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Network Protocols, 2000. Proceedings. 2000 International Conference on

Date 14-17 Nov. 2000

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  • Proceedings 2000 International Conference on Network Protocols

    Publication Year: 2000
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    Freely Available from IEEE
  • Author index

    Publication Year: 2000 , Page(s): 337 - 338
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    Freely Available from IEEE
  • Analysis of Internet multicast traffic performance considering multicast routing protocol

    Publication Year: 2000 , Page(s): 95 - 104
    Cited by:  Papers (1)
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    Recently audio and video delivery services are widely spread in the Internet. In order to deliver these data to multiple receivers at the same time, the multicast technologies are indispensable. In such a situation, the performance analysis of multicast traffic will be important in order to design and operate the Internet. Multicast traffic is controlled by its own routing protocol and the multicast routing protocol is more complex than conventional unicast routing protocols. In this paper we propose a new multicast performance analyzer considering distance vector multicast routing protocol (DVMRP) and protocol independent multicast-sparse mode (PIM-SM) routing protocols. It captures messages of a multicast routing protocol as well as multicast IP datagrams. It also analyzes DVMRP and PIM-SM messages in order to investigate the behaviors of multicast IP datagrams and measures the statistics of multicast traffic in detail. This paper describes the detailed design of the multicast performance analyzer and the results of analyzing multicast datagrams transmitted over networks View full abstract»

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  • Hop integrity in computer networks

    Publication Year: 2000 , Page(s): 3 - 11
    Cited by:  Papers (3)
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    A computer network is said to provide hop integrity iff when any router p in the network receives a message m supposedly from an adjacent router q, then p can check that m was indeed sent by q, was not modified after it was sent, and was not a replay of an old message sent from q to p. We describe three protocols that can be added to the routers in a computer network so that the network can provide hop integrity. These three protocols are a secret exchange protocol, a weak integrity protocol, and a strong integrity protocol. All three protocols are stateless, require small overhead, and do not constrain the network protocol in the routers in any way View full abstract»

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  • A scalable monitoring approach for service level agreements validation

    Publication Year: 2000 , Page(s): 37 - 48
    Cited by:  Papers (3)
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    In order to detect violations of end-to-end service level agreements (SLA) and to isolate trouble links and nodes based on a unified framework, managers of a service provider network need to gather quality of service (QoS) measurements from multiple nodes in the network. For a network carrying over thousands of flows with end-to-end SLAs, the information exchanged between network nodes and a central network management system (NMS) could be substantial. Moreover in situations where only, a small number of flows violate their respective SLAs, simple polling mechanisms can lead to huge unnecessary overhead in identifying these ill-behaved flows. We propose an algorithm called (ARM) (Aggregation and Refinement based Monitoring) to reduce the amount of information exchange. (ARM) uses a histogram-based dynamic QoS data aggregation/refinement technique at each network node and a reasoning engine at the NMS to minimized the amount of data exchange between network nodes and NMS. (ARM) not only reduces unnecessary reporting through selective refinement, it also performs well across a wide range of traffic loads. Our simulation results show that (ARM) is at least an order of magnitude more efficient than a simple polling scheme. It also outperforms two centralized highly optimized schemes that cannot be implemented in practice View full abstract»

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  • Building a programmable multiplexing service using concast

    Publication Year: 2000 , Page(s): 230 - 239
    Cited by:  Patents (4)
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    Concast is a scalable “inverse-multicast” network service: messages sent from multiple sources toward the same destination are merged into a single message that is delivered to the destination. The mapping from sent messages to received messages is programmable, so the service can be tailored to the needs of specific applications. However the service can also be used as a building block for other generic network services, such as a packet multiplexing service that encapsulates multiple small packets into a single larger packet and then unencapsulates the small packets at their (common) destination. Such a service offers several potential benefits, including reduced packet processing overhead and increased rate-sharing, but must also be carefully designed to avoid problems caused by added packet delays. We show how concast can serve as the basis for a multiplexing service that can be tailored to the needs of the application. We present simulation results showing that the benefits of our multiplexing service vary with delay. We also show that given certain queue-manipulation capabilities, benefits can be achieved with zero added delay View full abstract»

