Showing papers in "Telecommunication Systems in 2004"
TL;DR: The real-time event detection service using Data Service Middleware provides data-centric and group-based services for sensor networks and supports confidence functions which are designed based on data semantics, including relative importance of sub-events and historical patterns.
Abstract: This paper presents the real-time event detection service using Data Service Middleware (DSWare). DSWare provides data-centric and group-based services for sensor networks. The real-time event service handles unreliability of individual sensor reports, correlation among different sensor observations, and inherent real-time characteristics of events. The event service supports confidence functions which are designed based on data semantics, including relative importance of sub-events and historical patterns. When the failure rate is high, the event service enables partial detection of critical events to be reported in a timely manner. It can also be applied to differentiate between the occurrences of events and false alarms.
275 citations
TL;DR: An efficient minimalist algorithm which assumes that global information is not available is presented which deploys a network of radio beacons which assists the robot in coverage and also used by the robot for navigation.
Abstract: We consider the problem of coverage and exploration of an unknown dynamic environment using a mobile robot. The environment is assumed to be large enough such that constant motion by the robot is needed to cover the environment. We present an efficient minimalist algorithm which assumes that global information is not available (neither a map, nor GPS). Our algorithm deploys a network of radio beacons which assists the robot in coverage. The network is also used by the robot for navigation. The deployed network can also be used for applications other than coverage (such as multi-robot task allocation). Simulation experiments are presented which show the collaboration between the deployed network and mobile robot for the tasks of coverage/exploration, network deployment and maintenance (repair), and mobile robot recovery (homing behavior). We discuss a theoretical basis for our algorithm on graphs and show the results of the simulated scenario experiments.
246 citations
TL;DR: It is argued that AQM based TCP congestion control should be adaptive to the dynamically changing traffic situation in order to detect, control and avoid the current and the incipient congestion proactively.
Abstract: Current end-to-end Internet congestion control under tail-drop (TD) queue management experiences performance degradations such as multiple packet losses, high queueing delay and low link utilization. In this paper, we review recently proposed active queue management (AQM) algorithms for supporting end-to-end transmission control protocol (TCP) congestion control. We focus recently developed control theoretic design and analysis method for the AQM based TCP congestion control dynamics. In this context, we analyze the problems of existing AQM proposals in which congestion is detected and controlled reactively based on current and/or past congestion. Then we argue that AQM based TCP congestion control should be adaptive to the dynamically changing traffic situation in order to detect, control and avoid the current and the incipient congestion proactively. Finally, we survey two adaptive and proactive AQM algorithms, PID-controller and Pro-Active Queue Management (PAQM), designed using classical proportional-integral---derivative (PID) feedback control to overcome the reactive congestion control dynamics of existing AQM algorithms. A comparative study of these AQM algorithms with existing AQM algorithms is given. A simulation study under a wide range of realistic traffic conditions suggests that PID-controller and PAQM outperform other AQM algorithms such as random early detection (RED) [Floyd and Jacobson, 18] and proportional-integral (PI) controller [Hollot et al., 24].
94 citations
TL;DR: A distance-based decision fusion scheme is proposed exploiting the relationship between sensor to target distance, signal to noise ratio and classification rate, which requires less communication while achieving higher region classification rate when compared to conventional majority-vote-based fusion schemes.
Abstract: Target classification fusion problem in a distributed, wireless sensor network is investigated. We propose a distance-based decision fusion scheme exploiting the relationship between sensor to target distance, signal to noise ratio and classification rate, which requires less communication while achieving higher region classification rate when compared to conventional majority-vote-based fusion schemes. Several different methods are tested, and very encouraging simulation results using real world experimental data samples are also observed.
66 citations
TL;DR: The theoretical analysis shows that there is a critical minimum average neighborhood size of 15 for good accuracy, and simulation results show that position accuracy to within 20% of the local radio range can be achieved, even with upto 10% variation in the radio ranges.
