Survivable IP/MPLS-Over-WSON Multilayer Network Optimization

Ruiz, Marc; Pedrola, Oscar; Velasco, Luis; Careglio, Davide; Fernández-Palacios, Juan Pedro; Junyent, G.

doi:10.1364/jocn.3.000629

Cited by 52 publications

(31 citation statements)

References 19 publications

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“…To find the objective cost of SBVTs, we solved the IPoF problem for several values of f assuming that the cost of SBVTs is equal to that of the BVTs with the same capacity and compared solutions' CAPEX using equation (1). Note that, by definition, Δcost ≥ 0; when Δcost = 0 the cost of a SBVT and a BVT are the same.…”

Section: Ip/mpls-over-flexgrid Dimensioning (Ipof) Problemmentioning

confidence: 99%

“…In addition, a reduced number of interconnection routers support inter-operator connections. For efficiency and reach reasons, IP/MPLS networks are usually designed on top of optical networks [1]. The maturity of the flexgrid technology [2] providing fine spectral granularity makes bandwidth-variable optical cross-connects (BV-OXCs) based on that technology the candidates to be deployed in operators networks in the near future ( Fig.…”

Section: Introductionmentioning

confidence: 99%

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Finding an Objective Cost for Sliceable Flexgrid Transponders

Velasco

Dios

López

et al. 2014

Optical Fiber Communication Conference

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Abstract:We analyze the objective cost of SBVTs as a function of the traffic conveyed by IP/MPLS-over-flexgrid networks. Optimal results show that cost increment with respect to BVTs is related to the aggregation level. IntroductionNational IP/MPLS networks receive IP traffic from access networks and perform aggregation and routing. To minimize the number of ports a router hierarchy consisting of edge routers performing aggregation and transit routers providing routing flexibility is typically created. In addition, a reduced number of interconnection routers support inter-operator connections. For efficiency and reach reasons, IP/MPLS networks are usually designed on top of optical networks [1]. The maturity of the flexgrid technology [2] providing fine spectral granularity makes bandwidth-variable optical cross-connects (BV-OXCs) based on that technology the candidates to be deployed in operators networks in the near future ( Fig. 1).To take advantage from the mix of optical connection (lightpath) bitrates that can be created on flexgrid networks, bandwidth-variable optical transponders (BVT) can be used. The main advantages of BVTs with respect fixed transponders (FTP) are: i) the used spectrum width is a function of the actual lightpath's bitrate and ii) procurement and inventory is simplified, thus reducing operational expenditures (OPEX). However, when the associated lightpath's bitrate is low, BVT's capacity is wasted, thus increasing capital expenditures (CAPEX). For instance, imagine a 400Gb/s BVT currently used for a 100Gb/s lightpath. Notwithstanding, to ensure that the network can support the traffic forecast for the years to come, deploying transponders with lower capacity might also involve increasing CAPEX to replace those transponders in the near future. The answer to that dilemma is sharing each BVT among several lightpaths, as proposed in [3]. A sliceable bandwidth-variable optical transponder (SBVT) is thus a BVT that can be shared by multiple (f) lightpaths.We assume that IP/MPLS routers are connected to wavelength selective switches (WSS) in the local BV-OXC, similarly to the architecture in [4]. Virtual topologies are created by connecting IP/MPLS routers among them through lightpaths established in the flexgrid optical layer. IP/MPLS routers are dimensioned considering two main parameters: forwarding capacity and number of slots available in the chassis, which limits the number of cards that can be installed. Since the bitrate of the MPLS flows resulting from aggregating IP client flows at edge routers is usually low, those routers are connected to few transit routers and BVTs or FTPs are usually preferred. However, the connectivity of transit routers among other transit and interconnection routers is usually high, creating an almost full-mesh virtual topology among them (Fig. 2). Therefore, SBVTs could provide advantages by reducing the number of cards to be installed on transit and interconnection routers, thus saving CAPEX since cheaper routers could need to be installed.In this paper, ...

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Section: Ip/mpls-over-flexgrid Dimensioning (Ipof) Problemmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Finding an Objective Cost for Sliceable Flexgrid Transponders

Velasco

Dios

López

et al. 2014

Optical Fiber Communication Conference

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“…It is based on the recently proposed BRKGA metaheuristic [9] which has proved to effectively solve optimization problems, in particular, network related problems such as routing in single layer and multilayer optical networks [11].…”

Section: Heuristic Algorithmsmentioning

confidence: 99%

Path-based recovery in flexgrid optical networks

Castro

Ruiz

Velasco

et al. 2012

2012 14th International Conference on Transparent Optical Networks (ICTON)

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1With the advent of flexgrid optical networks, the rigid wavelength-division multiplexing (WDM) technology will be enhanced by providing better spectrum efficiency and flexibility. In those future flexible optical networks, optical connections (lightpaths) can allocate a flexible number of spectrum slices, also known as frequency slots, so to match better with its requested bitrate. In this paper, we propose to take advantage of this flexible spectrum allocation in recovery mechanisms to be triggered when a failure occurs to provide recovery of part of the requested bitrate, i.e. the allocated spectrum by backup lightpaths could be lower than that of the working lightpaths provided that client service level agreements are fulfilled. This reduction in the recovered bitrate (bitrate squeezing) allows optimizing the use of network capacity. We propose path-based recovery alternatives, based on protection and restoration, specially designed for flexgrid networks. The performance of the proposed recovery mechanisms is exhaustively evaluated on a national reference network. Keywords: Flexgrid Optical Networks, Bitrate squeezed recovery, Network Optimization. INTRODUCTIONFuture flexgrid optical networks featuring flexible and elastic spectrum allocation [1], [2] are attracting high interest from network operators and the research community in general as a result of its higher spectrum efficiency and flexibility with respect to wavelength switched optical networks (WSON) [3], based on the wavelength division multiplexing (WDM) technology. In flexgrid optical networks, the available optical spectrum is divided into frequency slots of fixed spectrum width, e.g. 25GHz or 12.5GHz. Optical connections (lightpaths) can use a variable number of these slots, which is a function of the requested bitrate, the modulation format used, and the slot width.Owing to the huge bitrate associated to each established path, recovery schemes need to be used to guarantee that the associated client connectivity demand continue being served even in case of failures [4]. As in WSON, recovery can be provided by either protection, where the failed working path is substituted by a pre-assigned backup one, or restoration, which is based on rerouting the working path. Backup lightpaths use resources, i.e. each of the frequency slots in a fiber link, that are dedicated to protect a single working path, or they can be shared to provide protection to multiple working lightpaths. As a consequence, the former scheme is called dedicated path protection (DPP) and the latter shared path protection (SPP).Although protection schemes reserve resources to guarantee that all protected lightpaths are recovered in case of any single failure, SPP provides better resource utilization than DPP due to spare resources are shared among several working lightpaths. On the other hand, restoration is the most efficient scheme since resources are only allocated after a failure impacts a working path and, for this very reason, no guarantees of recovery are given in dy...

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“…Multilayer IP/MPLS-over-DWDM networks [1] take advantage of grooming to achieve high spectrum efficiency, filling the gaps between users' flows and wavelength channels' capacity.…”

Section: Introductionmentioning

confidence: 99%