Multiprotocol label switching (MPLS) is rapidly emerging as an Internet Engineering Task Force (IETF) standard intended to enhance the speed, scalability, and service provisioning capabilities in the Internet. MPLS uses the technique of packet forwarding based on labels, to enable the implementation of a simpler high-performance packet forwarding engine. This also decouples packet forwarding from routing, facilitating the provision of varied routing services independent of the packet forwarding paradigm. The authors track the evolution of this technology in relation to other existing technologies. Then an overview of the MPLS architecture and design is provided. In addition, some of the work that was a precursor to MPLS is discussed, as well as related issues and debates.

Evolution of multiprotocol label switching

Multi-objective differential evolution (MODE) is a powerful and efficient population-based stochastic search technique for solving multi-objective optimization problems in many scientific and engineering fields. However, premature convergence is the major drawback of MODE, especially when there are numerous local Pareto optimal solutions. To overcome this problem, we propose a MODE with a diversity enhancement (MODE-DE) mechanism to prevent the algorithm becoming trapped in a locally optimal Pareto front. The proposed algorithm combines the current population with a number of randomly generated parameter vectors to increase the diversity of the differential vectors and thereby the diversity of the newly generated offspring. The performance of the MODE-DE algorithm was evaluated on a set of 19 benchmark problem codes available from http://www3.ntu.edu.sg/home/epnsugan. With the proposed method, the performances were either better than or equal to those of the MODE without the diversity enhancement.

Multi-objective differential evolution with diversity enhancement

Comparison and analysis of the revenue-based adaptive queuing models

This article presents a cross-layer packet scheduler to provide end-to-end QoS guarantees for Digital Video Broadcasting-Second Generation (DVB-S2) broadband satellite systems. The scheduler design is based on a cross-layer mechanism defined between the physical and the network layer. It includes an algorithm to guarantee the required QoS specifications established in the service level agreement. The algorithm calculation depends basically on two parameters: the available bandwidth present in a DVB-S2 satellite link and the QoS requirements of each traffic class defined by the satellite operator. The cross-layer scheduler's operation is demonstrated using the NS-2 simulator tool. The results show that the proposed mechanism maximizes the bandwidth utilization while enforcing the priority level of each service class when an extreme reduction of bandwidth caused by rain events is experienced.

Cross-layer packet scheduler for QoS support over Digital Video Broadcasting-Second Generation broadband satellite systems

Today’s wireless broadband networks are required to provide QoS guarantee as well as fairness to different kinds of traffic. Recent wireless standards (such as LTE and WiMAX) have special provisions at MAC layer for differentiating and scheduling data traffic for achieving QoS. The main focus of this paper is concerned with high speed packet queuing/scheduling at central node such as base station (BS) or router to handle network traffic. This paper proposes novel packet queuing scheme termed as Low Latency Weighted Round Robin (LL-WRR) which is simple and effective amendment to weighted round robin (WRR) for achieving low latency and improved fairness. Proposed LL-WRR queue scheduling scheme is implemented in NS-2 considering IEEE 802.16 network [1] with real time video and Constant Bit Rate (CBR) audio traffic connections. Simulation results show improvement obtained in latency and fairness using LL-WRR. The proposed scheme introduces extra complexity of computing coefficient but its overall impact is very small.

http://www.airccse.org/journal/jwmn/6414ijwmn05.pdf

Design and Implementation of Low Latency Weighted Round Robin (LL-WRR) Scheduling for High Speed Networks

This paper presents an adaptive resource allocation model that is based on the WRR queuing discipline. The model ensures QoS requirements and tries to maximize a service provider's revenue by manipulating weights of the WRR scheduler. To adjust the weights, it is proposed to use the revenue criterion, which controls the allocation of free resources. The simulation considers a single node with the implemented model that serves several classes with different QoS requirements and traffic characteristics. It is shown that the total revenue can be increased due to the allocation of unused resources to more expensive service classes. Furthermore, the adaptive model eliminates the need to find the optimal static weight values as they are calculated dynamically.

