I. Chlamtac, A. Farag, and T. Zhang. Optimizing the system of virtual paths. IEEE/ACM Transactions on Networking, 2, 6:581--587, 1994.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....share network resources. If the cost function in each edge is convex, then this problem can be solved in polynomial time [21] The problem is NP hard if the flows are required to be integral [11] or if each commodity is required to follow a single path from its source to its destination [9]. In Section 3, we propose variants of a GRASP with path relinking heuristic for this problem. Experimental results, reported in Section 4, show that the proposed heuristics are able to improve the solutions found with standard routing techniques on realistic size problems. Concluding remarks are ....

I. Chlamtac, A. Farago, and T. Zhang. Optimizing the system of virtual paths. IEEE/ACM Trans. on Networking, 2:581--587, 1994.

....traffic has preemptive priority in the reserve net. Figure 1 depicts the main steps for provisioning and configuration of QoS traffic. We note that the problem of provisioning a reserved net is a version of network optimization problem for which a rich literature exists (e.g. Dov91a, Dov91b, CFZ94, ACL94, Ash95, For96, Lee95, MMR96] However, the objective function of our problem is different as we explain in the next section. 3.1 Optimum Virtual Network The network is represented by a graph G = V; E) where node set V is partitioned into two distinct subsets, V = R [ S. The set R ....

I. Chlamtac, A. Farago, and T. Zhang. Optimizing the system of virtual paths. IEEE Trans. on Networking, 2(6):581--587, Dec. 1994.

....traffic classes. Bauschert: Multihour Design of Multi Hop Virtual Path based Wide Area ATM Networks 2 1 Introduction For the single hour design of a VP network on top of a physical network a number of different methods have been proposed in the literature, see e.g. 4] 5] 6] 7] 9] 10] [11], 12] 13] and [14] Most authors, except [6] 8] 9] 11] 12] 13] and [14] assume that for each end to end traffic relation one or more separate VPs are established, and that the end to end traffic streams are not allowed to mix. This VP operation mode is denoted Single Hop VP (SHVP) ....

.... Path based Wide Area ATM Networks 2 1 Introduction For the single hour design of a VP network on top of a physical network a number of different methods have been proposed in the literature, see e.g. 4] 5] 6] 7] 9] 10] 11] 12] 13] and [14] Most authors, except [6] 8] 9] [11], 12] 13] and [14] assume that for each end to end traffic relation one or more separate VPs are established, and that the end to end traffic streams are not allowed to mix. This VP operation mode is denoted Single Hop VP (SHVP) concept because every destination can be reached over one hop. In ....

J. Chlamtac, A. Farago, T. Zhang, "Optimizing the System of Virtual Paths," IEEE/ACM Transactions on Networking, vol. 2, no. 6, pp. 581-587, December 1994.

.... Path Layout problem, VPL problem for short, is an optimization problem in which, given a certain communication demand between pairs of nodes and constrained load and hop count, it is required to design a system of virtual paths such that some given cost function is minimized ( 4] 5] 6] [7]) A second general approach to the VPL problem is the one typical of complexity theory, which aims at a precise characterization of the relations occurring between the involved quantities. This approach makes use of more specialized graph theoretical techniques to derive upper and lower bounds ....

Chlamtac, I., Farago, A., Zhang, T.: Optimizing the System of Virtual Paths. IEEE Transactions on Networking (1994)

....Keywords: Routing, admission control, resource allocation algorithms, multi rate loss networks. 1 Introduction We consider a network that uses the Virtual Path (VP) concept. This concept is often used to simplify network management and to increase the apparent direct connectedness of the network [2, 8, 14]. Typically, a VP is installed between two nodes (switches) over a sequence of physical links, and bandwidth is allocated to it. Thus a virtual fully connected network can be overlayed over the physical network, where the VPs constitute the (virtual) links connecting the network nodes. Simple ....

