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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2018., This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections., Cataloged from student-submitted PDF version of thesis., Includes bibliographical references (pages 203-211)., The rapid maturation of the Internet of Things and the advent of the Smart City present an opportunity to revolutionize emergency services as both reactive and preventative. A well-designed Smart City will synthesize data from multiple heterogeneous sensors, relay information to and between emergency responders, and potentially predict and even preempt crises autonomously. In this thesis, we identify distinctive characteristics and networking requirements of the Smart City and then identify and evaluate the architectural constructs necessary to enable time-critical Smart City operations. Two major goals inform our architectural analysis throughout this work. First, critical traffic must be served within a specified delay without excessive throttling of non-critical traffic. Second, surges in critical traffic from a geographically-concentrated region must be handled gracefully. To achieve these goals, we motivate, evaluate, and finally recommend: 1.) connecting local area Smart City networks to the existing metropolitan area networking infrastructure, 2.) standing up a dedicated municipal data center inside the metropolitan area served by the Smart City, 3.) deploying a contention-based priority reservation MAC protocol that guarantees latency and throughput for some specified maximum number of critical users per wireless access point, 4.) configuring MAN routers to provide non-preemptive priority service at output queues to critical Smart City traffic, 5.) offering dedicated optical paths from edge routers to the municipal hub in order to effectively form a virtual star topology atop a MAN mesh and significantly reduce switching delays in the network, 6.) processing select applications at dedicated fog servers adjacent to edge routers in order to reduce upstream congestion in the MAN, and 7.) setting up a network orchestration engine that monitors traffic into and out of the Smart City data center in order to preemptively detect critical traffic surges and to direct, by Manishika Agaskar., Ph. D.

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2018., This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections., Cataloged from student-submitted PDF version of thesis., Includes bibliographical references (pages 203-211)., The rapid maturation of the Internet of Things and the advent of the Smart City present an opportunity to revolutionize emergency services as both reactive and preventative. A well-designed Smart City will synthesize data from multiple heterogeneous sensors, relay information to and between emergency responders, and potentially predict and even preempt crises autonomously. In this thesis, we identify distinctive characteristics and networking requirements of the Smart City and then identify and evaluate the architectural constructs necessary to enable time-critical Smart City operations. Two major goals inform our architectural analysis throughout this work. First, critical traffic must be served within a specified delay without excessive throttling of non-critical traffic. Second, surges in critical traffic from a geographically-concentrated region must be handled gracefully. To achieve these goals, we motivate, evaluate, and finally recommend: 1.) connecting local area Smart City networks to the existing metropolitan area networking infrastructure, 2.) standing up a dedicated municipal data center inside the metropolitan area served by the Smart City, 3.) deploying a contention-based priority reservation MAC protocol that guarantees latency and throughput for some specified maximum number of critical users per wireless access point, 4.) configuring MAN routers to provide non-preemptive priority service at output queues to critical Smart City traffic, 5.) offering dedicated optical paths from edge routers to the municipal hub in order to effectively form a virtual star topology atop a MAN mesh and significantly reduce switching delays in the network, 6.) processing select applications at dedicated fog servers adjacent to edge routers in order to reduce upstream congestion in the MAN, and 7.) setting up a network orchestration engine that monitors traffic into and out of the Smart City data center in order to preemptively detect critical traffic surges and to direct, by Manishika Agaskar., Ph. D.

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2018., This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections., Cataloged from student-submitted PDF version of thesis., Includes bibliographical references (pages 203-211)., The rapid maturation of the Internet of Things and the advent of the Smart City present an opportunity to revolutionize emergency services as both reactive and preventative. A well-designed Smart City will synthesize data from multiple heterogeneous sensors, relay information to and between emergency responders, and potentially predict and even preempt crises autonomously. In this thesis, we identify distinctive characteristics and networking requirements of the Smart City and then identify and evaluate the architectural constructs necessary to enable time-critical Smart City operations. Two major goals inform our architectural analysis throughout this work. First, critical traffic must be served within a specified delay without excessive throttling of non-critical traffic. Second, surges in critical traffic from a geographically-concentrated region must be handled gracefully. To achieve these goals, we motivate, evaluate, and finally recommend: 1.) connecting local area Smart City networks to the existing metropolitan area networking infrastructure, 2.) standing up a dedicated municipal data center inside the metropolitan area served by the Smart City, 3.) deploying a contention-based priority reservation MAC protocol that guarantees latency and throughput for some specified maximum number of critical users per wireless access point, 4.) configuring MAN routers to provide non-preemptive priority service at output queues to critical Smart City traffic, 5.) offering dedicated optical paths from edge routers to the municipal hub in order to effectively form a virtual star topology atop a MAN mesh and significantly reduce switching delays in the network, 6.) processing select applications at dedicated fog servers adjacent to edge routers in order to reduce upstream congestion in the MAN, and 7.) setting up a network orchestration engine that monitors traffic into and out of the Smart City data center in order to preemptively detect critical traffic surges and to direct, by Manishika Agaskar., Ph. D.

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2017., Cataloged from PDF version of thesis., Includes bibliographical references (pages 127-132)., In this thesis, we propose a hybrid flow network architecture for future data center. The hybrid flow architecture has its origins in the early 1990s with studies on all-optical networks and fiber-optical computer networks. Research in optical flow switching has spanned over two decades. Our contribution to the study of all-optical networks is on the performance of hybrid flow data center networks. We compare the delay performance of hybrid flow architectures and traditional packet switched networks in future data center. We present a simplified data center traffic model, where data center traffic is categorized into mice traffic and elephant flows. The electronic packet switched architecture allows for low overhead and complexity for small transactions. However, mice traffic suffers as the size, fraction, and arrival rates of elephant flows increase. In the hybrid flow architecture, elephant flows are transmitted on an all-optical flow-switched data plane, where wavelength channels are reserved for the duration of a flow. In addition, the hybrid flow architecture allows for the dynamic allocation of optical wavelengths. In electronic packet switched networks, wavelength assignments are static, where traditional networking protocols do not consider the optical domain in routing decisions. We show that the hybrid flow architecture allows for superior delay performance compared to the electronic packet switched architecture as data rates and data volume increase in future data center networks., by Henna Huang., Ph. D.

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2017., Cataloged from PDF version of thesis., Includes bibliographical references (pages 127-132)., In this thesis, we propose a hybrid flow network architecture for future data center. The hybrid flow architecture has its origins in the early 1990s with studies on all-optical networks and fiber-optical computer networks. Research in optical flow switching has spanned over two decades. Our contribution to the study of all-optical networks is on the performance of hybrid flow data center networks. We compare the delay performance of hybrid flow architectures and traditional packet switched networks in future data center. We present a simplified data center traffic model, where data center traffic is categorized into mice traffic and elephant flows. The electronic packet switched architecture allows for low overhead and complexity for small transactions. However, mice traffic suffers as the size, fraction, and arrival rates of elephant flows increase. In the hybrid flow architecture, elephant flows are transmitted on an all-optical flow-switched data plane, where wavelength channels are reserved for the duration of a flow. In addition, the hybrid flow architecture allows for the dynamic allocation of optical wavelengths. In electronic packet switched networks, wavelength assignments are static, where traditional networking protocols do not consider the optical domain in routing decisions. We show that the hybrid flow architecture allows for superior delay performance compared to the electronic packet switched architecture as data rates and data volume increase in future data center networks., by Henna Huang., Ph. D.

