waashk/dblp huggingface dataset:
design and performance analysis of a growable multicast atm switch. in this paper, we design and analyze a growable multicast atm switch. it can grow to a large size since both cell routing and contention resolution are designed to distribute over switch elements, and the switch structure is modular. the output ports are partitioned into groups to permit sharing of routing paths. the concept of group routing helps reduce an order of magnitude of switch elements. a two-stage switch architecture is described to illustrate our design principle. the switch can be easily expanded to a larger size by using more stages. the performance analysis of the switch in terms of cell loss rate, delay, mean queue length, mean waiting time, and throughput is conducted using the m/geom/1 model. experimental results show that the proposed atm switch not only meets the atm performance requirements either for unicasting or multicasting but also uses fewer switch elements and has less delay than other comparable switches.
movement-assisted sensor deployment. adequate coverage is very important for sensor networks to fulfill the issued sensing tasks. in many working environments, it is necessary to make use of mobile sensors, which can move to the correct places to provide the required coverage. in this paper, we study the problem of placing mobile sensors to get high coverage. based on voronoi diagrams, we design two sets of distributed protocols for controlling the movement of sensors, one favoring communication and one favoring movement. in each set of protocols, we use voronoi diagrams to detect coverage holes and use one of three algorithms to calculate the target locations of sensors if holes exist. simulation results show the effectiveness of our protocols and give insight on choosing protocols and calculation algorithms under different application requirements and working conditions.
re-routing in circuit switched networks. dynamic routing has been adopted in many circuit switched networks in many parts of the world. a number of dynamic routing schemes have been designed and studied with the aim of maximizing the network throughput. the least loaded routing (llr) is simple and efficient, while other more elaborate routing schemes can only provide marginal throughput gain over that of llr. re-routing is the practice of routing calls on alternate paths to direct paths or other less congested alternate paths. it allows the continuous re-distribution of network loads so that the congestion on direct paths can be relieved. in this paper, we study a re-routing scheme based on llr. an original analysis of re-routing is performed and numerical examples confirm the significant throughput gain over llr routing.
on dynamically establishing and terminating isochronous message streams in wdma-based local area lightwave networks. complement to our prior work in [11], we address in the paper the problem of dynamically establishing/terminating real-time message streams in response to call setup/clear requests in single-hop star-coupled wdma-based optical networks. we consider a star-coupled broadcast-and-select network architecture in which n stations are connected to a star coupler with w different wavelength channels (w
designing a distributed authorization service. we present the design of a distributed authorization service which parallels existing distributed authentication services. such a service would operate on top of an authentication substrate. there are two central ideas underlying our design: (1) the use of a language, called generalized access control list (gacl), as a common representation for authorization requirements. (2) the use of authenticated delegation to effect authorization offloading from an end server to an authorization server. we present the syntax and semantics of gacl, and illustrate how it can be used to specify authorization requirements that cannot be easily specified by ordinary acl. we also describe the protocols in our design.
a near-optimal packet scheduler for qos networks. a packet scheduler in a quality-of-service (qos) network should be sophisticated enough to support stringent qos constraints at high loads, but it must also have a simple implementation so that packets can be processed at the speed of the transmission link. the earliest-deadline-first (edf) scheduler is the optimal scheduler for bounded-delay services in the sense that it provides the tightest delay guarantees of any scheduler, but an implementation of edf requires the sorting of packets, a complex operation that is not practical for high-speed networks. in this study we present the design, implementation, and analysis of the novel rotating-priority-queues+ (rpq+) scheduler that is near-optimal in the sense that it can approximate edf with arbitrary precision. the rpq+ scheduler uses a set of prioritized fifo queues whose priorities are rearranged (rotated) periodically to increase the priority of waiting packets. we show that rpq+ has the following desirable properties: its implementation requires operations independent of the number of queued packets, it can provide worst-case delay guarantees, and it is always superior to a static-priority (sp) scheduler. for shared-memory architectures, we show that rpq+ can be implemented with little computational overhead. we derive expressions for the worst-case delays in an rpq+ scheduler and demonstrate that the achievable network utilization increases with the frequency of queue rotations, approaching that of edf in the limit. we use numerical examples, including examples based on mpeg video, to show that in realistic scenarios rpq+ can closely approximate edf even for infrequent queue rotations.
