Showing papers on "Overlay network published in 2021"

Agents-Based Algorithm for a Distributed Information System in Internet of Things

Abstract: Traditional information management approaches in distributed systems are most often unsuitable for modern Internet of Things (IoT) environments due to the huge amount and the extreme dynamism of the entities involved. Smart objects (enhanced devices or IoT services belonging to a smart system) interact and maintain relations which need of effective and efficient handling mechanisms better to meet users and services requirements. This article proposes an agent-based algorithm for achieving a distributed resources organization in an IoT environment. Software agents, representing each a single smart object, execute a set of local computations simultaneously, enabling an organized structure to emerge at global level. A natural language processing approach, able to capture the semantic context and represent objects with high-dimensional vectors, was exploited to map the IoT objects, so enabling advanced agents’ operations. The emerging organized virtual structure, i.e., a similarity-based overlay network of agents, allows building informed resource selection/discovery services, therefore more efficient, in a highly dynamic and, basically, unstructured environment. Preliminary results confirm the validity of the approach.

Under the Hood of the Ethereum Gossip Protocol

Abstract: Blockchain protocols’ primary security goal is consensus: one version of the global ledger that everyone in the network agrees on. Their proofs of security depend on assumptions on how well their peer-to-peer (P2P) overlay networks operate. Yet, surprisingly, little is understood about what factors influence the P2P network properties. In this work, we extensively study the Ethereum P2P network’s connectivity and its block propagation mechanism. We gather data on the Ethereum network by running the official Ethereum client, geth, modified to run as a “super peer” with many neighbors. We run this client in North America for over seven months, as well as shorter runs with multiple vantages around the world. Our results expose an incredible amount of churn, and a surprisingly small number of peers who are actually useful (that is, who propagate new blocks). We also find that a node’s location has a significant impact on when it hears about blocks, and that the precise behavior of this has changed over time (e.g., nodes in the US have become less likely to hear about new blocks first). Finally, we find prune blocks propagate faster than uncles.

Quality of service provisioning in network function virtualization: a survey

Abstract: Network function virtualization (NFV) is a promising paradigm for network service provisioning which decouples the network functions from the physical infrastructure, allowing to deploy the virtualized network functions (VNF) as modular software components over commodity servers. In this architecture, service function chaining (SFC) creates an application-specific network overlay which determines the placement and ordering of network functions in a specific service delivery chain. The diverse choices for VNF placement over physical hardware, scheduling of VNF instances to run over the servers and design of optimal chaining mechanisms for traffic steering in the network have direct consequences on the quality-of-service (QoS) perceived by the network users. Previous surveys have focused on categorizing and evaluating various aspects of SFC, NFV and SDN. Due to the tight coupling of QoS provisioning with NFV problems, our work aims primarily at complementing the existing surveys in the sense that we review and classify the state-of-art research efforts in NFV design and implementation from the perspective of QoS provisioning. Our survey provides a closer look at the design space of QoS-related NFV solutions and sheds light on the open research topics in relevance with QoS-based SFC. We also present a case study to evaluate the performance of some recent VNF placement algorithms.

BDS+: An Inter-Datacenter Data Replication System With Dynamic Bandwidth Separation

Abstract: Many important cloud services require replicating massive data from one datacenter (DC) to multiple DCs. While the performance of pair-wise inter-DC data transfers has been much improved, prior solutions are insufficient to optimize bulk-data multicast, as they fail to explore the rich inter-DC overlay paths that exist in geo-distributed DCs, as well as the remaining bandwidth reserved for online traffic under fixed bandwidth separation scheme. To take advantage of these opportunities, we present BDS+ , a near-optimal network system for large-scale inter-DC data replication. BDS+ is an application-level multicast overlay network with a fully centralized architecture, allowing a central controller to maintain an up-to-date global view of data delivery status of intermediate servers, in order to fully utilize the available overlay paths. Furthermore, in each overlay path, it leverages dynamic bandwidth separation to make use of the remaining available bandwidth reserved for online traffic. By constantly estimating online traffic demand and rescheduling bulk-data transfers accordingly, BDS+ can further speed up the massive data multicast. Through a pilot deployment in one of the largest online service providers and large-scale real-trace simulations, we show that BDS+ can achieve 3- $5\times $ speedup over the provider’s existing system and several well-known overlay routing baselines of static bandwidth separation. Moreover, dynamic bandwidth separation can further reduce the completion time of bulk data transfers by 1.2 to 1.3 times.

