waashk/dblp huggingface dataset:
improving the performance of interactive tcp applications using service differentiation. interactive tcp applications, such as telnet and the web, are particularly sensitive to network congestion. indeed, congestion-induced queueing and packet loss can be a significant cause of large delays and variability, thereby decreasing user-perceived quality. we consider addressing these effects using service differentiation, by giving priority to interactive applications' traffic in the network. we study different packet marking schemes and handling mechanisms (packet dropping and scheduling) in the network. for marking packets, two approaches are considered. first, we look into application-based marking, and show how the protection of telnet traffic against loss can eliminate large echo delays caused by retransmit timeouts, and how, by limiting packet loss for web page downloads, their delays can be significantly reduced, resulting in enhanced interactivity. second, we consider differentiation based on tcp state, where we present a marking algorithm that prioritizes packets at the source, based on each connection's window size. in addition, we describe the shaping mechanisms required for conformance to agreements with the network. we show how this marking results in good response times for short transfers, which are characteristic of interactive applications, without significantly affecting longer ones.
broadcast scheduling for information distribution. broadcast data delivery is encountered in many applications where there is a need to disseminate information to a large user community in a wireless asymmetric communication environment. in this paper, we consider the problem of scheduling the data broadcast such that the access latency experienced by the users is low. in a push-based system, where the users cannot place requests directly to the server and the broadcast schedule should be determined based solely on the access probabilities, we formulate a deterministic dynamic optimization problem, the solution of which provides the optimal broadcast schedule. properties of the optimal solution are obtained and then we propose a suboptimal dynamic policy which achieves mean access latency close to the lower bound. the policy has low complexity, it is adaptive to changing access statistics, and is easily generalizable to multiple broadcast channels. in a pull-based system where the users may place requests about information items directly to the server, the scheduling can be based on the number of pending requests for each item. suboptimal policies with good performance are obtained in this case as well. finally, it is demonstrated by a numerical study that as the request generation rate increases, the achievable performance of the pull- and push-based systems becomes almost identical.
minimum-expected-delay alternate routing. the authors consider the problem of finding a routing strategy that minimizes the expected delay from every source to a single destination in a network in which each link fails and recovers according to a markov chain. it is assumed that each node knows the current state of its own outgoing links and the state-transition probabilities for every link of the network. it is shown that the general problem is #p-complete, and two special cases are considered: case 1 assumes the network is a directed acyclic graph oriented toward the destination, and case 2 assumes that the link states are independent from slot to slot. for each case, it is proved that the optimal routing strategy has a simple state-independent representation. an efficient algorithm is presented for finding the optimal strategy.
a highly adaptive distributed routing algorithm for mobile wireless networks. we present a new distributed routing protocol for mobile, multihop, wireless networks. the protocol is one of a family of protocols which we term "link reversal" algorithms. the protocol's reaction is structured as a temporally-ordered sequence of diffusing computations; each computation consisting of a sequence of directed link reversals. the protocol is highly adaptive, efficient and scalable; being best-suited for use in large, dense, mobile networks. in these networks, the protocol's reaction to link failures typically involves only a localized "single pass" of the distributed algorithm. this capability is unique among protocols which are stable in the face of network partitions, and results in the protocol's high degree of adaptivity . this desirable behavior is achieved through the novel use of a "physical or logical clock" to establish the "temporal order" of topological change events which is used to structure (or order) the algorithm's reaction to topological changes. we refer to the protocol as the temporally-ordered routing algorithm (tora).
performance analysis of a multicast switch based on multistage interconnection networks. in this paper, we study multicasting in the self-routing multistage interconnection networks (mins) for asynchronous transfer mode (atm) switch architectures. many b-isdn applications require multicast connections in addition to conventional point-to-point connections. this paper presents a novel approach to support multicast connection, on the basis of a restricted address encoding scheme which constructs a short fixed-size multicast header and a recursive scheme that recycles a multicast packet one or more times through the network to send it to the desired destinations. the proposed two-phase multicast algorithm provides deadlock-free multiple multicast connections in min-based atm switches. the emphasis is on analyzing the performance of an unbuffered min-based switch using the multicast algorithm in terms of network throughput. the proposed algorithm can be easily applied to buffered min-based atm switches.
