Abstract: A system provides congestion control and includes multiple queues that temporarily store data and a drop engine. The system associates a value with each of the queues, where each of the values relates to an amount of memory associated with the queue. The drop engine compares the value associated with a particular one of the queues to one or more programmable thresholds and selectively performs explicit congestion notification or packet dropping on data in the particular queue based on a result of the comparison.

Abstract: A method is provided for queuing packets. A packet may be received and its flow identified. It may then be determined whether a flow queue has been assigned to the identified flow. The identified flow may be dynamically assigning to an available flow queue when it is determined that a flow queue has not been assigned to the identified flow. The packet may be enqueued into the available flow queue.

Abstract: An active queue management (AQM) process for network communications equipment. The AQM process is queue based and involves applying at a queue size threshold congestion notification to communications packets in a queue of a link via packet dropping; and adjusting said queue size threshold on the basis of the congestion level. The AQM process releases more buffer capacity to accommodate more incoming packets by increasing said queue size threshold when congestion increases; and decreases buffer capacity by reducing said queue size threshold when congestion decreases. Network communications equipment includes a switch component for switching communications packets between input ports and output ports, packet queues for at least the output ports, and an active queue manager for applying congestion notification to communications packets in the queues for the output ports via packet dropping. The congestion notification is applied at respective queue size thresholds for the queues, and the thresholds adjusted on the basis of the respective congestion levels of the queues of the output ports.

Abstract: Congestion is an important issue which researchers focus on in the Transmission Control Protocol (TCP) network environment. To keep the stability of the whole network, congestion control algorithms have been extensively studied. Queue management method employed by the routers is one of the important issues in the congestion control study. Active queue management (AQM) has been proposed as a router-based mechanism for early detection of congestion inside the network. In this paper we analyzed several active queue management algorithms with respect to their abilities of maintaining high resource utilization, identifying and restricting disproportionate bandwidth usage, and their deployment complexity. We compare the performance of FRED, BLUE, SFB, and CHOKe based on simulation results, using RED and Drop Tail as the evaluation baseline. The characteristics of different algorithms are also discussed and compared. Simulation is done by using Network Simulator(NS2) and the graphs are drawn using X- graph.

Abstract: Techniques for managing messages in computer systems are provided. In one embodiment, in response to a publisher attempting to enqueue a message in a queue, a determination is made whether a condition is satisfied. The condition is based on the current usage of the queue by the publisher. Based on whether the condition is satisfied, a decision is made whether to enqueue the message in the queue. The decision whether to enqueue the message may comprise restricting the publisher from enqueueing any more messages in the queue until the same or a different condition is satisfied.

Abstract: Lines of waiting customers are always very long in most of banks. The essence of this phenomenon is the low efficiency of queuing system. In this paper, the queuing number, the service windows number and the optimal service rate are investigated by means of the queuing theory. In technology, the optimal problem of the bank queuing is solved. The time of customer queuing is reduced. The customer satisfaction is increased. It was proved that this optimal model of the queuing is feasible. By the example, the results are effective and practical.

Abstract: A system for allocating constrained resources (e.g., downstream services, execution threads, database connections, input/output channels, computational resources, and/or memory) to requested services that are dependent on those resources may include multiple resource queues, each of which maintains a queue of requests for a respective constrained resource, and multiple service request queues, from which requests may be subsequently serviced. As each request reaches the head of a resource queue, it may receive a resource token for a respective constrained resource. Once the request has collected resource tokens for each of the constrained resources on which it depends, the request may be passed to a service request queue that maintains a queue of requests of a particular type. Requests in the multiple service request queues may be serviced on a round-robin or weighted round-robin basis. The number of tokens available for each constrained resource may be modified based on observed system performance.

Abstract: This disclosure relates to methods and systems for queuing traffic in packet-switched networks. In one of many possible embodiments, a queue management system includes a plurality of queues and a priority module configured to assign incoming packets to the queues based on priorities associated with the incoming packets. The priority module is further configured to drop at least one of the packets already contained in the queues. The priority module is configured to operate across multiple queues when determining which of the packets contained in the queues to drop. Some embodiments provide for hybrid queue management that considers both classes and priorities of packets.

