waashk/dblp huggingface dataset:
the single queue switch. in this paper we introduce a new approach to atm switching. we propose an atm switch architecture which: uses only a single shift-register-type buffering element to store and queue the cells; and within the same physical queue switches the cells by organizing them in logical queues destined to different output lines. the buffer is also a sequencer which allows flexible ordering the cells in each logical queue to achieve any appropriate scheduling algorithm.this switch is proposed for use as the building block of large-scale multi-stage atm switches and as the scheduler/controller for the ram-based switches. the single queue switch implements output queueing and performs full buffer sharing. the hardware complexity is low. the number of input and output lines can vary independently without affecting the switch core. the size of the buffering space can be increased by simply cascading the buffering elements to each other.
local optical distribution. the authors explore a metropolitan area network (man) configuration which assumes capabilities of optical fiber and optical components which are anticipated to be available within a ten-year time frame. there are two possible physical configurations: a basic topology, such as the star and the tree, and a compound configuration, such as the tree-star-tree. as a logical overlay which serves to route information packets between stations, a form of perfect shuffle, the shufflenet, is used. performance is calculated in terms of average packet delay as a function of traffic load. of particular interest is the effect of physical limitations on performance. in particular, the effect of a limitation on the bandwidth of optical amplifiers is delineated. this limitation increases the length of the path between originating and terminating stations
reliability and performance of multi-level loop computer networks. an improved network architecture which incorporates high reliability, high performance, and optimal accommodation to environmental topologies is presented. the network investigated is tree-shaped, where the leaves represent host computers or loop subnetworks and the vertices are ring adapters attaching hosts or bridges interconnecting subnetworks. for ease of modeling only balanced and homogeneous structures are considered where loop subnetworks have the same topology. multilevel hierarchical loop networks have minimal diameter when the number of nodes in the subnetworks is proportional to the root of the number of all attached stations. in this case, the diameter grows only with the logarithm of the number of stations. this implies that network reliability and performance are significantly improved using the proposed multilevel hierarchical architecture. the performance analysis assumes the protocol of buffer insertion
switch-aided flooding operations in atm networks. in this paper, we propose a flooding method, called switch-aided flooding (saf), for use in atm networks. saf-based protocols take advantage of hardware-supported cell relay and cell duplication, characteristic of such networks, in order to reduce the time needed to disseminate changes in network topology and resource availability. saf protocols use a spanning multipoint connection (smc), which is a hardware-switched network spanning tree, but revert to conventional link-by-link flooding when the spanning mc is unavailable or under construction. the results of a simulation study reveal that the proposed flooding protocols deliver network updates several times faster than conventional approaches, while using significantly less bandwidth.
dtcap - a distributed tunable-channel access protocol for multi-channel photonic dual bus networks. in a multi-channel photonic dual bus network, each unidirectional bus contains a number of channels (wavelengths) and the bus headend periodically generates fixed length slots on each of the channels. generally, one channel called the control channel is used to carry signals and the others are data channels. each station is equipped with one-fixed-transmitter and one fixed-receiver which are permanently tuned to the dedicated control channel, and n tunable-transmitters and m tunable-receivers are tunable over the entire wavelength range. for non-overlapping traffic in the network, the maximum network throughput will be achieved by applying the wavelength reusing concept. given a set of serving traffic, a set of new traffic requests, and c data channels (wavelengths), the wavelength/receiver assignment problem ((n, m, c)-wrap) is to assign a transmission wavelength and a receiver for each request such that the network throughput is maximized and the number of assigned wavelengths is minimized. in this paper, we prove that the (n, m, c)-wrap is np-hard. an efficient distributed tunable-channel access protocol (dtcap) is proposed for the (1, m, c)-wrap. based on the dtcap, three different schemes are proposed for assigning the wavelength/receiver. the performance of the three proposed schemes on the dtcap are evaluated and compared by simulation. simulation results demonstrate that for a limited number of wavelengths and receivers, the proposed schemes substantially improve the network throughput and access delay under general traffic demands.
