Browsing by Author "Monti, Paolo, 1973-"
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Item Achieving reliable networking for the generic autonomous platform for sensor systems (GAP4S)(The University of Texas at Dallas, 2013-06-18) Monti, Paolo, 1973-; Eric Jonsson School of Engineering and Computer Science.Networks of wireless integrated sensors are often used to monitor parameters distributed in the environment. These parameters are related to a variety of applications such as security, patient monitoring, chemical and biological hazard detection. Some solutions rely on replaceable batteries with a limited life-time to provide long-term sensor operation. Others envision short transmission range sensors (few meters) that harvest their energy from various environmental sources (e.g., solar, vibrations, acoustic noise). The Generic Autonomous Platform for Sensors (GAP4S) project explores an approach for wireless sensors that is complementary to these and other pre-existing solutions. In GAP4S, the wireless sensor micro-battery is remotely recharged via a microwave signal. Medium transmission ranges in the tens to hundreds of meters are possible. Within these wireless transmission ranges, a base-station collects data transmitted by the sensors and acts as the access point to a wider (typically wired) communication network, e.g., the Internet. The authorized user can, therefore, remotely connect to, monitor, and manage both the sensor network and the individual sensors. An essential component of GAP4S is its end-to-end network reliability solution, which ensures the delivery of data generated at the sensor to the interested user across both the wireless and wired segments. This dissertation investigates ways to achieve reliable networking for GAP4S over both the wireless and the wired segments. A specially designed solution is provided in each segment. In the wireless segment, error-free transmissions from the sensor node to the base-station is achieved using automatic repeat request (ARQ) protocols at layer 2. Two classes of ARQ protocols are designed and compared. The first is the conventional ARQ, whereby the data frame is retransmitted by the originating sensor until successfully received by the base-station. The second class takes advantage of cooperative radio communications, whereby multiple neighboring sensor nodes may combine their efforts during the retransmission process. The ARQ protocols are compared in terms of their saturation throughput, i.e., the maximum data flow that the sensor node can sustain constrained to the available energy amount. In a variety of scenarios--current and future expected circuit energy consumptions--the cooperative ARQ protocols may more than double the saturation throughput when compared to conventional ARQ protocols. Equivalently, it can be said that the energy required to operate the system may be reduced by half. In the wired segment, fault tolerant networking is achieved by means of protection switching at layer 3. Given the increasingly widespread use of Wavelength Division Multiplexed (WDM) backbone networks, the protection switching scheme is designed to operate in conjunction with WDM. Optical circuits are made reliable by means of a Shared Path Protection (SPP) switching scheme. The SPP scheme is generalized to guarantee Differentiated levels of Reliability (DiR) to the user. In the SPP-DiR combined scheme the desired level of reliability may be guaranteed while minimizing the required network resources, i.e., wavelengths. This feature makes it possible to support more optical connections and users when compared to other existing protection switching schemes.Item Building alternate multitasking trees in MPLS networks(The University of Texas at Dallas, 2013-05-23) Tang, Limin, 1977-; Billenhalli, Shreejith; Vardhan, Hars; Tacca, Marco, 1973-; Fumagalli, Andrea; Monti, Paolo, 1973-; Eric Jonsson School of Engineering and Computer Science. Open Networking Advanced Research (OpNeAR) Laboratory.; Next Generation Optical Network (NeGONet) Group; Kungl. Tekniska högskolan (KTH). Photonics and Microwave Engineering (FMI). School of Information and Communication Technology; Royal Institute of Technology (Kista, Sweden)An algorithm for computing alternate multicast trees in packet transport networks is proposed in this paper. The algorithm efficiently computes multiple sub-optimal tree candidates for a given multicast service request. The algorithm builds on the widely used computation of K ordered loopless shortest paths and can be applied to any connected network topology. Simulation experiments obtained for a multiprotocol label switching (MPLS) network are presented