| 1. |
- Billenahalli, Shreejith, et al.
(författare)
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A wavelength sharing and assignment heuristic to minimize the number of wavelength converters in resilient WDM networks
- 2009
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Ingår i: Proceedings of the 2009 7th International Workshop on the Design of Reliable Communication Networks, DRCN 2009. - 9781424450473 ; , s. 319-326
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Konferensbidrag (refereegranskat)abstract
- With the successful introduction of reconfigurable optical add-drop multiplexers (ROADMs) and related technologies, WDM networks are now growing in the number of optical nodes, wavelengths, and lambda services supported. In addition, shared path protection mechanisms - whereby lambda services are allowed to share protection wavelength channels - are possible at the optical (WDM) layer. Efficient strategies must be devised to both determine the set of services that must share a common protection wavelength channel and assign wavelengths to every service. One objective of these strategies is to minimize the total number of wavelength converters (WCs), which are required every time the wavelength continuity constraint cannot be met. This paper presents a scalable and efficient heuristic, whose goal is to minimize the number of WCs in resilient WDM networks supporting static sets of shared path protection lambda services. The heuristic comprises a set of polynomial algorithms that are executed sequentially to obtain a sub-optimal solution. In small size instances of the problem, the heuristic is compared against the optimal solution obtained from ILP formulation. For large size instances - tens of thousands of lambda services and hundreds of nodes - the heuristic yields an average number of WCs that is close to be linear in the number of services, despite the fact that the wavelength sharing factor increases.
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| 2. |
- Razo, Miguel, et al.
(författare)
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Design of hierarchical WDM networks
- 2009
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Ingår i: 2009 Asia Communications and Photonics Conference and Exhibition, ACP 2009. - Washington, D.C. : OSA. - 9781557528773
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Hierarchical (multi-core) Wavelength Division Multiplexing (WDM) networks present a challenging design problem to the network designer who wishes to establish all-optical circuits end-to-end and across multiple network cores. Due to the nature of the hierarchical structure and its traffi distribution, it is likely that the inner core requires more capacity when compared to the capacity required by the metro cores, which are individually connected to the inner core. This capacity mismatch cannot be addressed by assigning distinct transmission rates to each core, as this solution would result in using electronic time division add-drop multiplexer to interconnect the traffi across cores with distinct rates. An alternative solution to addressing the capacity mismatch between WDM metro and inner core is explored in this paper, which is based on a limited number of wavelengths (a subset of the full set) being used in the metro core, when compared to the full set of wavelengths being used in the inner core. Two available architectures are presented in the paper, discussing their respective advantages and disadvantages.
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| 3. |
- Razo, Miguel, et al.
(författare)
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Limiting Wavelength Converter Usage in Resilient WDM Networks
- 2010
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Ingår i: 2010 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS. - 9781424464043
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Konferensbidrag (refereegranskat)abstract
- A careful wavelength assignment (WA) to lambda services must be performed to reduce the total number of wavelength converters (WCs) that are required when the wavelength continuity constraint cannot be met in wavelength division multiplexing (WDM) networks. With the successful introduction of reconfigurable optical add-drop multiplexers (ROADMs), WDM networks are now growing in size, both in the number of optical nodes and the number of wavelengths supported. Fast and memory efficient WA algorithms are required to design cost effective large WDM networks. This paper presents a scalable and efficient WA heuristic algorithm aimed at reducing the total number of WCs that are required in (large) WDM networks bearing static lambda services. The WA algorithm is applied to both unprotected and (dedicated) protected lambda services. In the latter case, the wavelength continuity constraint between the working and protection path of a lambda service is taken into consideration when non-tunable optical transceivers are employed.
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| 4. |
- Razo, Miguel, et al.
(författare)
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The PlaNet-PTN Module : a Single Layer Design Tool for Packet Transport Networks
- 2009
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Ingår i: CAMAD. - 9781424435326 ; , s. 74-78
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Konferensbidrag (refereegranskat)abstract
- PlaNet is a multilayer network planning tool developed at the University of Texas at Dallas. This paper illustrates some of the features of PlaNet-PTN, one of the modules available in the PlaNet tool. PlaNet-PTN can be used to design and plan a single layer packet transport network (PTN). Quality of protection, routing constraints, minimization of the network equipment cost, and user’s desired run time of the tool are just some examples of the features available in PlaNet. As shown in the paper, the PlaNet-PTN planning module is able to provide, among others, optimization of Label Switched Path (LSP) routes, link capacity placement, node and link equipment configuration.
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| 5. |
- Tang, Limin, et al.
