The shift from fifth generation (5G) to sixth generation (6G) networks is anticipated to significantly advance network slicing. This progress is driven by the growing demand for next-generation applications and services. However, these advancements must be managed within the constraints of limited resources. This evolution opens up opportunities for resource sharing through emerging marketplaces, yet it introduces various business and technical complexities that need to be addressed. Additionally, finding cost-effective solutions is also essential for the future of networks. In this paper, we propose a blockchain-based architecture that utilizes non-fungible tokens (NFTs) for the trading of network resources within the 6G network slicing. To the best of our knowledge, this is the first study to represent network resources as NFTs within the context of network slicing. The architecture employs NFTs to authenticate and manage various network resources, providing a decentralized platform for their secure creation, management, and exchange. Using resource NFTs, our system ensures more granular and flexible control over network resources than existing state-of-the-art systems, where NFTs are tied to network slices. We implemented a prototype of this system to validate its viability. Our performance evaluation confirms that the proposed approach is efficient and cost-effective compared to baseline models in managing network resources within network slicing. These findings highlight the potential of our system to transform network management practices and effectively meet the demands of future networks.

As 6G networks introduce increasingly diverse and complex applications, network slicing is a key enabling technology for partitioning network resources to meet these dynamic demands. However, efficiently managing and allocating these finite resources has become vital. This necessity drives the adoption of an open marketplace model. To address the business and technical complexities associated with such open marketplaces, this paper presents the demonstration of a non-fungible token (NFT)-enabled resource trading marketplace tailored for 6G network slicing. The proposed solution is implemented on an Ethereum-based blockchain system to assess its viability.

The advent of 6th Generation(6G) networks and the rapid expansion of the Internet of Things (IoT) have heightened the security risk potential of such systems to cyberattacks, particularly Denial of Service (DoS) attacks. The 6G networks strongly rely on Artificial Intelligence(AI) for intrusion detection, which yields promising results. In parallel, attackers advance their attacking strategies dynamically, declining the AI-based DoS attack detection accuracy, thereby opening the network for potential attackers flagged as false negatives. This phenomenon, called concept drift, requires dynamic adaptation of the AI-based intrusion detection system using the latest attack data. Explainable AI(XAI) is one of the practical techniques that in-terprets the Machine Learning(ML) model outcome with feature contribution. This paper proposes a novel dynamic adaptation framework for 6G network intrusion detection, integrating real-time monitoring and identifying concept drift from adaptive adversaries using the Wilcoxon stat test. Our work leverages XAI-based feature importance interpretation to optimize required model retraining selectively. This work incorporated Shapley value-based local explanations for selected network traffic samples in the experiment with the UNSW-NB15 attack dataset. We comprehensively evaluated our work with supervised learning techniques for intrusion detection. The results reflect the marginal improvement of DoS classification accuracy by 4.49 % up to 93% in combination with Extreme Gradient Boost(XGB) while marginally reducing training and prediction time by 57.6 % and 47.7% with Gradient Boost(GB) for DoS attack detection beyond state of the art. The results showcase the effectiveness of our work for adaptive adversarial detection in 6G IoT networks with time-efficient dynamic retraining against concept drift with feature selection(19 and 21 out of 42) with improved accuracy.

Federated Learning (FL) is a privacy-preserving distributed Machine Learning (ML) technique. Hierarchical FL is a novel variant of FL applicable to networks with multiple layers. Instead of transmitting client models to the server, hierarchical FL performs aggregations in the layers between the devices and the server. This further reduces the traffic toward the higher layers, which helps efficient link utilization. An adversary can manipulate a set of clients and send malicious model updates toward upper layers to create a trained model with a malicious objective. These attacks, also known as poisoning attacks, disrupt the model training. Like FL, Hierarchical FL is also vulnerable to poisoning attacks since the aggregators do not possess raw data. The existing robust algorithms are designed for FL systems with$n$clients and a server. Therefore, they are not effective against poisoning attacks in hierarchical FL systems. This paper proposes SHIELD, a novel robust aggregation technique that defends hierarchical FL systems from poisoning attacks. We evaluate SHIELD with several datasets in different application areas with different attack strategies and data distributions. The evaluation results demonstrate that SHIELD effectively defends hierarchical FL systems from poisoning attacks with a negligible impact on the benign performance of the models.