Overlay Networks with Jamming and Energy Harvesting: Security Analysis

Abstract: In cognitive radio networks, direct communications between a primary sender–recipient pair may be blocked due to uncertainties such as deep fading. Therefore, this paper studies overlay networks where the message of the primary sender is relayed by the secondary transmitter who also transmits its privacy message to support this communications. However, messages of the secondary transmitter may also be overheard by eavesdroppers. To secure these messages, jammers are exploited to restrict overhearing. Moreover, in order to improve energy efficiency, the secondary transmitter and all jammers only use energy harvested from primary signals for their transmission. To evaluate the security capability of both primary and secondary networks without exhaustive simulations, exact closed-form expressions of primary/secondary secrecy outage probabilities are first proposed. Then, multiple theoretical/simulated results show the validity of the proposed expressions and security improvement with increasing the number of jammers. Finally, exhaustive search based on the proposed expressions can find optimum design parameters, which perfectly serve as design instructions.

A Survey on Video Streaming in Multipath and Multihomed Overlay Networks

Abstract: The focus of this survey is to study the protocols, mechanisms, and the latest standards proposed in the literature for improving the performance and quality of video content in multipath and multihomed overlay networks. Multipath is a broader term, but in the context of this survey, we define multipath as enhancing network routing technique by using various paths that are not necessarily completely disjoint. Multipath can furnish a variety of advantages such as reliability,connection persistence, increased perceived throughput and load balancing. On the other hand, multihoming is the ability to use multiple network interfaces when connecting to the Internet to increase reliability, resilience, and performance. Most existing surveys are specialized in one specific domain area related to multipath or multihoming. This study covers the research proposals at the different layers/sublayers of an overlay network from transport to the application and extends to cover the latest technologies like machine learning, Fog and Mobile Edge computing, VR 360 video, and the Internet of Multimedia Things (IoMT). As such, our work tries to be as comprehensive as possible to relate multipath and multihoming research solutions for video streaming to the current and emerging video streaming technologies.

IP Network Design Guide

Abstract: This redbook identifies some of the basic design aspects of IP networks and explains how to deal with them when implementing new IP networks or redesigning existing IP networks. This project focuses on internetwork and transport layer issues such as address and name management, routing, network management, security, load balancing and performance, design impacts of the underlying networking hardware, remote access, quality of service, and platform-specific issues. Application design aspects, such as e-mail, gateways, Web integration, etc., are discussed briefly where they influence the design of an IP network. After a general discussion of the aforementioned design areas, this redbook provides three examples for IP network design, depicting a small, medium and large network. You are taken through the steps of the design and the reasoning as to why things are shown one way instead of another. Of course, every network is different and therefore these examples are not intended to generalize. Their main purpose is to illustrate a systematic approach to an IP network design given a specific set of requirements, expectations, technologies and budgets. This redbook will help you design, create or change IP networks implementing the basic logical infrastructures required for a successful operation of such networks. This book does not describe how to deploy corporate applications such as e-mail, e-commerce, Web server or distributed databases, just to name a few.