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  • Differentiated predictive fair service for TCP flows

    Publication Year: 2000 , Page(s): 49 - 58
    Cited by:  Papers (3)
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    The majority of the traffic (bytes) flowing over the Internet today have been attributed to the Transmission Control Protocol (TCP). This strong presence of TCP has spurred further investigations into its congestion control mechanism and its effect on the performance of short and long data transfers. We investigate the interaction among short and long TCP flows, and how TCP service can be improved by employing a low-cost service differentiation scheme. Through control-theoretic arguments and extensive simulations, we show the utility, of isolating TCP flows into two classes based on their life-time/size, time/size one class of short flows and another of long flows. With such class-based isolation, short and long TCP flows have separate service queues at routers. This protects each class of flows from the other as they possess different characteristics, such as burstiness of arrivals/departures and congestion/sending window dynamics. We show the benefits of isolation, in terms of better predictability and fairness, over traditional shared queueing systems with both tail-drop and random-early-drop (RED) packet dropping policies View full abstract»

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  • Coordinated network scheduling: a framework for end-to-end services

    Publication Year: 2000 , Page(s): 69 - 79
    Cited by:  Papers (9)
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    In multi-hop networks, packet schedulers at downstream nodes have an opportunity to make up for excessive latencies due to congestion at upstream nodes. Similarly when packets incur low delays at upstream nodes, downs stream nodes can reduce priority and schedule other packets first. The goal of this paper is to define a framework for design and analysis of coordinated network scheduling (CNS) which exploit such inter-node coordination. The first provide a general CNS definition which enables us to classify a number of schedulers from the literature including, FIFO+, CEDF and work-conserving CJVC as examples of CNS schedulers. We then develop a distributed theory of traffic envelopes which enables us to derive end-to-end statistical admission control conditions for CNS schedulers. We show that CNS schedulers are able to limit traffic distortion to within a narrow range resulting in improved end-to-end performance and more efficient resource utilization View full abstract»

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  • An analysis of packet loss correlation in FEC-enhanced multicast trees

    Publication Year: 2000 , Page(s): 151 - 161
    Cited by:  Papers (3)
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    We study group loss probabilities of forward error correction (FEC) codes in shared loss multicast communication. We present a new analysis model with explicit state equations using recursive formulae. Our method looks at an FEC group as a whole, rather than analyze the number of transmissions of a particular packet. Our work applies to C(n,k) erasure codes, where any k out of n packets may decode the entire group. We find the cumulative distribution function that all leaf nodes in a shared loss tree successfully decode a C(n,k) FEC group, the probability mass function (p.m.f.) for the number of leaf nodes that successfully decode a transmission group, the expected number of packets received on successful decode and the expected number of missing packets on decode failure for a particular leaf node of the multicast tree, the p.m.f. that all leaf nodes hold the same packets in common, and the expected height of packet loss. Most of our findings generalize to arbitrary trees with non-uniform link loss. Our results also apply to non-FEC trees. We illustrate applications of our work with examples View full abstract»

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  • An analysis of multicast forwarding state scalability

    Publication Year: 2000 , Page(s): 105 - 115
    Cited by:  Papers (16)
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    Scalability of multicast forwarding state is likely to be a major issue facing inter-domain multicast deployment. We present a comprehensive analysis of the multicast forwarding state problem. Our goal is to understand the scaling trends of multicast forwarding state in the Internet, and to explore the intuitions that have motivated state reduction research. We conducted simulation experiments on both real and generated network topologies, with a range of parameters driven by multicast application characteristics. We found that the increase in peering among Internet backbone networks has led to more multicast forwarding state at a handful of core domains, but less state in the rest of the domains. We observed that scalability of multicast forwarding state with respect to session size follows a power law. Our findings show that distribution and concentration of multicast forwarding state in the Internet is significantly, impacted by the application characteristics. We investigated the proposals on non-branching multicast forwarding state elimination, and found substantial reduction is attainable even with very dense multicast sessions View full abstract»