I. Chlamtac, A. Farag'o, and T. Zhang. Optimizing the System of Virtual Paths. IEEE/ACM Transactions on Networking, 2(6):581--587, December 1994.

....that only consider paths with one VP and two VPs are used. Thus, admission tests have to be done on at most two links resulting in small VC setup times. In addition, the view maintained at a node would contain only those nodes at which VPs originate. In general, it is not clear how to install VPs [9]. Also, the static allocation of resources to VPs can result in resource under utilization and higher blocking probabilities [17] One approach to solve this problem is to install fewer VPs and thus use longer paths (i.e. consisting of more than two VPs) Another approach is to dynamically ....

I. Chlamtac, A. Farag'o, and T. Zhang. Optimizing the System of Virtual Paths. IEEE/ACM Transactions on Networking, 2(6):581--587, December 1994.

....with more than one route from Source to Destination while others [ARD94] provide multiple routing paths by running a shortest path algorithm jointly with the VP capacity al The VP Distribution Problem 9 location algorithm. A simple methodology for routing VPs with known capacities was given in [CHL94], but is not useful in our case because the VP capacities are not known in advance. 3. The VP Distribution Problem By observing the limitations of previous approaches to the VP distribution problem, we propose an algorithm that satisfies the following basic requirements: n supports any number ....

I. Chlamtac, A. Farago and T. Zhang, "Optimizing the System of Virtual Paths", IEEE/ACM Transactions on Networking, Vol. 2, No. 6, December 1994.

....provide a fixed set of VPs but with more than one route from Source to Destination while others [ARD94] provide multiple routing paths by running a shortest path algorithm jointly with the VP capacity allocation algorithm. A simple methodology for routing VPs with known capacities was given in [CHL94], but is not useful in our case because the VP capacities are not known in advance. 3.3 The VP Distribution Problem By observing the limitations of all previous approaches to the VP distribution problem, we propose an algorithm that satisfies the following basic requirements: n supports any ....

....utilization consideration is of less concern. The most important issue becomes the selection of a routing policy and the VP routes themselves. One way to approach the problem is to route the VPs so that the maximum reserved capacity from the network links is minimized. This approach is explored in [CHL94]. This optimization problem is known to be NP complete, and the authors propose a probabilistic algorithm that runs in polynomial time and produces suboptimal solutions in some cases. However, this approach is useful only when the VP capacity is known in advance and therefore is not suitable in ....

I. Chlamtac, A. Farago and T. Zhang, "Optimizing the System of Virtual Paths", IEEE/ACM Transactions on Networking, Vol. 2, No. 6, December 1994.

....with more than one route from Source to Destination while others [ARD94] provide multiple routing paths by running a shortest path algorithm jointly with the The VP Distribution Problem 9 VP capacity allocation algorithm. A simple methodology for routing VPs with known capacities was given in [CHL94], but is not useful in our case because the VP capacities are not known in advance. 3. The VP Distribution Problem By observing the limitations of previous approaches to the VP distribution problem, we propose an algorithm that satisfies the following basic requirements: n supports any number of ....

Chlamtac, Imrich, Farago, Andras and Zhang, Tao, "Optimizing the System of Virtual Paths", IEEE/ACM Transactions on Networking, Vol. 2, No. 6, December 1994.

....network utilization) Under uniform workload, both schemes provide similar revenue. 1 Introduction We consider a network that uses the Virtual Path (VP) concept. This concept is often used to simplify network management and to increase the apparent direct connectedness of the network [1, 4, 9]. Typically, a VP is installed between two nodes (switches) over a sequence of physical links, and bandwidth is allocated to it. Thus a virtual fully connected network can be overlayed over the physical network, where the VPs constitute the (virtual) links connecting the network nodes. Simple ....

I. Chlamtac, A. Farag'o, and T. Zhang. Optimizing the system of virtual paths. IEEE/ACM Transactions on Networking, 2(6):581--587, December 1994.