characterizing traffic behavior and providing end-to-end service guarantees within atm networks. we propose a rate-controlled service discipline for supporting b-isdn services. according to our approach, traffic streams from different connections can be well regulated at the output of each node based on their rate requirements. moreover, the traffic envelope of a connection inside the network can be effectively characterized. by assuming a leaky-bucket constrained input source, we further prove that the proposed scheme can provide end-to-end delay and jitter bounds for each connection passing through a multi-hop network. finally, we make a comparison of related works and show the effectiveness of our algorithm.
architecture for two-way data services over residential area catv networks. an architectural design for high speed residential data access using the traditional ieee 802.3 medium access protocol over the existing catv network is proposed. the described architecture is attractive in using the existing infrastructure combined with the exisiting access scheme in the residential area and thus it is cost effective and well-suited for home internet access. however, the traditional csma/cd protocol is not suitable for the cable tv network due to its long propagation delay. thus, we propose to combine the existing ieee 802.3 csma/cd mac with the segmented cable subnetworks so that a home user can get access to the internet as if he is using the ethernet at 10 mbps, or fast-ethernet at 100 mbps. only three subcarriers in the passband cable is used and therefore it will not interfere with the traditional broadcasting channels and the future digital video channels. the segmented cable are interconnected by the defined cable bridge (cb) and a simple flow control mechanism is proposed among the cbs. functional components and operations of each cb will also be described. for a fair performance among the subnetworks, a prioritized queueing scheme is also proposed on each cb.
uplink and downlink capacity analysis for two-tier cdma cellular systems. the combination of macrocell and microcell in a two-tier cellular system is attractive because it provides a balance between maximizing the number of users per unit area and minimizing the network control associated with handoff. in this paper, we study system capacity of a two-tier cellular architecture employing 3 tdma/cdma strategies. both the uplink and downlink are evaluated via mathematical analysis. it shows that system performance degrades for larger macrocell or microcell and the capacities are poor for users near the macrocells' boundary. it also shows that huge discrepancy between the results obtained for the center cell versus those obtained for the boundary cell.
fault detection with multiple observers. the authors propose to use a set of independent observers to detect faults in communication systems that are modeled by finite-state machines. an algorithm for constructing these observers and a fast real-time fault detection mechanism used by each observer are given. since these observers run in parallel and independently, one immediate benefit is that of graceful degradation; one failed observer will not cause collapse of the fault management system. in addition, each observer has a simpler structure than the original system and can be operated at higher speed
analysis on packet resequencing for reliable network protocols. packets are sometimes disordered in the network. reliable protocols such as tcp require packets to be accepted, i.e., delivered to the receiving application, in the order they are transmitted at the sender. in order to do so, the receiver's transport layer must resequence the packets with the help of a resequencing buffer. even if the application can consume the packets infinitely fast, the packets may still be delayed for resequencing. in this paper, we model packet disordering by adding an independently and identically distributed (iid) random propagation delay to each packet and analyze the required buffer size for packet resequencing and the resequencing delay for an average packet. we demonstrate that these two quantities can be significant and show how they scale with the network bandwidth.
a randomized error recovery algorithm for reliable multicast. an efficient error recovery algorithm is essential for reliable multicast in large groups. tree-based protocols (rmtp, tmtp, lbrrm) group receivers into local regions and select a repair server for performing error recovery in each region. hence a single server bears the entire responsibility of error recovery for a region. in addition, the deployment of repair servers requires topological information of the underlying multicast tree, which is generally not available at the transport layer. this paper presents rrmp, a randomized reliable multicast protocol which improves the robustness of tree-based protocols by diffusing the responsibility of error recovery among all members in a group. the protocol works well within the existing ip multicast framework and does not require additional support from routers. both analysis and simulation results show that the performance penalty due to randomization is low and can be tuned according to application requirements.
providing absolute differentiated services for real-time application in static-priority scheduling networks. in this paper, we propose and analyze a methodology for providing absolute differentiated services for real-time applications. we develop a method that can be used to derive delay bounds without specific information on flow population. with this new method, we are able to successfully employ a utilization-based admission control approach for flow admission. this approach does not require explicit delay computation at admission time and, hence, is scalable to large systems. we assume the underlying network to use static-priority schedulers. we design and analyze several priority assignment algorithms and investigate their ability to achieve higher utilization bounds. traditionally, schedulers in differentiated services networks assign priorities on a class-by-class basis, with the same priority for each class on each router. in this paper, we show that relaxing this requirement, that is, allowing different routers to assign different priorities to classes, achieves significantly higher utilization bounds.
