vern paxson
an analysis of link level protocols for error prone links  this paper analyzes the maximum throughput across a full duplex link, under three link level protocols. the three protocols all assume cumulative acknowledgements, but the sender's retransmission policy and the destination's policy on retaining correctly received packets which arrive before an expected retransmission do differ. the results quantify the throughput advantages in retaining all correctly received packets, for the two different retransmission policies. a retention policy on the part of the destination is most advantageous when the link is quite error-prone.  leslie jill miller
how computer architecture trends may affect future distributed systems: from infiniband clusters to inter-processor speculation (abstract)  the design of distributed systems is and will be altered by the computer architecture innovations enabled by moore's law. i will survey some of these issues and how they might affect the design of distributed systems. topics will include ideas for merging of clusters and large shared-memory multiprocessors, the emerging infiniband system area network standard, the effect of simultaneous multithreading, and the potential for softening the memory wall through inter-processor speculation.  mark d. hill
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, ot 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
transmitting time-critical data over heterogeneous subnetworks using standardized protocols  current communication networks consist of subnetworks of different types. therefore a common network protocol has to be used for the transmission of data in such a heterogeneous network. since some time the requirement of mobility in communication networks is showing up. for that reason wireless networks are playing an increasing role as subnetworks. on the other hand there is the need for multiplexed transmission of time- critical and non time- critical (normal) data within a heterogeneous network. in this paper we discuss the problem of multiplexed transmission of time- critical and of non time-critical data over a wireless type subnetwork using a common standardized network protocol. many of the available wireless subnetworks are of low or medium transmission speed and guarantee a fixed transmission bandwidth at the access point. we describe a mechanism to transmit time-critical data in such a type of subnetwork using a connectionless transport and a connectionless network protocol. the concurrent transmission of non time-critical data using a connection oriented transport and the same connectionless network protocol is assumed to be of lower priority; it is scheduled in a way to fill the remaining capacity, which has not been reserved for the transmission of time- critical data. in our discussion we concentrate on the standardized iso/osi protocools clnp as connectionless network protocol, cltp as connectionless transport protocol and tp4 as connection oriented transport protocol. we propose a header compression protocol and a fragmentation protocol for use on low bandwidth subnetworks.  w. storz g. beling
hardware/software cooperation in the iapx-432  the intel iapx-432 is an object-based microcomputer system with a unified approach to the design and use of its architecture, operating system, and primary programming language. the concrete architecture of the 432 incorporates hardware support for data abstraction, small protection domains, and language-oriented run-time environments. it also uses its object- orientation to provide hardware support for dynamic heap storage management, interprocess communication, and processor dispatching.  we begin with an overview of the 432 architecture so readers unfamiliar with its basic concepts will be able to follow the succeeding discussion without the need to consult the references. following that, we introduce the various forms of hardware/software cooperation and the criteria by which a function or service is selected for migration. this is followed by several of the more interesting examples of hardware/software cooperation in the 432. a comparison of cooperation in the 432 with several contemporary machines and discussions of development issues, past and future, complete the paper.  justin rattner
low load latency through sum-addressed memory (sam) load latency contributes significantly to execution time. because most cache accesses hit, cache-hit latency becomes an important component of expected load latency. most modern microprocessors have base+offset addressing loads; thus effective cache-hit latency includes an addition as well as the ram access.this paper introduces a new technique used in the ultrasparc iii microprocessor, sum-addressed memory (sam), which performs true addition using the decoder of the ram array, with very low latency. we compare sam with other methods for reducing the add part of load latency. these methods include sum-prediction with recovery, and bitwise indexing with duplicate-tolerance. the results demonstrate the superior performance of sam. william l. lynch gary lauterbach joseph i. chamdani
speeding up protocols for small messages many techniques have been discovered to improve performance of bulk data transfer protocols which use large messages. this paper describes a technique that improves protocol performance for protocols that use small messages, such as signalling protocols, by reducing memory system penalties. detailed measurements show that for tcp, most memory system costs are due to poor locality in the protocol code itself, rather than movement of data. we present a new technique, analogous to blocked matrix multiplication, for scheduling layer processing to reduce memory system costs, and analyze its performance in a synthetic environment. trevor blackwell
dataflow machine architecture  dataflow machines are programmable computers of which the hardware is optimized for fine-grain data-driven parallel computation. the principles and complications of data-driven execution are explained, as well as the advantages and costs of fine-grain parallelism. a general model for a dataflow machine is presented and the major design options are discussed.  most dataflow machines described in the literature are surveyed on the basis of this model and its associated technology. for general-purpose computing the most promising dataflow machines are those that employ packet-switching communication and support general recursion. such a recursion mechanism requires an extremely fast mechanism to map a sparsely occupied virtual space to a physical space of realistic size. no solution has yet proved fully satisfactory.  a working prototype of one processing element is described in detail. on the basis of experience with this prototype, some of the objections raised against the dataflow approach are discussed. it appears that the overhead due to fine- grain parallelism can be made acceptable by sophisticated compiling and employing special hardware for the storage of data structures. many computing- intensive programs show sufficient parallelism. in fact, a major problem is to restrain parallelism when machine resources tend to get overloaded. another issue that requires further investigation is the distribution of computation and data structures over the processing elements.  arthur h. veen
