Results 1 - 10
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58
On Path Selection for Traffic with Bandwidth Guarantees
- In Proceedings of IEEE International Conference on Network Protocols
, 1997
"... Transmission of multimedia streams imposesa minimum-bandwidth requirementon the path being used to ensureend-to-end Quality-ofService (QoS) guarantees. While any shortest-path algorithm can be used to select a feasible path, additional constraints that limit resource consumption and balance the netw ..."
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Cited by 190 (7 self)
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Transmission of multimedia streams imposesa minimum-bandwidth requirementon the path being used to ensureend-to-end Quality-ofService (QoS) guarantees. While any shortest-path algorithm can be used to select a feasible path, additional constraints that limit resource consumption and balance the network load are needed to achieve efficient resource utilization. We present a systematic evaluation of four routing algorithms that offer different tradeoffs between limiting the path hop count and balancing the network load. Our evaluation considers not only the call blocking rate but also the fairness to requests for different bandwidths, robustness to inaccurate routing information, and sensitivity to the routing information update frequency. It evaluates not only the performance of these algorithms for the sessions with bandwidth guarantees, but also their impact on the lower priority best-effort sessions. Our results show that a routing algorithm that gives preference to limiting the hop ...
An overview of constraint-based path selection algorithms for QoS routing
- IEEE Communications Magazine
, 2002
"... Constraint-based path selection aims at identifying a path that satisÞes a set of quality-ofservice (QoS) constraints. In general, this problem is known to be NP-complete, leading to the proposal of many heuristic algorithms. In this paper, we provide an overview of these algorithms, focusing on res ..."
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Cited by 71 (7 self)
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Constraint-based path selection aims at identifying a path that satisÞes a set of quality-ofservice (QoS) constraints. In general, this problem is known to be NP-complete, leading to the proposal of many heuristic algorithms. In this paper, we provide an overview of these algorithms, focusing on restricted shortest path and multi-constrained path algorithms. 1
Evaluating the Impact of Stale Link State on Quality-of-Service Routing
, 2001
"... Quality-of-service (QoS) routing satisfies application performance requirements and optimizes network resource usage by selecting paths based on connection traffic parameters and link load information. However, distributing link state imposes significant bandwidth and processing overhead on the net ..."
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Cited by 56 (0 self)
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Quality-of-service (QoS) routing satisfies application performance requirements and optimizes network resource usage by selecting paths based on connection traffic parameters and link load information. However, distributing link state imposes significant bandwidth and processing overhead on the network. This paper investigates the performance trade-off between protocol overhead and the quality of the routing decisions in the context of the source-directed, link-state routing protocols proposed for IP and ATM networks. We construct a detailed model of QoS routing that parameterizes the path-selection algorithm, link-cost function, and link-state update policy. Through extensive simulation experiments with several network topologies and traffic patterns, we uncover the effects of stale link-state information and random fluctuations in traffic load on the routing and set-up overheads. We then investigate how inaccuracy of linkstate information interacts with the size and connectivity of the underlying topology. Finally, we show that tuning the coarseness of the link-cost metric to the inaccuracy of underlying link-state information reduces the computational complexity of the path-selection algorithm without significantly degrading performance. This work confirms and extends earlier studies, and offers new insights for designing efficient quality-of-service routing policies in large networks.
Efficient Precomputation of Quality-of-Service Routes
, 1998
"... Quality-of-service (QoS) routing satisfies application performance requirements and improves network resource usage by selecting paths based on connection traffic parameters and available link capacity. However, QoS-routing protocols can introduce significant network overhead for computing routes an ..."
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Cited by 41 (4 self)
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Quality-of-service (QoS) routing satisfies application performance requirements and improves network resource usage by selecting paths based on connection traffic parameters and available link capacity. However, QoS-routing protocols can introduce significant network overhead for computing routes and distributing information about link load. Route precomputation is an effective way to amortize the cost of the path selection algorithm over multiple connection requests. This paper introduces efficient mechanisms for precomputing one or moreroutes to each destination, and on demand checking of the suitability of the routes at connection arrival, based on the most recent link-state information. Simulation experiments show that the route precomputation and route extraction techniques are effective at lowering the computational overheads for QoS routing, while achieving performance similar to the more expensive on-demand path-selection schemes.
Search Space Reduction in QoS Routing
- In Proceedings of the 19th International Conference on Distributed Computing Systems
, 2001
"... To provide real-time service or engineer constrained-based paths, networks require the underlying routing algorithm to be able to find low-cost paths that satisfy given Quality-of-Service (QoS) constraints. However, the problem of constrained... ..."
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Cited by 37 (3 self)
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To provide real-time service or engineer constrained-based paths, networks require the underlying routing algorithm to be able to find low-cost paths that satisfy given Quality-of-Service (QoS) constraints. However, the problem of constrained...