Abstract: A queue management system for e.g. supermarket checkouts uses counting devices located at checkouts and optimally entrances/exits in conjunction with P.O.S. information to produce a schedule of how many checkouts are needed to avoid queue length exceeding preset limits. The system includes a dynamic learning system which can optimise calculated schedules on the basis of historical data.

Abstract: This paper describes the Collaborative Departure Queue Management (CDQM) concept, which has been developed by Mosaic ATM under funding from the FAA's Surface Trajectory Based Operations (STBO) project and NASA [1–3]. Under CDQM procedures, airport departure capacity is allocated to flight operators and metering procedures are used to manage the length of the runway queue. This management of the runway departure queue allows fuel burn, emissions and airport surface congestion to be reduced. Operational field evaluations of CDQM have been conducted over the last year at the Memphis International Airport. This paper provides initial results of these CDQM field evaluations.

Abstract: A priority queue assignment technique for quality-of-service (“QoS”) network flows in a network is provided. A network path is determined for an incoming flow including a plurality of network switches associated, with a plurality of priority queue levels. A priority queue level is determined for the incoming flow for at least one of the plurality of network switches in the network path based on priority queue levels of existing flows. The priority queue level of the incoming flow is adjusted, to dynamically balance flows over the plurality of priority queue levels for at least one of the plurality of network switches in the network path based on quality-of-service (“QoS”) requirements associated with the incoming flow.

Abstract: The queue management algorithm, which is applied to a router, plays an important role in providing Quality of Service (QoS). In this paper we present a simulation-based performance evaluation and compare two popular queue management methods; Random Early Detection (RED) and Drop Tail, in terms of queue size, queuing delay, queuing delay variation, packet drop rate and bandwidth utilization. We also study the effect of buffer behavior on each one of these QoS measurements, as well as considering the effects of using ECN on RED Performance. Simulation results indicate that RED performed better related to Drop Tail in terms of queuing delay, queuing delay variation, and (lower) packet drop rate. Furthermore, using ECN improves RED's bandwidth usage and packet drop rate. Also by measuring the router CPU utilization, we indicate that the difference between active and passive queue management algorithms in terms of CPU utilization, is mostly depend on the buffer size and the network traffic load.

Abstract: In this article we introduce a new method of mitigating the problem of long wait times for low-priority customers in a two-class queuing system. To this end, we allow class 1 customers to be upgraded to class 2 after they have been in queue for some time. We assume that there are ci servers at station i, i=1, 2. The servers at station 1 are flexible in the sense that they can work at either station, whereas the servers at station 2 are dedicated. Holding costs at rate hi are accrued per customer per unit time at station i, i=1, 2. This study yields several surprising results. First, we show that stability analysis requires a condition on the order of the service rates. This is unexpected since no such condition is required when the system does not have upgrades. This condition continues to play a role when control is considered. We provide structural results that include a c-μ rule when an inequality holds and a threshold policy when the inequality is reversed. A numerical study verifies that the optimal control policy significantly reduces holding costs over the policy that assigns the flexible server to station 1. At the same time, in most cases the optimal control policy reduces waiting times of both customer classes.

Abstract: The Ration by Schedule (RBS) algorithm has been accepted by the aviation community as the basis of Collaborative Decision Making (CDM) in strategic Traffic Flow Management (TFM) initiatives such as Ground Delay Programs (GDPs) and Airspace Flow Programs (AFPs). However, applications of RBS to date have been limited to strategic metering applications in which the slots to be allocated to flights are all of equal duration, and the flights to be assigned to slots do not need to be differentiated. Decision support capabilities for the general Air Traffic Management (ATM) problem require planning and scheduling algorithms that properly recognize different flight characteristics such as weight class, runway, departure direction and other Air Traffic Control (ATC) procedural issues in determining the slot size that is required for each flight. In this paper, we describe our design and implementation of the Generalized RBS algorithm for a surface traffic management scheduling application which involves detailed flight-by-flight slot time assignment. This algorithm has been designed and developed to support the Collaborative Departure Queue Management (CDQM) component of the Surface Trajectory Based Operations (STBO) project. CDQM provides an equitable allocation of departure capacity to each flight operator at an airport for dynamic use in management of departure queues. The principles of the RBS algorithm are achieved through an initial planning pass based on scheduled data, followed by a second planning pass in which dynamic flight status is incorporated into the planning results.

