Optimal capacity placement for path restoration in STM or ATM mesh-survivable networks
TL;DR: A method for capacity optimization of path restorable networks which is applicable to both synchronous transfer mode (STM) and asynchronous transfermode (ATM) virtual path (VP)-based restoration and jointly optimizing working path routing and spare capacity placement.
Abstract: The total transmission capacity required by a transport network to satisfy demand and protect it from failures contributes significantly to its cost, especially in long-haul networks. Previously, the spare capacity of a network with a given set of working span sizes has been optimized to facilitate span restoration. Path restorable networks can, however, be even more efficient by defining the restoration problem from an end to end rerouting viewpoint. We provide a method for capacity optimization of path restorable networks which is applicable to both synchronous transfer mode (STM) and asynchronous transfer mode (ATM) virtual path (VP)-based restoration. Lower bounds on spare capacity requirements in span and path restorable networks are first compared, followed by an integer program formulation based on flow constraints which solves the spare and/or working capacity placement problem in either span or path restorable networks. The benefits of path and span restoration, and of jointly optimizing working path routing and spare capacity placement, are then analyzed.
Citations
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01 Jan 2003
TL;DR: In this paper, the authors examine the scalability of core optical mesh networks and compare a flat or one-tier architecture with a layered (hierarchical) architecture where the network is scaled by organizing it in layers.
Abstract: —In this paper, we examine the scalability of core optical mesh networks. As traffic demand grows and evolves, core network nodes need to switch ever-larger amounts of traffic at different rates (DS1, DS3, OC-3, OC-48, OC-192). In a flat or one-tier network architecture, each network node contains one or multiple identical switches that can switch at the lowest rate in the hierarchy, usually STS-1 level. As traffic grows, the switching capacity of a node can be scaled by interconnecting multiple such switches. However, scaling the network in this manner incurs a severe penalty in terms of interconnect capacity needed to interconnect switches in the same office. This penalty is dependent on the traffic forecast accurrecast uncertainty. We use acy, increasing with the fotheoretical and experimental results for scaling the switching capacity of a node by interconnecting multiple switches, and compare a flat or one-tier architecture with a layered (hierarchical) architecture where the network is scaled by organizing it in layers. There, layers are optimized to switch and groom at different rates. We show that there is a crossover point beyond which the layered architecture becomes more cost effective as the total traffic grows and as the traffic mix evolves toward higher rates.
1 citations
Proceedings Article•
10 Jul 2000TL;DR: This paper presents a genetic algorithm based method to solve the capacity and routing assignment problem arising in the design of self-healing networks using the Virtual Path (VP) concept and shows that the results obtained using Genetic Algorithm is better than those results obtained by using heuristic approaches.
Abstract: This paper presents a genetic algorithm based method to solve the capacity and routing assignment problem arising in the design of self-healing networks using the Virtual Path (VP) concept. Past research has revealed that Preplanned Backup Protection method and the Path Restoration scheme can provide a best compromise on the reserved spare capacity and the failure restoration time. Base on a set of customer traffic demands, we will determine the routings of the working and backup virtual paths to satisfy the demands, so that the traffic is 100% restorable under single point of failure and at the same time the amount of spare capacity can be minimized. In contrast to the past researches on this area, we will use Genetic Algorithm instead of linear programming. There are several advantages of using Genetic Algorithm which included faster and lower computation cost in reaching a reasonably good virtual path routing scheme, it can tackle multiple objectives function effectively, and less complex mathematical formulation. We will show that the results obtained using Genetic Algorithm is better than those results obtained by using heuristic approaches. Another contribution of this paper is our method not only can work on the Unicast traffic context just as the past researches, but also Multicast traffic.
1 citations
Dissertation•
01 Jan 2002
TL;DR: In this article, the capacity needed to build a restorable satellite network and design routing schemes to achieve high throughput is investigated, and the capacity requirements for a LEO satellite constellation are investigated.
Abstract: We investigate the capacity needed to build a restorable satellite network and design routing schemes to achieve high throughput Speci cally, the rst part of this thesis considers the link capacity requirement for a LEO satellite constellation We model the constellation as an N N mesh-torus topology under a uniform all-to-all traAEc model Both primary capacity and spare capacity for recovering from a link or node failure are examined In both cases, we use a method of \cuts on a graph" to obtain lower bounds on capacity requirements and subsequently nd algorithms for routing and failure recovery that meet these bounds Finally, we quantify the bene ts of path based restoration over that of link based restoration; speci cally, we nd that the spare capacity requirement for a link based restoration scheme is nearly N times that for a path based scheme In the second part of this thesis, we consider a packet switching satellite network in which each node independently generates packets with a xed probability during each time slot With a limited number of transmitters and bu er space onboard each satellite, contention for transmission inevitably occurs as multiple packets arrived at a node We consider three routing schemes in resolving these contentions: Shortest Hops Win, Random Packet Win and Oldest Packet Win; and evaluate their performance in terms of throughput Under no bu er case, the throughput of the three schemes are signi cantly di erent However, there is no appreciable di erence in the throughput when bu er is available at each node Also, a small bu er size at each node can achieve the same throughput performance as that of in nite bu er size Simulations suggests that our theoretical throughput analysis is very accurate Thesis Supervisor: Eytan Modiano Title: Assistant Professor
1 citations
Cites background or methods from "Optimal capacity placement for path..."
...Path restoration reroutes the a ected traÆc over a set of replacement paths between their source and destination nodes [1, 2, 3, 5, 6]....
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...stub release [5])....