virtual lan internetworking over atm networks for mobile stations. one of the most attractive features of the virtual lan (vlan) is the capability to group users into broadcast domains, which are independent of their locations on the physical network. this paper deals with the vlan services using atm lan emulation technology which operates on a client/server model. the focuses are on the issues of supporting transparent vlan services and internetworking among vlans for mobile stations. a mobile vlan (mvlan) architecture is proposed, perhaps for the first time, to efficiently maintain multiple vlan broadcast domains over a single atm network even when the vlans contain mobile stations. the proposed solution (1) ensures that layer 2 frames between a mobile station and any station, either static or mobile, that belongs to the original registered vlan can be exchanged transparently, (2) provides transparent communications between vlans using the layer 2 bridging approach, and (3) handles excessive server-to-server traffic efficiently, including the broadcast/multicast frames. the proposed mvlan architecture moves one step closer towards facilitating the mobility management in an atm network while conforming to the emerging lan emulation standard.
checkpoint and rollback in asynchronous distributed systems. this paper proposes a novel algorithm for taking checkpoints and rolling back the processes for recovery in asynchronous distributed systems. the algorithm has the following properties: (1) multiple processes can simultaneously initiate the checkpointing; (2) no additional message is transmitted for taking checkpoints; (3) a set of local checkpoints taken by multiple processes denotes a consistent global state; (4) multiple processes can initiate simultaneously the rollback recovery; (5) the minimum number of processes are rolled back; and (6) each process is rolled back asynchronously. the number of messages for rolling back the processes is o(l) where l is the number of channels. therefore, the system is kept highly available by the algorithm presented.
analyzing a two-stage entry monitor for high-speed networks. several researchers have suggested employing two-stage entry monitorsfor high-speed networks - the first stage enforcing a long term rate, the second stage enforcing a peak rate over a shorter time scale. in spite of this interest, little work on analyzing such systems has appeared. not only is the analysis hard because of the the correlation between the stages, but for the most popular policing scheme, the leaky bucket, prior work isnot easily generalized to two stages.this paper presents a performance analysis of a two-stage entry monitor,by analyzing the combined queue length of a two-stage system. our analysis is for a two-stage buffered moving window. analyzing such a conservative scheme enables us to bound the penalty of more optimistic schemes, in particular a two stage leaky bucket based system. we obtain a closed form analytical result, and show how to evaluate it for a wide range of parameters of interest. our results show that the performance penalty of having the second stage is minimal under reasonable rateassumptions.
earthworm: a network memory management technique for large-scale distributed multimedia applications. the two main operating constraints of today's multimedia servers are the i/o bandwidth and communication bandwidth limitations. both of these problems are addressed in this paper using a novel technique called "earthworm". in this scheme, the network memory is used as a huge cache for buffering multimedia data. dramatic reduction in the demand on the i/o bandwidth, therefore, can be achieved. this scheme also chains display stations to allow them to forward video streams. this strategy eliminates the congestion at the communication port of the server. removing this bottleneck allows our technique to operate on the vast aggregate bandwidth of the wan, rather than being constrained by the very limited local bandwidth available to the server. a unique feature of the earthworm approach is that every display station using the server attempts to make some contribution to the caching space and communication bandwidth. the arrival of a new request, therefore, can be seen as a contributor, rather than just a burden to the server. this characteristic ensures the scalability of our design to support very large multimedia applications.
a new had algorithm for optimal routing of hierarchically structured data networks. in this paper, a new algorithm based on hierarchical aggregation/disaggregation and decomposition/composition (had) scheme is proposed to solve the optimal routing problems (orp) for hierarchically structured networks of multi-layer backbones. our algorithm has two major differences with the existing had algorithms for hierarchically clustered networks [1], [2]: 1) our algorithm works with more general networks than the networks with the clustered structure; 2) our algorithm parallelizes the computations for different commodities (message flows defined by a pair of origin node and destination node) so that it speeds up with a parallel time complexity of o(mlog2(n)), which is much less than o(mlog2(n)) needed for the existing had algorithms. here, n is the number of nodes in the network; m is the number of commodities and m is a positive number usually much smaller than m and is a function of the patterns of all the commodities including the locations of all origin nodes and destination nodes, and the flow demand of each commodity. furthermore, our algorithm can make a trade-off between the run time and the optimality, i.e., by allowing the solution to be sub-optimal, our algorithm can save great amount of computation time. the implementation of the algorithm for a 200-node network is simulated using opnet simulation package (opnet or optimized network engineering tools is developed by mil3, inc.), and the test results are consistent with our analysis.