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  • Time-lined TCP for the TCP-friendly delivery of streaming media

    Publication Year: 2000 , Page(s): 165 - 176
    Cited by:  Papers (9)  |  Patents (1)
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    This paper introduces time-lined TCP (TLTCP). TLTCP is a protocol designed to provide TCP-friendly delivery of time-sensitive data to applications that are loss-tolerant, such as streaming media players. Previous work on unicast delivery, of streaming media over the Internet proposes using UDP and performs congestion control at the user level by regulating the application's sending rate. TLTCP, on the other hand is intended to be implemented at the transport level, and is based on TCP with modifications to support time-lines. Instead of treating all data as a byte stream TLTCP allows the application to associate data with deadlines. TLTCP sends data in a similar fashion to TCP with the deadline for a section of data has elapsed; at which point the now obsolete data is discarded in favor of new data. As a result, TLTCP supports TCP-friendly delivery of streaming media by retaining much of TCP's congestion control functionality. We describe an API for TLTCP that involves augmenting the recvmsg and sendmsg socket calls. We also describe how streaming media applications that use various encoding schemes like MPEG-1 can associate data with deadlines and use TLTCP's API. We use simulations to examine the behavior of TLTCP under a wide range of networks and workloads. We find that it indeed performs time-lined data delivery and under most circumstances the bandwidth is shared equally, among completing TLTCP and TCP flows. Moreover those scenarios under which TLTCP appears to be unfriendly are those under which TCP flows competing only with other TCP flows do not share bandwidth equitably View full abstract»

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  • A topology-independent fair queueing model in ad hoc wireless networks

    Publication Year: 2000 , Page(s): 325 - 335
    Cited by:  Papers (24)  |  Patents (2)
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    Fair queueing of rate and delay-sensitive packet flows in a shared-medium, multihop wireless network remains largely unaddressed because of the unique design issues such as location-dependent contention, spatial channel reuse, conflicts between ensuring fairness and maximizing channel utilization, and distributed fair scheduling. In this paper we propose a new topology-independent fair queueing model for a shared-medium ad hoc network. Our model ensures coordinated fair channel access among spatially contending flows while seeking to maximize spatial channel reuse. We describe packetized algorithms that realize the fluid fairness model with analytically provable performance bounds. We further design distributed implementations that approximate the ideal centralized algorithm. We evaluate our design through both simulations and analysis View full abstract»

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  • Generalized load sharing for packet-switching networks

    Publication Year: 2000 , Page(s): 305 - 314
    Cited by:  Papers (5)
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    We propose a framework to study how to effectively perform load sharing in multipath communication networks. A generalized load sharing (GLS) model has been developed to conceptualize how traffic is split ideally, on a set of active paths. A simple traffic splitting algorithm, called weighted fair routing (WFR), has been developed at two different granularity levels, namely, the packet level, and the call level, to approximate GLS with the given routing weight vector. The packet-by-packet WFR (PWFR) mimics GLS by transmitting each packet as a whole whereas the call-by-call WFR (CWFR) imitates GLS so that all packets belonging to a single flow are sent on the same path. We have developed some performance bounds for PWFR and formed that PWFR is a deterministically fair traffic splitting algorithm. This attractive property is useful in the provision of service with guaranteed performance when multiple paths can be used simultaneously to transmit packets which belong to the same flow. Our simulation studies, based on a collection of Internet backbone traces, reveal that WFR outperforms two other traffic splitting algorithms, namely, generalized round robin routing (GRR), and probabilistic routing (PRR). These promising results form a basis for designing future adaptive constraint-based multipoint path routing protocols View full abstract»

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  • GeoTORA: a protocol for geocasting in mobile ad hoc networks

