waashk/acm huggingface dataset:
transparent interconnection of incompatible local area networks using bridges  no single lan technology is sufficient to interconnect all the computers in a given plant, campus, or site. thus it is desirable to combine different types of lans, using a device called a bridge, to produce an extended lan. some lans in the extended lan may have incompatible data link formats. thus a bridge may need to encapsulate a frame originating on lan a inside the data link header of another (incompatible) lan b in order to allow the type a frame to travel over lan b. in general, frames sent between any pair of lans in the extended lan must be encapsulated across every incompatible lan in the path between the lans.  bridges learn their routing information from information contained in frames they forward. besides the problems of distinguishing various kinds of encapsulated and unencapsulated frames, the encapsulating protocol used by bridges must also solve the learning problem. this leads to a new set of considerations and solutions. we begin with a rough solution, and refine it using informal arguments and examples to lead to the final description. the stages in the description roughly mimic the design process.  r. perlman g. varghese
distributed systems support for adaptive mobile applications  mobile applications must operate in environments which experience rapid and significant fluctuations in the quality of service (qos) offered by their underlying communications infrastructure. these fluctuations may be the result of explicit changes between networks, increased competition for network resources or degradation of service due to environmental factors. in order to continue to operate effectively mobile applications must be capable of adapting to these changes. this paper reports on the design and implementation of a number of services to support adaptive applications. in particular, the paper describes in detail a remote procedure call protocol (rpc) called qex which has been designed to adapt to changes in communications qos and to provide feedback to applications when changes to the qos occur. qex has been implemented as part of the ansaware distributed systems platform and together with a number of other services described in this paper enables ansaware to support advanced mobile applications .  nigel davies adrian friday gordon s. blair keith cheverst
slow shadowing and macrodiversity in the capture-division packet access (cdpa)  recently, a new method for achieving spectrum reuse in cellular systems, called capture-division packet access (cdpa), has been introduced. the method uses a single frequency in all cells, and exploits packet switching and packet retransmission as a means to overcome destructive cochannel interference. as the cdpa key factor is packet retransmission, it is also very effective in fighting lognormal shadowing attenuation as long as this attenuation can be considered independent from slot to slot. in this paper we analyze cdpa in presence of "slow shadowing", to account for situations in which obstacles obscure the receiver for several transmission periods. the results show a severe throughput impairment with respect to the "fast shadowing" model. a variation of cdpa, macrodiversity cdpa, that uses three corner fed antennas and three packet receivers is analyzed. the numerical results show that m-cdpa is more efficient than cdpa and that it is only slightly affected by both fast and slow shadowing. to further investigate its robustness, a non-lognormal slow shadowing model, the hard shadowing model, is also analyzed.  flaminio borgonovo michele zorzi luigi fratta
agent-based forwarding strategies for reducing location management cost in mobile networks  an important issue in location management for dealing with user mobility in wireless networks is to reduce the cost associated with location updates and searches. the former operation occurs when a mobile user moves to a new location registration area and the network is being informed of the mobile user's current location; the latter operation occurs when there is a call for the mobile user and the netowrk must deliver the call to the mobile user. in this paper, we propose and analyze a class of new agent-based forwarding schemes with the objective to reduce the location management cost in mobile wireless networks. we develop analytical models to compare the performance of the proposed schemes with existing location management schemes to demonstrate their feasibility and also to reveal conditions under which our proposed schemes are superior to existing ones. our proposed schemes are particularly suitable for mobile networks with switches which can cover a large number of location registration areas.  ing-ray chen tsong-min chen chiang lee
the failure of tcp in high-performance computational grids  distributed computational grids depend on tcp to ensure reliable end- to-end communication between nodes across the wide-area network (wan). unfortunately, tcp performance can be abysmal even when buffers on the end hosts are manually optimized. recent studies blame the self-similar nature of aggregate network traffic for tcp's poor performance because such traffic is not readily amenable to statistical multiplexing in the internet, and hence computational grids.  in this paper, we identify a source of self-similarity previously ignored, a source that is readily controllable-tcp. via an experimental study, we examine the effects of the tcp stack on network traffic using different implementations of tcp. we show that even when aggregate application traffic ought to smooth out as more applications' traffic are multiplexed, tcp induces burstiness into the aggregate traffic load, thus adversely impacting network performance. furthermore, our results indicate that tcp performance will worsen as wan speeds continue to increase.  w. feng p. tinnakornsrisuphap