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...The work of [5] provides a method for capacity optimization of path restorable networks and quanti es the capacity bene ts of path over link restoration....
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...[1, 2, 3, 5]....
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01 Jan 2004
TL;DR: This represents the first work on capacity planning for survivable multiple-class-of-service IP/MPLS networks with non-linear performance constraints with an efficient solution approach based on the Lagrangian Relaxation and subgradient methods.
Abstract: It is essential for ISPs to offer both performance and survivability guarantees at the IP/MPLS layer. Capacity planning is needed to ensure there will be sufficient resource availability and quality of service under normal circumstances, and during network failures. In this paper we study the issue of capacity planning for survivable MPLS networks providing DiffServ EF and BE traffic classes. Our goal is to minimize the total link cost, subject to the performance and survivability constraints of both EF and BE classes. The problem is formulated as an optimization problem, where we jointly select the routes for edge to edge EF and BE user demand pairs, and assign a discrete capacity value for each link. Capacity for the EF class is fully restorable under the single link failure model, while restorability of the BE class can be adjusted by the network operator. We propose an efficient solution approach based on the Lagrangian Relaxation and subgradient methods. Computational results show that the solution quality is within a few percent of optimal, while the running time remains reasonable for networks with 1000 nodes, 2500 links, and 40,000 demand pairs. This represents the first work on capacity planning for survivable multiple-class-of-service IP/MPLS networks with non-linear performance constraints.
1 citations
Cites background from "Optimal capacity placement for path..."
...This represents the first work on capacity planning for survivable multiple-class-of-service IP/MPLS networks with non-linear performance constraints....
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01 Jan 2003
1 citations
References
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Book•
16 Feb 1970
TL;DR: Interestingly, integer programming and network flows that you really wait for now is coming, it's significant to wait for the representative and beneficial books to read.
Abstract: (1970). Integer Programming and Network Flows. Journal of the Operational Research Society: Vol. 21, No. 4, pp. 500-501.
638 citations
TL;DR: Self-healing network techniques suitable for ATM networks in order to realize a high-reliablity B-ISDN are proposed and high-speed restoration technique which exploits the benefits of the VP is proposed and described.
Abstract: This paper proposes self-healing network techniques suitable for ATM networks in order to realize a high-reliablity B-ISDN. First, the characteristics of the virtual paths (VP) and their influence on failure restoration are discussed. A high-speed restoration technique which exploits the benefits of the VP is then proposed and described. The technique simplifies the message transmission processes and reduces the number of generated messages by using preassigned backup virtual paths. Next, the scheme used to design the backup VP routes and spare resource distribution for each link is proposed in order to create a network that applies the proposed restoration scheme. Next, self-reconstruction techniques of backup virtual paths are proposed for the realization of a reversionless restoration cycle. Finally, the feasibility of the distributed control operation is discussed. >
233 citations
TL;DR: A comparative study of the effectiveness of KSP versus Max Flow as an alternative rerouting criteria in the context of transport network span restoration, and the hypothesis is made that a generalized "trap" topology is responsible for all KSP-Max Flow capacity differences.
Abstract: In the development of technologies for span failure restoration, a question arises about the restoration rerouting characteristics to be specified. In theory, maximal rerouting capacity is obtained with a maximum flow (Max Flow) criterion. However, rerouting that realizes the k-successively shortest link disjoint paths (KSP) may be faster, easier, and, in distributed implementation, more robust than a distributed counterpart for Max Flow. The issue is, therefore, what the restoration capacity penalty is if KSP is used instead of Max Flow. To explore this tradeoff, the authors present a comparative study of the effectiveness of KSP versus Max Flow as an alternative rerouting criteria in the context of transport network span restoration. The comparison applies to both centrally controlled and distributed restoration systems. Study methods include exhaustive span failure experiments on a range of network models, and parametric and analytical investigations for insight into the factors resulting in KSP versus Max Flow differences. The main finding is that KSP restoration capacity is more than 99.9% of that from Max Flow in typical network models. The hypothesis is made that a generalized "trap" topology is responsible for all KSP-Max Flow capacity differences. The hypothesis is tested experimentally and used to develop analytical bounds which agree well with observed results. These findings and data are relevant to standards makers and equipment developers in specifying and engineering future restorable networks. >
199 citations
NEC1
TL;DR: In order to achieve fast restoration, a distributed control mechanism that is applicable to both line and path restoration is proposed, and the shared use of spare channels for various failure scenarios, including multiple failure cases, are allowed.
Abstract: With the advent of networking technologies intelligent network elements, such as the digital cross-connect system (DCS), will make it possible to dynamically reconfigure a network for restoration purposes. Both restoration control of DCSs and spare-channel design issues are presented, and how they work together so that a fast and economical SONET self-healing network is obtained. In order to achieve fast restoration, a distributed control mechanism that is applicable to both line and path restoration is proposed. The proposed method allows the shared use of spare channels for various failure scenarios, including multiple failure cases, so that the efficient use of spare channels can be achieved. A linear-programming-based scheme is proposed to obtain spare-channel assignment, where a network-flow technique is used. Through a simulation study, a fast and economical self-healing network is verified. >
193 citations
"Optimal capacity placement for path..." refers background or methods in this paper
...Previous work used an IP approach based on -flow -cut considerations to solve the spare capacity placement problem in a span-restorable network [4], [11], [20]....
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...Issues related to the restoration mechanisms themselves are addressed in related works [1], [2], [4], [21], [27]....
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Proceedings Article•
01 Jan 1987
180 citations