Towards Sheaf Theoretic Analyses for Delay Tolerant Networking

Abstract: The goal of Delay Tolerant Networking (DTN) is to take a collection of heterogeneous, disparate connections between satellites, space assets, ground stations, and ground infrastructure and bring it together into a cohesive, functioning overlay network. Depending on the systems being considered, one can find links with a one-way light time exceeding minutes (and hours), periodic links which can sometimes be predicted by orbital mechanics, and restrictions based on the variety of capabilities built into these systems. These characteristics preclude traditional network models and routing techniques and have classically led to either rigid routing tables or purely probabilistic models. As the deeper underlying structures remain unknown, development of more DTN-optimized algorithms has lacked the necessary foundation. In a continuation of previous work, the goal of this paper is to identify and study these fundamental structures that exist in delay tolerant networks (DTN), with a focus on space networks. The current routing methodology has been to use contact graph routing (CGR) algorithms. CGR models a series of known contacts as a static graph. For CGR to work, this graph must be globally consistent and must have an accurate picture of the network. Because this is a globally controlled structure, there is little room for flexibility in the event of changes to the network which would naturally occur as the network grows. As a response to the desire for flexibility as the network changes, we introduced the mathematical structure known as sheaves to DTNs last year. The tag-line for sheaves is that they are a mathematically precise way of gluing local data together into unique global data. Thus, sheaves lend extra power to traditional models (and routing algorithms) by taking additional information and merging it, in as consistent a manner as possible, with the representation itself. The clearest example of how Earth-bound networks exhibit behavior that is “sheafy” is link state routers, which build a local-to-global picture of their network by gluing local information together into a global network, exactly as a sheaf would do. For routing within delay tolerant networks to truly exploit this structure, a deeper structure than a graph is required. In this paper, we develop sheaves that can work over directed graphs such as temporal flow networks, we construct a sheaf representation for Dijkstra's algorithm, and we outline a construction for routing sheaves capable of modeling multicast scenarios. Finally, there is a section of future work suggesting follow-on research.

Parallelizing packet processing in container overlay networks

Abstract: Container networking, which provides connectivity among containers on multiple hosts, is crucial to building and scaling container-based microservices. While overlay networks are widely adopted in production systems, they cause significant performance degradation in both throughput and latency compared to physical networks. This paper seeks to understand the bottlenecks of in-kernel networking when running container overlay networks. Through profiling and code analysis, we find that a prolonged data path, due to packet transformation in overlay networks, is the culprit of performance loss. Furthermore, existing scaling techniques in the Linux network stack are ineffective for parallelizing the prolonged data path of a single network flow. We propose Falcon, a fast and balanced container networking approach to scale the packet processing pipeline in overlay networks. Falcon pipelines software interrupts associated with different network devices of a single flow on multiple cores, thereby preventing execution serialization of excessive software interrupts from overloading a single core. Falcon further supports multiple network flows by effectively multiplexing and balancing software interrupts of different flows among available cores. We have developed a prototype of Falcon in Linux. Our evaluation with both micro-benchmarks and real-world applications demonstrates the effectiveness of Falcon, with significantly improved performance (by 300% for web serving) and reduced tail latency (by 53% for data caching).

Impact of channel estimation-and-artificial noise cancellation imperfection on artificial noise-aided energy harvesting overlay networks

Abstract: EHONs (Energy Harvesting Overlay Networks) satisfy stringent design requirements such as high energy-and-spectrum utilization efficiencies. However, due to open access nature of these networks, eavesdroppers can emulate cognitive radios to wire-tap legitimate information, inducing information security to become a great concern. In order to protect legitimate information against eavesdroppers, this paper generates artificial noise transmitted simultaneously with legitimate information to interfere eavesdroppers. Nonetheless, artificial noise cannot be perfectly suppressed at legitimate receivers as for its primary purpose of interfering only eavesdroppers. Moreover, channel information used for signal detection is hardly estimated at receivers with absolute accuracy. As such, to quickly evaluate impact of channel estimation-and-artificial noise cancellation imperfection on secrecy performance of secondary/primary communication in ANaEHONs (Artificial Noise-aided EHONs), this paper firstly proposes precise closed-form formulas of primary/secondary SOP (Secrecy Outage Probability). Then, computer simulations are provided to corroborate these formulas. Finally, various results are illustrated to shed insights into secrecy performance of ANaEHON with key system parameters from which optimum parameters are recognized. Notably, secondary/primary communication can be secured at different levels by flexibly adjusting various parameters of the proposed system model.

