Browsing by Author "Tacca, Marco, 1973-"
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Item Ad Hoc 802.11b cooperative protocols: performance in a slow fading channel(The University of Texas at Dallas, 2013-05-24) Agarwal, Niraj, 1977-; ChanneGowda, Divya, 1981-; Kannan, Lakshmi Narasimhan, 1984-; Tacca, Marco, 1973-; Fumagalli, Andrea; Eric Jonsson School of Engineering and Computer Science. Open Networking Advanced Research (OpNeAR) Laboratory.This paper investigates the use of cooperative communications in the context of ad hoc IEEE 802.11b to combat radio signal degradations due to slow fading. The performance gain of both an existing cooperative protocol and the one proposed in the paper is discussed. It is quantitatively shown how much the two cooperative protocols increase throughput, lower delivery latency, and extend transmission span, when compared to the conventional IEEE 802.11b protocol. These features may help improve connectivity and network performance in ad hoc applications, where nodes’ relative locations are difficult to control and predict.Item An analytical model with improved accuracy of IEEE 802.11 protocol under unsaturated conditions(The University of Texas at Dallas, 2013-05-23) Vijayasankar, Kumaran, 1984-; Taufique, Azar; Kannan, Lakshmi Narasimhan, 1984-; Tacca, Marco, 1973-; Fumagalli, Andrea; Eric Jonsson School of Engineering and Computer Science. Open Networking Advanced Research (OpNeAR) Laboratory.In this work the authors present an analytical model that - compared to previously published work- more accurately captures the delay of IEEE 802.11 protocol under low, medium, and near-saturation load conditions. A Markov chain is used to keep track of the instantaneous number of (active) nodes that have a frame to transmit. The number of active nodes varies over time and is a function of various parameters, including the frame individual maximum retransmission count. One advantage of the proposed analytical model is its ability to estimate the IEEE 802.11 protocol latency and delivery ratio in the presence of quality of service (QoS) classes, each class being defined by a specific maximum retransmission count. Such QoS classes can be adopted to support real time applications for which both latency and delivery ratio must be closely monitored for satisfactory operation. The analytical estimation of these performance parameters may offer useful feedback to admission control 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 Combining cooperative link layer protocols with distributed routing protocols in mobile ad hoc networks – perspectives and performance analysis(The University of Texas at Dallas, 2013-06-18) Vijayasankar, Kumaran, 1984-; Kannan, Lakshmi Narasimhan, 1984-; Ilango, Sathya; Tacca, Marco, 1973-; Fumagalli, Andrea; Eric Jonsson School of Engineering and Computer Science. Open Networking Advanced Research (OpNeAR) Laboratory.In cooperative link layer protocols the use of relay nodes may increase the capacity of the radio links. The study in this paper investigates what (if any) performance gain may be passed onto the routing protocol of a mobile ad hoc network. Two popular routing protocols are considered, AODV and OLSR, as each provides a unique route acquisition mechanism. A distributed procedure to choose the relay node at the link layer is combined with the two routing protocols. Analysis via simulation confirms some expected (and perhaps some other less expected) benefits when using a cooperative link layer protocol in place of a non-cooperative one, e.g., improved delivery ratio, end-to-end delay, and reduced signaling overhead.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 Cooperative communications in multihop networking: a case study based on the IEEE 802.11 protocol(The University of Texas at Dallas, 2013-05-24) Kannan, Lakshmi Narasimhan, 1984-; Vijayasankar, Kumaran, 1984-; ChanneGowda, Divya, 1981-; Agarwal, Niraj, 1977-; Fumagalli, Andrea; Tacca, Marco, 1973-; Eric Jonsson School of Engineering and Computer Science. Open Networking Advanced Research (OpNeAR) Laboratory.This paper combines multi-hop networking with single-hop cooperative communications. The solution is built upon the standard IEEE 802.11 protocol operating in the ad hoc mode. A simulation based comparison is carried out in order to evaluate the performance gains and benefit of cooperative communications applied to multi-hop networking. Preliminary results indicate that network performance in terms of both throughput and end-to-end delay improves. Additionally, cooperative communications increases robustness against uncertainties in the wireless channel.Item A cross layer routing metric with wireless cooperative protocols(The University of Texas at Dallas, 2013-06-18) Vijayasankar, Kumaran, 1984-; Kannan, Lakshmi Narasimhan, 1984-; Tacca, Marco, 1973-; Fumagalli, Andrea; Eric Jonsson School of Engineering and Computer Science. Open Networking Advanced Research (OpNeAR) Laboratory.Cooperative link layer protocols are typically used in single hop networks. In such protocols, a special node called the relay node helps deliver frames from a source to a destination. The performance benefits of cooperation at link layer can be streamlined into multi-hop networks as well. In multi-hop networks, a frame is sent from an original source to the final destination through a series of intermediate nodes. The paper extends the expected transmission time metric — proposed for multi-hop wireless ad hoc networks — to the context of cooperative IEEE 802.11 link layer protocol. The designed metric is called cooperative expected transmission time (CETT). CETT carefully accounts for the higher probability of successful frame transmission and therefore the reduction in expected