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2017., Cataloged from PDF version of thesis., Includes bibliographical references (pages 127-132)., In this thesis, we propose a hybrid flow network architecture for future data center. The hybrid flow architecture has its origins in the early 1990s with studies on all-optical networks and fiber-optical computer networks. Research in optical flow switching has spanned over two decades. Our contribution to the study of all-optical networks is on the performance of hybrid flow data center networks. We compare the delay performance of hybrid flow architectures and traditional packet switched networks in future data center. We present a simplified data center traffic model, where data center traffic is categorized into mice traffic and elephant flows. The electronic packet switched architecture allows for low overhead and complexity for small transactions. However, mice traffic suffers as the size, fraction, and arrival rates of elephant flows increase. In the hybrid flow architecture, elephant flows are transmitted on an all-optical flow-switched data plane, where wavelength channels are reserved for the duration of a flow. In addition, the hybrid flow architecture allows for the dynamic allocation of optical wavelengths. In electronic packet switched networks, wavelength assignments are static, where traditional networking protocols do not consider the optical domain in routing decisions. We show that the hybrid flow architecture allows for superior delay performance compared to the electronic packet switched architecture as data rates and data volume increase in future data center networks., by Henna Huang., Ph. D.

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2014., Cataloged from PDF version of thesis., Includes bibliographical references (pages 175-178)., Optical Flow Switching (OFS) that employs agile end-to-end lightpath switching for users with large transactions has been shown to be cost-effective and energy-efficient. However, whether it is possible to coordinate lightpath switching and scheduling at a global scale on a per-session basis, and how the control plane and data plane performance correlate remained un-answered. In this thesis, we have addressed the network management and control aspect of OFS, and designed a network architecture enabling both a scalable control plane and an efficient data plane. We have given an overview of essential network management and control entities and functionalities. We focused on the scheduling problem of OFS because its processing power and generated control traffic increase with traffic demand, network size, and closely correlate with data network architecture, while other routine maintenance type of control plane functionalities contribute either a fixed amount or negligibly to the total efforts. We considered two possible Wide Area Network architectures: meshed or tunneled, and developed a unified model for data plane performance to provide a common platform for the performance comparison of the control plane. The results showed that with aggregation of at least two wavelengths of traffic and allowing about two transactions per wavelength to be scheduled to the future, the tunneled architecture provides comparable data plane performance as the meshed architecture. We have developed a framework to analyze the processing complexity and traffic of the control plane as functions of network architecture, and traffic demand. To guarantee lightpath quality in presence of physical-layer impairments, we developed models for quality of EDFA-amplified optical links and impairment-aware scheduling algorithms for two cases, a) the known worst case of channel quality is when there is no "On" channel in a fiber, and b) detailed channel configuration of a fiber is needed to determine c, by Lei Zhang., Ph. D.

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2014., Cataloged from PDF version of thesis., Includes bibliographical references (pages 175-178)., Optical Flow Switching (OFS) that employs agile end-to-end lightpath switching for users with large transactions has been shown to be cost-effective and energy-efficient. However, whether it is possible to coordinate lightpath switching and scheduling at a global scale on a per-session basis, and how the control plane and data plane performance correlate remained un-answered. In this thesis, we have addressed the network management and control aspect of OFS, and designed a network architecture enabling both a scalable control plane and an efficient data plane. We have given an overview of essential network management and control entities and functionalities. We focused on the scheduling problem of OFS because its processing power and generated control traffic increase with traffic demand, network size, and closely correlate with data network architecture, while other routine maintenance type of control plane functionalities contribute either a fixed amount or negligibly to the total efforts. We considered two possible Wide Area Network architectures: meshed or tunneled, and developed a unified model for data plane performance to provide a common platform for the performance comparison of the control plane. The results showed that with aggregation of at least two wavelengths of traffic and allowing about two transactions per wavelength to be scheduled to the future, the tunneled architecture provides comparable data plane performance as the meshed architecture. We have developed a framework to analyze the processing complexity and traffic of the control plane as functions of network architecture, and traffic demand. To guarantee lightpath quality in presence of physical-layer impairments, we developed models for quality of EDFA-amplified optical links and impairment-aware scheduling algorithms for two cases, a) the known worst case of channel quality is when there is no "On" channel in a fiber, and b) detailed channel configuration of a fiber is needed to determine c, by Lei Zhang., Ph. D.

Thesis: S.M., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2015., Cataloged from PDF version of thesis., Includes bibliographical references (pages 107-109)., Optical networking is a powerful means of communication in modem times of high bandwidth demands and high data speeds. While developments in optical networking continue to progress, however, the security implications they create have not yet caught up. In this thesis, we characterize a selection of damaging attacks against optical networks. By providing a detailed description of the attacks, we are also able to better understand their effects across the different layers of the network model. We also propose the current best practices for sensing and detection of these attacks when they occur, as well as mitigation techniques to limit the damage they incur. The attacks are not fully eliminated, however, and so we also identify remaining vulnerabilities these attacks can exploit. After characterizing the attacks, we propose a method for diagnosing attacks as they occur within a network given the analysis we have conducted. We also propose an algorithm for diagnosing attacks, as well as a monitoring system framework that relies on the establishment of autonomous zones of the network in order to efficiently limit damage and quarantine problem areas from the rest of the healthy network. This framework can be applied to a wide variety of network set-ups and topologies, with the ability to customize it to fit the needs of the system., by Antonia Lynn Feffer., S.M.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002., Includes bibliographical references (p. 95-96)., by Lillian Lei Dai., S.M.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002., Includes bibliographical references (p. 93-95)., by Richard Thommes., S.M.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002., Includes bibliographical references (p. 95-96)., by Lillian Lei Dai., S.M.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002., Includes bibliographical references (p. 90)., by Etty J. Shin., S.M.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002., Includes bibliographical references (p. 90)., by Etty J. Shin., S.M.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002., Includes bibliographical references (p. 95-96)., by Lillian Lei Dai., S.M.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002., Includes bibliographical references (p. 95-96)., by Lillian Lei Dai., S.M.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002., Includes bibliographical references (p. 90)., by Etty J. Shin., S.M.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002., Includes bibliographical references (p. 93-95)., by Richard Thommes., S.M.

Thesis (S.B. and M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1999., Includes bibliographical references (leaf 40)., by John L. Benko., S.B.and M.Eng.