Federated Learning (FL) is a distributed Machine Learning (ML) technique that allows model training without sharing data. FL is vulnerable to poisoning attacks where an adversary manipulates the learning process by providing false information to the federation. Ensuring security in FL is vital before using FL in real applications, as the consequences can be adverse. Multi-stage FL is a novel variant of FL that performs intermediate model aggregations, thereby reducing the traffic toward the FL central server. The existing robust aggregation techniques are insufficient in multi-stage FL systems. This paper proposes a novel robust aggregation algorithm against poisoning attacks in a three-layer multi-stage FL system that consists of device, edge, and cloud layers. We evaluate the proposed robust algorithm considering an Augmented Reality (AR) application with different poisoner placements and attack strategies. The evaluation results show that the proposed algorithm can effectively defend against poisoning attacks in three-layer multi-stage FL systems.

Open radio access network (O-RAN) has been recognized as a revolutionized architecture to support the multi-class wireless services required in fifth-generation (5G) and beyond 5G networks. The openness and the distributed nature of the O-RAN architecture have created new forms of threat surfaces than the conventional RAN architecture and require complex anomaly detection mechanisms. Moreover, with the introduction of RAN intelligent controllers (RICs), it is possible to utilize advanced Artificial Intelligence (AI)/ Machine Learning (ML) algorithms based on closed control loops to detect anomalies in a data-driven manner. In this paper, we particularly investigate the use of Federated Learning (FL) for anomaly detection in the O-RAN architecture, which can further preserve data privacy. We propose a peer-to-peer (P2P) FL-based anomaly detection mechanism for the O-RAN architecture and provide a comprehensive analysis of four variants of P2P FL techniques. Moreover, we simulate the proposed models using the UNSW-NB15 dataset.

Many forms of machine learning (ML) and artificial intelligence (AI) techniques are adopted in communication networks to perform all optimizations, security management, and decision-making tasks. Instead of using conventional blackbox models, the tendency is to use explainable ML models that provide transparency and accountability. Moreover, Federate Learning (FL) type ML models are becoming more popular than the typical Centralized Learning (CL) models due to the distributed nature of the networks and security privacy concerns. Therefore, it is very timely to research how to find the explainability using Explainable AI (XAI) in different ML models. This paper comprehensively analyzes using XAI in CL and FL-based anomaly detection in networks. We use a deep neural network as the black-box model with two data sets, UNSW-NB15 and NSLKDD, and SHapley Additive exPlanations (SHAP) as the XAI model. We demonstrate that the FL explanation differs from CL with the client anomaly percentage.

The novel concept of factory-as-a-service (FaaS) allows the agility of adapting the manufacturing process by identifying the industry’s supply chain and user requirements. To cater to FaaS, flexibility in networking and cloud services is a must. 5G network slice broker (NSB) is a third-party mediator that caters to networking resource demand from clients to the service providers. Thus, this article introduces a secure blockchain-based NSB to facilitate FaaS. The proposed secure NSB (SNSB) provides secure, cognitive, and distributed network services for resource allocation and security service level agreement (SSLA) formation with coordination of slice managers and SSLA managers. In SNSB, we introduce a federated slice selection algorithm with Stackelberg game model and reinforcement learning algorithm to compute the real time and the optimal unit price and demand level. We provide an extensive implementation and performance evaluation of SNSB using the slice manager and a custom SSLA manager.

