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An Overview of QualityofService Routing for the Next Generation HighSpeed Networks: Problems and Solutions
"... The upcoming Gbps highspeed networks are expected to support a wide range of communicationintensive, realtime multimedia applications. The requirement for timely delivery of digitized audiovisual information raises new challenges for the next generation integratedservice broadband networks. On ..."
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Cited by 223 (21 self)
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The upcoming Gbps highspeed networks are expected to support a wide range of communicationintensive, realtime multimedia applications. The requirement for timely delivery of digitized audiovisual information raises new challenges for the next generation integratedservice broadband networks. One of the key issues is the QualityofService (QoS) routing. It selects network routes with sufficient resources for the requested QoS parameters. The goal of routing solutions is twofold: (1) satisfying the QoS requirements for every admitted connection and (2) achieving the global efficiency in resource utilization. Many unicast/multicast QoS routing algorithms were published recently, and they work with a variety of QoS requirements and resource constraints. Overall, they can be partitioned into three broad classes: (1) source routing, (2) distributed routing and (3) hierarchical routing algorithms. In this paper we give an overview of the QoS routing problem as well as the existing solutions. We present the strengths and the weaknesses of different routing strategies and outline the challenges. We also discuss the basic algorithms in each class, classify and compare them, and point out possible future directions in the QoS routing area.
A Distributed Algorithm for DelayConstrained Unicast Routing
 IEEE INFOCOM'97
, 1997
"... In this paper, we study the NPhard delayconstrained leastcost path problem, and propose a simple, distributed heuristic solution: the delayconstrained unicast routing (DCUR) algorithm. DCUR requires limited network state information to be kept at each node: a cost vector and a delay vector. We p ..."
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Cited by 100 (1 self)
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In this paper, we study the NPhard delayconstrained leastcost path problem, and propose a simple, distributed heuristic solution: the delayconstrained unicast routing (DCUR) algorithm. DCUR requires limited network state information to be kept at each node: a cost vector and a delay vector. We prove DCUR's correctness by showing that it is always capable of constructing a loopfree delayconstrained path within finite time, if such a path exists. The worst case message complexity of DCUR is O(V&sup3;) messages, where V is the number of nodes. However, simulation results show that,on the average, DCUR requires much fewer messages. Therefore, DCUR scales well to large networks. We also use simulation to compare DCUR to the optimal algorithm, and to the leastdelay path algorithm. Our results show that DCUR's path costs are within 10% from those of the optimal solution.
Evaluation of Multicast Routing Algorithms for RealTime Communication on HighSpeed Networks
 IEEE Journal on Selected Areas in Communications
, 1997
"... Abstract—Multicast (MC) routing algorithms capable of satisfying the quality of service (QoS) requirements of realtime applications will be essential for future highspeed networks. We compare the performance of all of the important MC routing algorithms when applied to networks with asymmetric li ..."
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Cited by 96 (5 self)
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Abstract—Multicast (MC) routing algorithms capable of satisfying the quality of service (QoS) requirements of realtime applications will be essential for future highspeed networks. We compare the performance of all of the important MC routing algorithms when applied to networks with asymmetric link loads. Each algorithm is judged based on the quality of the MC trees it generates and its efficiency in managing the network resources. Simulation results over random networks show that unconstrained algorithms are not capable of fulfilling the QoS requirements of realtime applications in widearea networks. Simulations also reveal that one of the unconstrained algorithms, reverse path multicasting (RPM), is quite inefficient when applied to asymmetric networks. We study how combining routing with resource reservation and admission control improves RPM’s efficiency in managing the network resources. The performance of one semiconstrained heuristic, MSC, three constrained Steiner tree (CST) heuristics, Kompella, Pasquale, and Polyzos (KPP), constrained adaptive ordering (CAO), and bounded shortest multicast algorithm (BSMA), and one constrained shortest path tree (CSPT) heuristic, the constrained Dijkstra heuristic (CDKS) are also studied. Simulations show that the semiconstrained and constrained heuristics are capable of successfully constructing MC trees which satisfy the QoS requirements of realtime traffic. However, the cost performance of the heuristics varies. BSMA’s MC trees are lower in cost than all other constrained heuristics. Finally, we compare the execution times of all algorithms, unconstrained, semiconstrained, and constrained. Index Terms—Admission control, multicast routing, quality of service, reverse path multicasting. I.