Abstract: Embodiments of the invention provide for managing attraction attendance levels through tracking current attendance levels and notifying patrons of incentives to alter their attraction selections in real-time. Examples identify an attraction queue that has a customer wait time failing to meet a threshold and determine a geographic relationship of a tracking device associated with a registered customer to the queue. Accordingly, an incentive is created from metadata associated with the queue and offered to the registered customer to urge the registered customer to take a queue balancing action. The queue balancing action may be leaving the queue if the customer wait time exceeds a threshold maximum wait time and the tracking device is within the queue, or choosing to enter the queue if the customer wait time is less than a threshold minimum wait time and the tracking device is outside of the queue.

Abstract: A first-in-first-out (FIFO) queue optimized to reduce latency in dequeuing data items from the FIFO. In one implementation, a FIFO queue additionally includes buffers connected to the output of the FIFO queue and bypass logic. The buffers act as the final stages of the FIFO queue. The bypass logic causes input data items to bypass the FIFO and to go straight to the buffers when the buffers are able to receive data items and the FIFO queue is empty. In a second implementation, arbitration logic is coupled to the queue. The arbitration logic controls a multiplexer to output a predetermined number of data items from a number of final stages of the queue. In this second implementation, the arbitration logic gives higher priority to data items in later stages of the queue.

Abstract: This research examines the production control problem in two-station tandem queueing systems under time constraints. In these two-station tandem queueing systems, jobs must first be processed at the upstream station and then the downstream station. For each job, the sum of the waiting and processing time in the downstream queue is limited by an upper bound. This time constraint is called the process queue time constraint. When the process queue time constraint is violated, a significant scrap cost will be accrued. In this research, we develop a Markov decision model to study the production control problem under process queue time constraints. The objective is to minimise the sum of the expected long-run average inventory holding costs and scrap costs. According to the Markov decision model, an interesting exhaustive structure of the optimal production control policy is found. Based on this exhaustive structure, an efficient algorithm is developed to solve the production control problem numerically. The pe...

Abstract: A method, performed by a server device, may include receiving a request from a user device to place a user, associated with the user device, in a particular queue; determining whether the user meets one or more qualifications associated with the queue; placing the user in the particular queue, when the user meets the one or more qualifications; monitoring whether the user continues to meet the one or more qualifications, while the user is in the queue; and removing the user from the particular queue, when the user fails to meet the one or more qualifications.

Abstract: Network based congestion avoidance which involves managing the queues in the network devices is an integral part of any network. Most of the mobile networks use Drop tail queue management where packets are dropped on queue overflow which is global synchronization problem. Especially in MANETs, packet loss results in increased overhead in terms of energy wasted to forward a packet which was dropped, additional energy required to retransmit this packet. Active Queue Management (AQM)[7] has been a solution to the global synchronization[2] problem in wired networks. However, if AQM is to be deployed in MANETs, it should be lightweight, proactive and easy to implement as mobile networks are resource constrained in terms of memory, processing power and battery life. This paper presents a predictive queue management strategy named PAQMAN that proactively manages the queue, is simple to implement and requires negligible computational overhead. The performance of PAQMAN has been compared with Drop tail and those results show that PAQMAN reduces packet loss ratio while at the same time increasing transmission efficiency.

Abstract: Ramp metering is beneficial for freeway throughput, but the ramp queues that are created should be prevented from extending to adjacent street junctions. A recently proposed ramp queue controller is investigated in conjunction with the local ramp-metering algorithm ALINEA. Microscopic simulation is used to compare the queue controller with a popular queue override scheme that is based on specifically designed scenarios and evaluation criteria. It is found that the queue controller outperforms the queue override and leads to fewer instances of ramp queue spillover. The concept is also demonstrated to work properly in an operational field environment.

Abstract: The invention provides a buffer queue management method used in a wireless local area network. In the wireless local area network, when related sites have large quantity and large data amount, network congestion phenomenon can happen. In order to detect the network congestion before the congestion happens or at the beginning period that the congestion happens, the in-queue detection of a data packet is realized by the buffer queue management method of exchanging nodes (such as AP), and a sending end is notified with the congestion by packet loss or setting an explicit congestion notification (ECN) of an IP packet head, so as to relieve the network congestion. The buffer queue management method provided by the invention uses the queue length and flux speed as congestion measurement, so that the invention can evaluate the network congestion degree more exactly, and the invention calculates different packet loss probability for each queue according to the priority difference of buffer queues to realize the random packet loss according to different priorities, so as to achieve the goal of distinguishing packet loss rate.