Abstract: We present an algorithm for achieving robust and reasonably accurate localization in a randomly placed wireless sensor network, without the use of global control, globally-accessible beacon signals, or accurate estimates of inter-sensor distances. We present theoretical analysis, simulation results and recent experimental results. The theoretical analysis shows that there is a critical minimum average neighborhood size of 15 for good accuracy, and simulation results show that position accuracy to within 20% of the local radio range can be achieved, even with upto 10% variation in the radio ranges.
60 citations
TL;DR: This paper describes a distributed parameterized algorithm for Sensor Topology Retrieval at Multiple Resolutions (STREAM), which makes a tradeoff between topology details and resources expended and defines various classes of topology queries and rules for optimal parameter selection to support these queries.
Abstract: Large-scale sensor networks need energy-efficient mechanisms to extract topology for various aspects of sensor network management. Some network properties can be inferred from a relatively low-resolution representation of topology. Different topology resolutions suffice for different management applications to perform at a desired level. In these cases, it is an overkill to retrieve the entire topology of large-scale networks particularly because sensor nodes are energy constrained. In this paper, we describe a distributed parameterized algorithm for Sensor Topology Retrieval at Multiple Resolutions (STREAM), which makes a tradeoff between topology details and resources expended. We also define various classes of topology queries and rules for optimal parameter selection to support these queries.
47 citations
TL;DR: A novel scheme to efficiently organize and utilize network resources for target localization by presenting a dynamic group management method to initiate and maintain multiple tracks in a distributed manner.
Abstract: The tradeoff between performance and scalability is a fundamental issue in distributed sensor networks. In this paper, we propose a novel scheme to efficiently organize and utilize network resources for target localization. Motivated by the essential role of geographic proximity in sensing, sensors are organized into geographically local collaborative groups. In a target tracking context, we present a dynamic group management method to initiate and maintain multiple tracks in a distributed manner. Collaborative groups are formed, each responsible for tracking a single target. The sensor nodes within a group coordinate their behavior using geographically-limited message passing. Mechanisms such as these for managing local collaborations are essential building blocks for scalable sensor network applications.
43 citations
TL;DR: An adaptive and decentralized algorithm that progressively refines the placement of operators by walking through neighbor nodes is described, which can achieve near optimal placement onto various graph topologies despite the risks of local minima.
Abstract: In-network query processing is critical for reducing network traffic when accessing and manipulating sensor data. It requires placing a tree of query operators such as filters and aggregations but also correlations onto sensor nodes in order to minimize the amount of data transmitted in the network. In this paper, we show that this problem is a variant of the task assignment problem for which polynomial algorithms have been developed. These algorithms are however centralized and cannot be used in a sensor network. We describe an adaptive and decentralized algorithm that progressively refines the placement of operators by walking through neighbor nodes. Simulation results illustrate the potential benefits of our approach. They also show that our placement strategy can achieve near optimal placement onto various graph topologies despite the risks of local minima.
39 citations
TL;DR: A new on-demand multicast routing protocol, named Source Routing-based Multicast Protocol (SRMP), which provides stable paths based on links' availability according to future prediction of links' states, and higher battery life paths.
Abstract: We focus on one critical issue in mobile ad hoc networks that is multicast routing. Advantages and limitations of existing routing protocols are illustrated. Optimal routes, stable links, power conservation, loop freedom, and reduced channel overhead are the main features to be addressed in a more efficient mechanism. In this paper, we propose a new on-demand multicast routing protocol, named Source Routing-based Multicast Protocol (SRMP). Our proposition addresses two important issues in solving routing problems: (i) path availability concept, and (ii) higher battery life paths. SRMP applies a source routing mechanism, and constructs a mesh to connect group members. It provides stable paths based on links' availability according to future prediction of links' states, and higher battery life paths. This protocol succeeded to minimize network load via designing optimal routes that guarantee reliable transmission and active adaptability. A performance comparison study with On-demand Multicast Routing Protocol (ODMRP) and Adaptive Demand-driven Multicast Routing (ADMR) protocol is undertaken. Analysis results show the strength of the SRMP nodes' selection criteria and its efficient energy consumption compared to the other two protocols.
