| 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. |
- Cerutti, Isabella, et al.
(författare)
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Plug and Play Networking with Optical Nodes
- 2006
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Ingår i: ICTON 2006. ; , s. 133-138
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Plug and play optical (PPO) nodes may be used to facilitate the deployment of optical networks. PPO nodes must be able to learn about the signal propagation properties of the surrounding optical fibers and make their wavelength routing decisions based on the collected data. This paper discusses what are the open challenges that must be overcome to provide cost effective and performing ad hoc networking solutions based on PPO nodes.
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| 3. |
- Cerutti, Isabella, et al.
(författare)
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Plug and play optical nodes : network functionalities and built-in fiber characterization techniques
- 2007
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Ingår i: Journal of Optical Networking. - 1536-5379. ; 6:6, s. 642-653
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Tidskriftsartikel (refereegranskat)abstract
- \textlessp\textgreater\textlessa href$=$"http://www.osa-jon.org/virtual_issue.cfm?vid$=$26"\textgreaterFeature Issue on Photonics in Switching\textless/a\textgreater\textless/p\textgreaterPlug and play optical (PPO) nodes may be used to facilitate the deployment of optical networks. PPO nodes must be able to learn about the signal propagation properties of the surrounding optical fibers and make their wavelength-routing decisions based on the collected data. We discuss what are the open challenges that must be overcome to provide optical networking solutions based on cost-effective PPO nodes. Three possible PPO node hardware architectures with trade-offs in complexity, cost, and functionality are presented along with their built-in fiber characterization techniques.
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| 4. |
- Das, Shovan, et al.
(författare)
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A Link State Advertisement Protocol for Optical Transparency Islands
- 2007
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Ingår i: 2007 WORKSHOP ON HIGH PERFORMANCE SWITCHING AND ROUTING. ; , s. 1-6
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Konferensbidrag (refereegranskat)abstract
- Plug and play optical (PPO) nodes enable fast, re-configurable, and flexible ad hoc deployment of optical networks. Once plugged, the PPO nodes provide all-optical circuits between client nodes to alleviate the electronic processing bottleneck of high speed networks. To offer these wavelength routing functionalities to client nodes the PPO nodes must self-adjust to possible changes of the optical physical topology and fiber propagation characteristics. To discover such changes the PPO nodes must make use of a link state advertisement (LSA) protocol that is scalable in the number of plugged PPO nodes. This paper describes a scalable LSA protocol with constrained message flooding to match the limited propagation reach of the optical signal, i.e., the PPO node transparency island (TI). Scalability is thus achieved naturally by limiting the link state advertisement scope to only those PPO nodes that need to receive the link updates. As discussed in the paper, the proposed protocol appears to be a viable solution when the TI size is relatively small, e.g., in optical networks without signal regeneration.
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| 5. |
- Das, Shovan, et al.
(författare)
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Optical Corridor Routing Protocols
- 2007
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Ingår i: ICTON 2007. ; , s. 188-192
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The scalability of routing and resource advertisement protocols is a key issue in large optical networks. A commonly used solution is based on the hierarchical approach adopted in IP/MPLS-TE networks, i.e., multiple areas or autonomous systems are pre-established to contain the geographical scope of the resource advertisement protocols and the related routing information. With arbitrarily pre-established areas, routing decision might be sub-optimal. Thus, special care must be paid by the network designer to subdivide effectively the network into areas. This paper presents and discusses an alternative routing technique that attempts to improve both optimality and scalability of routing and resource advertisement protocols without requiring the use of manually pre-established areas.
