waashk/dblp huggingface dataset:
performance analysis of statistical multiplexing of vbr sources. the authors propose a versatile point process as a model for a large class of variable bit rate sources and their superpositions. the process belongs to the class of discrete-time batch markovian arrival processes. its use leads to computationally tractable and accurate solutions for the following performance measures of the related statistical multiplexer: buffer occupancy distribution, cell loss probability, and conditional cell loss probability. it is shown that the output process of the multiplexer belongs to the same class of processes
object-oriented network protocols. a wide-range of various network communication services and protocols is required to efficiently support the diverse networks and their applications. it is usual to design a protocol for each new service which is required. an attractive alternative is to use a modular and object-oriented architecture for the design and implementation of network protocols. with it, protocols for individual service provision can be created by simply combining generic protocol functions blocks. the first part of this paper presents a new reference model which gives a foundation for the object-oriented design and implementation of modular network protocols. the second part discusses a case study of an existing object-oriented network communication system.
adaptive bandwidth allocation by hierarchical control of multiple atm traffic classes. the authors introduce a control strategy for bandwidth management in asynchronous transfer mode (atm) networks. a two-level hierarchy is defined, where one level performs fixed class-selective call admission control strategies that are periodically dynamically coordinated by a higher-level bandwidth allocation controller. each admission controller decides to accept or refuse an incoming call on the basis of a class-selective rule designed to maintain a certain quality of service. a decision is taken according to the virtual capacity share that is assigned to the various service classes by the allocation controller. bandwidth shares are periodically recomputed online by means of the constrained minimization of a cost function that takes cell loss probability and refused traffic into account. the control structure, the strategies, and the optimization algorithm used are described as well as the assumptions underlying the choices made. initial simulation results are reported
analysis of a fluid approximation to flow control dynamics. the authors consider a flow control mechanism that dynamically regulates the rate of data flow into a network based on feedback information about the network state. such mechanisms have been introduced in a variety of networks, and have been advocated for future high-speed networks. the authors first model the flow control mechanism by a discrete-space stochastic process and define appropriate performance measures for transient and steady-state regimes. however, the model does not appear to be analytically tractable, and the authors study it through simulation. they then simplify it to a continuous-space deterministic (or fluid) model for which closed-form solutions can be derived easily. it is found that the analytical results for the fluid model agree well with the simulation results obtained using the discrete-space model. both models explicitly consider delay of the feedback information, thus making them relevant for high-speed networks
busy period analysis for an atm switching element output line. the authors consider an n&times;n asynchronous transfer mode (atm) switching element with output queuing, under a uniformity assumption for the traffic arriving on the various input lines and for the output line address of the incoming cells. the traffic on each input line is modeled as a two-state markov chain. the distribution of the busy and idle periods for each output line is analytically derived. it is concluded that it is not easy to identify a simple two-state markov chain model that provides an adequate description for the output traffic. the implications of two different output line address assignment mechanisms for the incoming cells are quantitatively described. an alternative method is outlined for the computation of the steady-state distribution of the number of cells in the system. an analysis of the numerical results is presented
efficient scheduling of nonuniform packet traffic in a wdm/tdm local lightwave network with arbitrary transceiver tuning latencies. a passive-star-based, broadcast-and-select, local lightwave network which can support a limited number of wdm channels (on the order of ten), but serve a much larger number of nodes (a few tens or hundreds), is considered. each node is equipped with one tunable transmitter and one fixed receiver, and each wdm channel is operated in a tdm fashion for carrying packet traffic. bandwidth is allocated to the node pairs when traffic flow between them is non-uniform, while also accommodating transceiver tuning latency. our approach exploits well-known results from scheduling theory to create efficient transmission schedules.
user-level performance of channel-aware scheduling algorithms in wireless data networks. channel-aware scheduling strategies, such as the proportional fair algorithm for the cdma 1xev-do system, provide an effective mechanism for improving throughput performance in wireless data networks by exploiting channel fluctuations. the performance of channel-aware scheduling algorithms has mostly been explored at the packet level for a static user population, often assuming infinite backlogs. in the present paper, we focus on the performance at the flow level in a dynamic setting with random finite-size service demands. we show that in certain cases the user-level performance may be evaluated by means of a multiclass processor-sharing model where the total service rate varies with the total number of users. the latter model provides explicit formulas for the distribution of the number of active users of the various classes, the mean response times, the blocking probabilities, and the throughput. in addition we show that, in the presence of channel variations, greedy, myopic strategies which maximize throughput in a static scenario, may result in sub-optimal throughput performance for a dynamic user configuration and cause potential instability effects.