Thesis (S.B. and M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1999., Includes bibliographical references (leaf 40)., by John L. Benko., S.B.and M.Eng.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2011., Cataloged from PDF version of thesis., Includes bibliographical references (p. 217-220)., Ever since optical fiber was introduced in the 1970s as a communications medium, optical networking has revolutionized the telecommunications landscape. With sustained exponential increase in bandwidth demand, innovation in optical networking needs to continue to ensure cost-effective communications in the future. Optical flow switching (OFS) has been proposed for future optical networks to serve large transactions in a cost-effective manner, by means of an all-optical data plane employing end-to-end lightpaths. Due to noise added in the transmission and detection processes, the channel has non-zero probability of bit errors that may corrupt the useful data or flows transmitted. In this thesis, we focus on the end-to-end reliable data delivery part of the Transport Layer protocol and propose effective and efficient algorithms to ensure error-free end-to-end communications for OFS. We will analyze the performance of each algorithm and suggest optimal algorithm(s) to minimize the total delay. We propose four classes of OFS protocols, then compare them with the Transport Control Protocol (TCP) over Electronic Packet Switching (EPS) and indicate under what values of the parameters: file size, bit error rate (BER), propagation delay and loading factor is OFS better than EPS. This analysis can serve as important guidelines for practical protocol designs for end-to- end data transfer reliability of OFS., by Rui Li., S.M.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2012., Cataloged from PDF version of thesis., Includes bibliographical references (p. 135-136)., In this work, we explore transport layer protocol design for an optical flow-switched network. The objective of the protocol design is to guarantee the reliable delivery of data files over an all-optical end-to- end flow-switched network which is modeled as a burst-error channel. We observe that Transport Control Protocol (TCP) is not best suited for Optical Flow-Switching (OFS). Specifically, flow control and fair resource allocation through windowing in TCP are unnecessary in an OFS network. Moreover TCP has poor throughput and delay performance at high transfer rates due to window flow control and window closing with missing or dropped packets. In OFS, flows are scheduled and congestion control is performed by a scheduling algorithm. Thus, we focus on defining a more efficient transport protocol for optical flow-switched networks that is neither a modification of TCP nor derived from TCP. The main contribution of this work is to optimize the throughput and delay performance of OFS using file segmentation and reassembly, forward error-correction (FEC), and frame retransmission. We analyze the throughput and delay performance of four example transport layer protocols: the Simple Transport Protocol (STP), the Simple Transport Protocol with Interleaving (STPI), the Transport Protocol with Framing (TPF) and the Transport Protocol with Framing and Interleaving (TPFI). First, we show that a transport layer protocol without file segmentation and without interleaving and FEC (STP) results in poor throughput and delay performance and is not well suited for OFS. Instead, we found that interleaving across a large file (STPI) results in the best theoretical delay performance, though the large code lengths and interleaver sizes in this scheme will be hard to implement. Also, in the unlikely case that a file experiences an uncorrectable error, STPI requires extra network resources equal to that of an entire transaction for file retransmission and adds to the delay of the transa, by Henna Priscilla Huang., S.M.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2012., Cataloged from PDF version of thesis., Includes bibliographical references (p. 135-136)., In this work, we explore transport layer protocol design for an optical flow-switched network. The objective of the protocol design is to guarantee the reliable delivery of data files over an all-optical end-to- end flow-switched network which is modeled as a burst-error channel. We observe that Transport Control Protocol (TCP) is not best suited for Optical Flow-Switching (OFS). Specifically, flow control and fair resource allocation through windowing in TCP are unnecessary in an OFS network. Moreover TCP has poor throughput and delay performance at high transfer rates due to window flow control and window closing with missing or dropped packets. In OFS, flows are scheduled and congestion control is performed by a scheduling algorithm. Thus, we focus on defining a more efficient transport protocol for optical flow-switched networks that is neither a modification of TCP nor derived from TCP. The main contribution of this work is to optimize the throughput and delay performance of OFS using file segmentation and reassembly, forward error-correction (FEC), and frame retransmission. We analyze the throughput and delay performance of four example transport layer protocols: the Simple Transport Protocol (STP), the Simple Transport Protocol with Interleaving (STPI), the Transport Protocol with Framing (TPF) and the Transport Protocol with Framing and Interleaving (TPFI). First, we show that a transport layer protocol without file segmentation and without interleaving and FEC (STP) results in poor throughput and delay performance and is not well suited for OFS. Instead, we found that interleaving across a large file (STPI) results in the best theoretical delay performance, though the large code lengths and interleaver sizes in this scheme will be hard to implement. Also, in the unlikely case that a file experiences an uncorrectable error, STPI requires extra network resources equal to that of an entire transaction for file retransmission and adds to the delay of the transa, by Henna Priscilla Huang., S.M.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2011., Cataloged from PDF version of thesis., Includes bibliographical references (p. 217-220)., Ever since optical fiber was introduced in the 1970s as a communications medium, optical networking has revolutionized the telecommunications landscape. With sustained exponential increase in bandwidth demand, innovation in optical networking needs to continue to ensure cost-effective communications in the future. Optical flow switching (OFS) has been proposed for future optical networks to serve large transactions in a cost-effective manner, by means of an all-optical data plane employing end-to-end lightpaths. Due to noise added in the transmission and detection processes, the channel has non-zero probability of bit errors that may corrupt the useful data or flows transmitted. In this thesis, we focus on the end-to-end reliable data delivery part of the Transport Layer protocol and propose effective and efficient algorithms to ensure error-free end-to-end communications for OFS. We will analyze the performance of each algorithm and suggest optimal algorithm(s) to minimize the total delay. We propose four classes of OFS protocols, then compare them with the Transport Control Protocol (TCP) over Electronic Packet Switching (EPS) and indicate under what values of the parameters: file size, bit error rate (BER), propagation delay and loading factor is OFS better than EPS. This analysis can serve as important guidelines for practical protocol designs for end-to- end data transfer reliability of OFS., by Rui Li., S.M.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2011., Cataloged from PDF version of thesis., Includes bibliographical references (p. 217-220)., Ever since optical fiber was introduced in the 1970s as a communications medium, optical networking has revolutionized the telecommunications landscape. With sustained exponential increase in bandwidth demand, innovation in optical networking needs to continue to ensure cost-effective communications in the future. Optical flow switching (OFS) has been proposed for future optical networks to serve large transactions in a cost-effective manner, by means of an all-optical data plane employing end-to-end lightpaths. Due to noise added in the transmission and detection processes, the channel has non-zero probability of bit errors that may corrupt the useful data or flows transmitted. In this thesis, we focus on the end-to-end reliable data delivery part of the Transport Layer protocol and propose effective and efficient algorithms to ensure error-free end-to-end communications for OFS. We will analyze the performance of each algorithm and suggest optimal algorithm(s) to minimize the total delay. We propose four classes of OFS protocols, then compare them with the Transport Control Protocol (TCP) over Electronic Packet Switching (EPS) and indicate under what values of the parameters: file size, bit error rate (BER), propagation delay and loading factor is OFS better than EPS. This analysis can serve as important guidelines for practical protocol designs for end-to- end data transfer reliability of OFS., by Rui Li., S.M.