    Publication Year: 2000 , Page(s): 240 - 250
    Cited by:  Papers (31)  |  Patents (2)
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    This paper considers the problem of providing a geocast service in mobile ad hoc networks and presents a novel geocasting algorithm combining unicasting and flooding. Geocast is useful for sending messages to everyone in a specified geographical region. The proposed protocol is named GeoTORA, because it is derived from the TORA (unicast) routing protocol. Flooding is also incorporated in GeoTORA, but it is limited to nodes within a small region. This integration of TORA and flooding can significantly reduce the overhead of geocast delivery while maintaining reasonably high accuracy View full abstract»

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  • Convergent multi-path routing

    Publication Year: 2000 , Page(s): 273 - 282
    Cited by:  Patents (9)
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    We present a protocol for maintaining multiple paths to each destination in a network of processes. For each destination, each process in the network maintains a set of neighbors which are used as next-hops to reach the destination. This set is known as the successor set. Collectively, the successor sets from all processes in the network with respect to a given destination form a spanning, destination, and acyclic graph, whose only sink is the given destination. The protocol we present has two interesting properties. First the graph is maintained acyclic at all times, even though the successor set is dynamic. Second, the protocol tolerates all types of transient faults, even those which may not be detected. Therefore, if the protocol is started from an arbitrary initial state, it will converge to a normal operating state in which a spanning, directed, and acyclic graph is obtained and subsequently maintained View full abstract»

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  • An image transport protocol for the Internet

    Publication Year: 2000 , Page(s): 209 - 219
    Cited by:  Papers (3)  |  Patents (1)
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    Images account for a significant and growing fraction of Web downloads. The traditional approach to transporting images uses TCP, which provides a generic reliable, in-order byte-stream abstraction, but which is overly, restrictive for image data. We analyze the progression of image quality at the receiver with time and show that the in-order delivery abstraction provided by a TCP-based approach prevents the receiver application from processing and rendering portions of an image when they, actually, arrive. The end result is that an image is rendered in bursts interspersed with long idle times rather than smoothly. This paper describes the design, implementation, and evaluation of the Image Transport Protocol (ITP) for image transmission over loss-prone congested or wireless networks. ITP improves user-perceived latency using application level framing (ALF) and out-of-order pplication data unit (ADU) delivery achieving significantly better interactive performance as measured by the evolution of peak signal-to-noise ratio (PSNR) with time at the receiver ITP runs over UDP, incorporates receiver-driven selective reliability uses the congestion manager (CM) to adapt to network congestion, and is customizable for specific image formats (e.g., JPEG and JPEG2000). ITP enables a variety of new receiver post-processing algorithms such as error concealment that further improve the interactivity and responsiveness of reconstructed images. Performance experiments using our implementation across a variety of loss conditions demonstrate the benefits of ITP in improving the interactivity of image downloads at the receiver View full abstract»

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  • TCP performance analysis on asymmetric networks composed of satellite and terrestrial links

    Publication Year: 2000 , Page(s): 199 - 206
    Cited by:  Papers (1)
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    As the Internet users increase, asymmetric networks which provide asymmetric bandwidth or delay for the uplink and downlink have become a great attraction. However asymmetric networks which use both terrestrial and satellite links at the same time have not been adequately investigated. Therefore, this paper proposes a new formula for TCP performance evaluation for the asymmetric networks. Using this evaluation formula, we calculate the throughput of TCP Reno over the asymmetric networks taking slow start into account. The calculation results are compared with the following: (1) the value based on an existing theoretical formula, (2) the outputs of simulation by NS (Network Simulator), and (3) the experimental results using VSAT (Very Small Aperture Terminal) satellite communication system for satellite links and the Internet for terrestrial links. As a result, it is shown that the new formula is more precise than the one already proposed View full abstract»

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  • Dynamic Internet overlay deployment and management using the X-Bone