completeness theorems for non-cryptographic fault-tolerant distributed computation  every function of n inputs can be efficiently computed by a complete network of n processors in such a way that:  if no faults occur, no set of size t < n/2 of players gets any additional information (other than the function value),  even if byzantine faults are allowed, no set of size t < n/3 can either disrupt the computation or get additional information.  furthermore, the above bounds on t are tight!  michael ben-or avi wigderson
new parallelization and convergence results for nc: a negotiation-based fpga router  the negotiation-based routing paradigm has been used successfully in a number of fpga routers. in this paper, we report several new findings related to the negotiation-based routing paradigm. we examine in-depth the convergence of the negotiation-based routing algorithm. we illustrate that the negotiation-based algorithm can be parallelized. finally, we demonstrate that a negotiation- based parallel fpga router can perform well in terms of delay and speedup with practical fpga circuits.  pak k. chan martine d. f. schlag
improving tcp performance over asymmetric networks  bandwidth asymmetry is quite common among modern networks; e.g., adsl, cable tv, wireless, and satellite link with a terrestrial return path. in these networks, the bandwidth over one direction can be orders of magnitude smaller than that over the other. the performance of tcp transfer in the high bandwidth direction can be severly reduced by the delay acknowledgment packets experienced in the reverse direction. in this paper, we describe our proposed solution ace (acknowledgement based on cwnd estimation). in comparison to other solutions, ace requires only modification of the tcp stack at terminals attached to an asymmetric network. we evaluated the performance of ace over a cable modem network by simulation. we have also implemented ace on the linux platform and tested it on a small testbed network with an emulated asymmetric link. the performance improvement was significant especially when there is a high degree of asymmetry.  ivan tam ming- chit du jinsong weiguo wang
improving round-trip time estimates in reliable transport protocols as a reliable, end-to-end transport protocol, the arpa transmission control protocol (tcp) uses positive acknowledgements and retransmission to guarantee delivery. tcp implementations are expected to measure and adapt to changing network propagation delays so that its retransmission behavior balances user throughput and network efficiency. however, tcp suffers from a problem we call _retransmission ambiguity_: when an acknowledgment arrives for a segment that has been retransmitted, there is no indication which transmission is being acknowledged. many existing tcp implementations do not handle this problem correctly.this paper reviews the various approaches to retransmission and presents a novel and effective approach to the retransmission ambiguity problem. phil karn craig partridge
taming xunet iii an architecture for network management and control for emerging wide-area atm networks is presented. the architecture was implemented on xunet iii, a nationwide atm network deployed by at&amp;t.; the xunet network management system is based on the osi standards and includes configuration, fault and performance management. an osi agent resides at every switching node. its capabilities include monitoring of cell level quality of service in real time and estimation of the schedulable region. the complexity and accuracy of real-time monitoring functionalities is investigated. to provide realistic traffic loads, distributed traffic generation systems both at the cell and call level have been implemented. in order to study the trade- off between the network transport and signalling system we have implemented a virtual path signalling capability. our experiments show that the ability of a network to admit calls is limited by two distinct factors: the capacity of the network and the processing power of the signalling system. depending on the bandwidth requirement of calls, the limit of one or the other will be first reached. this is a key observation, unique to broadband networks. nikos g. aneroussis aurel a. lazar dimitrios e. pendarakis
experimentations with tcp selective acknowledgment this paper reports our experimentation results with tcp selective acknowledgments (tcp-sack), which became an internet proposed standard protocol recently. to understand the performance impact of tcp-sack deployment, in this study we examined the following issues: how much performance improvement tcp-sack may bring over the current tcp implementation, tcp-reno. we conducted experiments both on a lab testbed and over the internet, under various conditions of link delay and losses. in particular, how well tcp-sack may perform over long delay paths that include satellite links. what is the performance impact of tcp connections with sack options on those connections without sack when the two types running in parallel, if there is any. renaud bruyeron bruno hemon lixia zhang