Multicast at Edge: An Edge Network Architecture for Service-Less Crowdsourced Live Video Multicast

Abstract: Using smartphones, tablets, and other portable/handheld devices, we have become more reliant on the video streaming services for entertainment and remote work. Mobile data traffic has grown eighteen folds over the past five years accounting for the majority of IP traffic. YouTube Live, Facebook Live, Twitch, DouYu and other streaming as well as video conferencing services have increased in popularity so at any given moment they serve thousands of live video streams to millions of users. The Enhanced Multimedia Broadcast Multimedia Service (eMBMS) is the standard multicast protocol for 5G networks. Cellular multicast has gained considerable attention to efficiently utilize the limited spectrum to transmit multimedia content to cellular sites with co-located viewers, lowering the cost, and maximizing the Quality of Experience (QoE). However, popular live video content providers use unicast mode for live video delivery and have limited support in the eMBMS service-oriented network architecture. In this paper, we propose an overlay network architecture to augment eMBMS to address the limitations of the standard eMBMS architecture and enable service-less multicast for crowdsourced live video providers. We propose a Virtual Network Function (VNF) service that identifies potential multicast scenarios based on user requests for a live video within a confined area. The VNF Application Server collects information, validates a potential multicast scenario, and initiates an ad-hoc multicast service on the fly. We use a real-world dataset of Facebook Live videos to evaluate the proposed architecture. The simulation results depict considerable advantages in terms of cost, efficiency, and Quality of Experience (QoE). Our results show that the proposed architecture provides significant benefits in bandwidth saving at the backhaul, transit, and RAN links.

D-MQTT: design and implementation of a pub/sub broker for distributed environments

Abstract: MQTT is a publish/subscribe protocol whose usage is growing a lot in recent years, especially in the field of Internet of Things (IoT) and Wireless Sensor Networks (WSN) applications. The protocol is based on a central broker entity, which is in charge of collecting publications and subscriptions from clients and forwarding messages among them. In this work, we propose a distributed version of the protocol, named D-MQTT, where multiple brokers connect among themselves, allowing clients to communicate even if originally associated to different brokers. Distinctive features of our proposal are: (i) automatic broker discovery, (ii) creation of an optimized, failure-resistant overlay network among the brokers and (iii) efficient routing of the publication messages. We propose an implementation of D-MQTT based on the popular open-source Mosquitto broker and we evaluate its performance on a network of brokers using the Containernet framework, comparing its performance with the standard MQTT bridging distribution approach. The source-code of D-MQTT is made publicly available at https://tinyurl.com/MQTT-Distributed.

Impact of Artificial Noise on Security Capability of Energy Harvesting Overlay Networks

Abstract: Artificial noise, energy harvesting, and overlay communications can assure design metrics of modern wireless networks such as data security, energy efficiency, and spectrum utilization efficiency. This paper studies impact of artificial noise on security capability of energy harvesting overlay networks in which the cognitive transmitter capable of self-powering its operation by harvesting radio frequency energy and self-securing its communications against eavesdroppers by generating artificial noise amplifies and forwards the signal of the primary transmitter as well as transmits its individual signal concurrently. To quantify this impact, the current paper firstly suggests accurate expressions of crucial security performance indicators. Then, computer simulations are supplied to corroborate these expressions. Finally, numerous results are demonstrated to expose insights into this impact from which optimum specifications are determined. Notably, primary/cognitive communications can be secured at distinct degrees by flexibly controlling multiple specifications of the suggested system model.

Deploying an NFV-Based Experimentation Scenario for 5G Solutions in Underserved Areas.