asymptotic behavior of generalized processor sharing with long-tailed traffic sources. we analyze the asymptotic behavior of long-tailed traffic sources under the generalized processor sharing (gps) discipline. gps-based scheduling algorithms, such as weighted fair queueing, have emerged as an important mechanism for achieving differentiated quality-of-service in integrated-services networks. under certain conditions, we prove that in an asymptotic sense an individual source with long-tailed traffic characteristics is effectively served at a {\em constant} rate, which may be interpreted as the maximum feasible average rate for that source to be stable. thus, asymptotically, the source is only affected by the traffic characteristics of the other sources through their average rate. in particular, the source is essentially immune from excessive activity of sources with `heavier''-tailed traffic characteristics. this suggests that gps-based scheduling algorithms provide an effective mechanism for extracting high multiplexing gains, while protecting individual connections.
packet scale rate guarantee for non-fifo nodes. packet scale rate guarantee (psrg) is a generic node model which underlies the definition of expedited forwarding (ef) proposed in the context of internet differentiated services. for the case of first-in-first-out (fifo) nodes, psrg is equivalent to the well-understood concept of adaptive service curve. however, in practice, many devices do not necessarily preserve the fifo property, and therefore, known fifo results do not hold. this paper analyzes the properties of psrg in the absence of fifo assumption. our analysis is based on a novel characterization of psrg which avoids the use of virtual finish times and is obtained by min-max algebra. we use it to show that delay bounds previously obtained for the fifo case are still valid; in contrast, we find that this is not true for the characterization of the concatenation of two nodes.
the fairness of dqdb networks with slot reuse. the paper analyzes the fairness characteristics of two previously proposed slot reuse protocols for dqdb networks. in particular, the slot reuse protocol proposed for the ieee 802.6e standard [hassanein et al., 1994] results in unfair steady state bandwidth allocations for some overloaded dqdb networks and can cause unbounded access delays under some stable workloads. in contrast, a previously proposed simple counter protocol results in bandwidth allocations in overload that are shown to be at least weakly fair for all workloads and optimally fair for many important workloads. this simple protocol also guarantees bounded access delays for any stable workload. a new modified counter protocol is proposed that has superior fairness characteristics to either of the previous protocols.
copy emulation in checksummed, multiple-packet communication. data copying can be a bottleneck in end-to-end communication over high-speed networks. emulated copy is an alternative i/o data passing scheme that preserves the api and integrity guarantees of copying but avoids the latter using vm manipulations -- transient output copy-on-write (tcow), input alignment, and page swapping. we characterize and evaluate the support necessary in network adapters for emulated copy in checksummed, multiple-packet communication. our experiments on an atm network show that: (1) emulated copy gives performance better than that of copying even without hardware checksumming support; (2) tcow improves multiple-packet output performance without any hardware support or changes in applications; (3) page swapping provides additional similar improvements on multiple-packet input if there is input alignment, which requires either hardware support (early-demultiplexed/system-aligned buffering) or changes in applications (pooled/application-aligned buffering); and (4) the performance of application-aligned buffering is largely unaffected by header/data splitting, a common optimization.we propose a new optimization, buffer snap-off, that extends system-aligned buffering to the general case of arbitrary, unmatched data transfer and application input buffer lengths.
connectivity, performance, and resiliency of ip-based cdma radio access networks. ip-based radio access networks (ran) are expected to be the next generation access networks in umts and cdma networks. the question of connectivity, i.e., how best to connect base stations to the radio network controllers (rnc) in an ip-based ran, has not been addressed by researchers. furthermore, given a connection configuration, an rnc selection algorithm that assigns an incoming call to an rnc is also necessary. this paper examines ran connectivity and its impact on the performance and resiliency of the wireless network using different rnc selection algorithms. for homogeneous networks, we show that the proposed min-load-1 algorithm, which allows at most one hard handoff in order to accommodate each incoming call request, delivers performance close to the optimal algorithm. we also show that allowing a few base stations to connect to two rncs (a 10 percent increase in the number of links in our network) results in resiliency to rnc failures that is comparable to the resiliency of rans with full-mesh connectivity. finally, for heterogeneous networks, we show that the min-load-k algorithm (with at most k hard handoffs per call) is effective in handling load imbalances. these results provide strong motivation for deploying ip-based ran, as they suggest that enhancing current point-to-point ran with few additional links and allowing a few hard handoffs to accommodate incoming calls can result in significant gains in performance and resiliency.