to evaluate the effectiveness and performance of the algorithm.Item Cooperative and non-cooperative ARQ protocols for microwave recharged sensor nodes(The University of Texas at Dallas, 2013-06-18) Tacca, Marco, 1973-; Monti, Paolo, 1973-; Fumagalli, Andrea; Eric Jonsson School of Engineering and Computer Science. Open Networking Advanced Research (OpNeAR) Laboratory.The Generic Autonomous Platform for Sensor Systems, or GAP4S, is a maintenance-free wireless sensor network in which the sensor battery needs not be replaced. Power is delivered to the sensor 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. This paper describes three automatic retransmission request (ARQ) protocols that may be used in GAP4S to yield reliable and fair data transmission from the sensor nodes to the base-station. Two of the protocols take advantage of cooperative communication, whereby neighboring sensor nodes help during the retransmission process. The analysis presented on the saturation throughput of the ARQ protocols helps quantify the gain achievable when cooperative communication is used in GAP4S in a variety of working conditions.Item Finding a simple path with multiple must-include nodes(The University of Texas at Dallas, 2013-05-23) Vardhan, Hars; Billenahalli, Shreejith, 1982-; Huang, Wanjun, 1978-; Razo, Miguel; Sivasankaran, Arularasi; Tang, Limin, 1977-; Monti, Paolo, 1973-; Tacca, Marco, 1973-; Fumagalli, Andrea; Eric Jonsson School of Engineering and Computer Science. Open Networking Advanced Research (OpNeAR) Laboratory.This document presents an algorithm to find a simple path in the given network with multiple must-include nodes. The problem of finding a simple path with only one must-include node can be solved in polynomial time using lower bound max-flow approach. However, including multiple nodes in the path has been shown to be a NP-Complete. This problem may arise in network areas such as forcing the route to go through particular nodes, which have wavelength converter (optical), have monitoring provision (telecom), have gateway functions (in OSPF) or are base stations (in MANET). Also, network standards allow loose definition of routing by requiring one or more nodes to be in the routing of Link State Packet. In this document, a heuristic algorithm is described to find a simple path between a pair of terminals, which has constraint to pass through a certain set of other nodes. The algorithm is comprised into two main steps: (1) considering a pair of nodes in sequence from source to destination as a segment and then computing candidate paths between each segment, and (2) combining paths, one from each segment, in order to make simple path from source to destination. The max-flow approach is used to find candidate paths, a which provides maximum number of edge disjoint paths for individual segments. The second step of the algorithm uses backtracking algorithm for combining paths. The time complexity of the first step of the algorithm is O(kiVIIEI 2 ), where k is the number of must-include nodes. The time complexity of step (2) depends upon total number of candidate paths which are not touching any one of the candidates of other segments. So, the worse case time complexity of step (2) is O(.Ak), where .A is the maximum nodal degree of the network. However, we show that step (2) has minimal effect on the algorithm and it does not grow exponentially with k in this application. Later, we also show that initial re-ordering of the given sequence of must-include nodes can improve the result. The experimental results show that the algorithm is successful in computing near optimal path in reasonable time. keywords: constrained path computation, graph theory, heuristic algorithm, max flow, network route.Item A link state advertisement (LSA) protocol for optical transparency islands(The University of Texas at Dallas, 2013-06-18) Das, Shovan, 1979-; Tabrizi, Reza Roshani, 1976-; Monti, Paolo, 1973-; Tacca, Marco, 1973-; Fumagalli, Andrea; Eric Jonsson School of Engineering and Computer Science. Open Networking Advanced Research (OpNeAR) Laboratory.Plug and play optical (PPO) nodes can be used to ease the deployment of optical networks. Once plugged, PPO nodes provide all-optical circuits between client nodes to alleviate the electronic processing bottleneck of high speed networks. PPO nodes must self-adjust to changes of the optical physical topology and fiber propagation characteristics, and provide wavelength routing functionalities to client nodes. This paper presents a protocol, the TI-LSA protocol, for physical topology discovery at the PPO node layer, e.g., it may be used to advertise available optical