Abstract: Presently, a significant part of the world population does not have Internet access. The fifth-generation cellular network technology evolution (5G) is focused on reducing latency, increasing the available bandwidth, and enhancing network performance. However, researchers and companies have not invested enough effort into the deployment of the Internet in remote/rural/undeveloped areas for different techno-economic reasons. This article presents the result of a collaboration between Brazil and the European Union, introducing the steps designed to create a fully operational experimentation scenario with the main purpose of integrating the different achievements of the H2020 5G-RANGE project so that they can be trialed together into a 5G networking use case. The scenario encompasses (i) a novel radio access network that targets a bandwidth of 100 Mb/s in a cell radius of 50 km, and (ii) a network of Small Unmanned Aerial Vehicles (SUAV). This set of SUAVs is NFV-enabled, on top of which Virtual Network Functions (VNF) can be automatically deployed to support occasional network communications beyond the boundaries of the 5G-RANGE radio cells. The whole deployment implies the use of a virtual private overlay network enabling the preliminary validation of the scenario components from their respective remote locations, and simplifying their subsequent integration into a single local demonstrator, the configuration of the required GRE/IPSec tunnels, the integration of the new 5G-RANGE physical, MAC and network layer components and the overall validation with voice and data services.

Improving the performance of Machine Learning Algorithms for TOR detection

Abstract: The Onion Router (TOR) networks provide anonymity, in terms of identity and location, to the Internet users by encrypting traffic multiple times along the path and routing it via an overlay network of servers Although TOR was initially developed as a medium to maintain users’ privacy, cyber criminals and hackers take advantage of this anonymity, and as a result, many illegal activities are carried out using TOR networks With the ever-changing landscape of Internet services, traditional traffic analysis methods are not efficient for analyzing encrypted traffic and there is a need for alternative methods for analyzing TOR traffic In this paper, we develop a machine learning model to identify whether a given network traffic is TOR or nonTOR We use the ISCX2016 TOR-nonTOR dataset to train our model and perform random oversampling and random undersampling to remove data imbalance Furthermore, to improve the efficiency of our classifiers, we use k-fold cross-validation and Grid Search algorithms for hyperparameter tuning Results show that we achieve more than 90% accuracy with random sampling and hyperparameter tuning methods

Multiple Leader PBFT Based Blockchain Architecture for IoT Domains: Invited Paper

Abstract: In this paper we propose to implements blockchain technology for Internet of Things (IoT) networks that use Practical Byzantine Fault Tolerance (PBFT) consensus algorithm. To eliminate the reliance on a single leader and improve performance, we propose to allow multiple leaders to propose request batches independently and, possibly, concurrently, by using different overlay networks. Nodes participate in parallel consensus rounds without contention, and they only contend with others to reserve the next available spot for the atomic insertion of a new transaction batch or block into the replicated blockchain ledger. We develop an analytical model for the multiple leader PBFT ordering service by using a Discrete-time Markov chain. Our evaluations show that our model outperforms the original multiple entry point PBFT protocol in a wide range of parameter values, and that it scales well with the number of orderer nodes in the PBFT committee and block arrival rate.

TopoShot: Uncovering Ethereum's Network Topology Leveraging Replacement Transactions

Abstract: Ethereum relies on a peer-to-peer overlay network to propagate information. The knowledge of Ethereum network topology holds the key to understanding Ethereum's security, availability, and user anonymity. From a measurement perspective, an Ethereum network's topology is routing-table information hidden inside individual Ethereum nodes, measuring which poses challenges and remains an open research problem in the existing literature. This paper presents TopoShot, a new method uniquely repurposing Ethereum's transaction replacement/eviction policies for topology measurement. TopoShot can be configured to support Geth, Parity, and other major Ethereum clients. As validated on local nodes, TopoShot achieves 100% measurement precision and high recall 88% - 97%. To efficiently measure the large Ethereum networks in the wild, we propose a non-trivial schedule to run pair-wise measurements in parallel. To enable ethical measurement on Ethereum mainnet, we propose workload-adaptive configurations of TopoShot to minimize the service interruption to target nodes/network. We systematically measure a variety of Ethereum networks and obtain new knowledge including the full-network topology in major testnets (Ropsten, Rinkeby and Goerli) and critical sub-network topology in the mainnet. The results on testnets show interesting graph-theoretic properties, such as all testnets exhibit graph modularity significantly lower than random graphs, implying resilience to network partitions. The mainnet results show biased neighbor selection strategies adopted by critical Ethereum services such as mining pools and transaction relays, implying a degree of centralization in real Ethereum networks.

