G. Apostolopoulos, R. Guerin, S. Kamat, and S. Tripathi, "Improving QoS Routing Performance Under Inaccurate Link State Information." Proceedings of the 16th International Teletraffic Congress, June 7-11, 1999.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....global network state information is usually inaccurate. The inaccuracy may be introduced by many factors such as non negligible propagation delay and hierarchical topology aggregation [6] The inaccurate global network state information can greatly affect the performance of the routing algorithms [1], 9] An alternative to availability based routing is probability based routing [1] 4] 5] 6] In probability based routing, the resource availability probability information is either maintained or inferred, and the routing decision is made based on the probability information. Probability ....

.... by many factors such as non negligible propagation delay and hierarchical topology aggregation [6] The inaccurate global network state information can greatly affect the performance of the routing algorithms [1] 9] An alternative to availability based routing is probability based routing [1], 4] 5] 6] In probability based routing, the resource availability probability information is either maintained or inferred, and the routing decision is made based on the probability information. Probability based routing potentially offers the solutions for the problems caused by the ....

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G. Apostolopoulos, R. Guerin, S. Kamat, and S. Tripathi, "Improving QoS Routing Performance Under Inaccurate Link State Information." Proceedings of the 16th International Teletraffic Congress, June 7-11, 1999.

....problem is not severe. This paper studies the impact of resource reservation on the multi path routing schemes that use global network state information to make routing decisions. Studies on other network components, such as the link state update mechanisms and network topology, are reported in [1, 11]. Resource reservation adds another dimension to the network components and requires most of the performance issues to be revisited. In [3] the authors proposed a ticket based routing algorithm to solve the delay constrained least cost routing without considering resource reservation. We ....

....to exchange the control messages and the link state distribution messages while the data network is used to exchange data messages. The simulator simulates various link state update mechanisms including the periodical link state update mechanism and the sudden change link state update mechanism [1] which broadcasts link state information when the state of a link changes drastically. The simulator parameterizes many network components. For example, the network load is speci ed using three parameters, the connection request generation rate, the connection duration and the bandwidth ....

G. Apostolopoulos, R. Guerin, S. Kamat, and S. Tripathi, "Improving QoS Routing Performance Under Inaccurate Link State Information." Proceedings of the 16th International Teletrac Congress (ITC'16), Edinburgh, United Kingdom, June 7-11, 1999.

....devoted to the design and evaluation of traffic aware routing algorithms and protocols, and they can be broadly classified in two categories. Those with a traffic engineering focus, and those that target an on demand model (see [11] 25] 19] 6] for examples of the first, and [10] 1] [2] and [18] despite its title for examples of the second) In both settings, it is assumed that network topology and link capacities are known, and the two differ primarily in the traffic information available to routing. In the context of traffic engineering, the volume of traffic between different ....

G. Apostolopoulos, R. Guerin, S. Kamat, and S. Tripathi. Improving QoS routing performance under inaccurate link state information. In Proceedings of ITC'16, June 1999.

.... 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 ....

G. Apostolopoulos, R. Guerin, S. Kamat, S. K. Tripathi, "Improving QoS Routing Performance Under Inaccurate Link State Information", 16th International Teletraffic Congress (ITC-16), Edinburgh, UK, June 1999

....algorithm to tolerate the imprecise global network state information and make effective routing decisions in the presence of imprecise state information. A number of QoS routing methods that tolerate imprecise state information have been proposed. These methods include safety based routing [2], randomized routing 1 [2] multi path routing [3] and localized routing [9] Safety based routing was designed to deal with the deterministic imprecision caused by the link state update policy. It infers the range of the actual link state value from the link state updates, and finds the path ....

....the imprecise global network state information and make effective routing decisions in the presence of imprecise state information. A number of QoS routing methods that tolerate imprecise state information have been proposed. These methods include safety based routing [2] randomized routing 1 [2], multi path routing [3] and localized routing [9] Safety based routing was designed to deal with the deterministic imprecision caused by the link state update policy. It infers the range of the actual link state value from the link state updates, and finds the path that has the highest ....

[Article contains additional citation context not shown here]

G. Apostolopoulos, R. Guerin, S. Kamat, and S. Tripathi, "Improving QoS Routing Performance Under Inaccurate Link State Information." Proceedings of the 16th International Teletraffic Congress, June 7-11, 1999.