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| 6. |
- Monti, Paolo
(författare)
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Achieving reliable networking for the generic autonomous platform for sensor systems : (GAP4S)
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Networks of wireless integrated sensors are often used to monitorparameters distributed in the environment. These parameters arerelated to a variety of applications such as security, patientmonitoring, chemical and biological hazard detection. Some solutionsrely on replaceable batteries with a limited life-time to providelong-term sensor operation. Others envision short transmission rangesensors (few meters) that harvest their energy from variousenvironmental sources (e.g., solar, vibrations, acoustic noise). TheGeneric Autonomous Platform for Sensors (GAP4S) project explores anapproach for wireless sensors that is complementary to these andother pre-existing solutions. In GAP4S, the wireless sensor micro-battery is remotely rechargedvia a microwave signal. Medium transmission ranges in the tens tohundreds of meters are possible. Within these wireless transmissionranges, a base-station collects data transmitted by the sensors andacts as the access point to a wider (typically wired) communicationnetwork, e.g., the Internet. The authorized user can, therefore,remotely connect to, monitor, and manage both the sensor network andthe individual sensors. An essential component of GAP4S is itsend-to-end network reliability solution, which ensures the deliveryof data generated at the sensor to the interested user across boththe wireless and wired segments. This dissertation investigates ways to achieve reliable networkingfor GAP4S over both the wireless and the wired segments. A speciallydesigned solution is provided in each segment. In the wireless segment, error-free transmissions from the sensornode to the base-station is achieved using automatic repeat request(ARQ) protocols at layer 2. Two classes of ARQ protocols aredesigned and compared. The first is the conventional ARQ, wherebythe data frame is retransmitted by the originating sensor untilsuccessfully received by the base-station. The second class takesadvantage of cooperative radio communications, wherebymultiple neighboring sensor nodes may combine their efforts duringthe retransmission process. The ARQ protocols are compared in termsof their saturation throughput, i.e., the maximum data flow that thesensor node can sustain constrained to the available energy amount.In a variety of scenarios --- current and future expected circuitenergy consumptions --- the cooperative ARQ protocols may more thandouble the saturation throughput when compared to conventional ARQprotocols. Equivalently, it can be said that the energy required tooperate the system may be reduced by half. In the wired segment, fault tolerant networking is achieved by meansof protection switching at layer 3. Given the increasinglywidespread use of Wavelength Division Multiplexed (WDM) backbonenetworks, the protection switching scheme is designed to operate inconjunction with WDM. Optical circuits are made reliable by means ofa Shared Path Protection (SPP) switching scheme. The SPP scheme isgeneralized to guarantee Differentiated levels of Reliability (DiR)to the user. In the SPP-DiR combined scheme the desired level ofreliability may be guaranteed while minimizing the required networkresources, i.e., wavelengths. This feature makes it possible tosupport more optical connections and users when compared to otherexisting protection switching schemes.
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| 7. |
- Monti, Paolo, et al.
(författare)
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Optimized transmission power levels in a cooperative ARQ protocol for microwave recharged wireless sensors
- 2005
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Ingår i: Communications, 2005. ICC 2005. 2005 IEEE International Conference on. - : IEEE. - 0780389387 ; , s. 3290-3294
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Konferensbidrag (refereegranskat)abstract
- The generic autonomous platform for sensor systems (GAP4S) is a maintenance-free wireless sensor network in which the sensor node battery does not need to be replaced. Power is delivered to the sensor node via a microwave signal that is radiated by a base-station. The base-station also acts as the entry point to a wider communication network, e.g., the Internet. The paper describes an automatic repeat request (ARQ) protocol that may be used in GAP4S to yield reliable and fair data transmission from the sensor nodes to the base-station. The protocol takes advantage of cooperative communication, whereby neighboring sensor nodes help during the retransmission process. The transmission power level is optimized at each sensor node to increase the saturation throughput of the ARQ protocol.
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| 8. |
- Razo, Miguel, et al.
(författare)
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Demonstrating the PlaNet-PTN Module : a Single Layer Design Tool for Packet Transport Networks
- 2009
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Ingår i: IEEE Conference on Computer Communications (INFOCOM).
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Konferensbidrag (refereegranskat)abstract
- PlaNet is a multilayer network planning tool developed at the University of Texas at Dallas. This demo willillustrate some of the features of PlaNet-PTN, one of the modulesavailable in the PlaNet tool. PlaNet-PTN can be used to designand plan a single layer packet transport network (PTN). Qualityof protection, routing constraints, minimization of the networkequipment cost, and user’s desired run time of the tool are justsome examples of the features available in PlaNet. As shown inthe demo, the PlaNet-PTN planning module is able to provide,among others, optimization of LSP-tunnel routes, link capacityplacement, node and link equipment configuration.
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| 9. |
- Razo, M., et al.
(författare)
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Design of hierarchical WDM networks
- 2009
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Ingår i: Network Architectures, Management, and Applications VII. - : SPIE - International Society for Optical Engineering. - 9780819480354 ; , s. 76331I-
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Konferensbidrag (refereegranskat)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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| 10. |
- 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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