Browsing by Author "Fumagalli, Andrea"
Now showing 1 - 20 of 57
- Results Per Page
- Sort Options
Item A Programmable Optical Network Testbed in Support of C-RAN: A Reliability Study(Springer New York LLC) Ramanathan, Shunmugapriya; Tacca, Marco; Razo, Miguel; Mirkhanzadeh, Birkhanzadeh; Kondepu, K.; Giannone, F.; Valcarenghi, L.; Fumagalli, Andrea; 0000-0001-6002-060X (Taca, M); Ramanathan, Shunmugapriya; Tacca, Marco; Razo, Miguel; Fumagalli, AndreaWith both mobile network services and related data traffic volume on the rise, reliability of the radio access network is of the essence. A number of radio functional splits are defined by 3GPP to offer increased flexibility of implementation and feasibility of new mobile network services. For example, it is possible to implement certain radio functions in the Cloud, an architectural solution referred to as C-RAN. C-RAN solutions require highly reliable backhaul and fronthaul network designs. This paper describes PROnet, a programmable optical software-defined network testbed, which has been upgraded to offer backhaul and fronthaul transport capabilities in support of C-RAN functionalities with increased reliability. The testbed is upgraded with a specially designed 1 + 1 protection mechanism at the Ethernet layer in order to meet the stringent network round-trip requirements imposed by one of the C-RAN functional split options on the fronthaul. ©2019 Springer Science+Business Media, LLC, part of Springer Nature.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 Experimental End-to-End Delay Study of a Sub-1GHz Wireless Sensor Network with LTE Backhaul(Institute of Electrical and Electronics Engineers Inc., 2018-12-09) Arjona, Ricardo; Fumagalli, Andrea; Lee, C.; Vijayasankar, K.; Arjona, Ricardo; Fumagalli, AndreaThis paper describes an experimental study of network access delay from the end device to the cloud over a network based on Sub IGHz and LTE based network which may find many practical Internet of Things (IoT) applications when network response time is key and must be closely assessed. For this reason, the authors have built a test-bed using a low cost and ease of deployment wireless sensor network (WSN) based on the IEEE802.15.4g standard that is connected to an LTE modem, providing connectivity to a server in the cloud. The test-bed is used to measure end-to-end packet transfer time from the wireless IoT device to the cloud server, also providing a delay breakdown for every segment of the network. The presented results show the delay performance of the loT network architecture under varying values of the loT device periodic reporting time. While the operation modes of the WSN do not significantly affect the network latency, the LTE backhaul connectivity introduces some delay variability, which depends on the loT device periodic reporting time and other factors. By making use of these results the application designer can estimate the achievable network latency and make sure that the loT application requirements are met. © 2018 IEEE.Item An Experimental End-To-End Delay Study of a Sub-1GHz Wireless Sensor Network with LTE Backhaul(Institute of Electrical and Electronics Engineers Inc.) Arjona, Ricardo; Fumagalli, Andrea; Lee, C.; Vijayasankar, K.; Arjona, Ricardo; Fumagalli, AndreaThis paper describes an experimental study of network access delay from the end device to the cloud over a network based on Sub IGHz and LTE based network which may find many practical Internet of Things (IoT) applications when network response time is key and must be closely assessed. For this reason, the authors have built a test-bed using a low cost and ease of deployment wireless sensor network (WSN) based on the IEEE802.15.4g standard that is connected to an LTE modem, providing connectivity to a server in the cloud. The test-bed is used to measure end-to-end packet transfer time from the wireless IoT device to the cloud server, also providing a delay breakdown for every segment of the network. The presented results show the delay performance of the loT network architecture under varying values of the loT device periodic reporting time. While the operation modes of the WSN do not significantly affect the network latency, the LTE backhaul connectivity introduces some delay variability, which depends on the loT device periodic reporting time and other factors. By making use of these results the application designer can estimate the achievable network latency and make sure that the loT application requirements are met. © 2018 IEEE.Item An Internet of Things Platform for Improved Water Management Using Underground Soil Moisture Sensing(2021-05-01T05:00:00.000Z) Arjona Angarita, Ricardo Javier; Fumagalli, Andrea; Fei, Baofei; Razo-Razo, Miguel; Tacca, Marco; Tamil, Lakshman; Faragó, AndrásEfficient use of water resources is becoming of paramount importance in agriculture due to their scarcity and less predictable availability impacted by climate change. Profitability of traditional farming methods to meet the increasing population demand for food production has been negatively affected, thus requiring efficient irrigation systems and water management practices through technology. In this thesis, a cost-effective Internet of Things - IoT platform that incorporates underground soil moisture sensing is presented with the aim of increasing the penetration of applied technologies in the farming market. The platform features