37 citations
TL;DR: In this paper, the authors analyse residential demand by traffic destination, using a translogarithmic indirect utility function, and construct a model adapted to evaluate the characteristics of telecommunications demand in a competitive market.
Abstract: The main objective of this paper is to analyse residential demand by traffic destination, using a translogarithmic indirect utility function. We focus on five traffic directions, in order to construct a model adapted to evaluate the characteristics of telecommunications demand in a competitive market. The resulting price elasticities express high reactivity to own price changes for the main traffic directions, as well as little interactions between the different types of traffic. Moreover, the high values of income elasticities confirm the importance of income effects when analysing residential telecommunications demand. This model shows useful for welfare analysis. The computation of customers' income equivalent variation shows, on average, a higher willingness to pay for some traffic directions than the bill actually paid. Finally, we show that the optimal prices for the operator, in a cost minimisation point of view, are higher than the observed prices for local and national traffic directions. This emphasises the existence of important cross-subsidies among the different segments of customers.
37 citations
TL;DR: This paper proposes an optimal configuration for wireless video-surveillance networks which adapts to the radio channel state by effectively implementing FEC and ARQ techniques.
Abstract: In this paper, we address the design of data processing and error control strategies for a wireless sensor network for video-surveillance applications, so as to optimize its performance in terms of energy consumption, information delivery delay, and information quality. First, we suggest a video coding strategy based on intelligent distributed processing, which yields very low power consumption. Then, we investigate the interactions between energy consumption, quality, and delay, and analyze the system performance when ARQ- and FEC-based error-control techniques are applied. As a result, we propose an optimal configuration for wireless video-surveillance networks which adapts to the radio channel state by effectively implementing FEC and ARQ techniques.
TL;DR: A queuing system model for the performance analysis of IN call processing, presented as a network of queues where the total number of customers is fixed, thus forming a closed queuing network.
Abstract: With the wide deployment of intelligent network (IN) services, there is an urgent need to understand and solve teletraffic performance issues of the evolving network intelligence platform This paper discusses a queuing system model for the performance analysis of IN call processing The intelligent network is presented as a network of queues where the total number of customers (eg, SSPs) is fixed, thus forming a closed queuing network The IN distributed architecture is modeled as a finite source queuing model --- M/G/1/K/K The expected response time for that model is analyzed and computed The numerical results and the corresponding curves are provided and, related to open questions, future work is summarized
TL;DR: A novel SPT algorithm is proposed for optimizing the different objectives of a multi-objective traffic engineering scheme using different distribution trees to multicast several flows and shows polynomial complexity.
Abstract: In this paper, we propose a multi-objective traffic engineering scheme using different distribution trees to multicast several flows. The aim is to combine into a single aggregated metric, the following weighting objectives: the maximum link utilization, the hop count, the total bandwidth consumption, and the total end-to-end delay. Moreover, our proposal solves the traffic split ratio for multiple trees. We formulate this multi-objective function as one with Non Linear programming with discontinuous derivatives (DNLP). Results obtained using SNOPT solver show that several weighting objectives are decreased and the maximum link utilization is minimized. The problem is NP-hard, therefore, a novel SPT algorithm is proposed for optimizing the different objectives. The behavior we get using this algorithm is similar to what we get with SNOPT solver. The proposed approach can be applied in MPLS networks by allowing the establishment of explicit routes in multicast events. The main contributions of this paper are the optimization model and the formulation of the multi-objective function; and that the algorithm proposed shows polynomial complexity.
TL;DR: The DARIS architecture comprises a novel concept of dynamic and hierarchical aggregation, which acts on the network level of autonomous systems (ASes), which relieves management entities in intermediate ASes of processing load by reducing their managed reservation states as well as the number of signaling messages that have to be processed significantly.