a cellular wireless local area network with qos guarantees for heterogeneous traffic  a wireless local area network (wlan) or a cell with quality- of-service (qos) guarantees for various types of traffic is considered. a centralized (i.e., star) network is adopted as the topology of a cell which consists of a base station and a number of mobile clients. dynamic time division duplexed (tdd) transmission is used, and hence, the same frequency channel is time-shared for downlink and uplink transmissions under the dynamic control of the base station. we divide traffic into two classes: class i (real-time) and ii (non- real-time). whenever there is no eligible class-i traffic for transmission, class-ii traffic which requires no delay-bound guarantees is transmitted, while uplink transmissions are controlled with a reservation scheme. class-i traffic which requires a bounded delay and guaranteed throughput is handled with the framing strategy (golestani, ieee j. selected areas commun. 9(7), 1991) which consists of a smoothness traffic model and the stop-and-go queueing scheme. we also establish the admission test for adding new class-i connections. we present a modified framing strategy for class-i voice uplink transmissions which utilizes the wireless link efficiently at the cost of some packet losses. finally, we present the performance (average delay and throughput) evaluation of the reservation scheme for class-ii traffic using both analytical calculations and simulations.  sunghyun choi kang g. shin
a model for dataflow based vector execution  although the dataflow model has been shown to allow the exploitation of parallelism at all levels, research of the past decade has revealed several fundamental problems: synchronization at the instruction level, token matching, coloring and re- labeling operations have a negative impact on performance by significantly increasing the number of non-compute "overhead" cycles. recently, many novel hybrid von-neumann data driven machines have been proposed to alleviate some of these problems. the major objective has been to reduce or eliminate unnecesssary synchronization costs through simplified operand matching schemes and increased task granularity. moreover, the results from recent studies quantifying locality suggest sufficient spatial and temporal locality is present in dataflow execution to merit its exploitation.  in this paper we present a data structure for exploiting locality in a data driven environment: the vector cell. a vector cell consists of a number of fixed length chunks of data elements. each chunk is tagged with a presence bit, providing intra-chunk strictness and inter-chunk non- strictness to data structure access. we describe the semantics of the model, processor architecture and instruction set as well as a sisal to dataflow vectorizing compiler back-end. the model is evaluated by comparing its performance to those of both a classical fine-grain dataflow processor employing i-structures and a conventional pipelined vector processor. results indicate the model is surprisingly resilient to long memory and communication latencies, and is able to dynamically exploit the underlying parallelism across multiple processing elements at run time.  w. marcus miller walid a. najjar a. p. wim böhm
a reliable multicast framework for light-weight sessions and application level framing this paper describes srm (scalable reliable multicast), a reliable multicast framework for application level framing and light-weight sessions. the algorithms of this framework are efficient, robust, and scale well to both very large networks and very large sessions. the framework has been prototyped in wb, a distributed whiteboard application, and has been extensively tested on a global scale with sessions ranging from a few to more than 1000 participants. the paper describes the principles that have guided our design, including the ip multicast group delivery model, an end-to-end, receiver-based model of reliability, and the application level framing protocol model. as with unicast communications, the performance of a reliable multicast delivery algorithm depends on the underlying topology and operational environment. we investigate that dependence via analysis and simulation, and demonstrate an adaptive algorithm that uses the results of previous loss recovery events to adapt the control parameters used for future loss recovery. with the adaptive algorithm, our reliable multicast delivery algorithm provides good performance over a wide range of underlying topologies. sally floyd van jacobson steve mccanne ching-gung liu lixia zhang
performance analysis of centralized fh-cdma wireless networks  centralized cdma networks with unslotted aloha random-access mode are considered. users communicate with a central node by sharing a finite number of signature sequences assigned to the receivers at the central node. two methods for sharing preamble codes are considered. in one method a common preamble code is used by all receivers, and in the other method a distinct code is assigned for each receiver. a unified analysis framework for evaluating the performance of centralized fh-cdma networks is developed. closed form expressions for packet decoding error probabilities are derived. numerical results show that common preamble codes can support only low traffic levels. however, by appropriately selecting the design parameters, acceptable levels of packet loss probabilities are achievable with the receiver-based preambles.  khairi ashour mohamed lazlo pap
traffic characterization of the nsfnet national backbone  traditionally, models of packet arrival in communication networks have assumed either poisson or compound poisson arrival patterns. a study of a token ring local area network (lan) at mit [5] found that packet arrival followed neither of these models. instead, traffic followed a more general model dubbed the "packet train," which describes network traffic as a collection of packet streams traveling between pairs of nodes. a packet train consists of a number of packets travelling between a particular node pair.  this study examines the existence of packet trains on nsfnet, a high speed national backbone network. train characteristics on nsfnet are not as striking as those found on the mit local network; however, certain protocols exhibit quite strong train behavior given the great number of hosts communicating through the backbone.  descriptions of the packet train model can be found in [3] and [5].  steven a. heimlich