a Sub-1 GHz IEEE802.15.4g-based wireless sensor network concentrator (WSNC) with LTE backhaul which provides Internet connectivity in rural areas towards a cloud server. The WSNC connects sensor nodes to the collector node over a wireless link following a star topology network. The sensor node is enhanced with a helical antenna designed specifically for underground operation along with a power amplifier to compensate signal attenuation in the soil-air path to the WSNC. Based on the number of collectors and physical layers that are supported, the implemented WSNC offers three configurations: Single Collector (SC), Multi Collector (MC) and MC - Multi Rate (MR). The SC-WSNC supports a total of 50 sensor nodes whereas the MC-WSNC can support up to 200 devices by hosting several independent Wireless Sensor Networks (WSNs) operating on a unique frequency channel. To improve the system performance, a load balancing algorithm and a sensor handover mechanism are developed for the MC-WSNC to uniformly distribute the number of aggregated sensor nodes across the available collectors. The MR capability added to the MC-WSNC and the sensor nodes dynamically optimizes the energy consumption and radio link margin of the sensor nodes for improved battery lifetime and connection reliability. The SC-WSNC has been experimentally evaluated in terms of coverage range in aboveground and underground scenarios with a detailed end-to-end delay characterization using state-of-art tools in every network segment. The results reveal the limitations of the system in covering large farming areas due to both the high attenuation in the combined physical media and the limited number of sensor nodes that can be attached to one collector. In contrast, the MC-WSNC is evaluated using a test-bed consisting of up to four co-located collectors and fifty sensor nodes. The performance evaluation is carried out under race conditions in the WSNs to emulate high dense networks with different network sizes and channel gaps. The experimental results show that the MC-WSNC proportionally scales up the capacity of the network and reduces both the energy consumption and the packet error rate of the sensor nodes. The MR feature - implemented as a physical layer switch at the sensor nodes - further reduces the overall network power consumption and increases the network throughput while at the same time accounts for varying radio link conditions.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 Application-Triggered Automatic Distributed Cloud/Network Resource Coordination by Optically Networked Inter/Intra Data Center(Institute of Electrical and Electronics Engineers Inc.) Yamanaka, N.; Okamoto, S.; Hirono, M.; Imakiire, Y.; Muro, W.; Sato, T.; Oki, E.; Fumagalli, Andrea; Veeraraghavan, M.; Fumagalli, AndreaEverything is being connected to the Cloud and Internet of Things, and network robots with big data analy- sis are creating important applications and services. The cloud network architecture is moving towards mega-cloud data centers (DCs) provided by companies such as Amazon and Google in combination with distributed small DCs or edge computers. While the traditional restrictions im- posed by distance and bandwidth are being overcome by the development of advanced optical interconnection, modern applications impose more complex performance and quality of service requirements in terms of processing power, response time, and data amount. The rise in cloud perfor- mance must be matched by improvements in network per- formance. Therefore, we propose an application-triggered cloud network architecture based on huge-bandwidth optical interconnections. This paper addresses edge/center cloud and edge/edge integration with the use of virtual ma- chine migration. In addition, to reduce energy consumption, an application-triggered intra-DC architecture is described. Using the proposed architectures and technologies can real- ize energy-efficient and high-performance cloud service. © 2009-2012 OSA.Item An automatic repeat request protocol for cooperative slotted radio networks(The University of Texas at Dallas, 2013-06-18) Cerutti, Isabella, 1973-; Fumagalli, Andrea; Gupta, Puja, 1980-; Eric Jonsson School of Engineering and Computer Science. Open Networking Advanced Research (OpNeAR) Laboratory.In conventional (non-cooperative) radio networks, the data frames, that are corrupted by errors during the transmission in a fading environment, are retransmitted by the source. In cooperative radio networks, frame retransmission may be performed by a neighboring node that has successfully overheard the source’s frame transmission. The advantage of the latter is the spatial diversity that is provided by the cooperative node. In addition, the retransmitted frame may have incremental redundancy for improved performance. In this paper a simple automatic repeat request (ARQ) protocol is specified that takes advantage of coded cooperative communication in slotted, single-hop radio networks. An exact analytical formulation is presented to compute the delay experienced by Poisson arriving frames whose retransmission (when needed) is performed by one cooperative node. The study reports significant quantitative advantages of the coded cooperation ARQ protocol in terms of both throughput and latency, when compared to non-cooperative ARQ protocols.