Solving Routing and Spectrum Allocation Related Optimization Problems: From Off-Line to In-Operation Flexgrid Network Planning

Velasco, Luis; Castro, Alberto; Ruiz, Marc; Junyent, G.

doi:10.1109/jlt.2014.2315041

Cited by 90 publications

(50 citation statements)

References 25 publications

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“…1, where a 100 Gb/s light-tree is set-up in Fig. 1a connecting the switch in DC-A to the switches in DCs B, C, and D. It is clear that, similarly as for p2p connections [6], specific p2mp routing and spectrum allocation (RSA) algorithms, similar to the one proposed in [7], are needed to compute the route from the source to every leaf in the connection and allocate a contiguous and continuous spectrum slot. The resulting VNT consists in a single p2mp virtual link connecting the source switch to all the leaves (Fig.…”

Section: Approaches To Serve Multicast Connectivity Servicesmentioning

confidence: 92%

“…The feasibility of creating lighttrees in flexgrid networks was demonstrated in [4]. Authors in [5] compared the performance of using light-trees against p2p optical connections (lightpaths) and showed that, although resource utilization is improved using light-trees, its limitation lie in the spectrum continuity constraint [6] and the connections' length. Another approach to improve resource utilization is creating a virtual network topology (VNT) that can be used to serve both p2p and p2mp connections.…”

Section: Introductionmentioning

confidence: 99%

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Experimental Assessment of ABNO-Driven Multicast Connectivity in Flexgrid Networks

Gifre

Paolucci

Dios

et al. 2015

J. Lightwave Technol.

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Abstract-The increasing demand of internet services is pushing cloud services providers to increase the capacity of their data centers (DC) and create DC federations, where two or more cloud providers interconnect their infrastructures. As a result of the huge capacity required for the inter-DC network, the flexgrid optical technology can be used. In such scenario, applications can run in DCs placed in geographically distant locations and hence, multicast-based communication services among their components are required. In this paper, we study two different approaches to provide multicast services in multi-layer scenarios assuming that the optical network is based on the flexgrid technology: i) establishing a point-to-multipoint optical connection (light-tree) for each multicast request, and ii) using a multi-purpose virtual network topology (VNT) to serve both unicast and multicast connectivity requests. When that VNT is not able to serve an incoming request as a result of lack of capacity, it is reconfigured to add more resources. A control plane architecture based on the Applications-based Network Operations (ABNO) one, currently being standardized by the IETF, is presented; workflows are proposed and PCEP extensions are studied for the considered approaches. The experimental validation is carried-out on a testbed set-up connecting Telefonica, CNIT, and UPC premises.

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Section: Approaches To Serve Multicast Connectivity Servicesmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Experimental Assessment of ABNO-Driven Multicast Connectivity in Flexgrid Networks

Gifre

Paolucci

Dios

et al. 2015

J. Lightwave Technol.

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“…The MILP model is based in a link-path formulation for RSA [4] where a set of routes is computed for each of the candidate demands to be re-optimized. The K(d) set is computed using eq.…”

Section: B Milp Formulationmentioning

confidence: 99%

“…To that end, the Path Computation Element (PCE) [2] or a software-defined networking (SDN) controller [3] can be deployed. In flexgrid networks, path computation consists in solving the routing and spectrum allocation (RSA) problem [4], which involves two different constraints: the continuity constraint to ensure that the allocated slot is the same along the links in the route and the contiguity constraint to guarantee that the slices defining the slot are contiguous in the spectrum.…”

Section: Introductionmentioning

confidence: 99%

First Experimental Assessment of ABNO-Driven In-Operation Flexgrid Network Re-Optimization

Gifre

Paolucci

Velasco

et al. 2015

J. Lightwave Technol.

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Abstract-Traffic affected by link failures can be recovered using path restoration schemes. In dynamically operated networks provided with a control plane, restoration algorithms run in a centralized element, such as the Path Computation Element (PCE). To increase traffic restorability in flexgrid networks, multiple paths, sub-connections, can be used to restore every single affected connection. However, the multipath restoration scheme might result in a poor resource utilization entailing a lesser grade of service. In-operation network planning algorithms can be used to mitigate this problem once the failed link is repaired; we propose solving the so-called multipath after failure repair optimization problem (MP-AFRO) to reduce sub-connections count by aggregating those belonging to the same original connection and re-routing the resulting connection to release spectral resources. The MP-AFRO problem is modelled using a Mixed Integer Linear Program (MILP) formulation. In view of the complexity of the model and the limited time to solve the problem, we propose a heuristic algorithm that provides a good trade-off between complexity and optimality. The performance on the MP-AFRO heuristic is firstly validated by simulation. Next, the heuristic algorithm is deployed inside an in-operation planning tool in the form of back-end PCE (bPCE) inside the Application-based Network Operations (ABNO) architecture controlling a network; the bPCE is connected to the centralized active stateful PCE. MP-AFRO is experimentally demonstrated using a distributed field trial test-bed connecting the premises of Telefonica (Madrid), CNIT (Pisa), and UPC (Barcelona).

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“…Klinkowski et al (2016), Ruiz et al (2013) or Velasco et al (2014) focus on efficient methods to solve the problem of allocating unicast demands in an unprotected EON. It is worth mentioning that Ruiz et al (2013) and Velasco et al (2014) apply the CG technique directly to solve RSA while Klinkowski et al (2016) propose a branch-and-price approach that incorporates, among others, CG. Next, focus on optimization of anycast traffic in an unprotected EON wherein they model an anycast demand as a one-directional transmission from a DC to the client node.…”

mentioning

confidence: 99%

A column generation technique for routing and spectrum allocation in cloud–ready survivable elastic optical networks

Goścień

Walkowiak

2017

International Journal of Applied Mathematics and Computer Science

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Driven by increasing user requirements and expectations, the fast development of telecommunications networks brings new challenging optimization problems. One of them is routing and spectrum allocation (RSA) of three types of network flows (unicast, anycast, multicast) in elastic optical networks (EONs) implementing dedicated path protection (DPP). In the paper, we model this problem as integer linear programming (ILP) and we introduce two new optimization approaches-a dedicated heuristic algorithm and a column generation (CG)-based method. Then, relying on extensive simulations, we compare algorithm performance with reference methods and evaluate CG efficiency in detail. The results show that the proposed CG method significantly outperforms reference algorithms and achieves results very close to optimal ones (the average distance to optimal results was at most 2.1%).

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Solving Routing and Spectrum Allocation Related Optimization Problems: From Off-Line to In-Operation Flexgrid Network Planning

Cited by 90 publications

References 25 publications

Experimental Assessment of ABNO-Driven Multicast Connectivity in Flexgrid Networks

Experimental Assessment of ABNO-Driven Multicast Connectivity in Flexgrid Networks

First Experimental Assessment of ABNO-Driven In-Operation Flexgrid Network Re-Optimization

A column generation technique for routing and spectrum allocation in cloud–ready survivable elastic optical networks

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