waashk/dblp huggingface dataset:
modelling prioritized mpeg video using tes and a frame spreading strategy for transmission in atm networks. this paper presents an efficient transmission mechanism, using frame spreading, for variable bitrate (vbr) mpeg compressed video, through an atm multiplexer, such as a cable head-end. a priority scheme is implemented in a software mpeg encoder which produces a proportionate traffic in both (i.e., high and low) priority partitions for all three frame types (intraframe, predicted and interpolated) used in mpeg. an atm multiplexer with a pushout buffer scheme is implemented for the study, in order to provide priority scheduling at the multiplexer for the two priority partitions. the multiplexer is fed with vbr mpeg traffic and performance statistics such as the cell loss ratios are studied for various frame spreading scenarios. two statistical models are developed using tes (transform expand sample) for vbr mpeg video having two levels of priority. the first model is matched with the empirical histogram and autocorrelation function of each frame type (i, p and b). the second model is created with the assumption of a gamma distribution for the number of bits in each frame type. experiments are conducted using both models and the results are compared.
bihop: a bidirectional highly optimized pipelining technique for large-scale multimedia servers. we present a technique, called bidirectional highly optimized pipelining (bihop), for managing disks as a buffer for the tertiary storage of a multimedia server. we implement a simulator to compare its performance to that of a recently proposed scheme called sep. the results show that bihop performs significantly better. its superior performance is attributed to a novel caching approach, which caches every other data fragment of the multimedia file, rather than caches consecutive fragments as in traditional practice. this new approach allows us to use tiny staging buffers for pipelining, which can be implemented in the memory to conserve disk bandwidth. furthermore, the whole disk space can be dedicated for caching purposes to improve hit ratio. another important advantage of bihop is its ability to pipeline in either forward or reverse direction with the same efficiency. this unique feature, not possible with existing schemes, makes it natural for implementing vcr functions.
a very simple algorithm for flow control on high speed networks via la palice queueings. flow control algorithms specially designed for high speed networks are introduced. they are based on a new queuing model called the la palice queue. an algorithm that is simply an extrapolation of the classic flow control algorithm with a request to the destination and an answer to the source is presented. it is shown that the overflow occurrence is lowered to a certain probability by the application of the algorithm. an intermediate algorithm is presented that cancels overflow occurrence, but allows repetition of requests with a certain probability per multipacket message
a forwarding strategy to reduce network impacts of pcs. we propose a per-user forwarding strategy for locating users who move from place to place while using personal communications services (pcs). the forwarding strategy augments the basic location strategy proposed in existing standards such as gsm and is-41, with the objective of reducing network signalling and database loads in exchange for increased cpu processing and memory costs. with the forwarding strategy, calls to a given user will first query the user's home location register (hlr) to determine the first visitor location register (vlr) which the user was registered at, and then follow a chain of forwarding pointers to the user's current vlr. this strategy is useful for those users who receive calls infrequently relative to the rate at which they change registration areas. we use a reference pcs architecture and the notion of a user's call-to-mobility ratio (cmr) to quantify the costs and benefits of using forwarding and classes of users for whom it would be beneficial. we show that sender a variety of assumptions forwarding is likely to yield significant net benefits for certain classes of users, in exchange (possibly) for a small increase in mean call setup time. for instance, under certain cost assumptions, for users with cmr>1 forwarding can result in 20-60% savings over the basic strategy, with no increase in mean call setup time.
an assigned-buffer atm switching architecture. there has been a great technological advancement in microelectronics and communications, which forces, among others, investigations on atm switching architectures. researchers keep on searching an efficient architecture, able to perform at a wide range of traffic loads and patterns, ensuring both minimum probability of cell loss as well as minimum cell delay. the authors propose one more architecture. the main goal is to create an architecture capable of operating at very high data rates. as the result, the switch uses the fastest method of buffer management, and is characterized by sufficiently low probability of blocking and short delay time. appropriate simulation results are presented and some implementation issues are discussed.