Abstract: Global availability of on-demand services with an associated guaranteed quality-of-service (QoS) is still missing in the Internet today. The Differentiated Services architecture achieves scalability in the data plane by treating all flows with a specific type of service as one aggregate. In order to provide guaranteed end-to-end reservations, the control plane (e.g., performing admission control and management of resource reservations) has to be scalable as well. The DARIS architecture provides this essential linkage between scalability in the packet forwarding path and scalability of QoS management in the Internet. It comprises a novel concept of dynamic and hierarchical aggregation, which acts on the network level of autonomous systems (ASes). This relieves management entities in intermediate ASes of processing load by reducing their managed reservation states as well as the number of signaling messages that have to be processed significantly. Moreover, novel and special support for aggregation by a dedicated signaling protocol mechanism is provided.
TL;DR: This work proposes a security extension to SCTP named Secure S CTP (S-SCTP) to solve issues in an efficient and user-friendly way and introduce limitations or inefficiencies in standard security protocols such as TLS and IPsec.
Abstract: The Stream Control Transmission Protocol (SCTP) is a new general purpose transport protocol defined by the IETF. Originally intended for the transport of voice signaling data (SS7) over IP networks, SCTP together with newly defined extensions is increasingly considered for other application scenarios as well. These require strong security solutions to authenticate the communication partners and protect sensitive data with respect to integrity and confidentiality. Proposals have been issued on how to protect SCTP transport by using standard security protocols such as TLS and IPsec. However, these solutions introduce limitations or inefficiencies und thus may not be able to fully exploit the capabilities of SCTP. Therefore, we propose a security extension to SCTP named Secure SCTP (S-SCTP) to solve these issues in an efficient and user-friendly way.
TL;DR: This paper explores the use of Multi-Terminal Interval Decision Diagrams as the central structure of a firewall packet filtering mechanism by first relating the packet filtering problem to predicate logic, then implementing a prototype which is used in an empirical evaluation.
Abstract: This paper explores the use of Multi-Terminal Interval Decision Diagrams (MTIDDs) as the central structure of a firewall packet filtering mechanism. This is done by first relating the packet filtering problem to predicate logic, then implementing a prototype which is used in an empirical evaluation. The main benefits of the MTIDD structure are that it provides access to Boolean algebra over filters, efficient classification time, and a compact representation. Results from the empirical evaluation shows that MTIDDs are scalable in terms of memory usage: a 50,000 rule filter requires only 3MB of memory, and efficient for packet classification: it is able to handle more rules than the schemes it was compared to without causing a degradation in performance.
TL;DR: This paper focuses on a special class of spatiotemporal multicast called “mobicast” featuring a message delivery zone that moves at a constant velocity, and introduces four different mobicast protocols and two topological network compactness metrics.
Abstract: We propose a new multicast communication paradigm called "spatiotemporal multicast" for supporting applications which require spatiotemporal coordination in wireless sensor networks. In this paper we focus on a special class of spatiotemporal multicast called "mobicast" featuring a message delivery zone that moves at a constant velocity $$\vec v$$ . The key contributions of this work are: (1) the specification of mobicast and its performance metrics, (2) the introduction of four different mobicast protocols along with the analysis of their performance, (3) the introduction of two topological network compactness metrics for facilitating the design and analysis of spatiotemporal protocols, and (4) an experimental evaluation of compactness properties for random sensor networks and their effect on routing protocols.
TL;DR: The Preemptive Drop Policy is extended into the Adaptive PDP (APDP), which provides absolute QoS guarantees in OPS, and an analytical model of the PDP is introduced for switches with and without wavelength conversion.