cooperating leaky bucket for average rate enforcement of vbr video traffic in atm networks. because of the burstiness of video traffic, a very large sampling interval is needed to obtain acceptable cell loss probability. previous studies reported very high cell loss probabilities for well-behaved sources when using the leaky bucket mechanism (lb) to police vbr video sources. in this paper, a mean rate policing mechanism called cooperating leaky bucket (clb) is introduced. this mechanism can attain better cell loss probability by sharing the leaky buckets among all sources. in addition, it guarantees that the cell loss probability will never be higher than that obtained by lb. depending on the number of traffic sources available, the cell loss probability can be significantly reduced when compared to lb. at the same time, the combined traffic entering the network is enforced to below the total negotiated traffic rate. moreover, the additional overhead due to the implementation of clb is minimal.
adaptive multicast routing in single rate loss networks. propose a new approach, based on the maximum free circuit routing (mfcr) concept, toward multicast routing in single rate loss networks. two versions of the multicast routing problems are studied: static and dynamic. in the static version of the multicast routing problem, the identities of all destination nodes are available to the multicast routing algorithm at once. conversely, in the dynamic version of the multicast problem, the identities of the destination nodes are revealed to the routing algorithm one by one. the authors studied three mfcr-based multicast routing algorithms: one for the static multicast problem and two for the dynamic multicast problem. they also propose a new performance metric, referred to as fractional reward loss, for evaluating these three multicast routing algorithms. the performance of there three multicast routing algorithms are evaluated through simulations.
on designing improved controllers for aqm routers supporting tcp flows. tr#: 00-42 tr title: on designing improved controllers for aqm routers supporting tcp flows authors : c.v hollot, v. misra, d. towsley, w. gong address computer science department 140 governor''s drive university of massachusetts amherst, ma 01003-4601 date: 7/10/00 on designing improved controllers for aqm routers supporting tcp flows in this report we study a previously developed linearized model of tcp and aqm. we use classical control system techniques to develop controllers well suited for the application. the controllers are shown to have better theoretical properties than the well known red controller. we present guidelines for designing stable controllers subject to network parameters like load level, propogation delay etc. we also present simple implementation techniques which require a minimal change to red implementations. the performance of the controllers are verified and compared with red using \texttt{ns} simulations. the second of our designs, the proportional integral (pi) controller is shown to outperform red significantly.
llr routing in homogeneous vp-based atm networks. in atm networks, a virtual path (vp) concept has been proposed to simplify traffic control and resource management. as a consequence, cell routing becomes more flexible and significant call setup processing can be reduced when resources are reserved on vp's. in this paper, we study the routing problem in homogeneous vp-based atm networks in which vp's are used for traffic segregation such that all vc's in a vp have the same traffic characteristics and qos requirement. four adaptive routing algorithms based on the least loaded routing (llr) concept are designed and evaluated. our simulation results show that network blocking probability can be significantly reduced by llr routing.
the effect of processing delay and qos requirements in high speed networks. the authors examine the effects of call processing delay, propagation delay, the admission control function due to quality of service (qos) requirements, and routing algorithms on the call setup time in future b-isdn networks. three routing schemes from circuit-switched networks and two parallel versions of these routing schemes are investigated under various network parameters and different forms of admission control. analytic models for different routing algorithms are developed and were validated by simulation results. the results of the study indicate that call processing delay associated with the admission control function affects the network performance significantly while propagation delay does not affect the performance significantly
on the convergence of traffic measurement and queueing analysis: a statistical-match queueing (smaq) tool. the analytical tool developed in this paper provides a general solution technique for the integration of traffic measurement and queueing analysis. the frequency-domain approach is used to combine the advanced techniques in two areas: signal processing and queueing analysis. essentially, signal processing techniques are used to obtain the steady-state and second-order statistics of a traffic stream. the focus here is on the construction of a special class of markov chains that can statistically match with each given traffic stream (or superposition of different traffic streams). the analytical queueing solutions can therefore be obtained by the folding-algorithm based on the markov chain input modeling. comprehensive numerical examples show the great potential of the smaq tool to solve measurement-based traffic management issues.
usage-based pricing of packet data generated by a heterogeneous user population. usage-based pricing of offered traffic to a data network can be an effective technique for congestion control. to gain insight into the benefits usage-based pricing offers, the authors propose and study a simple model in which many users wish to transmit packets to a single-server queue. based on the announced price per packet and the available quality of service (qos) (e.g., mean delay), each user independently decides whether or not to transmit. given statistical assumptions about the incoming traffic streams and the qos as a function of offered load, the equilibrium relationship between price and qos is determined by a fixed-point equation. the relationships among price, qos, revenue, and server capacity are illustrated numerically, assuming a particular type of random user population. these examples indicate that adjusting the price to maximize revenue results in an efficient use of service capacity with an associated small mean delay.