In the current 5th Generation (5G) networking paradigm, the enforcement of Service Level Agreements (SLAs) is a non-trivial measure to ensure the scope and the quality of services and standards between tenants and service providers (SPs). On top of this, Secure Service Level Agreements (SSLA) are introduced to ensure that SPs deliver the most critical and required security-related standards defined in the contract, such as integrity, confidentiality, availability, non-repudiation, and privacy assurance. However, with the tendency for more distributed and multi-stakeholder networking architectures in next-generation networks, the management process of such SSLAs will be challenging due to the diversified security vulnerabilities and complexity of underlying technologies. Although blockchain is emerging as a platform to facilitate such distributed SSLA/SLA management frameworks, its currently available consensus mechanisms are more generic. Still, they need to improve in terms of applying in multi-stakeholder networks. Therefore, this paper presents a novel consensus mechanism called Proof-of-Monitoring (PoM) for a blockchain-based novel SSLA management framework. Moreover, we provide details about the prototype implementation of our proposed consensus algorithm and SSLA management framework. It is proven by comparing our proposal with the other existing solutions that our solution outperforms in many aspects, such as energy consumption, computation cost, and security features.

Network slicing enables the creation of multiple logical independent networks on physical networking infrastructure. Network slice deployment in a Fifth Generation (5G) mobile network can be classified as vertical and horizontal slicing. The paper compares the performance of the two slicing methods through solving two convex optimization problems, considering several smart hospital scenarios that differ from each other based on their medical speciality. The results are used to draw insights on the most appropriate slicing approach for each setup.

Network slicing is a versatile and distinguishing capability of the 5th and 6th Generation (5G & 6G) mobile networks. Network slicing enables the consumers to deliver individualized and customized telecommunication services on the commonly shared infrastructure. Slice brokering is the dedicated service to facilitate the tenants and resource providers in slice allocation process. We proposed SFSBroker (Secured and Federated Slice Broker) to leverage the slice brokering process with the application of game theory. We formulated the optimal slice selection problem into the Stackelberg game model. The computational logic has been incorporated on smart contracts. Furthermore, the proposed architecture includes Security Service Blockchain (SSB) which has been integrated for Denial of Service (DoS) attack prevention. We implemented the end to end setup including tenant request to slice creation using Hyperledger Fabric blockchain, Katana slice manager, and OpenStack. In this demonstration, the system provisions to obtain hands-on experience on the end to end workflow of slice brokering process.

Recent evolution of the industrial Internet of Things empowers the classical manufacturing model with cloud computing integration for Industry 4.0. Cloud integration advances the capabilities of manufacturing systems with cloud-based controlling and real-time process monitoring, which is renowned as cloud manufacturing (CM). However, cloud integration exposes the entire manufacturing ecosystem to a new set of security risks and increments in end-to-end latency. Moving security services toward the edge eradicates message routing latency toward the cloud and eliminates the central point of failure while leveraging the entire system’s performance. We propose a blockchain and fog-computing-enabled security service architecture that operates on fog nodes at the edge of manufacturing equipment clusters. The proposed service facilitates CM equipment authentication and equipment-cloud channel privacy protection while preserving anonymity and unlinkability over the blockchain. We implemented the proposed architecture with hyperledger fabric and compared the performance advantage over the state-of-the-art solutions.

The ever growing and revolutionizing demands in telecommunication industry to facilitate numerous business verticals are pushing towards more softwarized mobile communication technologies. Utilizing the capabilities of network softwarization, a novel telecommunication concept of local mobile network has been developed. The local mobile networks are getting popular due to their capability of providing efficient and reliable local services to a focused use case with higher flexibility. This paper presents the practical implementation aspects of a softwarized local mobile network and compare its performance with a conventional mobile network and a hybrid network.

Local 5G Operator (L5GO) concept is one of the most prominent versatile applications of the 5G in the near future. The popularity of L5GOs will trigger a greater number of roaming and offloading events between mobile operators. However, existing static and the operator-assisted roaming and offloading procedures are inefficient for L5GO ecosystem due to poor service quality, data privacy issues, data transferring delays, excessive costs for intermediary parties and existence of roaming fraud. To address these challenges, we propose a blockchain / Distributed Ledger Technology (DLT) based service platform for L5GOs to facilitate efficient roaming and offload services. As the key contribution, blockchain-based smart contract scheme is proposed to establish dynamic and automated agreements between operators. By using smart contracts, we introduce several novel features such as universal wallet for subscribers, service quality based L5GO rating system, user-initiated roaming process and the roaming fraud prevention system to improve the operational quality of a L5GO. A prototype of the proposed platform is emulated with the Ethereum blockchain platform and Rinkeby Testnet to evaluate the performance and justify the feasibility of the proposal. Upon an extensive evaluation on the prototype, it was observed that the proposed platform offered benefits such as cost effective, more secure and reliable experience.