Abstract: Optical Packet Switching (OPS) is a promising technology for future core networks due to the ability to handle bursty traffic, adaptability to changes in the network infrastructure and good network utilization. In order to provide sufficient Quality of Service (QoS) to the emerging range of real-time and critical business applications, service differentiation should be present in future OPS. This paper presents the Preemptive Drop Policy (PDP), which provides service differentiation in asynchronous bufferless OPS. Based on time-continuous Markov chains, we introduce an analytical model of the PDP for switches with and without wavelength conversion. We extend the PDP into the Adaptive PDP (APDP), which provides absolute QoS guarantees in OPS. Simulations performed validate our analytical model and show that the APDP operates properly in a dynamic changing system load scenario.
TL;DR: This work proposes a combination of contention reduction through congestion control and bursts retransmission to eliminate completely bursts loss and shows that the proposed protocol is a viable solution for effectively reducing the conflict and increasing the bandwidth utilization for optical burst switching.
Abstract: Optical burst switching (OBS) is a proposed new communications technology that seeks to expand the use of optical technology in switching systems. However, many challenging issues have to be solved in order to pave the way for an effective implementation of OBS. Contention, which may occur when two or more bursts compete for the same wavelength on the same link, is a critical issue. Many contention resolution methods have been proposed in the literature but many of them are very vulnerable to network load and may suffer severe loss in case of heavy traffic. Basically, this problem is due to the lack of information at the nodes and the absence of global coordination between the edge routers. In this work, we propose another approach to avoid contention and decrease the loss. In this scheme, the intermediate nodes report the loss observed to the edge nodes so that they can adjust the traffic at the sources to meet an optimal network load. Furthermore, we propose a combination of contention reduction through congestion control and bursts retransmission to eliminate completely bursts loss. This new approach achieves fairness among all the edge nodes and enhances the robustness of the network. We also show through simulation that the proposed protocol is a viable solution for effectively reducing the conflict and increasing the bandwidth utilization for optical burst switching.
TL;DR: STONE (Service Synthesizer on the Net) was designed to provide distributed transparency, service consistency, and context-awareness, and explored communication and computation technologies in a sensor-instrumented environment.
Abstract: Two major properties will characterize networks in the future: `3C everywhere' and `physical interaction'. These two properties promise a computing infrastructure that seamlessly and ubiquitously aids users in accomplishing their tasks and that renders the actual computing devices and technology largely invisible. This paper begins by providing a brief overview of the emerging technologies that may influence the new ubiquitous network (UbiNet) architecture. The following section presents our STONE (Service Synthesizer on the Net) project at the University of Tokyo. We designed STONE to provide distributed transparency, service consistency, and context-awareness, and explored communication and computation technologies in a sensor-instrumented environment.
TL;DR: Simulation shows that, in the case of a high workload and a high level of variation, fuzzy RED, by tracking system variation in an on-line manner, improves RED performance in a number of important router-based metrics like packet loss rate, average queueing delay, link utilization, and global power.
Abstract: One of the most promising active queue management schemes being proposed for deployment in the Internet is the Random Early Detection (RED) scheme. However, research results on RED performance are highly mixed, especially in the field of tuning its parameters. In this paper, a comprehensive performance analysis of RED is presented. We revisit some features in RED and study them in greater detail. We point out that RED, in general, does not possess proportional loss between flows as claimed and widely adopted in previous research. We suggest the generalization of the PASTA property and give a proof for TCP flows. We also evaluate the performance of the Exponential Weighted Moving Average (EWMA) algorithm in RED. We find that EWMA in RED is an unbiased estimator of the average queue-length, regardless of the weighting value w q . We also point out the theoretical and practical limits of EWMA in RED. Finally, we propose the use of fuzzy EWMA to RED (fuzzy RED) to alleviate the inflexibility of RED tuning. We use simulations to evaluate the performance of fuzzy RED and compare it with other versions of RED. Our simulations show that, in the case of a high workload and a high level of variation, fuzzy RED, by tracking system variation in an on-line manner, improves RED performance in a number of important router-based metrics like packet loss rate, average queueing delay, link utilization, and global power.