Evaluating the overheads of source-directed quality-of-service routing
- in Proceedings of IEEE International Conference on Network Protocols
, 1998
"... Quality-of-service (QoS) routing satisfies application performance requirements and optimizes network resource usage but effective path-selection schemes require the distribution of link-state information, which can impose a significant burden on the bandwidth and processing resources in the network ..."
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Cited by 34 (1 self)
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Quality-of-service (QoS) routing satisfies application performance requirements and optimizes network resource usage but effective path-selection schemes require the distribution of link-state information, which can impose a significant burden on the bandwidth and processing resources in the network. We investigate the fundamental trade-off between network overheads and the quality of routing decisions in the context of the source-directed linkstate routing protocols proposed for future IP and ATM networks. Through extensive simulation experiments with several representative network topologies and traffic patterns, we uncover the effects of stale link-state information, random fluctuations in traffic load, and variations of the link-cost metric on the routing and signalling overheads. The paper concludes by summarizing our key results as a list of guidelines for designing efficient quality-of-service routing policies in large backbone networks. 1
Supporting Dynamic Inter-Class Resource Sharing: A Multi-Class QoS Routing Algorithm
- In IEEE Infocom
, 1999
"... In an integrated services network, resources are shared by multiple traffic classes. Service classes that deliver guaranteed Quality-ofService (QoS) to applications have priority over others that do not. In such a multi-service network, routing decisions for high priority QoS traffic will affect wha ..."
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Cited by 33 (0 self)
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In an integrated services network, resources are shared by multiple traffic classes. Service classes that deliver guaranteed Quality-ofService (QoS) to applications have priority over others that do not. In such a multi-service network, routing decisions for high priority QoS traffic will affect what resources are available for lower priority traffic: Poor route selection can result in congestion for, or even starvation of, lower priority traffic. Whereas many studies have focused on routing algorithms that optimize the network throughput for individual service classes, little effort has been devoted to routing algorithms that address inter-class resource sharing. In this paper, we propose a routing algorithm that allows dynamic sharing of link resources among multiple traffic classes. The algorithm is based on the concept of "virtual residual bandwidth," which is derived from the link residual bandwidth by taking the congestion condition of low priority traffic into account. By using ...
An Efficient Algorithm for Finding a Path Subject to Two Additive Constraints
- Computer Communications Journal
, 2000
"... One of the key issues in providing end-to-end quality-of-service (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, delay-jitter) is an NP-complete problem ..."
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Cited by 33 (5 self)
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One of the key issues in providing end-to-end quality-of-service (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, delay-jitter) is an NP-complete 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 worst-case 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 ...
Routing Traffic with Quality-of-Service Guarantees in Integrated Services Networks
- In The 8th International Workshop on Network and Operating Systems Support for Digital Audio and Video (NOSSDAV 98
, 1998
"... Transmission of interactive multimedia streams requires stringent Quality-of-Service (QoS) guarantees in delay, delay jitter, and bandwidth, which imposes strict resource constraints on the paths being used. While the general problem of finding a path that meets multiple QoS constraints is NP comple ..."
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Cited by 29 (1 self)
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Transmission of interactive multimedia streams requires stringent Quality-of-Service (QoS) guarantees in delay, delay jitter, and bandwidth, which imposes strict resource constraints on the paths being used. While the general problem of finding a path that meets multiple QoS constraints is NP complete, we have shown that such a path can be found in polynomial time if the network service disciplines are rate proportional. However, two important issues remain unsolved. One issue is how to select among all feasible paths an efficient one that achieves high network throughput. We identify four optimality criteria and for each of them we propose a polynomial algorithm that selects paths that meet the criterion. Our simulation results show that, while the widest-shortest path performs best for heavy loads, the shortest-delay path has a performance edge for light loads. Surprisingly, the path that requires the reservation of the smallest amount of bandwidth performs the worst for both heavy a...
Dynamics of Quality-of-Service Routing with Inaccurate Link-State Information
, 1997
"... Quality-of-service (QoS) routing can satisfy application performance requirements and opti- mize network resource usage by selecting paths based on connection traffic parameters and link load information. However, effective path-selection schemes require the distribution of link-state information ..."
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Cited by 28 (4 self)
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Quality-of-service (QoS) routing can satisfy application performance requirements and opti- mize network resource usage by selecting paths based on connection traffic parameters and link load information. However, effective path-selection schemes require the distribution of link-state information, which can cause a significant burden on the bandwidth and processing resources in the network. Wc investigate the fundamental tension between network overheads and the quality of routing decisions in the context of source-directed QoS routing algorithms. In contrast to previous performance studies that compare different routing algorithms under specific network configurations, wc characterize how the performance and overheads of QoS routing relate to the link-state update policies, as a function of the underlying traffic load, network topology, and link-cost metrics. Wc explore the interplay between stale link-state information and random fluctuations in traffic load through a broad set of simulation experiments on a paramctcrizcd model of QoS routing. These results suggest ways to tune the frequency of link-state update messages and the link-cost functions to strike a careful balance between high accuracy and low complexity.