proactive network fault detection. the increasing role of communication networks in today's society results in a demand for higher levels of network availability and reliability. at the same time, fault management is becoming more difficult due to the dynamic nature and heterogeneity of networks. we propose an intelligent monitoring system using adaptive statistical techniques. the system continually learns the normal behavior of the network and detects deviations from the norm. within the monitoring system, the measurements are segmented, and features extracted from the segments are used to describe the behavior of the measurement variables. this information is combined in the structure of a bayesian network. the proposed system is thereby able to detect unknown or unseen faults. experimental results on real network data demonstrate that the proposed system can detect abnormal behavior before a fault actually occurs.
adaptive data structures for ip lookups. the problem of efficient data structures for ip lookups has been well studied in the literature. techniques such as lc tries and extensible hashing are commonly used. in this paper, we address the problem of generalizing lc tries, based on traces of past lookups, to provide performance guarantees for memory suboptimal structures. as a specific example, if a memory-optimal (lc) trie takes 6 mb and the total memory at the router is 8 mb, how should the trie be modified to make best use of the 2 mb of excess memory? we present a greedy algorithm for this problem and prove that, if for the optimal data structure there are b fewer memory accesses on average for each lookup compared with the original trie, the solution produced by the greedy algorithm will have at least 9 &times; b/11 fewer memory accesses on average (compared to the original trie). an efficient implementation of this algorithm presents significant additional challenges. we describe an implementation with a time complexity of o(&xi;(d)nlog n) and a space complexity of o(n), where n is the number of nodes of the trie and d its depth. the depth of a trie is fixed for a given version of the internet protocol and is typically o(log n). in this case, &xi;(d) &equals; o(log2 n). we also demonstrate experimentally the performance and scalability of the algorithm on actual routing data.
a synchronization mechanism for continuous media in multimedia communications. this paper proposes a media synchronization mechanism which adjusts the output timing among stored continuous media streams in multimedia communications. the proposed method consists of intra-stream and inter-stream synchronization mechanisms. the inter-stream synchronization control is performed after the intra-stream synchronization control. then, whether the intra-stream synchronization is still maintained or not is checked. the mechanism con be used in networks which have unknown delay bounds, and it does not suppose periodical generation of media units such as video frames. it also deals with two types of media streams depending on how strictly to synchronize media streams: tightly-coupled media streams and loosely-coupled media streams. furthermore, we enhance the mechanism to support real-time-inputted media streams as in tv conferencing.
a group synchronization mechanism for stored media in multicast communications. this paper proposes a group synchronization mechanism, which synchronizes slave destinations with the master destination, for stored media in multicast communications. at the master and slave destinations, intra-stream and inter-stream synchronization mechanisms which were proposed by the authors are employed to output the master media stream and slave media streams synchronously. we achieve group synchronization by adjusting the output timing of the master media stream at each slave destination to that at the master destination.we also deal with traffic control by media scaling and control of joining an in-progress multicast group. furthermore, the paper presents experimental results using an atm network. it shows the validity of the mechanism and illustrates the influence of parameters on the system performance.
bounds for the tail distribution in a queue with the superposition of general periodic markov sources. in this paper, we derive the bounds formulas for the asymptotic tail distribution in a queue whose arrival process is a superposition of general periodic markov sources. note that we make no assumption for the structure of the general periodic markov sources except that the underlying markov chains are irreducible. the periodic source model in this paper is thus rather general. taking initial state conditions of the periodic sources into account, we construct a superposed arrival process. contrary to the previous works, this implies that the periodic sources are not independent. we also provide examples to investigate the efficiency and the accuracy of our bound formulas.
performance of a mass storage system for video-on-demand. advancements in storage technology along with the fast deployment of high-speed networks has allowed the storage, transmission and manipulation of multimedia information such as text, graphics, still images, video and audio to be feasible. our study focused on, the performance of the mass storage system for a large-scale video-on-demand server. different video file striping schemes, such as application level striping and device driver level striping, were examined in order to study scalability and performance issues. to study the impact of different concurrent access patterns on the performance of a server, experimental results were obtained on group access on a single video file and multiple group accesses on multiple video files.