transmission time brought about by the relay node in the cooperative protocol. CETT jointly optimizes both the route computation and the selection of the cooperative relay at the link layer. Route optimization helps jointly choose the best set of intermediate nodes and cooperation optimization helps choose the best relay node for each link in the multi-hop. As a result, CETT helps distinguish the case wherein it is better to use a node as a relay as compared to using it as an intermediate node. For comparison, the case where cooperation is applied after route computation is also presented. Minimizing the expected transmission time may result in more efficient link utilization and increased overall end-to-end network throughput. It is also shown that joint optimization of route and relay selection is better than finding routes and then applying cooperation.Item Digital subcarrier optical networks (DSONs)(The University of Texas at Dallas, 2013-06-18) Huang, Wanjun, 1978-; Razo, Miguel; Tacca, Marco, 1973-; Fumagalli, Andrea; Hui, Rongqing; Eric Jonsson School of Engineering and Computer Science. Open Networking Advanced Research (OpNeAR) Laboratory.Energy efficient networks are increasingly becoming a desirable feature in today’s market. Both the number of users and the average amount of data traffic generated by each user continue to grow, requiring more powerful network routers and switches, which in turn dissipate large amount of electric power to operate. This problem is in part circumvented by deploying all-optical wavelength division multiplexing (WDM) solutions in the network, which eliminate any electronic processing of the in-transit data at the intermediate network nodes by dedicating a path of light (a wavelength) across the network to directly interconnect two edge nodes. However, the all-optical approach is only suitable when the average quantity of traffic to be exchanged by two edge nodes is sufficient large to warrant one entire (or many) dedicated wavelength(s). Considering that optical transmission rates are moving up from today’s 10 Gbps to 40, 100 and even 160 Gbps per wavelength, the fraction of edge nodes that exchange such amount of traffic is not (surprisingly) limited, as many of the edge node pairs would require only sub-wavelength connectivity. Sub-wavelength connectivity is today offered by either Optical Transport Network (OTN) or Multi Protocol Label Switching with Transport Profile (MPLS-TP). These solutions run on top of the WDM layer. Unfortunately, the amount of required electronic processing in these solutions is such that an order of magnitude higher power consumption results compared to all-optical networks. Part of this extra power consumption is due to the electronic buffering of the in-transit data at the intermediate nodes. This paper points to an alternative solution to achieving sub-wavelength bandwidth assignment to edge node pairs, which eliminates the need for data buffering at the intermediate nodes. Sub-wavelength channels or circuits are creating by using spectrally efficient orthogonal frequencies in each wavelength, with each frequency arrying a fraction of the wavelength bandwidth. By assigning one or more such frequencies to one edge node pair, an end-to-end sub-wavelength circuit is created. At the intermediate nodes, incoming frequencies are switched to outgoing frequencies via specially designed frequency selective switches or cross-connects. The power consumption required to switch frequencies in and out is estimated to be only a fraction of the power dissipated by current transport solutions, thus mitigating the energy consumption struggle when assigning subwavelength capacities to edge nodes.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 High-speed self-configuring networks based on cost-effective plug-and-play optical (PPO) nodes(The University of Texas at Dallas, 2013-06-18) Fumagalli, Andrae; Hui, Rongqing; Maloberti, F. (Franco); Gregori, Stefano; Cerutti, Isabella, 1973-; Tacca, Marco, 1973-; Eric Jonsson School of Engineering and Computer Science.This proposal visualizes a future ad-hoc multi-gigabit network infrastructure connecting a very large number of inexpensive optical nodes. Such nodes will look like today’s Fast Ethernet switches, providing however, 2-3 orders of magnitude higher bandwidth, and larger geographical network coverage. Users will connect nodes using already installed fibers by a simple plug-and-play operation. Once connected, the Plug-and-Play Optical (PPO) nodes will continuously communicate with other nodes for a self-configuration of both network and nodes. An on-board optical micro-lab, advanced transmission models and an intensive signal processing are the key components to build a system that is able to intelligently adjust optical data flows and wavelength selection. The PPO node configuration will account for varying traffic patterns and changing conditions of the optical physical layer, e.g., introduction and removal of PPO nodes, aging of optical components, temperature changes, soft failure of network elements. The objective of this proposal is to identify the required technologies, to study protocols and algorithms, to develop suitable transmission models, to design and fabricate critical parts of an integrated optical micro-lab that will make the envisioned scenario a reality, and to amalgamate all the achieved results for proving the PPO node concept feasibility.