    Publication Year: 2000 , Page(s): 59 - 68
    Cited by:  Papers (4)  |  Patents (9)
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    The X-Bone dynamically deploys and manages Internet overlays to reduce their configuration effort and increase network component sharing. The X-Bone discovers, configures, and monitors network resources to create overlays over existing IP networks. Overlays are useful for deploying overlapping virtual networks on a shared infrastructure and for simplifying topology. The X-Bone extends current overlay management by adding dynamic resource discovery, deployment, and monitoring and allows simultaneous participation in multiple overlays. Its two-layer IP in IP tunneled overlays support existing applications and unmodified routing, multicast, and DNS services in unmodified operating systems. This two-layer scheme uniquely supports recursive overlays, useful for fault tolerance and dynamic relocation. The X-Bone uses multicast to simplify resource discovery, and provides secure deployment as well as secure overlays. This paper presents the X-Bone architecture, and discusses its components and features, and their performance impact View full abstract»

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  • Characterization and performance evaluation for proportional delay differentiated services

    Publication Year: 2000 , Page(s): 295 - 304
    Cited by:  Papers (6)
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    We consider a proportional delay model for Internet differentiated services. Under this model, an ISP can control the “spacing” of waiting times between different classes of traffic. Specifically, the ISP tries to ensure that the average waiting time of class i traffic relative to that of class i-1 traffic is consistently a specifiable ratio. If the ratio is less than one, the ISP can legitimately charge users of class i traffic a higher tariff rate (compared to the rate for class i-1 traffic), since class i users consistently enjoy better performance than class i-1 users. We use time-dependent priority scheduling to realize the proportional delay model. We formally characterize the feasible regions in which given delay ratios can be achieved. Moreover a set of scheduling parameters for obtaining the desired delay ratios can be determined by an efficient control algorithm. Experiments are carried out to illustrate the short-term, medium-term and long-term relative waiting time performances for different service classes View full abstract»

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  • Malicious packet dropping: how it might impact the TCP performance and how we can detect it

    Publication Year: 2000 , Page(s): 263 - 272
    Cited by:  Papers (6)
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    Among various types of denial of service attacks, “dropping attack” is probably the most difficult one to handle. This paper explores the negative impacts of packet dropping attacks and a method to detect such attacks. First, three dropping patterns are classified and investigated. We demonstrate that attackers can choose different dropping patterns to degrade TCP service to different levels, and selectively dropping a very, small number of packets can result in severe damage to TCP performance. Second, we show that a hacker can utilize a DDoS attack tool to control a “uncompromised” router to emulate dropping attacks. This proves that dropping attacks are indeed practically very possible to happen in today's Internet environment. Third, we present a statistical analysis module for the detection of TCP packet dropping attacks. Three measures, session delay, the position and the number of packet reorderings, have been implemented in the statistical module. This paper has evaluated and compared their detection performance View full abstract»

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  • A performance study of multiple access control protocols for wireless multimedia services

    Publication Year: 2000 , Page(s): 283 - 292
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    The multiple access control (MAC) problem in a wireless network has intrigued researchers for years. For a broadband wireless multimedia network such as wireless ATM, an effective MAC protocol is very much desired because efficient allocation of channel bandwidth is imperative in accommodating a large user population with satisfactory quality of service. Indeed, MAC protocols for a wireless ATM network, in which user traffic requirements are highly heterogeneous (classified into CBR, VBR, and ABR), are even more intricate to design. Considerable research efforts expended in tackling the problem have resulted in a myriad of MAC protocols. While each protocol is individually shown to be effective by the respective designers, it is unclear how these different protocols compare against each other on a unified basis. We quantitatively compare seven previously proposed TDMA-based MAC protocols for integrated wireless data and voice services. We first propose a taxonomy of TDMA-based protocols, from which we carefully select seven protocols, namely SCAMA, DTDMA/VR, DTDMA/PR, D4RUMA, DPRMA, DSA++, and PRMA/DA, such that they are devised based on rather orthogonal design philosophies. The objective of our comparison is to highlight the merits and demerits of different protocol designs View full abstract»

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  • Multidomain load balancing