resources and changing conditions of the optical physical layer. The protocol is based on the link state advertisement (LSA) principle and modified to take advantage of the transparency island (TI) properties in the optical data plane. As discussed in the paper, the proposed TI-LSA protocol is a scalable solution to the problem of topology discovery and update in PPO networks when the optical transparency island size is relatively small.Item The PlaNet-PTN module: a single layer design tool for packet transport networks(The University of Texas at Dallas, 2013-05-23) Razo, Miguel; Litovsky, Arie; Huang, Wanjun, 1978-; Sivasankaran, Arularasi; Tang, Limin, 1977-; Vardhan, Hars; Tacca, Marco, 1973-; Fumagalli, Andrea; Monti, Paolo, 1973-; Eric Jonsson School of Engineering and Computer Science. Open Networking Advanced Research (OpNeAR) Laboratory.PlaNet is a multilayer network planning tool developed at the University of Texas at Dallas. This paper illustrates some of the features of PlaNet-PTN, one of the modules available in the PlaNet tool. PlaNet-PTN can be used to design and plan a single layer packet transport network (PTN). Quality of protection, routing constraints, minimization of the network equipment cost, and user's desired run time of the tool are just some examples of the features available in PlaNet. As shown in the paper, the PlaNet-PTN planning module is able to provide, among others, optimization of Label Switched Path (LSP) routes, link capacity placement, node and link equipment configuration.Item Plug and play optical (PPO) nodes: network functionalities and built-in fiber characterization techniques(The University of Texas at Dallas, 2007-05-07) Cerutti, Isabella, 1973-; Fumagalli, Andrea; Hui, Rongqing; Monti, Paolo, 1973-; Paradisi, Alberto; Tacca, Marco, 1973-; Eric Jonsson School of Engineering and Computer Science.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. Three possible PPO node hardware architectures trading off complexity, cost and functionalities are presented along with their built-in fiber characterization techniques.Item Reconfigurable optical networks: a cross layer approach(The University of Texas at Dallas, 2013-05-24) Roshani-Tabrizi, Reza, 1976-; Monti, Paolo, 1973-; Tacca, Marco, 1973-; Fumagalli, Andrea; Eric Jonsson School of Engineering and Computer Science. Open Networking Advanced Research (OpNeAR) Laboratory.This paper presents the Pruning with Memory (PWM) algorithm, which computes a cross layer optimal reconfiguration sequence in reconfigurable IP/MPLS over optical networks.Item A scalable wavelength assignment algorithm using minimal number of wavelength converters in resilient WDM networks(The University of Texas at Dallas, 2013-06-18) Razo, Miguel; Billenahalli, Shreejith; Huang, Wanjun, 1978-; Sivasankaran, Arularasi; Tang, Limin, 1977-; Vardhan, Hars; Tacca, Marco, 1973-; Fumagalli, Andrea; Monti, Paolo, 1973-; Eric Jonsson School of Engineering and Computer Science. Open Networking Advanced Research (OpNeAR) Laboratory.; Royal Institute of Technology. NeGONet Group.Careful wavelength assignment (WA) to support lambda services is necessary to reduce the total number of wavelength converters (WCs), which are required every time the wavelength continuity constraint cannot be met in wavelength division multiplexing (WDM) networks. With the successful introduction of reconfigurable optical add-drop multiplexers (ROADMs) and related technologies, WDM networks are now growing in size, both in the number of optical nodes and number of wavelengths supported, thus requiring WA algorithms that scale with the network size. This paper presents a scalable and efficient WA algorithm that aims to reduce the total number of WCs in WDM networks bearing static lambda services. The WA algorithm is applicable to both unprotected and (dedicated) protected lambda services. In the latter case, wavelength continuity constraint between the working and the protection path is taken into account. The WA algorithm is then used to quantify the tradeoff between using tunable optical transceivers versus number of WCs to cope with the wavelength continuity constraint.Item Shared protection ILP formulation(The University of Texas at Dallas, 2013-06-18) Huang, Wanjun, 1978-; Razo, Miguel; Billenahalli, Shreejith; Sivasankaran, Arularasi; Tang, Limin, 1977-; Vardhan, Hars; Monti, Paolo, 1973-; Tacca, Marco, 1973-; Fumagalli, Andrea; Eric Jonsson School of Engineering and Computer Science. Open Networking Advanced Research (OpNeAR) Laboratory.; Royal Institute of Technology. NeGONet Group.Item Trading network management complexity for blocking probability when placing optical regenerators(The University of Texas at Dallas, 2013-05-24) Savasini, Marcio S.; Monti, Paolo, 1973-; Fumagalli, Andrea; Tacca, Marco, 1973-; Waldman, Helio; Eric Jonsson School of Engineering and Computer Science. Open Networking Advanced Research (OpNeAR) Laboratory.; State University of Campinas. Faculdade de Engenharia Eletrica e de Computacao.Optical signal regenerators (3R) are required to overcome the adverse effect of fiber and other transmission impairments. 