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 Building Resiliency Into 5G Open-source and Disaggregated Architecture(December 2023) Ramanathan, Shunmugapriya 1982-; Kantarcioglu, Murat; Fumagalli, Andrea; Tamil, Lakshman; Razo-Razo, Miguel; Tacca, MarcoToday in the Internet era, communication service providers face tremendous constraints on increasing capital expenditures and operating expenses compared to the much less income growth. Cloud Radio Access Network (C-RAN) architecture has emerged as a potential candidate for the future wireless network that highlights the notion of service cloud, service-oriented resource scheduling, and management, thereby facilitating the utilization of both Network Functions Virtualization and Software-Defined Networking (NFV-SDN) technologies. The transport network reliability of the disaggregated C-RAN components is paramount to ensure reliable data communication. Our first contribution focuses on providing transport network resiliency support for the C-RAN architecture using a programmable optical software-defined network testbed. The testbed supports C-RAN functionalities by offering fronthaul, midhaul, and backhaul transport capabilities with increased reliability. The C-RAN components are further disaggregated and run as either virtual machines (VMs) or containers in a virtualized environment. To ensure load-balancing and fault-tolerance of the C-RAN components, our Optical programmable testbed with SDN capabilities supports live migration of C-RAN functions among data centers. OS container-based virtualization enables faster application instantiation than the hypervisor-based VM because of its smaller footprint size. However, in the context of the mobile network protocol stack, the open- source container migration software has yet to be developed to the full extent. Our second and third contributions focus on the live migration of containerized core network and RAN central unit virtual functions. The live migration is made feasible through our proof-of- concept implementation of the open-source container migration software. In the C-RAN architecture, the Next Generation NodeB (gNB) functions are decoupled into three entities, namely Radio Unit (RU), Distributed Unit (DU), and Central Unit (CU). These entities will likely be virtualized and distributed in micro and macro data centers. The virtualized CUs (vCUs) are decoupled further into virtualized CU Control-Plane (vCU- CP) and virtualized CU User-Plane (vCU-UP) to optimize the location of the RAN functions for 5G vertical use case scenarios and performance requirements. The vCU-CP handles the signaling functionality, such as connection establishment and hand-over. All the 5G Core Network control plane modules have a single point of contact with vCU-CP. Therefore, a study on resiliency on vCU-CP is important to avoid the single point of failure, which comes under our fourth contribution. Our proof-of-concept guaranteed the fronthaul network reliability of the 5G transport network and during VNF live migration, it ensured end-user service continuity without permanent UE interruption. In addition, the temporary downtime experienced during the live-migration is significantly lowered by more than 50% when using our container migration prototype compared to traditional VM solutions.Item Chromatic dispersion and self-phase modulation in multi-hop multi-rate WDM rings(The University of Texas at Dallas, 2013-06-18) Cerutti, Isabella, 1973-; Fumagalli, Andrea; Potasek, Mary J.; Eric Jonsson School of Engineering and Computer Science. Open Networking Advanced Research (OpNeAR) Laboratory.; New York University. Courant Institute.When compared to first generation and single-hop optical networks, multi-hop and multirate (M & M) network architectures have the advantage of significantly reducing network design cost under a variety of wavelength-to-terminal cost ratios. This report investigates how fiber chromatic dispersion and self-phase modulation may affect such cost reduction in M & M WDM rings.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 ARQ protocols in slotted radio networks(The University of Texas at Dallas, 2013-06-18) Cerutti, Isabella, 1973-; Fumagalli, Andrea; Gupta, Puja, 1980-; Eric Jonsson School of Engineering and Computer Science. Open Networking Advanced Research (OpNeAR) Laboratory.In conventional (non-cooperative) automatic repeat request (ARQ) protocols for radio networks, the corrupted data frames that cannot be correctly decoded at the destination are retransmitted by the source. In cooperative ARQ protocols, data frame retransmissions may be performed by a neighboring node (the relay) that has successfully overheard the source’s frame transmission. One advantage of the latter group of ARQ protocols is the spatial diversity provided by the relay. The first delay model for cooperative ARQ protocols is presented in this paper. The model is analytically derived for a simple set of retransmission rules that make use of both uncoded and coded cooperative communications in slotted radio network. The model estimates the delay experienced by Poisson arriving frames, whose retransmissions (when required) are performed also by a single relay. Saturation throughput, frame latency and buffer occupancy at the source, and relay are quantified and compared against two non-cooperative ARQ protocols.