real-time block transfer under a link sharing hierarchy. most application-level data units are too large to be carried in a single packet (or cell) and must be segmented for network delivery. to an application, the end-to-end delays and loss rate of its data units are much more relevant performance measures than ones specified for individual packets (or cells). the concept of a burst (or block) was introduced to represent a sequence of packets (or cells) that carry an application data unit. in this paper, we describe how a real-time vbr service, with qos parameters for block transfer delay and block loss rate, can be provided by integrating concepts and delay guarantee results from our previous work on burst scheduling, together with ideas from atm block transfer. two new contributions are presented herein. first, we design an admission control algorithm to provide the following classes of service: bounded-delay block transfer with no loss, and bounded-delay block transfer at a specified block loss rate. second, we show how to extend existing end-to-end delay bounds to networks with hierarchical link sharing.
rate-based headend-controlled bandwidth allocation in unidirectional bus metropolitan area networks. the authors introduce and analyze a protocol for unidirectional bus networks in which bandwidth allocation and access fairness are adaptively controlled by the head end of the bus on the basis of traffic measurements. the proposed protocol can control the admitted traffic of a particular type to a desired fraction of the bus capacity and at the same time enforce access fairness faster than other existing protocols, such as the one used in the recently approved ieee 802.6 metropolitan area network (man) standard
performance of statistical multiplexers with finite number of inputs and train arrivals. a slotted statistical multiplexer with a finite number of input links is considered. messages arriving on each input link contain a fixed number of fixed-length packets and are carried to the multiplexer in the form of a packet train at the rate of one packet per slot. several messages may arrive contiguously on an input link; idle periods are geometrically distributed. the multiplexer buffer is modeled as a discrete-time single-server queuing system with train arrivals. by means of a generating function approach, a technique to derive the moments of the buffer occupancy is developed, and an explicit expression for the mean buffer occupancy is given. furthermore, an approximate method is presented to obtain a tight upper bound for the tail distribution of the buffer occupancy, especially for large traffic load
individual qos versus aggregate qos: a loss performance study. this paper explores the differences that can exist between individual and aggregate loss guarantees in an environment where guarantees are only provided at the aggregate level. the focus is on understanding which traffic parameters are responsible for inducing possible deviations and to what extent. in addition, we seek to evaluate the level of additional resources, e.g., bandwidth or buffer, required to ensure that all individual loss measures remain below their desired target. this paper's contributions are in developing analytical models that enable the evaluation of individual loss probabilities in settings where only aggregate losses are controlled, and in identifying traffic parameters that have a major influence on the differences between individual and aggregate losses. the latter allows us to further construct practical tools and guidelines for rapidly assessing if specific traffic sources can be safely multiplexed into a common service class.
restoration strategies and spare capacity requirements in self-healing atm networks. this paper studies the capacity and flow assignment problem arising in the design of self-healing atm networks using the virtual path (vp) concept. the problem is formulated here as a linear programming problem which is solved using standard methods. the objective is to minimize the spare capacity cost for the given restoration requirement. the spare cost depends on restoration strategies used in the network. in the paper we will compare several restoration strategies, notably, global versus failure-oriented reconfiguration, path versus link based restoration and state-dependent versus state-independent restoration, quantitatively in terms of spare cost. the advantages and disadvantages of various restoration strategies are also highlighted. such comparisons provide useful guidance for real network design. further, a new heuristic algorithm is developed in this paper for the design of large self-healing atm networks using path based restoration. numerical results illustrate that the heuristic algorithm is efficient and can give near-optimal solutions for the spare capacity allocation and flow assignment.
multicast atm switches using buffered min structure: a performance study. a (large) multicast atm switch with an external structure of output queueing and an internal structure of buffered mins (multistage interconnection networks) is considered, where the buffered mins (also called a switching network) are composed of switching elements with shared buffer output queueing. a cell replication while routing scheme is used in the switch to implement the multicast function. in this paper, we study the performance of the switch with multicast traffic, mainly via computer simulations. the multicast traffic can be random and bursty. from our study we found that for multicast traffic with a truncated geometric distribution of cell fanouts it has only a slightly worse impact on the performance of the switching elements in isolation or in the last stage of the switching network. the multicast traffic has no worse effect on the switch output buffer behaviour and cell delay in the switching network. moreover, traffic splitting can substantially improve the switching network performance for highly bursty traffic. some analytical approximations are given which could be useful in the dimensioning of switching networks.