Several recent works talk about the potential use of network slice brokering mechanism to facilitate the resource allocation of network slicing in next generation networks. This involves network tenants on the one hand and resource/infrastructure providers on the other hand. However, the potential downside of deploying Network Slice Broker (NSB) is that it can be victimized by DoS (Denial of Service) attack. Thus, the aim of this work is three fold. First, to present the possible ways in which DoS/DDoS attacks can be mounted on NSB and their adverse effects. Second, to propose and implement initial blockchain-based solution named as Security Service Blockchain (SSB) to prevent DoS attacks on NSB. Third, to enumerate the challenges and future research directions to effectively utilize blockchain for mitigating DoS/DDoS attacks on NSB. To evaluate the performance the proposed SSB framework is implemented using Hyperledger Fabric. The results manifest that the latency impact of the legitimate slice creation over scaled up malicious traffic remains minimal with the use of SSB framework. The integration of SSB with NSB results in gaining several fold reduction in latency under DoS attack scenario.

Data is central to the Internet of Things (IoT) ecosystem. With billions of devices connected, most of the current IoT systems are using centralized cloud-based data sharing systems, which will be difficult to scale up to meet the demands of future IoT systems. The involvement of such a third-party service provider requires also trust from both the sensor owner and sensor data user. Moreover, fees need to be paid for their services. To tackle both the scalability and trust issues and to automatize the payments, this paper presents a blockchain-based marketplace for sharing of the IoT data. We also use a proxy re-encryption scheme for transferring the data securely and anonymously, from data producer to the consumer. The system stores the IoT data in cloud storage after encryption. To share the collected IoT data, the system establishes runtime dynamic smart contracts between the sensor and data consumer without the involvement of a trusted third-party. It also uses a very efficient proxy re-encryption scheme which allows that the data is only visible by the owner and the person present in the smart contract. This novel combination of smart contracts with proxy re-encryption provides an efficient, fast and secure platform for storing, trading and managing sensor data. The proposed system is implemented using off-the-shelf IoT sensors and computer devices. We also analyze the performance of our hybrid system by using the permission-less Ethereum blockchain and compare it to the IBM Hyperledger Fabric, a permissioned blockchain.

The deployment of edge computing infrastructure requires a careful placement of the edge servers, with an aim to improve application latencies and reduce data transfer load in opportunistic Internet of Things systems. In the edge server placement, it is important to consider computing capacity, available deployment budget, and hardware requirements for the edge servers and the underlying backbone network topology. In this paper, we thoroughly survey the existing literature in edge server placement, identify gaps and present an extensive set of parameters to be considered. We then develop a novel algorithm, called PACK, for server placement as a capacitated location–allocation problem. PACK minimizes the distances between servers and their associated access points, while taking into account capacity constraints for load balancing and enabling workload sharing between servers. Moreover, PACK considers practical issues such as prioritized locations and reliability. We evaluate the algorithm in two distinct scenarios: one with high capacity servers for edge computing in general, and one with low capacity servers for Fog computing. Evaluations are performed with a data set collected in a real-world network, consisting of both dense and sparse deployments of access points across a city area. The resulting algorithm and related tools are publicly available as open source software.