TL;DR: The problem is formulated as a two-stage stochastic program with mixed-integer recourse, and the solution procedure is applied, solving scenario subproblems by means of branch and cut.
Abstract: We consider a network design problem arising in mobile communications. At the core of the network is a number of mobile switching centers (MSCs), each serving a number of base station controllers (BSCs). The network design problem involves three major groups of decisions --- deployment of a number of new MSCs, allocation of BSCs to new and existing MSCs, and capacity expansion of transmission links interconnecting the MSCs. These decisions must be made so as to minimize the incurred costs while meeting customer demand and observing the capacity restrictions. We formulate the problem as a two-stage stochastic program with mixed-integer recourse. To solve the problem we apply a dual decomposition procedure, solving scenario subproblems by means of branch and cut. The solution procedure has been tested on a real life problem instance provided by SONOFON, a Danish mobile communication network operator, and we report results of our computational experiments.
TL;DR: This paper proposes an analytical model to study the performance of TCP in a DiffServ network under the different proposed schemes, based on a Markovian fluid approach and compares the service differentiation provided by the proposed schemes under different subscription levels, different reservations, and different round-trip times.
Abstract: In a Differentiated Services network, the use of TCP by an application impacts the service it gets from the network. TCP congestion control algorithms are designed to provide a fair sharing of resources in a best effort network as the current Internet. TCP is not conscious of the new services proposed by DiffServ, namely the different priorities packets are injected with into the network. Many schemes have been proposed to support TCP traffic in a DiffServ network. These schemes have been often validated with simulations. In this paper we propose an analytical model to study the performance of TCP in a DiffServ network under the different proposed schemes. The model is based on a Markovian fluid approach. We present first a general version of the model, then we specify it to the different proposed schemes. For each scheme, we compute the throughput achieved by a TCP connection. We compare then the service differentiation provided by the proposed schemesunder different subscription levels, different reservations, and different round-trip times. Our model forms a good tool for the evaluation of new solutions to support TCP traffic in a DiffServ network.
TL;DR: A dynamic game theoretical model of cooperation in ad hoc networks, based on evolutionary game theory, is proposed, which shows that if an ad hoc network implements a reputation mechanism, all long term equilibrium points of the system will include cooperating nodes.
Abstract: The problem of cooperation among selfish nodes in ad hoc networks has gained recently a considerable attention. In this paper we propose a dynamic game theoretical model of cooperation in ad hoc networks, based on evolutionary game theory. Our model enables us to make predictions about possible equilibrium points of the network composed of the selfish and learning nodes, which can dynamically adjust their strategy in order to maximize their own payoff. In particular, we show that if an ad hoc network implements a reputation mechanism, all long term equilibrium points of the system will include cooperating nodes. In fact, in most of the equilibrium points, the cooperators will constitute a majority of the nodes. We believe that this new approach, borrowing from biological research, can have broader applications for studying dynamics of distributed communication systems.
TL;DR: The proposed st-routing protocol provides a systematic way to retry alternative paths without generating any duplicate packets, and works for only those networks that can be represented by biconnected graphs.
Abstract: A routing protocol chooses one of the several paths (routes) from a source node to a destination node in the computer network, to send a packet of information. In this paper, we propose a new routing protocol, which we call st-routing protocol, based on st-numbering of a graph. The protocol fits well in noisy environments where robustness of routing using alternative paths is a major issue. The proposed routing protocol provides a systematic way to retry alternative paths without generating any duplicate packets. The protocol works for only those networks that can be represented by biconnected graphs.
TL;DR: Simulation results indicate that the feedback controllers can guarantee the predetermined call dropping probability under a variety of traffic conditions, and so can utilize the scarce wireless resource efficiently by accepting more new calls.
