R.Gu'erin, A.Orda. QoS-based Routing in Networks with Inaccurate Information: theory and Algorithms. Proc. IEEE Infocom 97, 1997.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....usage. However, dynamic QoS routing requires the dissemination of link attributes or metrics, such as link load information, which can consume considerable bandwidth. The routing computation based on these parameters can also become very expensive in terms of processing and memory consumption [7, 10, 20]. Scalability is ensured by limiting the amount of routing information propagated in the network. Routing information is thus exchanged on a regular basis with a small frequency. Another method used to control the routing overhead consists in broadcasting only significant information in term ....

....frequency. Another method used to control the routing overhead consists in broadcasting only significant information in term of marginal variations (a variation of Sigma30 for instance) As a result, routing decisions may be inappropriate, as they may be based on out of date information [7]. Since the routing information updating policy is critical to network performance, a careful trade off between accuracy and scalability must be found. Hierarchy. Scalability is also ensured by clustering hierarchically the network in separate routing domains (or so called peer groups in PNNI) ....

R.Gu'erin, A.Orda. QoS-based Routing in Networks with Inaccurate Information: theory and Algorithms. Proc. IEEE Infocom 97, 1997.

.... traffic conditions to improve performance with respect to the simple Shortest Path (SP ) algorithm, which is used in present day Internet [6] 7] Other works studied the problem of information distribution, exploring the influence of stale information on the performance of several algorithms [8], 9] Either a packet based network simulator or a call level simulator is generally used to provide simulation results. All these works assumed a synthetic load of the network where connections duration is determined a priori, obtained extracting a random variable, like in traditional circuit ....

R. Gu'erin, A. Orda, "QoS-based Routing in Networks with Inaccurate Information", Proceedings of the IEEE INFOCOM '97, Kobe, Japan, April 1997

....is a typical example of this effort. Although this approach and the hierarchical approach reduce the overhead by disseminating less frequent and smaller link state messages, they both cause the inaccuracy of link state information, thus leading 9 to undue routing and or signaling failures [28]. A routing failure is said to occur if the source cannot find a route based on link state information kept in its own database even if a qualified route exists. And a signaling failure occurs if one of the intermediate nodes on the route determined by the source cannot reserve the resources ....

....1, there are basically two approaches to QoS routing: sourcedirected and flooding based. Although source directed routing, specifically link state routing, incurs smaller signaling overhead, it has the problem of signaling and routing failure due to the inaccurate information kept at each node [28, 78] and generates huge overhead when link state information is distributed. On the other hand, flooding based QoS routing can avoid such failures due to out dated information, but it incurs huge signaling overhead since signaling is executed through message flooding. In this chapter, we propose a ....

Gu'erin and A. Orda, "QoS-based routing in networks with inaccurate information: Theory and algorithms," in INFOCOM' 97, apr 1997.

....topology distribution cost and the efficiency of routing in large networks. Note that, aggregation methods introduce inaccuracy on routing information as a summarized connectivity is derived. Researches on how routing information inaccuracy would affect routing performance have been performed. In [9], routing connections with QoS requirements across one or more networks is investigated under the situations that the information available for making routing decisions is inaccurate and expressed in some probabilistic manner. The main focus of this study is to determine the impact of such ....

R. Gu'erin and A. Orda. QoS-based routing in networks with inaccurate information: Theory and algorithms. IEEE/ACM Transactions on Networking, 7(3):350 -- 364, 1999.

....presents to the outside world compressed information that enables routing entities to make intelligent decisions as to which subnetwork to use and to select the appropriate entry points to each subnetwork. The mathematical property of routing in such a scenario were studied by Gu erin and Orda [GO99] Methods for compact graph representation that can be used to aggregate topology information were studied in the past years. A spanner [PU88, PS89, ADD 93] of a graph G is a subgraph G 0 Corresponding author. shavitt lucent.com. Tel: 732) 949 2303, Fax: 732) 949 0399 that includes all ....

Roch Gu'erin and Ariel Orda. QoS-based routing in networks with inaccurate information: Theory and algorithms. IEEE/ACM Transactions on Networking, 7(3):350 -- 364, June 1999.

....to the outside world compressed information that enables routing entities to make intelligent decisions as to which subnetwork to use and to select the appropriate entry points to each subnetwork. The mathematical property of routing in such a scenario were recently studied by Gu erin and Orda [5]. Methods for compact graph representation that can be used to aggregate topology information were studied in the past years. A spanner [7, 6, 1] of a graph G is a subgraph G 0 that includes all the node of G but only a subset of the edges. Spanners with stretch t, t spanners, have the property ....

R. Gu'erin and A. Orda. QoS-based routing in networks with inaccurate information: Theory and algorithms. In IEEE INFOCOM'97, pages 75 -- 83, Apr. 1997.

....to the outside world compressed information that enables routing entities to make intelligent decisions as to which subnetwork to use and to select the appropriate entry points to each subnetwork. The mathematical property of routing in this scenario were recently studied by Gu erin and Orda [GO97] Methods for compact graph representation that can be used to aggregate topology information were studied in the past years. A spanner [PU88, PS89, ADD 93] of a graph G is a subgraph G 0 that includes all the node of G but only a subset of the edges. Spanners with stretch t, t spanners, ....

Roch Gu'erin and Ariel Orda. QoS-based routing in networks with inaccurate information: Theory and algorithms. In IEEE INFOCOM'97, pages 75 -- 83, April 1997.