mobility-based predictive call admission control and bandwidth reservation in wireless cellular networks. this paper presents call admission control and bandwidth reservation schemes in wireless cellular networks that have been developed based on assumptions more realistic than existing proposals. in order to guarantee the handoff dropping probability, we propose to statistically predict user mobility based on the mobility history of users. our mobility prediction scheme is motivated by computational learning theory, which has shown that prediction is synonymous with data compression. we derive our mobility prediction scheme from data compression techniques that are both theoretically optimal and good in practice. in order to utilize resource more efficiently, we predict not only the cell to which the mobile will handoff but also when the handoff will occur. based on the mobility prediction, bandwidth is reserved to guarantee some target handoff dropping probability. we also adaptively control the admission threshold to achieve a better balance between guaranteeing handoff dropping probability and maximizing resource utilization. simulation results show that the proposed schemes meet our design goals and outperform the static-reservation and cell-reservation schemes.
ip multicasting for point-to-point local distribution. while support for ip multicasting continues to spread enabling new applications, an increasing number of hosts connects to the worldwide internet via low bandwidth point-to-point links, such as wireline or wireless telephone lines. in this paper we discuss existing proposals for local and wide area ip multicasting and their implications for point-to-point links, identify problems with their integration in this environment, and propose alternative special purpose mechanisms to solve these problems. the main problems are overhead due to igmp leave latency and unnecessary continuous probing of potentially power constrained hosts. our solution is an alternative to igmp mechanisms based on join/leave messages for tracking group membership over ptp networks. after presenting the implementation requirements of our proposed and the existing mechanisms, we compare them with respect to performance, interoperability, robustness and implementation complexity, demonstrating that our join/leave protocol is uniformly superior.
a new protocol test sequence generation method based on uios. the authors propose a novel method for test sequence generation based on uios which only needs a minimal verification part. they also prove that the uiov method (or revised unique input/output method) has the same applicability as the characteristic set method. the uiov method can find a test sequence for any minimal finite-state machine. the proposed method has the same applicability as the uiov method. in addition, the method uses a simple test on a given protocol specification to decide whether a verification part is needed for detecting transfer faults, the method can generate a minimal number of input/output sequences for a verification part. a more efficient algorithm for generating uioss and signature sets is presented. it is proven that the upper bound on the length of a uios is (n-1)&times;n rather than nn, where n is the number of states in a finite-state machine
performance characteristics of the d channel access control scheme. in the basic user/network interface of n-isdn (itu-t recommendation i.430), the d-channel is shared by up to 8 terminals for signal and data packets. an analytical model is proposed to reveal the performance characteristics of the access control scheme for the d-channel. numerical and simulation results are shown to demonstrate the performance differentiation of the terminals with different priorities. it is observed that the mean signal delay at low load may become large because of long service time for packets, and that the priority mechanism may not work properly when the loads at terminals are very asymmetric. keywords: n-isdn user-network interface, d channel access control scheme, queueing model, priority mechanism, performance evaluation, simulation
sensitivity analysis of the loss probability in a stationary gradual queue for high-speed networks. in atm networks, each node has its own buffer to store some cells. the buffer size represents a trade-off between cell loss and transmission delay, and therefore, it is a significant concern to evaluate the performance with respect to the buffer size. in this paper, we investigate the sensitivity of the loss probability with respect to the buffer size by considering a gradual input queue with a finite buffer. gradual inputs are considered as those representing a bursty traffic of cells. applying the perturbation analysis technique to this model, we derive the strongly consistent sensitivity estimates, and combining with the likelihood ratio method, we confirm that our estimates lead to the reasonable simulation results.
multi-channel deflection crossbar (mcdc): a vlsi optimized architecture for multi-channel atm switching. we propose the multi-channel deflection crossbar (mcdc) as a promising architecture for broadband atm switching under the realistic constraints imposed by vlsi technology. mcdc is an internally nonblocking, buffer efficient, crossbar based architecture. mcdc is also capable of multi-channel switching with cell sequence integrity preserved. through a comparative study against a well-known atm switch architecture, we show that the proposed mcdc architecture is able to incorporate a greater number of input channels and buffers for a given ic die size and requires a lower clocking rate.