Cloud-based Network Virtualization in IoT with OpenStack

Abstract: In Cloud computing deployments, specifically in the Infrastructure-as-a-Service (IaaS) model, networking is one of the core enabling facilities provided for the users. The IaaS approach ensures significant flexibility and manageability, since the networking resources and topologies are entirely under users’ control. In this context, considerable efforts have been devoted to promoting the Cloud paradigm as a suitable solution for managing IoT environments. Deep and genuine integration between the two ecosystems, Cloud and IoT, may only be attainable at the IaaS level. In light of extending the IoT domain capabilities’ with Cloud-based mechanisms akin to the IaaS Cloud model, network virtualization is a fundamental enabler of infrastructure-oriented IoT deployments. Indeed, an IoT deployment without networking resilience and adaptability makes it unsuitable to meet user-level demands and services’ requirements. Such a limitation makes the IoT-based services adopted in very specific and statically defined scenarios, thus leading to limited plurality and diversity of use cases. This article presents a Cloud-based approach for network virtualization in an IoT context using the de-facto standard IaaS middleware, OpenStack, and its networking subsystem, Neutron. OpenStack is being extended to enable the instantiation of virtual/overlay networks between Cloud-based instances (e.g., virtual machines, containers, and bare metal servers) and/or geographically distributed IoT nodes deployed at the network edge.

A Distributed Flow Correlation Attack to Anonymizing Overlay Networks Based on Wavelet Multi-Resolution Analysis

Abstract: Government agencies rely more and more heavily on the availability of flexible and intelligent solutions for the interception and analysis of Internet-based telecommunications. Unfortunately, the global lawful interception market has been recently put into a corner by the emerging sophisticated encryption, obfuscation and anonymization technologies provided by modern overlay communication infrastructures. To face this challenge, this work proposes a novel strategy for defeating the anonymity of traffic flows, collected within and at the exit of these anonymizing networks, relying on distributed flow-capture, characterization and correlation attacks driven by wavelet-based multi-resolution analysis. Such a strategy, starting from a properly formalized attack model, results in an effective and promising framework that can be easily deployed on real-life network equipment and can potentially scale by working according to different distribution/parallelization scenarios.

Flexible Semantic-based Data Networking for IoT Domains

Abstract: The rapid adoption of the Internet of Things (IoT) as a means for digital transformation is sketching a new landscape of heterogeneous data and distributed, machine learning-based, applications. The intertwine of the two combined with the varying availability of data, generated in different parts of the domain, raises the need to exchange bulks of relevant data on demand across application(s) points. Data relevance escalates the role of semantics in identifying and locating suitable data; particularly at the network layer, to provide efficient mapping of data supply and demand. This paper proposes a semantic-based data networking framework, for managed IoT domains, embracing principles of information-centric networking without restrictions on the routing function. Managed semantics are used to provide flexible (label-based) data addressing scheme and a scalable semantic locator function, designed as an overlay network of distributed instances that can be realized on top of any routing or forwarding solution. Nonetheless, we outline different routing solutions and their suitability to such scenarios, to then draw a recommendation of the most suitable underlying routing fabric. We evaluate our framework over an example IoT domain of the Pervasive Nation (PN), Ireland national IoT network. Through our example, we show that the number of managed semantics in such a domain can be vastly smaller than that expected on an Internet scale. We analyze our semantic aggregation scheme over the example PN network, and show the high flexibility in mapping data while maintaining a small state in the semantic locator function.