Thesis (M.B.A.)--Massachusetts Institute of Technology, Sloan School of Management; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science; in conjunction with the Leaders for Global Operations Program at MIT, 2012., Cataloged from PDF version of thesis., Includes bibliographical references (p. [104])., Mobile device companies typically manage supply and pricing for components that are used in production by their Vertical Integrators (VIs). By controlling the component pricing and supply chain, mobile device companies are able to increase their pricing and supply chain leverage over smaller component suppliers. Maintaining this leverage is crucial in ensuring that mobile device companies can mass-produce high quality products at efficient costs. However these advantages require that companies incur additional operational expenses associated with supply chain management. To reduce costs and improve lead times, OEM companies should consider having 1st Tier suppliers directly manage 2 nd Tier suppliers. This project will investigate VI capabilities to manage quality, design, and cost across the entire range of hardware used in Nokia phones. Alternatively, we will also identify specific program and commodity areas which may benefit from having a more integrated supply chain. We will also investigate how Nokia can reduce supply chain management costs to meet future business needs related to cash flow.' By analyzing Nokia's historical supply chain performance, we will develop a model to quantify Nokia's "level of control" over its supply chain. We define this "level of control" in terms of the Operational Expenses and Investment which Nokia incurs in managing its supply chain. With this model, we will assess how future business constraints will affect Nokia's supply chain control. By evaluating key parameters which influence supply chain control, we can recommend how Nokia can allocate control across its supply chain. Finally, we will apply this model to recommend how Nokia should outsource supply chain management responsibility., by Ethan Y. Xu., S.M., M.B.A.

Thesis (M.B.A.)--Massachusetts Institute of Technology, Sloan School of Management; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science; in conjunction with the Leaders for Global Operations Program at MIT, 2012., Cataloged from PDF version of thesis., Includes bibliographical references (p. [104])., Mobile device companies typically manage supply and pricing for components that are used in production by their Vertical Integrators (VIs). By controlling the component pricing and supply chain, mobile device companies are able to increase their pricing and supply chain leverage over smaller component suppliers. Maintaining this leverage is crucial in ensuring that mobile device companies can mass-produce high quality products at efficient costs. However these advantages require that companies incur additional operational expenses associated with supply chain management. To reduce costs and improve lead times, OEM companies should consider having 1st Tier suppliers directly manage 2 nd Tier suppliers. This project will investigate VI capabilities to manage quality, design, and cost across the entire range of hardware used in Nokia phones. Alternatively, we will also identify specific program and commodity areas which may benefit from having a more integrated supply chain. We will also investigate how Nokia can reduce supply chain management costs to meet future business needs related to cash flow.' By analyzing Nokia's historical supply chain performance, we will develop a model to quantify Nokia's "level of control" over its supply chain. We define this "level of control" in terms of the Operational Expenses and Investment which Nokia incurs in managing its supply chain. With this model, we will assess how future business constraints will affect Nokia's supply chain control. By evaluating key parameters which influence supply chain control, we can recommend how Nokia can allocate control across its supply chain. Finally, we will apply this model to recommend how Nokia should outsource supply chain management responsibility., by Ethan Y. Xu., S.M., M.B.A.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2012., Cataloged from PDF version of thesis., Includes bibliographical references (p. 135-136)., In this work, we explore transport layer protocol design for an optical flow-switched network. The objective of the protocol design is to guarantee the reliable delivery of data files over an all-optical end-to- end flow-switched network which is modeled as a burst-error channel. We observe that Transport Control Protocol (TCP) is not best suited for Optical Flow-Switching (OFS). Specifically, flow control and fair resource allocation through windowing in TCP are unnecessary in an OFS network. Moreover TCP has poor throughput and delay performance at high transfer rates due to window flow control and window closing with missing or dropped packets. In OFS, flows are scheduled and congestion control is performed by a scheduling algorithm. Thus, we focus on defining a more efficient transport protocol for optical flow-switched networks that is neither a modification of TCP nor derived from TCP. The main contribution of this work is to optimize the throughput and delay performance of OFS using file segmentation and reassembly, forward error-correction (FEC), and frame retransmission. We analyze the throughput and delay performance of four example transport layer protocols: the Simple Transport Protocol (STP), the Simple Transport Protocol with Interleaving (STPI), the Transport Protocol with Framing (TPF) and the Transport Protocol with Framing and Interleaving (TPFI). First, we show that a transport layer protocol without file segmentation and without interleaving and FEC (STP) results in poor throughput and delay performance and is not well suited for OFS. Instead, we found that interleaving across a large file (STPI) results in the best theoretical delay performance, though the large code lengths and interleaver sizes in this scheme will be hard to implement. Also, in the unlikely case that a file experiences an uncorrectable error, STPI requires extra network resources equal to that of an entire transaction for file retransmission and adds to the delay of the transa, by Henna Priscilla Huang., S.M.

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2011., Cataloged from PDF version of thesis., Includes bibliographical references (p. 133-134)., Advancements in technology are fueling huge growth in network traffic capacity. Demand for low cost, reliable, and high bitrate transmissions grows 40-110% internationally every year. To date, most research has focused on cost minimization of wide area and metropolitan area networks. In this thesis, we concentrate instead on finding scalable WAN designs with respect to power constraints and optimal MAN topologies with minimal capital and operating expenditures. We find optical bypass networks to be most scalable with respect to power consumption, especially when quality of service and network flexibility, reliability, and protection are considered. The power consumption of the standard bypass network can be lowered further through a hybrid design in which whole wavelengths of core, stable traffic between node pairs are routed via direct, fixed lightpaths using patch panelling and unexpected, bursty traffic is switched on a standard optical bypass network. We analyze power distribution among components and find the OXC switch most scalable at each node and O/E/O switches and routers wasteful. Finally, we prove that shortest path and minimum hop routing is power optimal and traffic balanced routing should be avoided. We approximate MAN topologies with regular graphs for tractable analysis. We augment a previous cost-based joint optimization formulation [13] with power expenditure modelling and obtain closed form solutions for optimal node degree and normalized network costs. We find that the optimal node connectivity increases 20-25% due to the added operating expenditures. Normalized network cost and normalized network cost per unit traffic also rise by approximately 25%. Our results show that the Generalized Moore graph with node degree between 0.05N and 0.08N is both power and cost minimal for a purely optical network., by Katherine Xiaoyan Lin., M.Eng.

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2010., Cataloged from PDF version of thesis., Includes bibliographical references (p. 93-94)., Transmission Control Protocol (TCP) is a widely used transport protocol in today's multimedia applications. TCP was originally designed for wired networks, and its performance is highly degraded in networks with stochastically variable links, such as satellite and wireless networks. One significant class of degradation is caused by link dropouts, which may occur due to multipath fading effects in wireless networks, or due to signal attenuation by changing weather conditions and turbulence in satellite channels. In this thesis, we study the effects of a diversity routing strategy on TCP performance in networks with stochastic links. This strategy allows each data sender to send copies of data packets along multiple paths in order to reduce the probability of packet losses. We define TCP efficiency to be the ratio of a data sender's throughput to the network capacity used by this sender. We explore the optimization of TCP efficiency by varying the number of paths along which data packets are sent,denoted as n. We find the optimal number of diversity routing paths n* that maximizes the TCP efficiency, and we observe that the value of n* depends on the variability of the stochastic links., by Yinuo (Mia) Qian., M.Eng.