a virtual topology for wdm multihop lightwave networks. wdm multihop networks require that their virtual topology and routing algorithm be simple and efficient while providing extremely high performance. to comply with this, the interconnections of the bidirectional manhattan street network (bmsn) is hierarchically rearranged. the resulting virtual topology constitutes a four-connected msn-based network called the hierarchical msn (hmsn). having the same node degree as bmsn, the proposed hmsn increases no h/w complexity. routing in hmsn is not also a serious burden to the overall processing overhead since it is a simple two-level extension of the deflection routing used in the two-connected msns. nevertheless, hmsn performs better than the competing bmsn. this improvement in network delay and throughput is verified through numerical implementations.
performance analysis of two-level forward error correction for lost cell recovery in atm networks. the major source of errors in b-isdn/atm systems is expected to be buffer overflow during congested conditions, resulting in atm cell losses which degrade the quality of service. it has been shown by many authors that the performance of the end-to-end system can be made much less sensitive to cell loss by means of forward error correction. this paper discusses the use of a two-level forward error correction scheme for virtual channel and virtual path connections in atm networks. the scheme exploits simple block coding and code interleaving simultaneously. the simple block, interleaved, and joint coding schemes are studied and analyzed by using a novel and accurate discrete-time analytical method which enables the burstiness of cell losses be captured precisely. detailed performance calculations, which indicate that it is possible to reduce the cell loss rate by several orders of magnitude over a wide range of network load for various traffic conditions, are discussed, and compared with simulation results. the comparisons show that the method is very accurate for bursty traffic. the advantages of the three coding techniques are quantified for different traffic characteristics and scenarios.
qlwfq: a queue lenght based weighted fair queueing algorithm in atm networks. a work conserving o(1) per-vc queueing algorithm named qlwfq (queue length based weighted fair queueing) for high-speed atm networks is proposed. the basic process in qlwfq is the comparison of the current queue length with the weight when a cell arrival or departure occurs. qlwfq has upward compatibility with fair queueing and fifo, and can be considered to be a simplified version of weighted round robin. a delay bound and a fairness index are derived analytically for the qlwfq algorithm. the simulation results for heavily and lightly loaded conditions are also presented. the analytical and simulation results show that qlwfq achieves a better balance between traffic isolation and traffic sharing than timestamp based algorithms.
m/g/infinity input processes: a versatile class of models for network traffic. we suggest the m|g|\infty input process as a viable model for network traffic due to its versatility and tractability. we characterize the process as short or long--range dependent by means of a simple test. to gauge its performance, we study the large buffer asymptotics of a multiplexer driven by an m|g|\infty input process. the decay rate of the tail probabilities for the buffer content (in steady--state) is investigated using large deviations techniques suggested by duffield and o'connell. we show that the selection of the appropriate large deviations scaling is related to the forward recurrence time of the service time distribution, and a closed--form expression is derived for the corresponding generalized limiting log--moment generating function associated with the input process. we apply our results to cases where the service time distribution in the m|g|\infty input model is (i) rayleigh (ii) gamma (iii) geometric (iv) weibull (v) log--normal and (vi) pareto -- cases (v) and (vi) have recently been found adequate for modeling packet traffic streams in certain networking applications. finally, we comment on the insufficiency of the short-- vs. long--range dependence characterization of an input process as a means to accurately describe the corresponding buffer dynamics.
on the performance behavior of atm end-stations. shaping of traffic at its source is a prominent congestion control solution in atm networks. the "leaky bucket" with a "cell spacer" is a very popular traffic shaping approach. by sizing the leaky bucket and spacer parameters, an end-station shapes its traffic to conform to a "good behavior" contract with the network. the leaky bucket delays the transmission of selected number of cells, while the spacer forces a minimum time-distance between transmitted cells. when a contracted transmission rate is close to the traffic generation rate by the end-station, this traffic stream will utilize most of the bandwidth available on its virtual connection. the high utilization of such a connection leads to large queues of frames and cells at the end-station, with high adverse consequences to the end-to-end delay and jitter. in this paper, based on the negotiated traffic parameters and source traffic characteristics, we study, through simulations, the contribution of the leaky bucket plus cell spacer subsystem to the delay and jitter in an end-station. we also study the distribution of the size of the burst of cells leaving the end-station and entering the network. finally, we derive the theoretical upper bound for the size of bursts of cells.