Low-Cost Search in Tree-Structured P2P Overlays: The Null-Balance Benefit

Abstract: Peer-to-Peer (P2P) networks are one way to create large-scale distributed systems. A single peer has only a limited view on other peers. Thus, efficient searching for other peers or their content is a key performance indicator. In this paper, we investigate the search efficiency in an m-ary tree-structured P2P overlay. While previous work aimed for balancing the maximum height of a node's sub-trees, we show that keeping the height balanced throughout the overall network – a property called null-balance – will increase search performance considerably. Simulations using the ns-3 discrete-event simulator show 50% better performance w.r.t. required routing hops in these null-balanced trees. Therefore, we develop algorithms that keep a tree null-balanced if a node joins or departures. I.e., we prevent the need for restructuring. As we show, the cost of our efficient structure-preserving algorithms is easily set off by a relatively small number of search operations.

Analysis and modelling the effects of mobility, Churn rate, node’s life span, intermittent bandwidth and stabilization cost of finger table in structured mobile P2P networks

Abstract: Today P2P (Peer-to-Peer) networks are gaining popularity for sharing the contents. Due to massive spreading of Internet, these networks are also growing fast. MP2P (Mobile P2P) networks are attracting many users due to increase in the Internet-based mobile applications. These networks suffer from many challenges which are not considered for analysis and modelling adequately. We focus on few challenges like mobility of users, churn rate, intermittent bandwidth, shorter life span of mobile nodes, stabilization of finger table, etc. in this paper. We analytically analyse these challenges and define the effects of different parameters over the performance. Traditional P2P protocols are designed for wired networks and when these are implemented for mobile networks then mobility effect of users adds more challenge for researchers. We select two types of mobility models namely FF (Fluid Flow) and RWP (Random Waypoint) models to model the users’ mobility. The churn rate of the mobile nodes makes network overlay management and content searching more difficult in MP2P networks. We select finger table-based protocols which are widely deployed in the P2P networks. But these protocols can’t perform well in the mobile P2P networks due to mobility of the users. The mobility of the users and churn rate of the mobile nodes create failure in lookup of finger table and induce more cost to update the finger table. We consider these challenges and quantify the failure rate of mobile nodes, life span of mobile nodes, available bandwidth, cost of stabilization of finger table per node, etc. in this proposal. The proposed model is useful for modelling the performance of MP2P networks performance in various wireless environments like Mobile Ad hoc Networks (MANETs), Wireless Mesh Networks (WMNs), Wireless Sensor Networks (WSNs), Vehicular Ad hoc Networks (VANETs), Wireless LAN (WLAN), Wireless MAN (WMAN), etc.

TopoShot: uncovering Ethereum's network topology leveraging replacement transactions

Abstract: Ethereum relies on a peer-to-peer overlay network to propagate information. The knowledge of Ethereum network topology holds the key to understanding Ethereum's security, availability, and user anonymity. However, an Ethereum network's topology is stored in individual nodes' internal routing tables, measuring which poses challenges and remains an open research problem in the existing literature. This paper presents TopoShot, a new method uniquely repurposing Ethereum's transaction replacement/eviction policies for topology measurement. TopoShot can be configured to support Geth, Parity and other major Ethereum clients. As validated on local nodes, TopoShot achieves 100% measurement precision and high recall (88% ~ 97%). To efficiently measure the large Ethereum networks in the wild, we propose a non-trivial schedule to run pair-wise measurements in parallel. To enable ethical measurement on Ethereum mainnet, we propose workload-adaptive configurations of TopoShot to minimize the service interruption to target nodes/network. We systematically measure a variety of Ethereum networks and obtain new knowledge including the full-network topology in major testnets (Ropsten, Rinkeby and Goerli) and critical sub-network topology in the mainnet. The results on testnets show interesting graph-theoretic properties, such as all testnets exhibit graph modularity significantly lower than random graphs, implying resilience to network partitions. The mainnet results show biased neighbor selection strategies adopted by critical Ethereum services such as mining pools and transaction relays, implying a degree of centralization in real Ethereum networks.