MultiConstrained Optimal Path Selection
, 2001
"... Providing qualityofservice (QoS) guarantees in packet networks gives rise to several challenging issues. One of them is how to determine a feasible path that satisfies a set of constraints while maintaining high utilization of network resources. The latter objective implies the need to impose an a ..."
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Cited by 80 (1 self)
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Providing qualityofservice (QoS) guarantees in packet networks gives rise to several challenging issues. One of them is how to determine a feasible path that satisfies a set of constraints while maintaining high utilization of network resources. The latter objective implies the need to impose an additional optimality requirement on the feasibility problem. This can be done through a primary cost function (e.g., administrative weight, hopcount) according to which the selected feasible path is optimal. In general, multiconstrained path selection, with or without optimization, is an NPcomplete problem that cannot be exactly solved in polynomial time. Heuristics and approximation algorithms with polynomialand pseudopolynomialtime complexities are often used to deal with this problem. However, existing solutions suffer either from excessive computational complexities that cannot be used for online network operation or from low performance. Moreover, they only deal with special cases of the problem (e.g., two constraints without optimization, one constraint with optimization, etc.). For the feasibility problem under multiple constraints, some researchers have recently proposed a nonlinear cost function whose minimization provides a continuous spectrum of solutions ranging from a generalized linear approximation (GLA) to an asymptotically exact solution. In this paper, we propose an efficient heuristic algorithm for the most general form of the problem. We first formalize the theoretical properties of the above nonlinear cost function. We then introduce our heuristic algorithm (H MCOP), which attempts to minimize both the nonlinear cost function (for the feasibility part) and the primary cost function (for the optimality part). We prove that H MCOP guarantees at least t...
Heuristic algorithms for multiconstrained qualityofservice routing
 Michigan State University, Michigan, in
, 2002
"... Multi–constrained Quality of Service (QoS) routing finds a route in the network that satisfies multiple independent quality of service constraints. This problem is NP–hard and a number of heuristic algorithms have been proposed to solve the problem. This paper studies two heuristics, the limited gra ..."
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Cited by 79 (2 self)
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Multi–constrained Quality of Service (QoS) routing finds a route in the network that satisfies multiple independent quality of service constraints. This problem is NP–hard and a number of heuristic algorithms have been proposed to solve the problem. This paper studies two heuristics, the limited granularity heuristic and the limited path heuristic, for solving general –constrained problems. Analytical and simulation studies are conducted to compare the time/space requirements of the heuristics and the effectiveness of the heuristics in finding the paths that satisfy the QoS constraints. We prove analytically that for an nodes and edges network with (a small constant) independent QoS constraints, the limited granularity heuristic must maintain a table of size in each node to be effective, which results in a time complexity of. We also prove that the limited path heuristic can achieve very high performance by maintaining entries in each node, which indicates that the performance of the limited path heuristic is not sensitive to the number of constraints. We conclude that although both the limited granularity heuristic and the limited path heuristic can efficiently solve –constrained QoS routing problems, the limited path heuristic is superior to the limited granularity heuristic in solving –constrained QoS routing problems "!$ # when. Our simulation study further confirms this conclusion. 1
Distributed QoS Routing with Imprecise State Information
"... The goal of QualityofService (QoS) routing is to find a network path which has sufficient resources to satisfy certain constraints on metrics such as delay and bandwidth. The state information maintained at every node is often imprecise in a dynamic network because of nonnegligible propagation d ..."
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Cited by 65 (7 self)
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The goal of QualityofService (QoS) routing is to find a network path which has sufficient resources to satisfy certain constraints on metrics such as delay and bandwidth. The state information maintained at every node is often imprecise in a dynamic network because of nonnegligible propagation delay of state messages, periodic updates due to overhead concern, and hierarchical state aggregation. The information imprecision makes QoS routing difficult. The traditional shortestpath routing algorithm does not provide satisfactory performance when the state information is imprecise, and the flooding algorithm has an excessively high overhead. We propose a distributed routing scheme, called ticketbased probing, which searches multiple paths in parallel for a qualified one. The scheme is based on a realistic imprecision state model. The number of paths searched is determined in a flexible way, which allows the dynamic tradeoff between the overhead and the routing performance. The proposed routing algorithms collectively utilize the state information of the intermediate nodes to guide the routing messages along the most appropriate paths, so that the success probability is maximized with limited overhead. The algorithms consider not only the QoS requirement but also the optimality of the routing path. Lowcost paths are given preference in order to improve the overall network performance.