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 Cross-Layer Design Approaches Accounting for Optical Physical, Network, and Application Layers(2017-08) Wang, Xue; Fumagalli, AndreaWith the rapid growth of Internet traffic, the current network architecture is facing various challenges on network resource control and management. First, emerging applications such as Video on Demand and web conferencing require higher transmission bandwidth. Second, with the development of cloud services such as self-provisioned IT services and elastic computing, the user traffic becomes more dynamic, which requires flexibility on network resource management. In addition, multiple types of resources must be made available in the cloud infrastructure to the applications in order to achieve desired Quality of Service (QoS). To deal with these challenges, efficient network optimization solutions are needed to tackle the increasing bandwidth demand and adapt to the dynamic nature of the future traffic. Software-defined Networking (SDN) is enabling networks to be programmable by decoupling the control plane and the data plane, which are currently integrated in most network equipment. This control framework has been widely accepted as an efficient network technology capable of applying cross-layer orchestration. SDN can control and manage network resources in a more efficient way by allowing the information access and exchange between different layers. For example, application can have the knowledge of the network resource status. In this dissertation, a cross-layer design approach is firstly presented to apply the optimization between network layer and physical layer. Routing and wavelength assignment strategies are jointly considered with the characteristics and power control of the physical layer devices in order to increase the network throughput and the signal robustness. The cross-layer optimization is also investigated between network layer and application layer. Multiple online resource allocation strategies are proposed while taking into account the requirements of the cloud applications to increase the resource utilization and reduce the link bandwidth over-provisioning.Item Destination-initiated wavelength-weighted reservation protocol in WDM rings(The University of Texas at Dallas, 2013-06-03) Pitchumani, Sudhakar, 1978-; Cerutti, Isabella, 1973-; Fumagalli, Andrea; Eric Jonsson School of Engineering and Computer Science. Open Networking Advanced Research (OpNeAR) Laboratory.In networks that require dynamic assignment of wavelengths, it is known that destination initiated reservation protocols lower the blocking robability - caused by unavailable wavelengths or convergence problems of the network status information -, when compared to source initiated reservation protocols [1]. Choosing the wavelength using weights based on past performance may further lower such blocking probability, when compared to random selection strategies [2]. This paper presents a Destination initiated Weighted-Wavelength Reservation DW2R protocol that improves the performance of destination initiated reservation protocol and does not require any additional signaling messages. Wavelength weights are computed based on past blocking probabilities and stored at the source. A meticulous simulation study carried out on ring networks reveals for the first time a number of interesting properties of the proposed DW2 R protocol: a reduced (backward) blocking probability when compared to other reservation protocols, a good scalability in the number of ring nodes (links) and in the number of wavelengths, and a contained performance degradation due to an increase of either the ring signaling latency or the frequency of traffic changes.Item Digital subcarrier cross-connects (DSXCs)(The University of Texas at Dallas, 2013-06-18) Hui, Rongqing; Huang, Wanjun, 1978; Razo, Miguel; Tacca, Marco, 1973; Fumagalli, Andrea; Eric Jonsson School of Engineering and Computer Science. Open Networking Advanced Research (OpNeAR) Laboratory.Traditional (analog) Frequency Division Multiplexing (FDM) was widely used in the pre-SONET/SDH era, to multiplex transport channels together using spectral diversity. These transport solutions were then gradually abandoned due in part to their low spectral efficiency and with the advent of Time Division Multiplexing (TDM), which lead to synchronous transmission techniques, such as SONET and SDH. Another problem of traditional FDM or Subcarrier Multiplexing (SCM) ─ being analog ─ is its susceptibility to accumulated waveform distortion and crosstalk. For these reasons FDM is not competitive in today’s transport networks. Digital signal processing continues to reach new record high rates, thus enabling Digital Subcarrier Crossconnects (DSXCs) to operate even at the high transmission rates of optical signals. In DSXC, the incoming subcarriers are switched to the outgoing subcarriers by a controlled Radio Frequency (RF) crossbar switch. The power consumption required to switch subcarriers in and out is estimated to be only a fraction of the power dissipated by current TDM and packet switching based transport network solutions. Multiple DSXCs can be combined to design Digital Subcarrier Optical Networks (DSONs) [1], which are a promising energy efficient alternative to current electronic-based transport network techniques, e.g., OTN/SONET/SDH/MPLS-TP. The DSXC’s basic functionalities and modules are introduced and discussed in this paper.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.
- «
- 1 (current)
- 2
- 3
- »