scalability and flexibility in authentication services: the kryptoknight approach. this paper studies the issues of flexibility and scalability in the context of network security. in particular, it concentrates on authentication and key distribution services suited for a variety of communication paradigms, network environments, and end-devices. we present the design criteria, specification, and step-by-step construction of authentication and key distribution services based on experience in the kryptoknight project. the central goal of the kryptoknight project was the construction of basic network security functions in a minimal, flexible (thus, versatile) and scalable manner. protocol minimality (in terms of resource usage) and flexibility are not merely theoretical goals; they have clear advantages in environments where computational resources are limited and connectivity is restricted. kryptoknight was aimed at such environments: small and anemic wireless devices, simple network and data-link entities, embedded micro-devices and other special-purpose communication equipment and configurations. furthermore, scalability of protocols makes their deployment possible in the presence of rapid network growth and inter-domain communication.
regular multicast multihop lightwave networks. a class of multicast multihop lightwave networks (mlns) is presented. these networks have a two-layered architecture, with the upper "logical layer" implemented electronically, and supported by an underlying "physical layer" implemented as a purely optical network. the unique feature studied is that the logical topology has a regular multicast structure, which is created through the use of optical multicast in the physical layer. it is shown that this type of logical topology yields networks which have significantly superior performance features, when compared with either purely optical networks, or with multihop networks based on point-to-point connections. special regular logical topologies based on kautz hypergraphs are used in designing the networks.
message delay analysis of the dqdb (ieee 802.6) network. the analytical evaluation of the message delay in a distributed queue dual bus (dqdb) network is investigated. the authors extend the results obtained by c. bisdikian et al. (1990), which assumes that each network station can queue at most one packet, to the case of station queues each holding an entire message containing l packets. an expression is obtained for the number of requests queued ahead of an arriving message. given this expression, the average message delay can be calculated. one conclusion drawn from the analysis is that the average steady-state message delay is linear in sufficiently large l . it is also concluded that the message delay increases considerably with the network load. the analytical results predict the position-dependent characteristics of stations in a heavily loaded network and explain some observations and results of earlier simulation studies
dynamic node activation in networks of rechargeable sensors. we consider a network of rechargeable sensors, deployed redundantly in a random sensing environment, and address the problem of how sensor nodes should be activated dynamically so as to maximize a generalized system performance objective. the optimal sensor activation problem is a very difficult decision question, and under markovian assumptions on the sensor discharge/recharge periods, it represents a complex semi-markov decision problem. with the goal of developing a practical, distributed but efficient solution to this complex, global optimization problem, we first consider the activation question for a set of sensor nodes whose coverage areas overlap completely. for this scenario, we show analytically that there exists a simple threshold activation policy that achieves a performance of at least 3/4 of the optimum over all possible policies. we extend this threshold policy to a general network setting where the coverage areas of different sensors could have partial or no overlap with each other, and show by simulations that the performance of our policy is very close to that of the globally optimal policy. our policy is fully distributed, and requires the sensor nodes to only keep track of the node activation states in its immediate neighborhood. we also consider the effects of spatial correlation on the performance of the threshold activation policy, and the choice of the optimal threshold.
routing restorable bandwidth guaranteed connections using maximum 2-route flows. routing with service restorability is of much importance in multi-protocol label switched (mpls) networks, and is a necessity in optical networks. for restoration, each connection has an active path and a link-disjoint backup path. the backup path enables service restoration upon active path failure. for bandwidth efficiency, backups may be shared. this requires that at least the aggregate backup bandwidth used on each link be distributed to nodes performing route computations. if this information is not available, sharing is not possible. also, one scheme in use for restorability in optical networks is for the sender to transmit simultaneously on the two disjoint paths and for the receiver to choose data from the path with stronger signal. this has the advantage of fast receiver-initiated recovery upon failure but it does not allow backup sharing.in this paper, we consider the problem of efficient dynamic routing of restorable connections when backup sharing is not allowed. our objective is to be able to route as many connections as possible for one-at-a-time arrivals and no knowledge of future arrivals. since sharing cannot be used for achieving efficiency, the goal is to achieve efficiency by improved path selection. we show that by using the minimum-interference ideas used for nonrestorable routing, we can develop efficient algorithms that outperform previously proposed algorithms for restorable routing such as routing with the min-hop like objective of finding two disjoint paths with minimum total hop-count. we present two new and efficient algorithms for restorable routing without sharing, and one of them requires only shortest path computations. we demonstrate that both algorithms perform very well in comparison to previously proposed algorithms.