Towards software defined low maintenance structured peer-to-peer overlays

Abstract: Structured Peer-to-Peer (P2P) overlay networks are scalable and efficient networks. This efficiency comes at a cost as there is a need for regular maintenance of an overlay structure to handle the continuous churn of peers. This results in huge overhead in terms of maintenance traffic generated by peers. This problem becomes more critical when logical overlay topology differs from actual physical network topology, a common phenomenon in P2P overlay networks. In this paper, we present a novel approach to designing a Distributed Hash Table (DHT) based P2P overlays with the help of Software Defined Networks (SDN) concepts. SDN is an upcoming technology that provides enough flexibility in deciding application-specific network policies and rules dynamically. In our approach, we have attempted to bring the overlay topology closer to actual physical topology and reduce the maintenance traffic as much as possible. We have also tested our work on a hybrid network consisting of both virtual and physical switches. The experimental results suggest and establish the applicability of our approach.

Efficient Resource Discovery and Sharing Framework for Fog Computing in Healthcare 4.0

Abstract: Nowadays, healthcare industry is leveraging the technical innovations for providing better facilities to the patients. A number of high quality medical devices are available to record a patient’s health based on numerous parameters. Such sensor-based health monitoring devices generate high volume of data which is analyzed to provide the appropriate treatment. Such monitoring requires the storage and analysis of data on a remote cloud. Though cloud-based services provide efficient storage, they suffer from the delays incurred while sending the data and retrieving the analysis. Fog computing has proven to be an efficient solution to this problem. A fog node can be considered as an edge node, network device, healthcare equipment, etc., having a limited computation power. These devices are located in proximity to the sensor nodes. Fog nodes can be used to perform data analysis in a distributed manner without adding network delay. However, without any proper infrastructure, it is difficult to identify a fog node having sufficient resources to analyze a set of data. This problem can be addressed by using publish/subscribe paradigm over distributed hash tables (DHTs). Publish/subscribe system provides an event triggered approach which can be used to identify a fog node capable to service a data processing request. Further, a DHT is a peer-to-peer overlay network which is used for efficient resource sharing among the peer nodes. In this chapter, a DHT-based peer-to-peer network of fog nodes is proposed. The objective of the proposed networking infrastructure is to create an overlay of physical fog nodes to provide efficient resource discovery. It is achieved by using publish/subscribe communication and peer-to-peer overlays enabling the nodes to share their computation capabilities with each other.

Integration of 5G Experimentation Infrastructures into a Multi-Site NFV Ecosystem.

Abstract: Network Function Virtualization (NFV) has been regarded as one of the key enablers for the 5th Generation of mobile networks, or 5G. This paradigm allows to reduce the dependence on specialized hardware to deploy telecommunications and vertical services. To this purpose, it relies on virtualization techniques to softwarize network functions, simplifying their development and reducing deployment time and costs. In this context, Universidad Carlos III de Madrid, Telefonica, and IMDEA Networks Institute have developed an NFV ecosystem inside 5TONIC, an open network innovation center focused on 5G technologies, enabling the creation of complex, close to reality experimentation scenarios across a distributed set of NFV infrastructures, which can be made available by stakeholders at different geographic locations. This article presents the protocol that has been defined to incorporate new remote NFV sites into the multi-site NFV ecosystem based on 5TONIC, describing the requirements for both the existing and the newly incorporated infrastructures, their connectivity through an overlay network architecture, and the steps necessary for the inclusion of new sites. The protocol is exemplified through the incorporation of an external site to the 5TONIC NFV ecosystem. Afterwards, the protocol details the verification steps required to validate a successful site integration. These include the deployment of a multi-site vertical service using a remote NFV infrastructure with Small Unmanned Aerial Vehicles (SUAVs). This serves to showcase the potential of the protocol to enable distributed experimentation scenarios.