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 MAGIC: Mobile Auxiliary Gateways Improve Connectivity of wireless sensor networks(The University of Texas at Dallas, 2013-06-18) Fumagalli, Andrea; Maloberti, F. (Franco); Nosratinia, A.; Panahi, I. M.; Saquib, M.; Tacca, Marco, 1973-; Eric Jonsson School of Engineering and Computer Science.Item Multi-rate and multi-hop optical carriers in WDM ring(The University of Texas at Dallas, 2013-04-18) Cerutti, Isabella, 1973-; Fumagalli, Andrea; Tacca, Marco, 1973-; Lardies, Ana; Jagannathan, Rajesh Shanmugavel, 1971-; Eric Jonsson School of Engineering and Computer Science. Center for Advanced Telecommunications Systems and Services (CATSS); Texas Higher Education Coordinating BoardTransparency of the optical layer offers the possibility to design a network that operates at varying transmission bit rates. While variable bit rate interfaces are being tested and will soon provide the possibility to optimally select the transmission rate for each lightpath, the potential advantages of relying upon multiple transmission rates in the optical network are ready yet to be fully explored. In this paper we define the concept of Multi-hop and Multi-rate (M&M) network in which the tributary signal is transmitted over a sequence of lightpaths, with each lightpath operating at its own transmission rate, which is determined by a number of factors including the end node's interface, amount of multiplexed traffic and cost of the network components. The potential advantages provided by the M&M network when compared to first generation optical networks (i.e., SONET/SDH), single- and multi-hop (constant bit rate) optical networks, are discussed in general and demonstrated numerically in a WDM ring. Presented results show that the network cost reduction achieved by the M&M design is a function of the cost ratio between the optical bandwidth (wavelengths) and the optical terminals.Item Optimized transmission power levels in a cooperative ARQ protocol for microwave recharged wireless sensors(The University of Texas at Dallas, 2013-06-18) Monti, Paolo, 1973; Tacca, Marco, 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 node battery does not need to be replaced. Power is delivered to the sensor node via a microwave signal that is radiated by a base-station. The base-station also acts as the entry point to a wider communication network, e.g., the Internet. This paper describes an automatic repeat request (ARQ) protocol that may be used in GAP4S to yield reliable and fair data transmission from the sensor nodes to the base-station. The protocol takes advantage of cooperative communication, whereby neighboring sensor nodes help during the retransmission process. The transmission power level is optimized at each sensor node to increase the saturation throughput of the ARQ protocol.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 A practical perspective in designing mesh networks based on 1 : N self-healing wavelength division multiplexing rings(The University of Texas at Dallas, 2013-06-18) Fumagalli, Andrea; Tacca, Marco, 1973-; Cerutti, Isabella, 1973-; Masetti-Placci, Francesco; Jagannathan, Rajesh Shanmugavel, 1971-; Eric Jonsson School of Engineering and Computer Science. Department of Electrical Engineering.; US Army Space and Strategic Defense CommandA fundamental task of the optical layer in modern telecommunication systems consists of providing a fast protection mechanism against possible faults in the network. A particularly attractive protection technique in the optical layer is the so called shared line protection, in which network lines are protected using shared resources. A previous work of the authors formally describes the problem of minimizing the total wavelength mileage necessary in a Wavelength Routing mesh network to provide shared line protection. However, two practical issues remain to be addressed: the solution feasibility in presence of design constraints and the problem complexity in large size networks. This paper presents an approach to addressing the above two issues based on: 1) an algorithm that identifies a feasible solution with the minimal, possibly null, violation of the design constraints, 2) an intelligent pruning technique of the search space that reduces the complexity of the optimization problem. Using the proposed approach, a study on the total wavelength mileage is carried out for the European network (19 nodes) and the Pan American network (79 nodes) to assess the influence that some design constraints have on this cost function.Item A queueing model for PCEP (Path Computation Element Protocol)(The University of Texas at Dallas, 2013-06-18) Yu, Juanjuan, 1978-; He, Yue; Wu, Kai; Tacca, Marco, 1973-; Fumagalli, Andrea; Vasseur, Jean-Phillippe; Eric Jonsson School of Engineering and Computer Science. Open Networking Advanced Research (OpNeAR) Laboratory.Path computation elements (PCE’s) are used to compute end-to-end paths across multiple areas. Multiple PCE’s may be dedicated to each area to provide sufficient path computation capacity and redundancy. An open problem is which PCE should be chosen to send the path computation request to, that may be a non trivial problem if PCE’s have uneven processing capacities. This paper presents a product form queueing model to estimate the latencies in path computation while accounting for the arrival rate of path computation requests. The model is used to find the PCE selection policy to minimize the average expected latencies in path computation. The model is validated against two simulation benchmarks obtained using OPNET, i.e., a network of queues and the multi protocol label switching with traffic engineering (MPLSTE) network running the PCE communication protocol (PCEP). The study shows that the use of product form yields approximations that are up to 15% at practical offered loads. Moreover, the PCE selection policy derived under the product form assumption is showed to be effective in minimizing the overall expected latencies in path computation.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.