atmtrap: an asynchronous transfer mode traffic and performance measurement tool. the analysis and development of atm network traffic control algorithms is often performed using theoretical traffic models. algorithms for traffic shaping, policing, flow control, and switch architectures have been proposed based on these models. while the models help to obtain preliminary solutions, the success and validity of the proposed algorithm will be a function of how close the assumed models resemble real traffic patterns. the paper presents atmtrap, an experimental prototype asynchronous transfer mode traffic and performance measurement tool which could be used in the characterization of sources and elements that form the atm network. atmtrap has been used in the nectar gigabit testbed to collect preliminary traffic statistics from sources, such as, a cray c-90 supercomputer, sun workstations, and an iwarp systolic array.
improving the performance of input-queued atm packet switches. the authors propose a single way to dramatically improve the performance of input-queued atm packet switches beyond the 82% saturation point obtained in previous work. the method is an extension of the independent output-port schedulers technique and is based on the notion of recycled time slots, i.e. reusing time slots normally wasted due to scheduling conflicts. in contrast to previous results, the technique yields a throughput improvement from 65% to 92% without speedup, trunking, or complicated hardware. if input grouping with a group size of four is also employed, then the method can yield up to 95% throughput
prevention of deadlocks and livelocks in lossless, backpressured packet networks. no packets will be dropped inside a packet network, even when congestion builds up, if congested nodes send backpressure feedback to neighboring nodes, informing them of unavailability of buffering capacity-stopping them from forwarding more packets until enough buffer becomes available. while there are potential advantages in backpressured networks that do not allow packet dropping, such networks are susceptible to a condition known as deadlock in which throughput of the network or part of the network goes to zero (i.e., no packets are transmitted). in this paper, we describe a simple, lossless method of preventing deadlocks and livelocks in backpressured packet networks. in contrast with prior approaches, our proposed technique does not introduce any packet losses, does not corrupt packet sequence, and does not require any changes to packet headers. it represents a new networking paradigm in which internal network losses are avoided (thereby simplifying the design of other network protocols) and internal network delays are bounded.
an energy efficient mac protocol for wireless lans. this paper presents an optimization of the power saving mechanism in the distributed coordination function (dcf) in ieee 802.11 standard. in the 802.11 power saving mode specified for dcf, time is divided into so-called {\em beacon intervals}. at the start of each beacon interval, each node in the power saving mode periodically wakes up for a duration called the {\em atim window}. the nodes are required to be synchronized to ensure that all nodes wake up at the same time. during the atim window, the nodes exchange control packets to determine whether they need to stay awake for the rest of the beacon interval. the size of the atim window has a significant impact on energy saving and throughput achieved by the nodes. this paper proposes an adaptive mechanism to dynamically choose a suitable atim window size. we also allow the nodes to stay awake for only a fraction of the beacon interval following the atim window. on the other hand, 802.11 dcf mode requires the nodes to stay awake either for the entire beacon interval following the atim window or none at all. simulation results show that the proposed approach outperforms the ieee 802.11 power saving mechanism in terms of throughput and the amount of energy consumed.
performance analysis of the rotating slot generator scheme. a thorough investigation of the performance of the rotating slot generator (rsg) scheme, based on simulation, is presented. rsg is a medium access control protocol appropriate for high-capacity long-distance metropolitan area networks (mans). it uses the looped bus architecture of the distributed queue dual bus (dqdb) in which the slot generators for both busses are colocated inside the same station. however in rsg, all the stations, one after the other in a cyclic order, undertake the task of generating and destroying the slots on both busses. in this way the location of the station relative to the slot generator changes dynamically, and its effect on the performance is drastically reduced. the authors investigate the fairness and performance of rsg under symmetric and asymmetric loading, underload and overload conditions, and under the presence of a single or multiple priority classes of traffic. they also compare its performance with different variations of dqdb
fdq: the fair distributed queue man. a new protocol, fair distributed queue (fdq), suitable for very high speed metropolitan area networks (mans), is presented. fdq is a slotted system implemented on a unidirectional fiber bus. it has similarities to the distributed queue dual bus (dqdb) protocol. fdq achieves full throughput efficiency independent of the bus length, the transmission speed, and the number of nodes. fdq allocates equal bandwidth under heavy load to all active users in a time period less than or equal to the round-trip propagation delay without wasting bandwidth. its delay characteristics were studied via simulation and compared to dqdb. fdq has lower average delays under a poisson load than the dqdb protocol with or without the bandwidth balancing mechanism. the implementation of priority levels and detailed timing structure of the protocol are also described. it was shown that fdq's delay and throughput characteristics were only slightly affected by increasing distances or the number of nodes