    Publication Year: 2000 , Page(s): 315 - 324
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    This paper investigates dynamic load balancing issues in the multidomain environment where local area networks (LANs) are interconnected by the Internet. Because of the much slower Internet communication speed and limited bandwidth, existing load balancing algorithms for LANs are unsuitable for the multidomain environment. New issues such as lag time in updating load information and network cost of transferring jobs must be addressed. To tackle these problems, the conventional least load scheduler is extended to the multidomain environment by employing a hierarchical structure, and several quick update techniques are proposed. Also, a heuristic taking both the machine load and the network cost into consideration is developed to evaluate the benefits of sending jobs to computers in different domains. A set of experiments conducted on the BALANCE testbed showed that the proposed techniques provide significant performance improvement over existing algorithms View full abstract»

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  • General AIMD congestion control

    Publication Year: 2000 , Page(s): 187 - 198
    Cited by:  Papers (71)
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    Instead of the increase-by-one decrease-to-half strategy used in TCP for congestion window adjustment, we consider the general case such that the increase value and decrease ratio are parameters. That is, in the congestion avoidance state, the window size is increased by α per window of packets acknowledged and it is decreased to β of the current value when there is congestion indication. We refer to this window adjustment strategy as general additive increase multiplicative decrease (GAIMD). We present the (mean) sending rate of a GAIMD flow as a function of α, β, loss rate, mean round-trip time, mean timeout value, and the number of packets acknowledged by each ACK. We conducted extensive experiments to validate this sending rate formula. We found the formula to be quite accurate for a loss rate of up to 20%. We also present a simple relationship between α and β for a GAIMD flow to be TCP-friendly, that is, for the GAIMD flow to have approximately the same sending rate as a TCP flow under the same path conditions. We present results from simulations in which TCP-friendly GAIMD flows (α=0.31, β=7/8) compete for bandwidth with TCP Reno flows and with TCP SACK flows, on a DropTail link as well as on a RED link. We found that the GAIMD flows were highly, TCP-friendly. Furthermore, with β at 7/8 instead of 1/2, these GAIMD flows have reduced rate fluctuations compared to TCP flows View full abstract»

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  • Monitoring reachability in the global multicast infrastructure

    Publication Year: 2000 , Page(s): 141 - 150
    Cited by:  Papers (2)
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    The multicast infrastructure has transitioned to a topology that now supports hierarchical routing. Instead of a flat virtual topology originally called the Multicast Backbone (MBone) there now exists a hierarchy where routing information is exchanged between autonomous systems (ASes). In today's multicast infrastructure reachability problems are common. Unlike in the MBone, the possibility of limited connectivity between domains is now possible. We present a system called sdr-monitor. This tool collects session directory information from numerous places around the world and presents an application layer view of reachability. Using data collected over the last year, we present an analysis of long term reachability characteristics for the global multicast infrastructure. Our findings are that overall reachability is generally quite poor. However, having identified some of the reasons, we believe there is not a fundamental infrastructure problem, but rather protocol bugs and a lack of management tools View full abstract»

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  • Scalable object-tracking through unattended techniques (SCOUT)

    Publication Year: 2000 , Page(s): 253 - 262
    Cited by:  Papers (7)
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    A scalable object location service can enable users to search for various objects in an environment where many small, networked devices are attached to objects. We investigate two hierarchical, self-configuring or unattended approaches for an efficient object location service. Each approach has its advantages and disadvantages based on the anticipated load. The first approach, SCOUT-AGG, is based on aggregation of object names. The second approach, SCOUT-MAP, is based on indirection, where information about an object is stored at the locator sensor for the object. The relative efficiency of SCOUT-AGG and SCOUT-MAP can be characterized by the query to mobility, update rate of the system. SCOUT-AGG performs better for low query to update rate but its performance deteriorates in general relative to SCOUT-MAP as the queries to update rate increases. The rate of performance deterioration depends on query specificity (i.e., queries for a specific object or for any object of a particular type). SCOUT-MAP generally exhibits better load balancing than SCOUT-AGG for various scenarios. We support the above results through simple analytical modeling and simulation View full abstract»

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