(författare)
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A customizable two-step framework for general equipment provisioning in Optical Transport Networks
- 2011
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Ingår i: ONDM 2011 - 15th Conference on Optical Network Design and Modeling. - 9783901882425
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Konferensbidrag (refereegranskat)abstract
- Optical Transport Network (OTN) is a standard approach to offering transport support to a variety of existing service technologies, e.g., ESCON, HDTV, GE, etc. Multiple service technologies can be concurrently multiplexed onto one common transport network, which offers hierarchical transmission rate wrappers physically supported by Wavelength Division Multiplexing (WDM) lambda channels. Algorithms to perform grooming and routing in OTN are expected to be complicated due to the large number of grooming options that are available in the standard. In addition, these algorithms are likely to be designed by the vendor engineers, who have full knowledge of the grooming, switching, and routing capabilities of their own equipment. Yet the authors of this paper propose a relatively simple algorithm framework for equipment provisioning in OTN that can be customized by the network designer. Taking advantage of the multi-rate nature of supported services in OTN, traffic demands can be divided into two groups based on their bandwidth requirement. Demands with bandwidth request below a bandwidth threshold are placed on newly provisioned resources and demands with bandwidth request above the threshold are preferably routed over already provisioned resources. The latter procedure is more time consuming but yields more efficient traffic grooming when compared to the former procedure. The bandwidth threshold can be set by the network designer either to decrease running time of the algorithm, or conversely, to increase optimality of the solution found.
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| 6. |
- Tang, Limin, et al.
(författare)
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Computing alternate multicast trees with maximum latency guarantee
- 2010
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Ingår i: 2010 International Conference on High Performance Switching and Routing, HPSR 2010. - 9781424469710 ; , s. 82-87
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Konferensbidrag (refereegranskat)abstract
- The growing demand for online media content delivery and multi-player gaming is expected to increase the amount of multicast service requests in both public and private networks. Careful traffic engineering of multicast service requests is becoming increasingly essential, as establishing the lowest cost tree, e.g., shortest path tree, in the network for every individual multicast request does not always ensure a global optimization. In this paper, the authors investigate the use of alternate tree routing, according to which multiple sub-optimal tree candidates are computed for each multicast request. When performing global routing optimization, each request is then assigned one of the tree candidates, in a way that yields the desired result, e.g., to minimize the number of (active) links that are required in the network to bear the entire set of requests. A key component of the investigated approach is the timely construction of the set of alternate trees for every given root and destination set. An algorithm is proposed to compute multiple sub-optimal tree candidates with a guaranteed upper bound on the maximum end-to-end transmission latency. The algorithm builds on the widely used K shortest path algorithm, generalizing the technique of computing K candidate shortest paths to obtain a number of candidate sub-optimal trees with desirable properties. Simulation experiments obtained for a multi-protocol label switching (MPLS) traffic engineering network are discussed to investigate the effectiveness, performance, and scalability of the proposed algorithm.
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| 7. |
- Tang, Limin, et al.
(författare)
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The PlaNet-OTN module : A double layer design tool for optical transport networks
- 2009
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Ingår i: ICTON 2009: 11th International Conference on Transparent Optical Networks. - 9781424448265 ; , s. 744-748
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- PlaNet is a multilayer network planning tool designed and developed at the University of Texas at Dallas. This paper illustrates some of the features of PlaNet-OTN, one of the modules available in the PlaNet tool. PlaNet-OTN can be used to design and plan an optical transport network (OTN), which is comprised of two layers: wavelength division multiplexing (WDM) layer, which deals with wavelength allocation and routing of WDM services, and optical transport network (OTN) layer, which deals with optical data unit (ODU) equipment provisioning and routing of ODU services. Features of the PlaNet-OTN module include: multiple protection schemes and routing constraints for both WDM and ODU services, network equipment cost minimization, load balancing of traffic, and user-controlled run time of the optimization process. As shown in this paper, the PlaNet-WDM and OTN layers and optimizing equipment usage, hence reducing the cost of the whole network.
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| 8. |
- Vardhan, Hars, et al.
(författare)
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Finding a simple path with multiple must-include nodes
- 2009
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Ingår i: 2009 IEEE INTERNATIONAL SYMPOSIUM ON MODELING, ANALYSIS & SIMULATION OF COMPUTER AND TELECOMMUNICATION SYSTEMS (MASCOTS). - 9781424449262 ; , s. 607-609
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Konferensbidrag (refereegranskat)abstract
- This paper presents an algorithm to find a simple path in the given network with multiple must-include nodes in the path. The problem of finding a path with must-include node(s) can be easily found in some special cases. However, in general, including multiple nodes in the simple path has been shown to be NP-Complete. This problem may arise in network areas such as forcing the route to go through particular nodes, which have wavelength converter (optical), have monitoring provision (telecom), have gateway functions (in OSPF) or are base stations (in MANET). In this paper, a heuristic algorithm is described that follows divide and conquer approach, by dividing the problem in two subproblems. It is shown that the algorithm does not grow exponentially in this application and initial re-ordering of the given sequence of must-include nodes can improve the result. The experimental results demonstrate that the algorithm successfully computes in reasonable time.
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