Abstract: Emerging mobile wireless networks are characterized by significant uncertainties in mobile user population and system resource state. Such networks require adaptive resource management that continuously monitor the system and dynamically adjust resource allocations for adherence to the desired system performance requirements. We propose adaptive resource management technique based on control theory. The controller dynamically solves resource allocation problem using feedback control laws. In the base algorithm, the number of guard channels is dynamically adjusted by feeding back the current handoff call dropping probability. The base algorithm is then enhanced in two ways: feeding back the instantaneous number of handoff calls and by probabilistically implementing a fractional number of guard channels. We study the effects of parameter choices on the performance of the proposed algorithms using discrete event simulation. Simulation results indicate that the feedback controllers can guarantee the predetermined call dropping probability under a variety of traffic conditions, and so can utilize the scarce wireless resource efficiently by accepting more new calls.
TL;DR: This paper presents a code assignment algorithm for NOVSF codes, which does not require any code reassignments, and simulation results show that NOVSf codes achieve better throughput than OVSF code, even though code reassignment are allowed in the assignments of O VSF codes.
Abstract: OVSF codes are used as channelization codes in WCDMA. Due to code blocking property of OVSF codes, the bandwidth available in the system is severely limited. Code reassignments mitigate the impact of the blocking property at the expense of causing delays and decreasing the throughput of the system. Nonblocking OVSF (NOVSF) codes have been proposed to alleviate the adverse effect of code reassignments. This paper presents a code assignment algorithm for NOVSF codes, which does not require any code reassignments. Simulation results show that NOVSF codes achieve better throughput than OVSF codes, even though code reassignments are allowed in the assignments of OVSF codes.
TL;DR: The impact of introducing active networking on traditional packets flowing through the active nodes of a network is investigated and performance measures such as loss rates of standard packets and the node latency for this kind of packets are investigated.
Abstract: We investigate the impact of introducing active networking on traditional packets flowing through the active nodes of a network. Using two approaches, the process algebra formalism PEPA and the simulation package SimJava, we compare the performance of an active node and of a traditional one. We are mainly interested in performance measures such as loss rates of standard packets and the node latency for this kind of packets.
TL;DR: This paper presents a performance analysis of optical burst switching networks with ring and chordal ring topologies, being focused on the following protocols: just-in-time (JIT), Jumpstart, JIT+, just-enough- time (JET) and Horizon.
Abstract: This paper presents a performance analysis of optical burst switching (OBS) networks with ring and chordal ring topologies. The performance analysis considers signaling protocols with one-way reservation schemes, being focused on the following protocols: just-in-time (JIT), Jumpstart, JIT+, just-enough-time (JET) and Horizon. It is shown that for a network with 20 nodes, the nodal degree gain due to the increase of nodal degree from two (ring) to three (chordal ring) is about three orders of magnitude in the first hop of both topologies, and is between two and three orders of magnitude in the last hop of each topology. It is also shown that the largest chord length gain, in a 20-node OBS network with a chordal ring topology, is slightly less than two orders of magnitude.
TL;DR: The impact of the shaping delay is studied and insight is provided into the issue of enforcing effective rates to traffic streams and traffic modeling conclusions related to the proposed shaping algorithm are derived.
Abstract: This paper presents experimental results aiming at underpinning a traffic engineering framework for traffic control and resource management in IP-based networks, which has significant theoretical qualities. Initially, the paper reviews the major components of a packet level traffic control framework:
(a) a general traffic shaping algorithm for effective rate enforcement
(b) mechanisms for aggregating, splitting and policing streams shaped with this algorithm, and
(c) a calculus for quantitative end-to-end QoS.
Following the illustration of the theoretical concepts the paper focuses on aspects pertaining to the applicability of the framework. Specifically, we study the impact of the shaping delay and we provide insight into the issue of enforcing effective rates to traffic streams. These studies take into account results from simulating the shaping algorithm, which are based on analyzing, processing and simulating real traffic traces collected from an HTTP server. Moreover, traffic modeling conclusions related to the proposed shaping algorithm, are derived and presented.