exact and approximate analysis of dqdb under heavy load. the distributed queue dual bus (dqdb) standard is studied under heavy load conditions. the dqdb protocol for asynchronous traffic is reviewed. the network model and analysis are presented when there are two active nodes. analytic expressions are derived for the steady-state nodal throughputs and the average value of the request counters of inactive nodes. the three-station case is considered by providing an accurate approximation for the situation when the third node is in between the two initially active nodes. simulation results are given for comparison. the effect of the position of a node was studied via simulation in the three-station case. the case when one of the active nodes becomes inactive in a network with three initially active nodes is analyzed. the state the network assumes is studied in terms of nodal throughputs after one of the nodes turns off, and the impact on the request counters of the inactive nodes are investigated
a comparison of server-based and receiver-based local recovery approaches for scalable reliable multicast. local recovery approaches for reliable multicast have the potential to provide significant performance gains in terms of reduced bandwidth and delay, and higher system throughput. in this report we examine one server--based and two receiver--based approaches, and compare their performance. the server--based approach makes use of specially designated hosts, called repair servers, co--located with routers inside the network. in the receiver-based approach, only the end hosts (sender and receivers) are involved in error recovery. using analytical models, we first show that the three local recovery approaches yield significantly higher protocol throughput and lower bandwidth usage than an approach that does not use local recovery. next, we demonstrate that server--based local recovery yields higher protocol throughput and lower bandwidth usage than receiver--based local recovery when the repair servers have processing power slightly higher than that of a receiver and a few hundred kilobytes of buffer per multicast session.
congestion control policies for ip-based cdma radio access networks. as cdma-based cellular networks mature, the current point-to-point links used in connecting base stations to network controllers will evolve to an ip-based radio access network (ran) for reasons of lower cost due to statistical multiplexing gains, better scalability and reliability, and the projected growth in data applications. in this paper, we study the impact of congestion in a best-effort ip ran on cdma cellular voice networks. we propose and evaluate three congestion control mechanisms, admission control, diversity control, and router control, to maximize network capacity while maintaining good voice quality. we first propose two new enhancements to cdma call admission control that consider a unified view of both ip ran and air interface resources. next, we introduce a novel technique called diversity control that exploits the soft-handoff feature of cdma networks and drops selected frames belonging to multiple soft-handoff legs to gracefully degrade voice quality during congestion. finally, we study the impact of router control where an active queue management technique is used to reduce delay and minimize correlated losses. using simulations of a large mobile network, we show that the three different control mechanisms can help gracefully manage 10-40 percent congestion overload in the ip ran.
comparison of dynamic multicast routing algorithms for wide-area packet switched (asynchronous transfer mode) networks. this paper compares three dynamic multipoint routing algorithms for wide-area packet switched networks like asynchronous transfer mode (atm) networks. the three algorithms compared are the greedy algorithm, the source rooted shortest path (sp) algorithm and the geographic spread dynamic multicast (gsdm) routing algorithm. we present simulation results over random graphs that demonstrate the performance of these algorithms. the algorithms are evaluated via a series of multiple simulations in terms of the number of packet copies per node and their (in)efficiency. a near optimal steiner tree heuristic algorithm called the kmb algorithm is used as a measure of the (in)efficiency of the algorithms.
stwnet: a high bandwidth space-time-wavelength multiplexed optical switching network. we propose stwnet, a self-routing high bandwidth optical network architecture for interconnecting users, grouped together as g groups with w users per group. stwnet uses the three dimensions of space, time, and wavelength by combining the advantages of space and temporal switching with the benefits of wavelength parallel data transmissions. technologically difficult switching of individual wavelengths is avoided by prearranging transmissions in a way that they can be switched in a wavelength insensitive manner. wavelengths are reused within the network thus allowing for a larger switching fabric.the proposed architecture can be internally expanded either in the spatial or temporal dimension to allow for multiple packets to be delivered to the same destination group. the expansion factor is determined based on the group knockout principle and given typical traffic patterns is a small number. stwnet allows easy group to group multicasting and broadcasting while system-wide multicasts and broadcasts can be achieved through repetitive group-to-group transmissions. the network uses readily available components such as opto-electronic directional couplers, fixed wavelength transmitters, and diffraction based parallel receivers while avoiding the use of relatively slow and expensive tunable components.