....schemes with a multi path QoS routing algorithm and compares the performance of these two resource reservation schemes with that of the forward resource reservation scheme. Studies on other network components, such as the link state update mechanisms and network topology, are reported in [1, 10]. Resource reservation adds another dimension to the network components and requires most of the performance issues to be revisited. In [2] the authors proposed a ticket based routing algorithm to solve the delay constrained least cost routing without considering resource reservation. We use a ....

....network is used to exchange control packets and link state packets while the data network is used to exchange data messages. ffl The simulator simulates various link state update mechanisms including the periodical link state update mechanism and the sudden change link state update mechanism [1] which broadcasts link state information when the state of a link changes drastically. ffl The simulator parameterizes the following protocol, network and traffic parameters: reservation scheme. The user can choose to simulate forward reservation protocols, backward reservation protocols or ....

G. Apostolopoulos, R. Guerin, S. Kamat, and S. Tripathi, "Improving QoS Routing Performance Under Inaccurate Link State Information." Proceedings of the 16th International Teletraffic Congress (ITC'16), Edinburgh, United Kingdom, June 7-11, 1999.

....the QoS state update interval is large. Due to these drawbacks, it has been shown that when the QoS update interval is large relative to the flow dynamics, the performance of global QoS routing schemes degrades significantly [1, 25, 31] Though there have been some remedial solutions proposed in [10, 1, 2] to deal with the inaccuracy at a source node, the fundamental problem is still not completely eliminated. As a viable alternative to the global QoS routing schemes, in [25, 26] we have proposed a localized approach to QoS routing. Under this approach, no global QoS state information exchange ....

G. Apostolopoulos, R. Guerin, S. Kamat, S. Tripathi, "Improving QoS Routing Performance under Inaccurate Link State Information", ITC'16, June 1999.

....N) time where N is the number of nodes and E is the total number of links in the network. Assuming precomputation of a set of paths R to each destination, to avoid searching the whole graph for path selection, it still need to traverse all the links 1 Some remedial solutions were proposed in [1, 2] to deal with the inaccuracy at a source node. However, the fundamental problem remains and the observations made in this paper still apply. of these precomputed paths to identify the widest shortest path. This amounts to an overhead of O(L ) where L is the total number of links in the set R ....

G. Apostolopoulos, R. Guerin, S. Kamat, S. Tripathi, "Improving QoS Routing Performance under Inaccurate Link State Information", ITC'16, June 1999.

....utilization in heavily loaded networks with uniform traffic pattern [12] Indeed, it is easy to prove that shortest path is the best routing algorithm for an overloaded homogeneous network with uniform traffic, or when the network topology is optimized for a given traffic pattern. Recent studies [4, 6] addressed the problem of unreliable link state information, analyzing different policies for triggering information exchange among nodes. These works clearly show that different policies for information exchange lead to different performance of routing algorithms; however, these studies are not ....

G. Apostolopoulos, R. Guerin, S. Kamat, S. K. Tripathi, "Improving QoS Routing Performance Under Inaccurate Link State Information", 16th International Teletraffic Congress (ITC-16), Edinburgh, UK, June 1999

....paths. Safety based QoS routing draws on knowledge of the link state update triggering algorithm and the last advertised value to compute the probability that a link has sufficient resources. Using these probabilities routers can rank paths by their likelihood of accommodating the request [26]. These techniques avoid the problem of targeting the one seemingly best path, but only extend the range of linkstate update periods under which conventional load sensitive routing performs well. Ultimately, flapping still arises when the timescale of the arriving and departing traffic is small ....

G. Apostolopoulos, R. Guerin, S. Kamat, and S. K. Tripathi, "Improving QoS routing performance under inaccurate link state information," in Proceedings of International Teletraffic Congress (ITC-16), (Edinburgh, UK), June 1999.

....and the single path routing schemes. However, the impact of resource reservation on multi path routing is unclear and has not been studied. This paper aims at filling in this gap. Studies on other network components, such as the link state update mechanisms and network topology, are reported in [1, 11]. Resource reservation adds another dimension and requires most of the performance issues to be revisited. In [3] the authors proposed a ticket based routing algorithm to solve the delay constrained least cost routing without considering resource reservation. We incorporate resource ....

....network is used to exchange control packets and link state packets while the data network is used to exchange data messages. The simulator simulates various link state update mechanisms including the periodical link state update mechanism and the sudden change link state update mechanism [1] which broadcasts link state information when the state of a link changes drastically. The simulator allows the user to specify the following parameters: network load. The network load is specified using three parameters, the connection request generation rate (r) the connection duration ....