There is a global hype in the development of digital healthcare infrastructure to cater the massive elderly population and infectious diseases. The digital facilitation is expected to ensure the patient privacy, scalability, and data integrity on the sensitive life critical healthcare data, while aligning to the global healthcare data protection standards. The patient data sharing to third parties such as research institutions and universities is also concerned as a significant contribution to the society to sharpen the research and investigations. The emergence of 5G communication technologies eradicates the borders between patients, hospital and other institutions with high end service standards. In patients' perspective, healthcare service delivery through the digital medium is beneficial in terms of time, costs, and risks. In this paper, we propose a novel Multi-access Edge Computing(MEC) and blockchain based service architecture utilizing the lightweight ECQV (Elliptic Curve Qu-Vanstone) certificates for the realtime data privacy, integrity, and authentication between IoT, MEC, and cloud. We further attached storage offloading capability to the blockchain to ensure scalability with a massive number of connected medical devices to the cloud. We introduced a rewarding scheme to the patients and hospitals through the blockchain to encourage data sharing. The access control is handled through the smart contracts. We evaluated the proposed system in a near realistic implementation using Hyperledger Fabric blockchain platform with Raspberry Pi devices to simulate the activity of the medical sensors.

Internet of Things (IoT) is a key topic of interest in modern communication context with the evolution of 5G and beyond ecosystems. 5G will interconnects billions of IoT devices wirelessly. The wireless communication exposes the devices to massive security risks in different dimensions. The Public Key Infrastructure (PKI) is one of the promising solutions to eliminate security risks. It ensures the authentication and communication integrity by using public key certificates. However, the overhead of certificate storage is a significant problem for the resource constrained IoT devices. We propose an application of Elliptic Curve Qu Vanstone (ECQV) certificates, which are lightweight in size for the resource restricted IoT devices. Furthermore, we incorporate the blockchain based smart contracts to handle the certificate related operations. We utilize the smart contracts in the certificate issuance and developed a smart contract based threat scoring mechanism to automatically revoke the certificates. The lightweight nature of ECQV certificates enables the distributed ledger to store, update, and revoke the certificates. We evaluated the proposed solution in Hyperledger Fabric blockchain platform.

5G calls for a network architecture that ensures ultraresponsive and ultrareliable communication links, in addition to the high degree of flexibility and customization required by different vertical sectors. The novel concept called local 5G networks enables a versatile set of stakeholders to operate 5G networks within their premises with guaranteed quality and reliability to complement mobile network operators' (MNOs) offerings. This article proposes a descriptive architecture for a local 5G operator which provides user specific and location-specific services in a spatially confined environment, i.e., industrial Internet environment. In addition to that, the article proposes hybrid architecture options where both the local 5G operator and MNO collaboratively contribute to establish the core network to cater to such communications. The architecture is discussed in terms of network functions (NFs) and the operational units which entail the core and radio access networks in a smart factory environment which supports Industry 4.0 standards. Moreover, to realize the conceptual design, the article provides simulation results for the latency measurements of the proposed architecture options with respect to an augmented reality (AR), massive wireless sensor networks, and mobile robots use cases. Thereby the article discusses the benefits of deploying core NFs locally to cater to specialized user requirements, rather than continuing with the conventional approach where only MNOs can deploy cellular networks.

The widespread Internet of Things (IoT) ecosystems empower the deployment of various Bluetooth Low Energy (BLE) sensor nodes in many ambient assisted living (AAL) type applications. Regardless of their limitations, these low-power IoT sensor nodes need pervasive and secure connections to transfer the aggregated data to the central servers located in remote clouds which will perform further processing and storing functions. The common practice is to use one or multiple dedicated gateways to assist the communication between the sensor and the cloud. This paper presents a mobile-based relay assistance solution for establishing secure end-to-end (E2E) connectivity between low-power IoT sensors and cloud servers without using a dedicated gateway. za The prototype implementation and the described security features verify the technical readiness of the proposed solution.

In addition to the high degree of flexibility and customization required by different vertical sectors, 5G calls for a network architecture that ensures ultra-responsive and ultra-reliable communication links. The novel concept called micro-operator (uO) enables a versatile set of stakeholders to operate local 5G networks within their premises with a guaranteed quality and reliability to complement mobile network operators' (MNOs) offerings. In this paper, we propose a descriptive architecture for emerging 5G uOs which provides user specific and location specific services in a spatially confined environment. The architecture is discussed in terms of network functions and the operational units which entail the core and radio access networks in a smart factory environment which supports industry 4.0 standards. Moreover, in order to realize the conceptual design, we provide simulation results for the latency measurements of the proposed uO architecture with respect to an augmented reality use case in industrial internet. Thereby we discuss the benefits of having uO driven local 5G networks for specialized user requirements, rather than continuing with the conventional approach where only MNOs can deploy cellular networks.