3R units may be placed either at every node (full placement) or at some selected nodes (sparse placement) of the optical network. It has been argued [1] that while the latter placement strategy may not be optimal in terms of the total number of 3R units required to support a given set of static traffic demands, it offers a number of practical advantages over the former, e.g., a contained complexity of network management in terms of signaling overhead. In this paper the full and sparse placement strategies are compared in a dynamic optical network, whereby lightpaths are set up and torn down to best fit the offered changing demands. The study shows that the blocking probability due to the lack of available 3R units achieved by the sparse placement strategy may be comparable to the one achieved by the full placement strategy. Surprisingly, it may even be lower in some cases, thus providing an additional motivation in favor of the sparse placement strategy. The study also shows that the algorithm used to choose the nodes where to place the 3R units must be designed carefully. Two placement algorithms are compared, reporting differences in signaling overhead level as high as 6 times (when achieving a desired level of lightpath connectivity) and differences in blocking probabilities as high as two orders of magnitude (when using the same level of signaling overhead).Item Wireless multimedia networks: cross-layer access protocols based on sequential opportunistic decoding (SOD)(The University of Texas at Dallas, 2013-05-23) Jegbefume, Onyemelem, 1977-; Saquib, M.; Tacca, Marco, 1973-; Fumagalli, Andrea; Monti, Paolo, 1973-; Eric Jonsson School of Engineering and Computer Science.Spread spectrum (SS) solutions offer well understood advantages to wireless networking, e.g., robustness to noise and interference, concurrent asynchronous transmissions, effective power and transmission rate control mechanisms. One of the authors' recent advances in this field makes it possible to take SS solutions to the next performance level, i.e., sequential opportunistic decoding, or SOD for short. SOD is based on transmitting data symbols multiple times within the frame using non-orthogonal partial signature waveforms or mini-frames. Depending on the received instantaneous signal-to-interference-plus-noise ratio (SINR), a given subset of such mini-frames may suffice to reliably decode the data symbols. The best performing subset contains mini-frames that are received under better-than-average SINR channel conditions - i.e., these are referred to as the opportunistic mini-frames. By instantaneously controlling the number of mini-frames transmitted, SOD also offers distributed adaptable processing gain. The objective of this report is to propose cross-layer medium access control (MAC) protocols based on SOD. These protocols are especially suited to operate in a crowded radio spectrum, e.g., when multiple WLANs and/or wireless sensor networks coexist in the same radio space, possibly supporting multimedia applications. This unique advantage originates from the integration of two sub-layers. The lower sub-layer (SOD-MAC) applies the SOD adaptable processing gain to contain both the level of interference in the radio channel and network latency. It also minimizes the power consumption at the node and supports multiple c1asses of service. The upper sub-layer (ARQ-MAC) enables statistical multiplexing of an unbounded number of attempts of frame transmission generated by uncoordinated active nodes and it provides the automatic retransmission request (ARQ) capabilities. In essence, the uniqueness of these cross-layer access protocols is their ability to achieve efficient statistical multiplexing of traffic generated by uncoordinated nodes while containing the level of interference in the radio channel. The challenge is to combine frame retransmission schemes and SOD adaptable processing gain strategies in the most effective way, while keeping the access protocols in the stable region. The payoff is the ability to: increase the radio channel utilization, contain network latency, reduce energy consumption at the wireless node, and provide a QoS platform for both real-time and datagram traffic.