G. Apostolopoulos, R. Guerin, S. Kamat, and S. Tripathi, "Improving QoS Routing Performance Under Inaccurate Link State Information." Proceedings of the 16th International Teletraffic Congress, Edinburgh, United Kingdom, June 7-11, 1999.

....update triggering mechanisms to trigger an update at the right time [2] The triggering mechanisms include change based updates and timer based updates. The second approach is to use appropriate routing algorithms to tolerate the less frequent updates, for example safety based routing [1] and multi path routing [4] 5] 2] In this paper, we provide a systematic performance study of topology aggregation, based on simulations of relatively largescale networks. We also propose new aggregation algorithms that are intended to achieve better performance than traditional approaches. ....

G. Apostolopoulos, R. Guerin, S. Kamat, and S. Tripathi. Improving QoS routing performance under inaccurate link state information. To appear in Proceedings of the 16th International Teletraffic Congress.

....if the difference between the current value and the last advertised one is greater than, say 50 , implies some maximum value for this gap. This information can then be used during the path selection phase to assess the likelihood that a given amount of bandwidth is available. For example, 12] and [13] illustrate how this can be used together with the path selection method described in Section II of this paper. However, there are other cases where estimating the value of this gap is more difficult. In particular, as illustrated in [6] timer based mechanisms can induce more arbitrary ....

....imprecise link bandwidth information. This understanding can then drive the exploration of specific cases, and the construction of distributions which are not only realistic models to represent state inaccuracy in real networks, but also enable tractable solutions to the QoS routing problem (see [13] for a detailed experimental investigation of this issue, and its use in the context of the methods proposed in this paper) In this context, for a new flow with bandwidth requirement w, we wish to find the path that is most likely to be able to accom modate this new request. For that purpose, ....

[Article contains additional citation context not shown here]

G. Apostolopoulos, R. Guerin, S. Kamat, and S. Tripathi, "Improving QoS routing performance under inaccurate link state information," in Proceedings of ITC'16, June 1999, (To appear).

....the parameters are random variables. For example, this is the model of [26, Section B.2] where call durations are only approximately known, i.e. in the form of their distribution. Similarly, in [10] uncertainty in available link bandwidth is modeled through the use of random variables, and [1] demonstrates that this is a reasonable assumption. In [9] we assess how this additional dimension affects path selection. Consider first the basic feasibility problem described in Subsection III A, but with the duration of connection i being a random variable with probability distribution ....

G. Apostolopoulos, R. Guerin, S. Kamat, and S. Tripathi. Improving QoS routing performance under inaccurate link state information. In Proceedings of ITC'16, Edinburgh, Scotland, June 1999.

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G. Apostolopoulos, R. Gu'erin, S. Kamat, and S. K. Tripathi, "Improving QoS Routing Performance Under Inaccurate Link State Information." Proceedings of ITC'16, Edinburgh, Scotland, June, 1999.

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G. Apostolopoulos, R. Guerin, S. Kamat, and S. Tripathi, "Improving QoS Routing Performance Under Inaccurate Link State Information." Proceedings of the 16th International Teletraffic Congress, June 7-11, 1999.

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G. Apostolopoulos, R. Guerin, S. Kamat and S. Tripathi, "Improving QoS Routing Performance Under Inaccurate Link State Information," in Proc. 16th ITC, Edinburgh, UK, June 1999.

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G. Apostolopoulos, R. Guerin, S. Kamat, and S. Tripathi, "Improving QoS Routing Performance Under Inaccurate Link State Information." Proceedings of the 16th International Teletrac Congress, June 7-11, 1999.

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G. Apostolopoulos, R. Guerin, S. Kamat, and S. Tripathi, "Improving QoS Routing Performance Under Inaccurate Link State Information." Proceedings of the 16th International Teletraffic Congress, June 7-11, 1999.

No context found.

G. Apostolopoulos, R. Guerin, S. Kamat, and S. Tripathi, "Improving QoS Routing Performance Under Inaccurate Link State Information." Proceedings of the 16th International Teletra#c Congress, Edinburgh, United Kingdom, June 7-11, 1999.

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G. Apostolopoulos, R. Guerin, S. Kamat, and S. Tripathi. Improving QoS routing performance under inaccurate link state information. To appear in Proceedings of the 16th International Teletraffic Congress.

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