a generic flow control protocol for b-isdn. a generic flow control (gfc) protocol is proposed to regulate multiple terminals within the broadband-isdn customer premises network. the gfc protocol is based on multipriority distributed queuing preceded by a traffic shaping function, and meets the requirements for flexible allocation of service parameters, control of jitter and guarantee of bandwidth. this gfc protocol provides the necessary flexibility to match the constant bit rate (cbr) jitter performance and variable bit rate (vbr) service requirements to the particular service type. it integrates well with usage parameter control without imposing excessive burstiness on each virtual connection cell stream delivered to the network. by allowing connectionless users to access at the lowest priority, only when no higher priority users are queued, there is no reduction in guaranteed capacity available for other vbr and cbr users
mv routing and capacity building in disruption tolerant networks. disruption-tolerant networks (dtns) differ from other types of networks in that capacity is created by the movements of network participants. this implies that understanding and influencing the participants' motions can have a significant impact on network performance. in this paper, we introduce the routing protocol mora, which learns structure in the movement patterns of network participants and uses it to enable informed message passing. we also propose the introduction of autonomous agents as additional participants in dtns. these agents adapt their movements in response to variations in network capacity and demand. we use multi-objective control methods from robotics to generate motions capable of optimizing multiple network performance metrics simultaneously. we present experimental evidence that these strategies, individually and in conjunction, result in significant performance improvements in dtns.
fine-grained layered multicast. abstract traditional approaches to receiver-driven layered multicast have advocated the benefits of cumulative layering, which can enable coarse-grained congestion control that complies with tcp-friendliness equations over large time scales. in this paper, we quantify the costs and benefits of using non-cumulative layering and present a new, scalable multicast congestion control scheme which provides a fine-grained approximation to the behavior of tcp additive increase / multiplicative decrease (aimd). in contrast to the conventional wisdom, we demonstrate that fine-grained rate adjustment can be achieved with only modest increases in the number of layers and aggregate bandwidth consumption, while using only a small constant number of control messages to perform either additive increase or multiplicative decrease.
optimal routing and flow control in networks with real-time traffic. we address the problem of flow control and routing of `real-time traffic'' in a network, where messages must arrive at their destination within given deadlines; otherwise they are considered lost. performance in thisd case is measured in terms of the probability of losing a message. for the case of `n'' parallel links, the problem is formulated as one of optimal flow allocation and solved under gernal conditions. it is shown that for a `fcfs'' service discipline an admission policy rejecting messages before link assignment is optimal when the load exceeds a critical value. thus, we take advantage of the fact that if some messages will exceed their deadlines anyway, it is beneficial not to admit them in the first place. an efficient algorithm for explicitly solving the problem is presented and specific examples are analyzed. we also discuss the applicability of on- line algorithms for this problem when modelling assumptions cannot be made.
server selection using dynamic path characterization in wide-area networks. using tools to measure available bandwidth and round trip latency (rtt), we demonstrate dynamic server selection and compare it to previous static approaches. we show that because of the variability of paths in the internet, dynamic server selection consistently outperforms static policies, reducing response times by as much as 50%.however, we also must adopt a systems perspective and consider the impact of the measurement method on the network. therefore, we look at alternative low-cost approximations and find that the careful measurements provided by our tools can be closely approximated by much lighter-weight measurements. we propose a protocol using this method which is limited to at most a 1% increase in network traffic but which often costs much less in practice.
a new class of qos routing strategies based on network graph reduction. this paper discusses a new approach to qos routing, introducing the notion of algorithm resilience (i.e., its capability to adapt to network and load modifications) as performance index of the algorithm itself.the new approach can be summarized as network graph reduction, i.e., a modification of the graph describing the network before the routing path is computed, in order to exclude from the path selection over-congested portions of the network. this solution leads to a class of two-step routing algorithms, where both steps are simple, hence allowing efficient implementation.simulation experiments, run on randomly-generated topologies and traffic patterns, show that these routing algorithms perform consistently better than both the standard minimum hop algorithm and those qos-based algorithms based on the same metrics but not using the notion of network graph reduction.