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2011., Cataloged from PDF version of thesis., Includes bibliographical references (p. 133-134)., Advancements in technology are fueling huge growth in network traffic capacity. Demand for low cost, reliable, and high bitrate transmissions grows 40-110% internationally every year. To date, most research has focused on cost minimization of wide area and metropolitan area networks. In this thesis, we concentrate instead on finding scalable WAN designs with respect to power constraints and optimal MAN topologies with minimal capital and operating expenditures. We find optical bypass networks to be most scalable with respect to power consumption, especially when quality of service and network flexibility, reliability, and protection are considered. The power consumption of the standard bypass network can be lowered further through a hybrid design in which whole wavelengths of core, stable traffic between node pairs are routed via direct, fixed lightpaths using patch panelling and unexpected, bursty traffic is switched on a standard optical bypass network. We analyze power distribution among components and find the OXC switch most scalable at each node and O/E/O switches and routers wasteful. Finally, we prove that shortest path and minimum hop routing is power optimal and traffic balanced routing should be avoided. We approximate MAN topologies with regular graphs for tractable analysis. We augment a previous cost-based joint optimization formulation [13] with power expenditure modelling and obtain closed form solutions for optimal node degree and normalized network costs. We find that the optimal node connectivity increases 20-25% due to the added operating expenditures. Normalized network cost and normalized network cost per unit traffic also rise by approximately 25%. Our results show that the Generalized Moore graph with node degree between 0.05N and 0.08N is both power and cost minimal for a purely optical network., by Katherine Xiaoyan Lin., M.Eng.

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2010., Cataloged from PDF version of thesis., Includes bibliographical references (p. 93-94)., Transmission Control Protocol (TCP) is a widely used transport protocol in today's multimedia applications. TCP was originally designed for wired networks, and its performance is highly degraded in networks with stochastically variable links, such as satellite and wireless networks. One significant class of degradation is caused by link dropouts, which may occur due to multipath fading effects in wireless networks, or due to signal attenuation by changing weather conditions and turbulence in satellite channels. In this thesis, we study the effects of a diversity routing strategy on TCP performance in networks with stochastic links. This strategy allows each data sender to send copies of data packets along multiple paths in order to reduce the probability of packet losses. We define TCP efficiency to be the ratio of a data sender's throughput to the network capacity used by this sender. We explore the optimization of TCP efficiency by varying the number of paths along which data packets are sent,denoted as n. We find the optimal number of diversity routing paths n* that maximizes the TCP efficiency, and we observe that the value of n* depends on the variability of the stochastic links., by Yinuo (Mia) Qian., M.Eng.

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2011., Cataloged from PDF version of thesis., Includes bibliographical references (p. 133-134)., Advancements in technology are fueling huge growth in network traffic capacity. Demand for low cost, reliable, and high bitrate transmissions grows 40-110% internationally every year. To date, most research has focused on cost minimization of wide area and metropolitan area networks. In this thesis, we concentrate instead on finding scalable WAN designs with respect to power constraints and optimal MAN topologies with minimal capital and operating expenditures. We find optical bypass networks to be most scalable with respect to power consumption, especially when quality of service and network flexibility, reliability, and protection are considered. The power consumption of the standard bypass network can be lowered further through a hybrid design in which whole wavelengths of core, stable traffic between node pairs are routed via direct, fixed lightpaths using patch panelling and unexpected, bursty traffic is switched on a standard optical bypass network. We analyze power distribution among components and find the OXC switch most scalable at each node and O/E/O switches and routers wasteful. Finally, we prove that shortest path and minimum hop routing is power optimal and traffic balanced routing should be avoided. We approximate MAN topologies with regular graphs for tractable analysis. We augment a previous cost-based joint optimization formulation [13] with power expenditure modelling and obtain closed form solutions for optimal node degree and normalized network costs. We find that the optimal node connectivity increases 20-25% due to the added operating expenditures. Normalized network cost and normalized network cost per unit traffic also rise by approximately 25%. Our results show that the Generalized Moore graph with node degree between 0.05N and 0.08N is both power and cost minimal for a purely optical network., by Katherine Xiaoyan Lin., M.Eng.

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2010., Cataloged from PDF version of thesis., Includes bibliographical references (p. 93-94)., Transmission Control Protocol (TCP) is a widely used transport protocol in today's multimedia applications. TCP was originally designed for wired networks, and its performance is highly degraded in networks with stochastically variable links, such as satellite and wireless networks. One significant class of degradation is caused by link dropouts, which may occur due to multipath fading effects in wireless networks, or due to signal attenuation by changing weather conditions and turbulence in satellite channels. In this thesis, we study the effects of a diversity routing strategy on TCP performance in networks with stochastic links. This strategy allows each data sender to send copies of data packets along multiple paths in order to reduce the probability of packet losses. We define TCP efficiency to be the ratio of a data sender's throughput to the network capacity used by this sender. We explore the optimization of TCP efficiency by varying the number of paths along which data packets are sent,denoted as n. We find the optimal number of diversity routing paths n* that maximizes the TCP efficiency, and we observe that the value of n* depends on the variability of the stochastic links., by Yinuo (Mia) Qian., M.Eng.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2010., Cataloged from PDF version of thesis., Includes bibliographical references (p. 97-99)., Optical Flow Switching (OFS) is a key enabler of future scalable optical networks. In the past decade, the OFS architecture has been studied to build an all-optical data plane to provide an end-to-end, cost-effective data transport to users with large transactions. Flow switching provides low-cost service to high-end users by relieving the IP routers on the edge of wide area networks from large transactions. However, the scheduling process of OFS presents possible queuing delays of several transaction durations. For some special applications with urgent time deadlines, the users want to bypass the queuing and pay more to use the network as soon as possible. In this thesis, we propose a fast scheduling algorithm which utilizes a probing approach to enable OFS to set up end-to-end connections for users with urgent transactions with a delay of slightly more than one round-trip time. A central control manager is used to periodically collect from network regions their most recent entropy evolutions of the network states and broadcast this information across the whole network in the control plane. With this information, fast setups of end-to-end all-optical connections for OFS are achieved by probing independent paths between source and destination, and reserving the available light paths along the way. A modified Bellman-Ford algorithm is designed to select the paths with the least blocking probabilities. By grouping details of network states into the average entropy, we can greatly reduce the information collected and disseminated by the centralized controller, making the network management and control system scalable to large networks. Since our algorithm makes no assumptions about network models or traffic statistics, it is robust against model variations, and any future changes in network topologies and traffic patterns. The technique can also be used in heterogeneous networks, in which networks from different domains are interconnected to provide a broader coverage., by Lei Zhang., S.M.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2010., Cataloged from PDF version of thesis., Includes bibliographical references (p. 337-341)., Optical communication through the atmospheric channel is commonly known as free-space optical (FSO) communication. When communicating through a clear FSO channel, not only is there atmospheric turbulence which results in fading of the received signal, but there may also be interference that scatters into the receiver and deteriorates performance. In this thesis, we consider mitigating the fading and interference with diversity coherent and diversity incoherent detection. We derive the performance of diversity coherent and diversity incoherent receivers in the presence of fading and various worst case interference types. Diversity coherent detection provides significant power gain over diversity direct detection, and most of the benefit can be achieved with a moderate amount of diversity. Moreover, diversity always improves the performance of coherent detection, whereas diversity improves the performance of direct detection only until an optimal diversity value, beyond which it degrades the performance. We also derive the improvement in expected outage length with diversity, and quantify the amount of interference that the system can handle while still achieving a given outage probability. Although signal fades or 'outages' in an FSO link can be mitigated on the Physical Layer, they cannot be completely eliminated. In a free-space optical network, these outages affect the performance and design of the Transport Layer. The effect of outages on the TCP sender is to diminish its throughput significantly due to drastic reduction of its rate when its packets do not get received through the outage. We consider a class of TCP-based protocols that is better suited for free-space optical networks. In particular, the protocols in this class have the sender distinguish whether a packet loss is due to an outage or congestion and not reduce its rate if the loss was due to an outage. We analyze, using an approximate channel model for FSO links, the maximum performance that can be, by Etty J. Lee., Ph.D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2010., Cataloged from PDF version of thesis., Includes bibliographical references (p. 337-341)., Optical communication through the atmospheric channel is commonly known as free-space optical (FSO) communication. When communicating through a clear FSO channel, not only is there atmospheric turbulence which results in fading of the received signal, but there may also be interference that scatters into the receiver and deteriorates performance. In this thesis, we consider mitigating the fading and interference with diversity coherent and diversity incoherent detection. We derive the performance of diversity coherent and diversity incoherent receivers in the presence of fading and various worst case interference types. Diversity coherent detection provides significant power gain over diversity direct detection, and most of the benefit can be achieved with a moderate amount of diversity. Moreover, diversity always improves the performance of coherent detection, whereas diversity improves the performance of direct detection only until an optimal diversity value, beyond which it degrades the performance. We also derive the improvement in expected outage length with diversity, and quantify the amount of interference that the system can handle while still achieving a given outage probability. Although signal fades or 'outages' in an FSO link can be mitigated on the Physical Layer, they cannot be completely eliminated. In a free-space optical network, these outages affect the performance and design of the Transport Layer. The effect of outages on the TCP sender is to diminish its throughput significantly due to drastic reduction of its rate when its packets do not get received through the outage. We consider a class of TCP-based protocols that is better suited for free-space optical networks. In particular, the protocols in this class have the sender distinguish whether a packet loss is due to an outage or congestion and not reduce its rate if the loss was due to an outage. We analyze, using an approximate channel model for FSO links, the maximum performance that can be, by Etty J. Lee., Ph.D.