an asymmetric protocol for digital cellular communications. describes the design, validation, implementation and performance of an asymmetric link-layer protocol for a wireless link. the motivation for designing a new link-layer protocol is to obtain better performance in terms of end-to-end throughput and latency by correcting errors in an unreliable wireless link in addition to end-to-end correction rather than by correcting errors only by end-to-end retransmissions. the protocol described concentrates on asymmetry, although the concept of adaptive forward error correction is briefly introduced. the protocol also supports mobility. the asymmetry is needed in the design because the wireless terminals have limited power and smaller processing capability than the base stations. the key ideas in the design consist of placing the bulk of the intelligence in the base station as opposed to placing it symmetrically, in requiring the wireless terminal to combine several acknowledgments into a single acknowledgment to conserve power, and in designing the base stations to send periodic status messages, while making the acknowledgment from the wireless terminal event driven. the asymmetry in the protocol design results in a one-third reduction of the compiled code and a two-thirds reduction of processing overhead in the wireless terminal. some performance results are also presented.
locating faults in a systematic manner in a large heterogeneous network. presents several techniques for locating faults in a network which is modeled as an undirected graph. the novelty of these techniques lies in combining the process of collecting status information (from each network element) with the process of locating a fault, which is completely different from the existing techniques in which fault location begins after all the status information has been collected. the techniques presented in the paper have different characteristics and hence they are applicable in different networking environments. however, an intelligent combination of the techniques can be used in a large scale heterogeneous network in an efficient manner for locating faults.
a scalable approach to the partition of qos requirements in unicast and multicast. supporting quality of service (qos) in large-scale broadband networks poses major challenges, due to the intrinsic complexity of the corresponding resource allocation problems. an important problem in this context is how to partition qos requirements along a selected topology (path for unicast and tree for multicast). as networks grow in size, the scalability of the solution becomes increasingly important. this calls for efficient algorithms, whose computational complexity is less dependent on the network size. in addition, recently proposed precomputation-based methods can be employed to facilitate scalability by significantly reducing the time needed for handling incoming requests.we present a novel solution technique to the qos partition problem(s), based on a "divide-and-conquer" scheme. as opposed to previous solutions, our technique considerably reduces the computational complexity in terms of dependence on network size; moreover, it enables the development of precomputation schemes. hence, our technique provides a scalable approach to the qos partition problem, for both unicast and multicast. in addition, our algorithms readily generalize to support qos routing in typical settings of large-scale networks.
incentive pricing in multi-class communication networks. we consider a communication network that offers multi-class services to multiple types of traffic. users choose service classes so as to optimize their own performance. the network associates with each traffic type a nominal service class. optimal prices should provide incentives for the users to assign each traffic type to its nominal service class. we establish necessary and sufficient conditions for the existence of optimal prices and provide an algorithm for their computation. we indicate that optimal prices can tolerate fluctuations in the various parameters. we then devise a distributed algorithm, with which the network can compute optimal prices even when it does not have sufficient knowledge on the traffic characteristics. next, we consider an extended model which explicitly includes congestion effects. a key factor which emerges here is the amount of traffic at the disposal of each user. we consider the typical cases of individual, social and type optimization, for which we generalize our results.
analytical and numerical results for feedback based flow control of b-isdn/atm networks with significant propagation delays. we consider a system comprising of a single bottleneck node fed by multiple markov modulated fluid sources each of which is policed by a corresponding access regulator that marks all excess traffic as well as drops some of the excess traffic. the amount of excess traffic released is varied dynamically based on delayed feedback from the bottleneck. we present analytical and numerical results for this model that allow us to study the role of delayed feedback vis-a-vis certain time constants and traffic parameters associated with the system. in particular we show that even for a large propagation delay such as that required for the length of the continental usa the feedback policy is more effective, though the relative improvement of the feedback policy decreases as the delay increases. we also find that the feedback policy is most effective when the sources are moderately bursty.
dynamic behavior of feedback congestion control schemes. the paper examines the asymptotic behavior of solutions of a simple network model using feedback control under the presence of delays. it shows numerically the existence of complex asymptotic behavior dependent on both parameter values and initial conditions. the presence of multiple asymptotic periodic orbits of different characteristics at the same parameter values indicates that the interaction of asymptotic behavior with parameter ranges and initial histories is an extremely delicate matter.