an efficient location management protocol for wireless atm customer premises networks  in this paper, we present a new location management protocol for wireless atm networks, called lmcp (location management and control protocol). this protocol is based on the pnni (private network-to-network interface) routing functionality to advertise the movement of mobile terminals within predefined areas. moreover, lcmp uses specialized entities to store and retrieve the current location area of the mobile terminals. these entities are located in mobility enhanced switches that control the execution of mobility procedures (e.g., handovers).  the main benefit from the application of lmcp is the establishment of connections that do not contain any misrouted segments. furthermore, it requires minor modifications to the pnni and enables its inter-working with other location management mechanisms. the protocol is compared with other similar mechanisms, and its efficiency is demonstrated by the results of an analytical model.  evangelos zervas alexandros kaloxylos lazaros merakos
enhanced reserved polling multiaccess technique for multimedia personal communication systems  this article describes a multiaccess technique which allows the transport of multimedia information across global personal communication systems (pcs). impressive growth in the application of wireless technologies to telecommunications has sparked active research on a new generation of mobile radio networks projected to handle heterogeneous traffic types. one of the key requirements of these advanced systems is the multiaccess protocol which must guarantee quality of service and provide efficient access to multirate broadband applications that combine voice, video and data communications. in addition, the protocol is required to operate with the demanding constraints imposed by moving users, dynamic traffic load variations and highly sensitive wireless links. to this end, a multiaccess scheme called "enhanced reserved polling" is proposed. the scheme is designed to execute many pcs-related functions including radio resource assignment, connection control and mobility management. it accommodates a diverse mixture of delay classes/message priorities and can also enhance the bandwidth sharing among different cells in the network.  benny bing regu subramanian
interleaved parallel schemes: improving memory throughput on supercomputers  on many commercial supercomputers, several vector register processors share a global highly interleaved memory in a mimd mode. when all the processors are working on a single vector loop, a significant part of the potential memory throughput may be wasted due to the asynchronism of the processors.  in order to limit this loss of memory throughput, a simd synchronization mode for vector accesses to memory may be used. but an important part of the memory bandwidth may be wasted when accessing vectors with an even stride.  in this paper, we present ips, an interleaved parallel scheme, which ensures an equitable distribution of elements on a highly interleaved memory for a wide range a vector strides. we show how to organize access to memory, such that unscrambling of vectors from memory to the vector register processors requires a minimum number of passes through the interconnection network.  andre seznec jacques lenfant
dynamics of tcp traffic over atm networks  we investigate the performance of tcp connections over atm networks without atm-level congestion control, and compare it to the performance of tcp over packet-based networks. for simulations of congested networks, the effective throughput of tcp over atm can be quite low when cells are dropped at the congested atm switch. the low throughput is due to wasted bandwidth as the congested link transmits cells from "corrupted" packets, i.e., packets in which at least one cell is dropped by the switch. this fragmentation effect can be corrected and high throughput can be achieved if the switch drops whole packets prior to buffer overflow; we call this strategy early packet discard. we also discuss general issues of congestion avoidance for best-effort traffic in atm networks.  allyn romanow sally floyd
dataflow computer development in japan  this paper describes the research activity on dataflow computing in japan focusing on dataflow computer development at the electrotechnical laboratory (etl). first, the history of dataflow computer development in japan is outlined. some distinguished milestones in the history are mentioned in detail. second, two types of dataflow computing systems developed at etl, sigma-1 and em-4, are described with their research goals. the fundamental characteristics of the both systems are given and some comparisons are made. finally, future problems toward new generation computer systems to meet the challenge of tera flops machines are discussed.  toshitsugu yuba toshio shimada yoshinori yamaguchi kei hiraki shuichi sakai
an integrated congestion management architecture for internet hosts this paper presents a novel framework for managing network congestion from an end-to-end perspective. our work is motivated by trends in traffic patterns that threaten the long-term stability of the internet. these trends include the use of multiple independent concurrent flows by web applications and the increasing use of transport protocols and applications that do not adapt to congestion. we present an end-system architecture centered around a congestion manager (cm) that ensures proper congestion behavior and allows applications to easily adapt to network congestion. our framework integrates congestion management across all applications and transport protocols. the cm maintains congestion parameters and exposes an api to enable applications to learn about network characteristics, pass information to the cm, and schedule data transmissions. internally, it uses a window-based control algorithm, a scheduler to regulate transmissions, and a lightweight protocol to elicit feedback from receivers.we describe how tcp and an adaptive real-time streaming audio application can be implemented using the cm. our simulation results show that an ensemble of concurrent tcp connections can effectively share bandwidth and obtain consistent performance, without adversely affecting other network flows. our results also show that the cm enables audio applications to adapt to congestion conditions without having to perform congestion control or bandwidth probing on their own. we conclude that the cm provides a useful and pragmatic framework for building adaptive internet applications. hari balakrishnan hariharan s. rahul srinivasan seshan
the n-ary stack algorithm for the wireless random access channel  the emergence of wireless and personal communication networks has brought random access protocols for packet radio networks back to the research forefronts. most such protocols are based on the ever popular aloha protocol. unfortunately, this protocol is inherently unstable and requires sophisticated schemes to stabilize it. another class of random access schemes, called limited sensing or stack algorithms, has been proposed that is stable and allows for the dynamic incorporation of new stations into the network. in this paper, we will review the simple to implement n-ary stack algorithm, and we will study its performance under various system parameters in the presence of capture, and also in the presence of feedback errors. finally, we will investigate its maximum system throughput under various traffic generation processes.  chatschik c. bisdikian