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2009., Includes bibliographical references (p. 83-87)., This thesis focuses on the design and analysis of scheduling approaches for Optical Flow Switching (OFS) serving high performance applications with very stringent time deadline constraints. In particular, we attempt to meet setup times only slightly longer than one roundtrip time with networks at moderate to high loading. In this work, we propose three possible scheduling mechanisms for OFS connection setup in a WDM network: (i) a simple algorithm, which awards pre-emptive priority to applications requiring time deadline performance; (ii) a multi-path probing mechanism using only coarse average loading information (i.e., no detailed network state information) but without pre-emption; and (iii) a multi-path probing mechanism using periodically updated network state information and without pre-emption. The updating scheme calls for a slow control plane, which refreshes and broadcast network states only periodically on the order of seconds or longer. Our results show that for a low blocking probability, the update interval must be a fraction of the mean service time of transactions. We conclude that this algorithm, a combination of both slow centralized and fast distributed processes, delivers an efficient and scalable control design for a high-speed transport network of the future., by Anurupa Ganguly., M.Eng.

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2009., Includes bibliographical references (p. 83-87)., This thesis focuses on the design and analysis of scheduling approaches for Optical Flow Switching (OFS) serving high performance applications with very stringent time deadline constraints. In particular, we attempt to meet setup times only slightly longer than one roundtrip time with networks at moderate to high loading. In this work, we propose three possible scheduling mechanisms for OFS connection setup in a WDM network: (i) a simple algorithm, which awards pre-emptive priority to applications requiring time deadline performance; (ii) a multi-path probing mechanism using only coarse average loading information (i.e., no detailed network state information) but without pre-emption; and (iii) a multi-path probing mechanism using periodically updated network state information and without pre-emption. The updating scheme calls for a slow control plane, which refreshes and broadcast network states only periodically on the order of seconds or longer. Our results show that for a low blocking probability, the update interval must be a fraction of the mean service time of transactions. We conclude that this algorithm, a combination of both slow centralized and fast distributed processes, delivers an efficient and scalable control design for a high-speed transport network of the future., by Anurupa Ganguly., M.Eng.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2010., Cataloged from PDF version of thesis., Includes bibliographical references (p. 337-341)., Optical communication through the atmospheric channel is commonly known as free-space optical (FSO) communication. When communicating through a clear FSO channel, not only is there atmospheric turbulence which results in fading of the received signal, but there may also be interference that scatters into the receiver and deteriorates performance. In this thesis, we consider mitigating the fading and interference with diversity coherent and diversity incoherent detection. We derive the performance of diversity coherent and diversity incoherent receivers in the presence of fading and various worst case interference types. Diversity coherent detection provides significant power gain over diversity direct detection, and most of the benefit can be achieved with a moderate amount of diversity. Moreover, diversity always improves the performance of coherent detection, whereas diversity improves the performance of direct detection only until an optimal diversity value, beyond which it degrades the performance. We also derive the improvement in expected outage length with diversity, and quantify the amount of interference that the system can handle while still achieving a given outage probability. Although signal fades or 'outages' in an FSO link can be mitigated on the Physical Layer, they cannot be completely eliminated. In a free-space optical network, these outages affect the performance and design of the Transport Layer. The effect of outages on the TCP sender is to diminish its throughput significantly due to drastic reduction of its rate when its packets do not get received through the outage. We consider a class of TCP-based protocols that is better suited for free-space optical networks. In particular, the protocols in this class have the sender distinguish whether a packet loss is due to an outage or congestion and not reduce its rate if the loss was due to an outage. We analyze, using an approximate channel model for FSO links, the maximum performance that can be, by Etty J. Lee., Ph.D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2010., Cataloged from PDF version of thesis., Includes bibliographical references (p. 337-341)., Optical communication through the atmospheric channel is commonly known as free-space optical (FSO) communication. When communicating through a clear FSO channel, not only is there atmospheric turbulence which results in fading of the received signal, but there may also be interference that scatters into the receiver and deteriorates performance. In this thesis, we consider mitigating the fading and interference with diversity coherent and diversity incoherent detection. We derive the performance of diversity coherent and diversity incoherent receivers in the presence of fading and various worst case interference types. Diversity coherent detection provides significant power gain over diversity direct detection, and most of the benefit can be achieved with a moderate amount of diversity. Moreover, diversity always improves the performance of coherent detection, whereas diversity improves the performance of direct detection only until an optimal diversity value, beyond which it degrades the performance. We also derive the improvement in expected outage length with diversity, and quantify the amount of interference that the system can handle while still achieving a given outage probability. Although signal fades or 'outages' in an FSO link can be mitigated on the Physical Layer, they cannot be completely eliminated. In a free-space optical network, these outages affect the performance and design of the Transport Layer. The effect of outages on the TCP sender is to diminish its throughput significantly due to drastic reduction of its rate when its packets do not get received through the outage. We consider a class of TCP-based protocols that is better suited for free-space optical networks. In particular, the protocols in this class have the sender distinguish whether a packet loss is due to an outage or congestion and not reduce its rate if the loss was due to an outage. We analyze, using an approximate channel model for FSO links, the maximum performance that can be, by Etty J. Lee., Ph.D.