Adaptive scheduling using the revenue-based weighted round robin

Theswift growth of Internethasboostedtheuseof Webbasedservicesandin somepracticalcaseshas led to overwhelmingrequestburststo servers.Relationaldatabasequeries,imagestorage/retrie val andothernew typesof applicationtransactionshave becomeincreasinglypopular. Their coexistencein commercialparalleland distributedsystemshave generatedsomeuniquelynew loadingproblems.For example,the constantincreaseof requestratefinally leadsto processingpowerrequirement exceedingthatof theaccessedserver. As aconsequence, the responsetimesincreaseandsomeportionof the requestsarelost. Clusteringof serversto meetthe growing demandfor serverprocessingcapacity, especiallyin web-basedservicesupply, havecreatedtheneedfor intelligent switchingat front-enddevices.As aconsequence of clustering,multilayerswitchingschemeshavebeendeveloped to enableoptimumloadingof the individual serversin a cluster. In this paper , we formulatethe load balancing problemtaking the QoSinto considerationandintroducea QoSawareloadbalancingalgorithm(QoS-LB).The performanceof thealgorithmis simulatedandresultsindicatingtheloadbalancingcapabilityof thealgorithmare presented.Theoverall ideaof this paperis to describeanalgorithmthatactuallyprovidesClassof Servicebased differentiatedaccessto serverclusters,andoffersbetterplaygroundfor QoSmechanismsin client-serverenvironments.Theengineeringtaskto offerQoSguarantees with suchadifferentationtool is outof thescopeof thispaper .

Adaptive parameter setting for QoS aware load balancing

Due to the evolution of the Internet and its services, the process of forwarding packets in routers is becoming more complex. In order to execute the sophisticated routing logic of modern firewalls, multidimensional packet classification is required. Unfortunately, the multidimensional packet classification algorithms are known to be either time or storage hungry in the general case. It has been anticipated that more feasible algorithms could be obtained for conflict-free classifiers. This paper proposes a novel two-dimensional packet classification algorithm applicable to the conflict-free classifiers. It derives from the well-known tuple space paradigm and it has the search cost of O(log w) and storage complexity of O(n2 w log w), where w is the width of the protocol fields given in bits and n is the number of rules in the classifier. This is remarkable because without the conflict-free constraint the search cost in the two-dimensional tuple space is Θ(w).

/pdf/diagonal-tuple-space-search-in-two-dimensions-2xmardks7m.pdf

Diagonal Tuple Space Search in Two Dimensions

This paper presents an adaptive resource allocation model that is based on the DRR queuing policy. The model ensures QoS requirements and tries to maximize a service provider's revenue by manipulating quantum values of the DRR scheduler. To calculate quantum values, it is proposed to use the revenue criterion that controls the allocation of free resources. The simulation considers a single node with the implemented model that serves several service classes with different QoS requirements and traffic characteristics. It is shown that the total revenue can be increased due to the allocation of unused resources to more expensive service classes. At the same time, bandwidth and delay guarantees are provided. Furthermore, the adaptive model eliminates the need to find the optimal static quantum values because they are calculated dynamically.

Revenue-Based adaptive deficit round robin

In this paper we present an algorithm for balancing traffic flows between lightpaths in WDM networks. The load balancing is based on classification of the traffic flows and the use of state information of the links and optical cross-connects. Higher priority traffic flows are directed to less loaded lightpaths thus providing them with higher throughput and lower transport delay than is available for lower priority flows. The load levels of the lightpaths are tuned dynamically to support the required quality of service. Additionally, the algorithm ensures that the aggregate load of the incoming data flows does not exceed the overall capacity of the parallel lightpaths.

Pertti Raatikainen

Papers

Adaptive scheduling using the revenue-based weighted round robin

Adaptive parameter setting for QoS aware load balancing

Diagonal Tuple Space Search in Two Dimensions

Revenue-Based adaptive deficit round robin

A lightpath allocation scheme for WDM networks with QoS