....to the outside world compressed information that enables routing entities to make intelligent decisions as to which subnetwork to use and to select the appropriate entry points to each subnetwork. The mathematical property of routing in such a scenario were recently studied by Gu erin and Orda [GO97] Methods for compact graph representation that can be used to aggregate topology information were studied in the past years. A spanner [PU88, PS89, ADD 93] of a graph G is a subgraph G 0 that includes all the node of G but only a subset of the edges. Spanners with stretch t, t spanners, ....

Roch Gu'erin and Ariel Orda. QoS-based routing in networks with inaccurate information: Theory and algorithms. In IEEE INFOCOM'97, pages 75 -- 83, April 1997.

....a subgraph G (k) of the original graph by keeping only the edges with residual capacities R i;j s at least as high as R (k) E(G (k) f(i; j)jR i;j R (k) g. Now for each subgraph G (k) we define the cost of path P as Cost (k) P ) X n i 2V (P ) C i =R (k) D i ) 10) where V (P ) is the vertex set of P . For simplicity, we let the C i and D i of the destination be zero. We first define the following subproblem. Problem 1 (Per hop Constrained Shortest Path) Find a shortest path (path with the lowest cost) P = s = n 0 ; n 1 ; n l = t) satisfying the ....

....1 if and only if P satisfies the buffer bound conditions in Lemma 1 with service rate R (k) Proof : Assume P is a path in G (k) satisfying the perhop constraints. For any network node n j on path P , let P 0 be the prefix of P ending on n j . By the definitions of the cost function (10) and Problem 1, the following inequalities are equivalent: Cost(P 0 ) B j Gamma b) r b (Cost(P 0 ) r b ( B j Gamma b) r)r b ( P j i=0 C i =R (k) P j i=0 D i )r B j B(j) B j ut Theorem 2 There is a feasible path for the guaranteed connection request if and only if, ....

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R. Gu'erin and A. Orda. QoS-based Routing in Networks with Inaccurate Information. In Proceedings of the IEEE INFOCOM '97, 1997.

....into an end to end QoS requirement partition problem, namely local allocation of QoS requirements along the topology. The support of QoS connections has been the subject of extensive research in the past few years. Several studies and proposals considered the issue of QoS routing, e.g. [2, 7, 8, 17, 20] and references therein. Mechanisms for providing various QoS guarantees have been also widely investigated, e.g. 6, 18] Although there are proposals for resource reservation, most notably RSVP [3] they address only the signaling mechanisms and do not provide the allocation policy. Indeed, the ....

....[4] too concluded that more complex (optimal) partition schemes should be investigated. These two studies provide interesting insights into our framework, and strongly motivate the optimization problems that we investigate. Another sequence of studied that is related to the present one is [8, 12]. These studies investigated QoS partitioning and routing for unicast connections, in networks with uncertain parameters. Their goal was to select a path, and partition the QoS requirements along it, so as to maximize the probability of meeting the QoS requirements. As shall be shown, the link ....

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R. Gu'erin and A. Orda. QoS-Based Routing in Networks with Inaccurate Information: Theory and Algorithms. In Proceedings of the IEEE INFOCOM'97, pages 75--83, Kobe, Japan, April 1997.

....metric value at any instant given its last advertised value. Due to this property we call this type of inaccuracy, systematic inaccuracy. This property can be exploited by a clever path selection algorithm to suitably account for the inaccuracy and thereby increase the probability of success (see [8] for some examples) However, often a large clamp down timer is used since that is the only direct means of controlling the protocol overhead and limiting it to a tolerable level. Unfortunately, the degree of inaccuracy in this case is much larger and almost impossible to estimate. We will term ....

R. Gu'erin, and A. Orda, "QoS Based Routing in Networks With Inaccurate Information: Theory and Algorithms, " in proceedings of INFOCOM, 1997

....capable of achieving good routing performance while operating with relatively insensitive triggering policies and, therefore, inaccurate information. The main vehicle for achieving the above will be safety based routing. Safety based routing and the notion of link safety was introduced in [3,9]. Given the requested amount of bandwidth, the last advertised value of available bandwidth, and the knowledge of the triggering policy parameters, it is possible to compute the range of feasible values for the actual available bandwidth on a link. Knowledge of this range, coupled with assumptions ....

....at the cost of a fairly severe reduction in routing performance. We need solutions that will allow the routing algorithm to operate with triggering policy settings that yield low update overheads, while still achieving good routing performance. 4. Safety Based Routing As was first proposed in [3,9], the inaccuracy introduced by the triggering policy can be modeled when the operating details of the policy are known. For all change based triggering policies, given the last known value of available bandwidth on a link b adv , it is possible to determine the range of values that the actual ....

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R. Gu'erin, and A. Orda, QoS Based Routing in Networks With Inaccurate Information: Theory and Algorithms, in proceedings of INFOCOM, 1997.

....alternatives that trade accuracy of link state information for protocol overhead. Potential enhancements to the path selection algorithm, which seek to (directly) account for the inaccuracies in link metrics, are described in [GOW97] while a comprehensive treatment of the subject can be found in [GO97, LO] In Section 4, we also describe the design choices made in a reference implementation, to allow future extensions and experimentation with different link state update mechanisms. The rest of this document is structured as follows. In Section 2, we describe the general design choices and ....

R. Gu'erin and A. Orda. QoS-Based Routing in Networks with Inaccurate Information: Theory and Algorithms. In Proceedings of INFOCOM'97, pages 75--83, Kobe, Japan, April 1997.

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