A unified approach to constrained mapping and routing on networkonchip architectures
 in Proceedings of the 3rd IEEE/ACM/IFIP International Conference on Hardware/Software Codesign and Systems Synthesis (CODES+ISSS ’05
, 2005
"... One of the key steps in NetworkonChip (NoC) based design is spatial mapping of cores and routing of the communication between those cores. Known solutions to the mapping and routing problem first map cores onto a topology and then route communication, using separated and possibly conflicting obje ..."
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Cited by 51 (12 self)
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One of the key steps in NetworkonChip (NoC) based design is spatial mapping of cores and routing of the communication between those cores. Known solutions to the mapping and routing problem first map cores onto a topology and then route communication, using separated and possibly conflicting objective functions. In this paper we present a unified singleobjective algorithm, called Unified MApping, Routing and Slot allocation (UMARS). As the main contribution we show how to couple path selection, mapping of cores and TDMA timeslot allocation such that the network required to meet the constraints of the application is minimized. The timecomplexity of UMARS is low and experimental results indicate a runtime only 20 % higher than that of path selection alone. We apply the algorithm to an MPEG decoder SystemonChip (SoC), reducing area by 33%, power by 35% and worstcase latency by a factor four over a traditional multistep approach.
Lagrange Relaxation Based Method for the QoS Routing Problem
, 2001
"... In this paper a practically efficient QoS routing method is presented, which provides a solution to the delay constrained least cost routing problem. The algorithm uses the concept of aggregated costs and provides an efficient method to find the optimal multiplier based on Lagrange relaxation. This ..."
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Cited by 47 (0 self)
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In this paper a practically efficient QoS routing method is presented, which provides a solution to the delay constrained least cost routing problem. The algorithm uses the concept of aggregated costs and provides an efficient method to find the optimal multiplier based on Lagrange relaxation. This method is proven to be polynomial and it is also efficient in practice. The benefit of this method is that it also gives a lower bound on the theoretical optimal solution along with the result. The difference between the lower bound and the cost of the found path is very small proving the good quality of the result. Moreover, by further relaxing the optimality of paths, an easy way is provided to control the tradeoff between the running time of the algorithm and the quality of the found paths. We present a comprehensive numerical evaluation of the algorithm, by comparing it to a wide range of QoS routing algorithms proposed in the literature. It is shown that the performance of the proposed polynomial time algorithm is close to the optimal solution computed by an exponential algorithm. KeywordsQoS routing, delay, optimization, Lagrange relaxation I.
Search Space Reduction in QoS Routing
 In Proceedings of the 19th International Conference on Distributed Computing Systems
, 2001
"... To provide realtime service or engineer constrainedbased paths, networks require the underlying routing algorithm to be able to find lowcost paths that satisfy given QualityofService (QoS) constraints. However, the problem of constrained... ..."
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Cited by 37 (3 self)
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To provide realtime service or engineer constrainedbased paths, networks require the underlying routing algorithm to be able to find lowcost paths that satisfy given QualityofService (QoS) constraints. However, the problem of constrained...
An Efficient Algorithm for Finding a Path Subject to Two Additive Constraints
 Computer Communications Journal
, 2000
"... One of the key issues in providing endtoend qualityofservice (QoS) guarantees in packet networks is how to determine a feasible route that satisfies a set of constraints. In general, finding a path subject to multiple additive constraints (e.g., delay, delayjitter) is an NPcomplete problem ..."
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Cited by 33 (5 self)
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One of the key issues in providing endtoend qualityofservice (QoS) guarantees in packet networks is how to determine a feasible route that satisfies a set of constraints. In general, finding a path subject to multiple additive constraints (e.g., delay, delayjitter) is an NPcomplete problem that cannot be exactly solved in polynomial time. Accordingly, several heuristics and approximation algorithms have been proposed for this problem. Many of these algorithms suffer from either excessive computational cost or low performance. In this paper, we provide an efficient approximation algorithm for finding a path subject to two additive constraints. The worstcase computational complexity of this algorithm is within a logarithmic number of calls to Dijkstra's shortest path algorithm. Its average complexity is even much lower than that, as demonstrated by simulation experiments. The performance of the proposed algorithm is justified via theoretical bounds that are provided for ...