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2009., Includes bibliographical references (p. 83-87)., This thesis focuses on the design and analysis of scheduling approaches for Optical Flow Switching (OFS) serving high performance applications with very stringent time deadline constraints. In particular, we attempt to meet setup times only slightly longer than one roundtrip time with networks at moderate to high loading. In this work, we propose three possible scheduling mechanisms for OFS connection setup in a WDM network: (i) a simple algorithm, which awards pre-emptive priority to applications requiring time deadline performance; (ii) a multi-path probing mechanism using only coarse average loading information (i.e., no detailed network state information) but without pre-emption; and (iii) a multi-path probing mechanism using periodically updated network state information and without pre-emption. The updating scheme calls for a slow control plane, which refreshes and broadcast network states only periodically on the order of seconds or longer. Our results show that for a low blocking probability, the update interval must be a fraction of the mean service time of transactions. We conclude that this algorithm, a combination of both slow centralized and fast distributed processes, delivers an efficient and scalable control design for a high-speed transport network of the future., by Anurupa Ganguly., M.Eng.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2010., Cataloged from PDF version of thesis., Includes bibliographical references (p. 337-341)., Optical communication through the atmospheric channel is commonly known as free-space optical (FSO) communication. When communicating through a clear FSO channel, not only is there atmospheric turbulence which results in fading of the received signal, but there may also be interference that scatters into the receiver and deteriorates performance. In this thesis, we consider mitigating the fading and interference with diversity coherent and diversity incoherent detection. We derive the performance of diversity coherent and diversity incoherent receivers in the presence of fading and various worst case interference types. Diversity coherent detection provides significant power gain over diversity direct detection, and most of the benefit can be achieved with a moderate amount of diversity. Moreover, diversity always improves the performance of coherent detection, whereas diversity improves the performance of direct detection only until an optimal diversity value, beyond which it degrades the performance. We also derive the improvement in expected outage length with diversity, and quantify the amount of interference that the system can handle while still achieving a given outage probability. Although signal fades or 'outages' in an FSO link can be mitigated on the Physical Layer, they cannot be completely eliminated. In a free-space optical network, these outages affect the performance and design of the Transport Layer. The effect of outages on the TCP sender is to diminish its throughput significantly due to drastic reduction of its rate when its packets do not get received through the outage. We consider a class of TCP-based protocols that is better suited for free-space optical networks. In particular, the protocols in this class have the sender distinguish whether a packet loss is due to an outage or congestion and not reduce its rate if the loss was due to an outage. We analyze, using an approximate channel model for FSO links, the maximum performance that can be, by Etty J. Lee., Ph.D.