a model for description of communication protocol  this paper presents a model for the description of communication protocol in view of the total behavior of terminal equipment. in this model, a protocol entity is modeled as a group of processes and monitors, and synchronization between input and output processes is represented by the synchronizing mechanism based on the concept of the monitor. furthermore, it is possible to specify the relation between entities of different layers of the protocol, including the relation between communication and local functions of terminal equipment. as an example of protocol description based on this model, teletex document layer protocol written in concurrent pascal language is illustrated.  kazuhiko chiba kazunori konishi akira kurematsu
potential of the gsm air interface to support cdma operation  the ongoing development of third generation systems sets the path for evolution of the existing second generation systems. important issues are the need for compatibility and the establishment of a path of migration from the current operative mobile systems. this paper considers the feasibility of supporting cdma capabilities within the gsm air interface in order to provide umts services. it produces performance estimates for two specific examples joint detection cdma channels, and multicarrier ds - cdma channels. it is shown that a number of advantages can be obtained by using a hybrid cdma scheme.  j. a. pons puig j. dunlop
measured capacity of an ethernet: myths and reality ethernet, a 10 mbit/sec csma/cd network, is one of the most successful lan technologies. considerable confusion exists as to the actual capacity of an ethernet, especially since some theoretical studies have examined operating regimes that are not characteristic of actual networks. based on measurements of an actual implementation, we show that for a wide class of applications, ethernet is capable of carrying its nominal bandwidth of useful traffic, and allocates the bandwidth fairly. we discuss how implementations can achieve this performance, describe some problems that have arisen in existing implementations, and suggest ways to avoid future problems. d. r. boggs j. c. mogul c. a. kent
satellite communications systems move into the twenty-first century  this paper discusses the evolution of communication satellite systems and communications satellite technology from the 1960's to the 1990's. the paper identifies the key attributes of satellite communications that has driven this evolution and now drives the future directions such systems will take. the paper then discusses the future direction of communication satellite systems including dbs, mss, fss and hybrid satellite/terrestrial systems. the paper points to the continued evolution of the satellite payload to use of spot beams, onboard processing and switching, and intersatellite links, with capability for higher eirps. the paper also identifies the earth station trends to more compact, lower cost stations, produced in higher volumes, with the handheld phone for mss operation being the prime example of this trend. the paper then points to some revolutionary trends in satellite communication networks being proposed for mss and fss applications involving fleets of ngso satellites combined with more extensive ground networks involving new networking concepts, new services (such as multimedia) and new hybrid configurations working with terrestrial networks, involving a host of new network issues and operations.  leonard s. golding
a comparison of sender-initiated and receiver-initiated reliable multicast protocols  sender-initiated reliable multicast protocols, based on the use of positive acknowledgments (acks), lead to an ack implosion problem at the sender as the number of receivers increases. briefly, the ack implosion problem refers to the significant overhead incurred by the sending host due to the processing of acks from each receiver. a potential solution to this problem is to shift the burden of providing reliable data transfer to the receivers---thus resulting in a receiver-initiated multicast error control protocol based on the use of negative acknowledgments (naks). in this paper we determine the maximum throughputs of the sending and receiving hosts for generic sender-initiated and receiver-initiated protocols. we show that the receiver-initiated error control protocols provide substantially higher throughputs than their sender- initiated counterparts. we further demonstrate that the introduction of random delays prior to generating naks coupled with the multicasting of naks to all receivers has the potential for an additional substantial increase in the throughput of receiver-initiated error control protocols over sender-initiated protocols.  sridhar pingali don towsley james f. kurose
challenges for nomadic computing: mobility management and wireless communications  in this paper, we present several challenges and innovative approaches to support nomadic computing. the nomadic computing environment is characterized by mobile users that may be connected to the network via wired or wireless means, many of whom will maintain only intermittent connectivity with the network. furthermore, those accessing the network via wireless links will contend with limitations of the wireless media. we consider three general techniques for addressing these challenges: (1) asymmetric design of applications and protocols, (2) the use of network- based proxies which perform complex functions on behalf of mobile users, and (3) the use of pre- fetching and caching of critical data. we examine how these techniques have been applied to several systems, and present results in an attempt to quantify their relative effectiveness.  thomas f. la porta krishan k. sabnani richard d. gitlin