Abstract: Development of reliable strategies to overcome adverse mobility impacts of highway work zones requires accurate computation of delay and queues in work zones. This paper presents a methodology for quantifying the mobility impacts that considers the effects of roadway and traffic on speeds (and delays) of cars and heavy vehicles separately. Several factors such as roadway width, speed variation, and differences in speed of cars and heavy vehicles on delay and queue length are considered. The delay caused due to the differences in speeds of different vehicles can be significant when there is limited opportunity for passing or there are significant slow-moving vehicles. It is proposed to determine the impact of such factors on the operating speeds of the vehicles in work zones and use it to compute the capacity-at-operating-speed from the speed-flow curves developed for work zones. Then the speed and capacity are used to compute delay and queue length. Delay is divided into queue delay and moving delay. The moving delay is computed using delay-based passenger car equivalent (PCE) values for work zones. Queue delay is computed based on input-output analysis approach using the capacity as determined in this study. The methodology is illustrated by a step-by-step procedure for computing delay and queue length.

Abstract: The main feature of the next generation wireless communication systems is the ability to establish ubiquitous and seamless access to various radio access technologies (RATs) and standards. For this reason the integration of cellular and wireless local area networks (WLANs) and performance evaluation of the interaction between these technologies is now an important research area. Modelling such systems for performance evaluation is essential to improve the architecture according to the quality ofbservice (QoS) requirements and performance characteristics. In this paper, an analytical model for performance evaluation of an integrated cellular network and a WLAN is considered. WLAN is deployed inside of the cellular network to support handoffs between cellular networks with higher bandwidth. Such an integrated system can be modelled as a two stage open network. An analytical model is proposed together with an exact solution technique in order to evaluate the performance of an integrated system consisting of a cellular network and a WLAN. A two stage queuing system is considered for this purpose. Numerical results are presented for mean queue length values of cellular system as well as the WLAN.

Abstract: A queue interface system and method for queuing voice calls for use with a communication system having queues includes a queue selector allowing a user to select a queue from a list of queues on a display. In an embodiment, one or more of the queues on the list of queues is a service agent queue. Further, the queue interface system includes an expected wait time component for displaying an expected wait time for a customer for the selected queue. The system also includes a call options selector providing a hold option and a call option. The hold option places a call in the selected queue and the call option causes a call to occur. In an embodiment, the call option further includes assigning a placeholder for a customer in the selected queue and causing a call to the customer to occur after the expected wait time.

Abstract: This paper investigates an application-oriented bandwidth allocation scheme to ensure fairness among queues with diversified quality-of-serice (QoS) requirements in EPONs. Formerly, differentiated services (DiffServ) were suggested to be used in EPON so as to provision some queues with higher QoS over others. However, owing to the coarse granularity, DiffServ can hardly facilitate any particular QoS profile of an application in EPONs. In this paper, we define application utilities to quantify users' quality-of-experience (QoE) as a function of network layer QoS metrics. Then, we formulate the fair resource allocation issue into a utility max-min optimization problem, which is quasiconcave over queues' delayed traffic and dropped traffic. Utilizing the quasiconvex property, we propose to employ the bisection method to solve the optimization problem. The optimal value can be achieved by proper bandwidth allocation and queue management in EPONs. Detailed implementation of the proposed algorithm is discussed, and simulation results show that our proposed scheme can ensure fairness and guarantee QoS with fine granularity.

Abstract: Subway footway and passenger flux were described as a queuing system at rush hours,a queuing optimization model was built based on the analysis of parameter characteristics,and a new approach for determining subway footway width was developed by combining the level of service for passengers with the calculation of subway footway capacity.A simulation model was proposed to testify the theoretical model above,which was capable of simulating the queuing system with any arrival process and any distribution of service time.Comparison result shows that the results of queuing optimization model and stochastic simulation at the lowest level of service are both close to the values of existing design norm,but with the improvement of service level,the values calculated by the former two methods show a remarkable trend of simultaneous growth,while those derived from the existing design norm show a level trend.2 tabs,3 figs,10 refs.