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2009., Includes bibliographical references (p. 83-87)., This thesis focuses on the design and analysis of scheduling approaches for Optical Flow Switching (OFS) serving high performance applications with very stringent time deadline constraints. In particular, we attempt to meet setup times only slightly longer than one roundtrip time with networks at moderate to high loading. In this work, we propose three possible scheduling mechanisms for OFS connection setup in a WDM network: (i) a simple algorithm, which awards pre-emptive priority to applications requiring time deadline performance; (ii) a multi-path probing mechanism using only coarse average loading information (i.e., no detailed network state information) but without pre-emption; and (iii) a multi-path probing mechanism using periodically updated network state information and without pre-emption. The updating scheme calls for a slow control plane, which refreshes and broadcast network states only periodically on the order of seconds or longer. Our results show that for a low blocking probability, the update interval must be a fraction of the mean service time of transactions. We conclude that this algorithm, a combination of both slow centralized and fast distributed processes, delivers an efficient and scalable control design for a high-speed transport network of the future., by Anurupa Ganguly., M.Eng.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2009., Includes bibliographical references (p. 253-279)., In the four decades since optical fiber was introduced as a communications medium, optical networking has revolutionized the telecommunications landscape. It has enabled the Internet as we know it today, and is central to the realization of Network-Centric Warfare in the defense world. Sustained exponential growth in communications bandwidth demand, however, is requiring that the nexus of innovation in optical networking continue, in order to ensure cost-effective communications in the future. In this thesis, we present Optical Flow Switching (OFS) as a key enabler of scalable future optical networks. The general idea behind OFS-agile, end-to-end, all-optical connections-is decades old, if not as old as the field of optical networking itself. However, owing to the absence of an application for it, OFS remained an underdeveloped idea-bereft of how it could be implemented, how well it would perform, and how much it would cost relative to other architectures. The contributions of this thesis are in providing partial answers to these three broad questions. With respect to implementation, we address the physical layer design of OFS in the metro-area and access, and develop sensible scheduling algorithms for OFS communication. Our performance study comprises a comparative capacity analysis for the wide-area, as well as an analytical approximation of the throughput-delay tradeoff offered by OFS for inter-MAN communication. Lastly, with regard to the economics of OFS, we employ an approximate capital expenditure model, which enables a throughput-cost comparison of OFS with other prominent candidate architectures. Our conclusions point to the fact that OFS offers significant advantage over other architectures in economic scalability., (cont.) In particular, for sufficiently heavy traffic, OFS handles large transactions at far lower cost than other optical network architectures. In light of the increasing importance of large transactions in both commercial and defense networks, we conclude that OFS may be crucial to the future viability of optical networking., by Guy E. Weichenberg., Ph.D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2009., Includes bibliographical references (p. 253-279)., In the four decades since optical fiber was introduced as a communications medium, optical networking has revolutionized the telecommunications landscape. It has enabled the Internet as we know it today, and is central to the realization of Network-Centric Warfare in the defense world. Sustained exponential growth in communications bandwidth demand, however, is requiring that the nexus of innovation in optical networking continue, in order to ensure cost-effective communications in the future. In this thesis, we present Optical Flow Switching (OFS) as a key enabler of scalable future optical networks. The general idea behind OFS-agile, end-to-end, all-optical connections-is decades old, if not as old as the field of optical networking itself. However, owing to the absence of an application for it, OFS remained an underdeveloped idea-bereft of how it could be implemented, how well it would perform, and how much it would cost relative to other architectures. The contributions of this thesis are in providing partial answers to these three broad questions. With respect to implementation, we address the physical layer design of OFS in the metro-area and access, and develop sensible scheduling algorithms for OFS communication. Our performance study comprises a comparative capacity analysis for the wide-area, as well as an analytical approximation of the throughput-delay tradeoff offered by OFS for inter-MAN communication. Lastly, with regard to the economics of OFS, we employ an approximate capital expenditure model, which enables a throughput-cost comparison of OFS with other prominent candidate architectures. Our conclusions point to the fact that OFS offers significant advantage over other architectures in economic scalability., (cont.) In particular, for sufficiently heavy traffic, OFS handles large transactions at far lower cost than other optical network architectures. In light of the increasing importance of large transactions in both commercial and defense networks, we conclude that OFS may be crucial to the future viability of optical networking., by Guy E. Weichenberg., Ph.D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2009., Includes bibliographical references (p. 253-279)., In the four decades since optical fiber was introduced as a communications medium, optical networking has revolutionized the telecommunications landscape. It has enabled the Internet as we know it today, and is central to the realization of Network-Centric Warfare in the defense world. Sustained exponential growth in communications bandwidth demand, however, is requiring that the nexus of innovation in optical networking continue, in order to ensure cost-effective communications in the future. In this thesis, we present Optical Flow Switching (OFS) as a key enabler of scalable future optical networks. The general idea behind OFS-agile, end-to-end, all-optical connections-is decades old, if not as old as the field of optical networking itself. However, owing to the absence of an application for it, OFS remained an underdeveloped idea-bereft of how it could be implemented, how well it would perform, and how much it would cost relative to other architectures. The contributions of this thesis are in providing partial answers to these three broad questions. With respect to implementation, we address the physical layer design of OFS in the metro-area and access, and develop sensible scheduling algorithms for OFS communication. Our performance study comprises a comparative capacity analysis for the wide-area, as well as an analytical approximation of the throughput-delay tradeoff offered by OFS for inter-MAN communication. Lastly, with regard to the economics of OFS, we employ an approximate capital expenditure model, which enables a throughput-cost comparison of OFS with other prominent candidate architectures. Our conclusions point to the fact that OFS offers significant advantage over other architectures in economic scalability., (cont.) In particular, for sufficiently heavy traffic, OFS handles large transactions at far lower cost than other optical network architectures. In light of the increasing importance of large transactions in both commercial and defense networks, we conclude that OFS may be crucial to the future viability of optical networking., by Guy E. Weichenberg., Ph.D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2008., MIT Barker Engineering Library copy: printed in pages., Also issued printed in pages., Includes bibliographical references (leaves 255-262)., All-optical switching, in place of electronic switching, of high data-rate lightpaths at intermediate nodes is one of the key enabling technologies for economically scalable future data networks. This replacement of electronic switching with optical switching at intermediate nodes, however, presents new challenges for fault detection and localization in reconfigurable all-optical networks. Presently, fault detection and localization techniques, as implemented in SONET/G.709 networks, rely on electronic processing of parity checks at intermediate nodes. If similar techniques are adapted to all-optical reconfigurable networks, optical signals need to be tapped out at intermediate nodes for parity checks. This additional electronic processing would break the all-optical transparency paradigm and thus significantly diminish the cost advantages of all-optical networks. In this thesis, we propose new fault-diagnosis approaches specifically tailored to all-optical networks, with an objective of keeping the diagnostic capital expenditure and the diagnostic operation effort low. Instead of the aforementioned passive monitoring paradigm based on parity checks, we propose a proactive lightpath probing paradigm: optical probing signals are sent along a set of lightpaths in the network, and network state (i.e., failure pattern) is then inferred from testing results of this set of end-to-end lightpath measurements. Moreover, we assume that a subset of network nodes (up to all the nodes) is equipped with diagnostic agents - including both transmitters/receivers for probe transmission/detection and software processes for probe management to perform fault detection and localization. The design objectives of this proposed proactive probing paradigm are two folded: i) to minimize the number of lightpath probes to keep the diagnostic operational effort low, and ii) to minimize the number of diagnostic hardware to keep the diagnostic capital expenditure low., (cont.) The network fault-diagnosis problem can be mathematically modeled with a group testing-over-graphs framework. In particular, the network is abstracted as a graph in which the failure status of each node/link is modeled with a random variable (e.g. Bernoulli distribution). A probe over any path in the graph results in a value, defined as the probe syndrome, which is a function of all the random variables associated in that path. A network failure pattern is inferred through a set of probe syndromes resulting from a set of optimally chosen probes. This framework enriches the traditional group-testing problem by introducing a topological structure, and can be extended to model many other network-monitoring problems (e.g., packet delay, packet drop ratio, noise and etc) by choosing appropriate state variables. Under the group-testing-over-graphs framework with a probabilistic failure model, we initiate an information-theoretic approach to minimizing the average number of lightpath probes to identify all possible network failure patterns. Specifically, we have established an isomorphic mapping between the fault-diagnosis problem in network management and the source-coding problem in Information Theory. This mapping suggests that the minimum average number of lightpath probes required is lower bounded by the information entropy of the network state and efficient source-coding algorithms (e.g. the run-length code) can be translated into scalable fault-diagnosis schemes under some additional probe feasibility constraint. Our analytical and numerical investigations yield a guideline for designing scalable fault-diagnosis algorithms: each probe should provide approximately 1-bit of state information, and thus the total number of probes required is approximately equal to the entropy of the network state., (cont.) To address the hardware cost of diagnosis, we also developed a probabilistic analysis framework to characterize the trade-off between hardware cost (i.e., the number of nodes equipped with Tx/Rx pairs) and diagnosis capability (i.e., the probability of successful failure detection and localization). Our results suggest that, for practical situations, the hardware cost can be reduced significantly by accepting a small amount of uncertainty about the failure status., by Yonggang Wen., Ph.D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2009., Includes bibliographical references (p. 253-279)., In the four decades since optical fiber was introduced as a communications medium, optical networking has revolutionized the telecommunications landscape. It has enabled the Internet as we know it today, and is central to the realization of Network-Centric Warfare in the defense world. Sustained exponential growth in communications bandwidth demand, however, is requiring that the nexus of innovation in optical networking continue, in order to ensure cost-effective communications in the future. In this thesis, we present Optical Flow Switching (OFS) as a key enabler of scalable future optical networks. The general idea behind OFS-agile, end-to-end, all-optical connections-is decades old, if not as old as the field of optical networking itself. However, owing to the absence of an application for it, OFS remained an underdeveloped idea-bereft of how it could be implemented, how well it would perform, and how much it would cost relative to other architectures. The contributions of this thesis are in providing partial answers to these three broad questions. With respect to implementation, we address the physical layer design of OFS in the metro-area and access, and develop sensible scheduling algorithms for OFS communication. Our performance study comprises a comparative capacity analysis for the wide-area, as well as an analytical approximation of the throughput-delay tradeoff offered by OFS for inter-MAN communication. Lastly, with regard to the economics of OFS, we employ an approximate capital expenditure model, which enables a throughput-cost comparison of OFS with other prominent candidate architectures. Our conclusions point to the fact that OFS offers significant advantage over other architectures in economic scalability., (cont.) In particular, for sufficiently heavy traffic, OFS handles large transactions at far lower cost than other optical network architectures. In light of the increasing importance of large transactions in both commercial and defense networks, we conclude that OFS may be crucial to the future viability of optical networking., by Guy E. Weichenberg., Ph.D.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2006., This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections., Includes bibliographical references (p. 125-127)., Analog RF phase modulation of optical signals has been a topic of interest for many years, mainly focusing on Intensity Modulation Direct Detection (IMDD). The virtues of coherent detection combined with the advantages of Frequency Modulation, however, have not been explored thoroughly. By employing Frequency Modulation Coherent Detection (FMCD), the wide optical transmission bandwidth of optical fiber can be traded for higher signal-to-noise performance. In this thesis, we derive the FM gain over AM modulation -- the maximum achievable signal-to-noise ratio (by spreading the signal's spectrum) for specific carrier-to-noise ratio. We then employ FMCD for a scheme of remote antennas for which we use optical components and subsystem to perform signal processing such as nulling of interfering signals. The performance of optical processing on different modulation schemes are compared, and some important conclusions are reported relating to the use of conventional FMCD, FMCD with optical discriminator (FMCD O-D), and IMDD. Specifically, the superiority of conventional FMCD is shown; and, on the other hand, the inferiority of FMCD O-D is shown (same performance as IMDD) because of the use of an O-D. Finally, the remote antenna scheme is generalized for N antennas and N users., by Nikolas I. Andrikogiannopoulos., S.M.