a scheme for smoothing delay-sensitive traffic offered to atm networks. the authors present a scheme for smoothing delay-sensitive traffic offered to an asynchronous transfer mode (atm) network. they outline such a smoothing scheme, which, when applied to variable bit rate (vbr) coded video traffic, is both optimal and avoids violation of delay constraints. the scheme is based on the assumption that recent behavior of the traffic stream can be used to predict the behavior of the input stream in the near future. the effectiveness of the scheme was evaluated by simulation. the conclusion is that even with a rudimentary forecasting rule, smoothing can lower cell losses and increase the effectiveness of vbr schemes for video transmission
scalable, low-overhead network delay estimation. estimating the network delays between each pair of nodes in a multicast session is the key parameter in reliable multicast; it is used, among other things, in suppressing the implosion of request and repair packets, and in detecting congestion. existing implementations use $o(n)$ multicasts with $o(n)$ message size each (total of $o(n^2)$ bits); here, $n$ is the session size. we present a new protocol that requires $o(n)$ multicasts only with $o(1)$ message size each. we also present another protocol that estimates delays from each receiver to the sender without causing feedback implosion. because of reduced message complexity and feedback implosion, these protocols enhance the scalability of reliable multicast. furthermore, they do not require synchronized clocks, or any knowledge of network topology or the session size.
leaky bucket access control for vbr mpeg video. the leaky bucket (lb) access control scheme has been widely proposed as the usage parameter control (upc) mechanism at the user-network interface (uni) for b-isdn. an important goal for any upc scheme is that it be able to accommodate a wide range of services. in this paper, we investigate the performance of the lb as an access control mechanism for transmission of variable bit rate (vbr) mpeg video. in particular, we focus on the following issues: 1) the requirements for lossless video transmission, 2) the trade-offs between token pool size and token regeneration rate, 3) the effect of traffic smoothing and 4) the performance of different encoded video sequences. finally, we present a new technique for vbr video transmission using multiple lb's and we discuss the advantages of this techniques when cell losses occur.
analysis of multipath impulse response of diffuse and quasi-diffuse optical links for irr-wlan. this paper studies the variation on the power budget, in an infrared optical link for indoor channels with multipath propagation. the multipath propagation produces heavy distortion over the received signal and reduces the maximum baud rate for a given bit error rate. focusing on ir wireless local area network (irwlan), we study some emitter and receiver configurations. in order to allow computer portability these links can be diffuse or quasi-diffuse. these channels do not rely upon the line-of-the-sight path. this works deals not only with the total received power, but with its time and spatial distribution. this paper considers the channel as characterized by its channel transfer function in a deterministic way. this is a good approximation if the variations in the environmental conditions are slow enough compared with the baud rate of the communication system. the source is an ir emitter diode (ired) with different values of directivity, pointing to a reflecting surface, while the receiver is a photodiode characterized through its field of view (f.o.v.) value. the results show that an optical q-diffuse link improves the performances of a diffuse one. we use for the comparative analysis the rms spread delay of the impulse response, the spatial distribution of received power and its standard deviation from the mean. we present extensive simulation results, an emitter configuration and the first measured results obtained using an apd as receiver.
analysis of a queueing network model with class dependent window flow control. the authors consider a multiclass open queueing network with class-dependent window flow control; that is, the total number of jobs of each class that may be present in the network cannot exceed a given value. a job that arrives at the network during the time that the current number of jobs of the same class is equal to the population constraint, is forced to wait in an external queue. a method is presented for obtaining an approximate solution of such a queueing network. the method is based on the use of an equivalent closed queuing network model, which is analyzed using an approximate product-form solution technique. the performance parameters of the original open queueing network are easily derived from the equivalent closed queueing network. numerical results show that this method is fairly accurate
connection preemption: issues, algorithms, and a simulation study. connection preemption can be a means to provide available and reliable services to high-priority connections when a network is heavily loaded and connection request arrival patterns are unknown, or when the network experiences link or node failures. we present a simulation study of preemption in a general connection-oriented network setting. based on the observations made in this study, we have developed two optimal connection preemption selection algorithms that operate in a decentralized/distributed network where individual link managers run the algorithm for connection preemption selection on their outgoing links. the first algorithm optimizes the criteria of (i) the number of connections to be preempted, (ii) the bandwidth to be preempted, and (iii) the priority of connections to be preempted, in that order, and has polynomial complexity. the second algorithm optimizes the criteria of (i) the bandwidth to be preempted, (ii) the priority of connections to be preempted, and (iii) the number of connections to be preempted, in that order, and has exponential complexity. we conclude that the polynomial algorithm is almost as good as the exponential algorithm in terms of overall network performance.