fast algorithms for measurement-based traffic modeling. this paper develops fast algorithms for construction of circulant modulated rate process to match with two primary traffic statistical functions: distribution $f(x)$ and autocorrelation $r(\tau)$ of the rate process. using existing modeling techniques, $f(x)$ has to be limited to certain forms such as gaussian or binomial; $r(\tau)$ can only consist of one or two exponential terms which are often real exponentials rather than complex. in reality, these two functions are collective from real traffic traces and generally expressed in much complicated form. our emphasis here is placed on the algorithmic design for matching complicated $r(\tau)$ in traffic modeling. the typical cpu time for the traffic modeling with $r(\tau)$ consisting of five or six complex exponential terms is found in the range of a few minutes by the proposed algorithms. our study further shows an excellent agreement between original traffic traces and sequences generated by the matched analytical model.
design of virtual channel queue in an atm broadband terminal adaptor. it is desirable to interconnect different computer hosts and local area networks (lans) through the asynchronous transfer mode (atm) network via broadband terminal adaptors (btas). the bta must have a sufficiently large buffer, called a virtual channel queue (vcq), to temporarily store multiple, partially received packets from different virtual channels. the buffer requirement of a shared-memory vcq is studied for different packet loss probabilities and virtual channel numbers. two different architectures for implementing the shared-memory vcq are compared. the second architecture with multiple linked queues in the shared-memory requires less memory and has better scalability to accommodate a large number of virtual channels and is adopted in the analysis. several possible error conditions, such as shared-memory overflow, the received packet exceeding its maximum length, and the corruption of the pointer in the logical queue, are discussed. corresponding solutions are proposed in the vcq designs
ascent: adaptive self-configuring sensor networks topologies.. advances in microsensor and radio technology will enable small but smart sensors to be deployed for a wide range of environmental monitoring applications. the low per-node cost will allow these wireless networks of sensors and actuators to be densely distributed. the nodes in these dense networks will coordinate to perform the distributed sensing and actuation tasks. moreover, as described in this paper, the nodes can also coordinate to exploit the redundancy provided by high density so as to extend overall system lifetime. the large number of nodes deployed in these systems will preclude manual configuration, and the environmental dynamics will preclude design-time preconfiguration. therefore, nodes will have to self-configure to establish a topology that provides communication under stringent energy constraints. ascent builds on the notion that, as density increases, only a subset of the nodes are necessary to establish a routing forwarding backbone. in ascent, each node assesses its connectivity and adapts its participation in the multihop network topology based on the measured operating region. this paper motivates and describes the ascent algorithm and presents analysis, simulation, and experimental measurements. we show that the system achieves linear increase in energy savings as a function of the density and the convergence time required in case of node failures while still providing adequate connectivity.
resource optimization in qos multicast routing of real-time multimedia. we consider a network design problem, where applications require various levels of quality-of-service (qos) while connections have limited performance. suppose that a source needs to send a message to a heterogeneous set of receivers. the objective is to design a low-cost multicast tree from the source that would provide the qos levels (e.g., bandwidth) requested by the receivers. we assume that the qos level required on a link is the maximum among the qos levels of the receivers that are connected to the source through the link. in accordance, we define the cost of a link to be a function of the qos level that it provides. this definition of cost makes this optimization problem more general than the classical steiner tree problem. we consider several variants of this problem all of which are proved to be np-hard. for the variant where qos levels of a link can vary arbitrarily and the cost function is linear in its qos level, we give a heuristic that achieves a multicast tree with cost at most a constant times the cost of an optimal multicast tree. the constant depends on the best constant approximation ratio of the classical steiner tree problem. for the more general variant, where each link has a given qos level and cost we present a heuristic that generates a multicast tree with cost o(min {log r, k}) times the cost of an optimal tree, where r denotes the number of receivers, and k denotes the number of different levels of qos required. we generalize this result to hold for the case of many multicast groups.
optical switch configuration and lightpath assignment in wavelength routing multihop lightwave networks. a wide-area transparent optical network can be constructed by using wavelength routers and switches, each dealing with only a small number of wavelengths. in this work we consider the problem of configuring the wavelength routers based on the observed traffic. various policies for wavelength routing, and the corresponding assignment of wavelengths along the routes have been studied before, which are based on minimizing congestion, average hop-distance, and call blocking probability or on maximizing carried traffic, and the number of clear channels. however these approaches often lead to scenarios where a significant number of available wavelengths at the input/output ports of the routers cannot be used due to potential wavelength conflict. the wavelength routing and assignment algorithms presented in this paper focus on maximizing the wavelength-utilization at the switching devices which also improve the overall network performance.