....measures. 3 SIMULATION OF LPR AND LLR IN VIR TUAL PATH BASED NETWORKS In this section, we compare LLR and LPR in a network that uses the Virtual Path (VP) concept. This concept is often used to simplify network management and to increase the apparent direct connectedness of the network [6, 15, 29]. Typically, a VP is installed between two nodes (switches) over a sequence of physical links, and bandwidth is allocated to it. Thus a virtual fullyconnected network can be overlayed over the physical network, where the VPs constitute the (virtual) links connecting the network nodes. Simple ....

I. Chlamtac, A. Farago, and T. Zhang. Optimizing the System of Virtual Paths. IEEE/ACM Transactions on Networking, 2(6):581--587, December 1994.

....links. We have previously proposed a bandwidth allocation model for Virtual Trees [3] that yields optimal VT configurations in a similar manner to VP configurations. One of the main difficulties in using these optimization models is that determining optimal configurations is an NP Hard problem [7]. We have developed approximate optimization models that, while not yielding an optimal solution, provide good solutions in a reasonable amount of time. Two such models named Graph Reduction and Underloaded Neighbors respectively, both start with shortest path configurations and modify them in ....

....links) of the total bandwidth allocated on each link to all the Virtual Paths or Trees weighted by the link cost. We have presented in [3] an optimization model that yields such a VT configuration. It has been shown that the problem of determining optimal configurations for Virtual Paths is NPHard [7]. Clearly, the algorithm to solve the optimization model for Virtual Trees is at least as hard. We have conducted simulation studies of our optimization model and found that it was difficult to use it for networks of more than about 10 nodes because of the excessive time required to find the ....

I. Chlamtac, A. Farago, and T. Zhang. Optimizing the system of virtual paths. IEEE/ACM Transactions on Networking, 2(6):581--587, December 1994.

.... physical link capacities, and a predicted traffic pattern between various source destination pairs, we need algorithms to construct VT configurations (sets of VTs that can carry the given traffic) Finding such configurations that are optimal (minimize total network cost) is an NP Hard problem [6]. We have developed two approximate optimization algorithms for finding VT and VP configurations that, while not yielding an optimal solution, provide good solutions in a reasonable amount of time [7] The two algorithms named Graph Reduction and Underloaded Neighbors both start with shortest ....

I. Chlamtac, A. Farago, and T. Zhang. Optimizing the system of Virtual Paths. IEEE/ACM Transactions on Networking, 2(6):581--587, December 1994.

....of about 1.6. 3 Simulation of LPR and LLR in Virtual Path Based Networks In this section, we compare LLR and LPR in a network that uses the Virtual Path (VP) concept. This concept is often used to simplify network management and to increase the apparent direct connectedness of the network [8, 17, 30]. Typically, a VP is installed between two nodes (switches) over a sequence of physical links, and bandwidth is allocated to it. Thus a virtual fully connected network can be overlayed over the physical network, where the VPs constitute the (virtual) links connecting the network nodes. Simple ....

I. Chlamtac, A. Farag'o, and T. Zhang. Optimizing the System of Virtual Paths. IEEE/ACM Transactions on Networking, 2(6):581--587, December 1994.

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I. Chlamtac, A. Farag, and T. Zhang. Optimizing the system of virtual paths. IEEE/ACM Transactions on Networking, 2, 6:581--587, 1994.

No context found.

I. Chlamtac, A. Farag, and T. Zhang. Optimizing the system of virtual paths. IEEE/ACM Transactions on Networking, 2, 6:581--587, 1994.

No context found.

I. Chlamtac, A. Farago, and T. Zhang, "Optimizing the system of virtual paths," IEEE/ACM Trans. Networking, vol. 2, pp. 581--587, Dec. 1994.

No context found.

Imrich Chlamtac, Andras Farago, Tao Zhang, "Optimizing the System of Virtual Paths," IEEE/ACM Transactions on Networking, December, 1994.

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