The healthcare industry is constantly reforming and adopting new shapes with respect to the technological evolutions and transitions. One of the crucial requirements in the current smart healthcare systems is the protection of patients sensitive data against the potential adversaries. Therefore, it is vital to have secure data access mechanisms that can ensure only authorized entities can access the patients medical information. Hence, this paper considers blockchain technology as a distributed approach protect the data in healthcare systems. This research proposes a blockchain based secure and efficient data accessibility mechanism for the patient and the doctor in a given healthcare system. Proposed system able to protect the privacy of the patients as well. The security analysis of our scheme shows that it can resist to well-known attacks along with maintaining the integrity of the system. Moreover, an Ethereum based implementation has used to verify the feasibility of our proposed system.

Blockchain is so far well-known for its potential applications in financial and banking sectors. However, blockchain as a decentralized and distributed technology can be utilized as a powerful tool for immense daily life applications. Healthcare is one of the prominent applications area among others where blockchain is supposed to make a strong impact. It is generating wide range of opportunities and possibilities in current healthcare systems. Therefore, this paper is all about exploring the potential applications of blockchain technology in current healthcare systems and highlights the most important requirements to fulfill the need of such systems such as trustless and transparent healthcare systems. In addition, this work also presents the challenges and obstacles needed to resolve before the successful adoption of blockchain technology in healthcare systems. Furthermore, we introduce the smart contract for blockchain based healthcare systems which is key for defining the pre-defined agreements among various involved stakeholders.

Cash-less payment via a variety of credit, debit or prepaid cards is pervasive in our interconnected society, but not so ubiquitous in remote rural regions where network connectivity is intermittent. We proposed a cash-less payment scheme for remote villages based on blockchains that allow maintaining a record of verifiable transactions in a distributed manner. We overcome the limitations of intermittent network connectivity by solely relying on blockchain mining nodes in the village for transaction processing and verification. The bank joins as a peer and monitors node behaviors, rewards miners and processes currency exchanges whenever the connectivity is available. We take advantage of the Ethereum network to develop our solution and demonstrate the feasibility of the proposed system on off-the-shelf computing devices. We emulate a remote village scenario with intermittent network connectivity and show the robustness and reliability of the proposed system.

Internet of Things (IoT) devices need pervasive and secure connections to transfer the aggregated data to the central servers located in remote clouds where the collected data further processed and stored. However, most low-power IoT devices cannot transmit the collected the data directly to such servers due the limited transmission power and range. Thus, third-party devices such as smart mobile phones are used as a relay to establish the communication link between IoT devices and the cloud server. This paper demonstrates a mobile-based relay assistance solution for secure end-to-end connectivity between low-power IoT sensors and cloud servers by using Bluetooth Low Energy (BLE) technology. The prototype implementation verifies the technical readiness of the proposed solution.

Recent developments in Internet of Things (IoT) technologies have already put a huge impact on the medical and health sector. Thus, the patient treatment can be performed in more efficient ways compared with traditional methods. Secure identification is a key system requirement for patients to acquire these health related services. Fast and convenient identification is important in the case of critical and elderly or disabled patients who required frequent health services. In this paper, we are presenting concept of the Naked environment where patients can get health services from smart and intelligent surroundings of hospital without using explicit gadgets. Patients would have direct interaction with the environment and get identified through it. We propose a biometric based authentication scheme for the Naked hospital environment that also protects the patients identity privacy. In addition, we show that this authentication scheme can resist various well known attacks such as insider attacks, replay attacks and identity privacy among others.

Energy efficiency is a powerful measure for promoting sustainability in technological evolution and ensuring feasible battery life of mobile end-user devices. Peer-to-peer technology provides decentralized and self-organizing, but also energy-inefficient technology for distributing content between devices in networks that scale up almost infinitely. The dissertation [1] summarized in this paper makes four contributions towards enabling energy-aware peer-to-peer networking in mobile environments: 1) an empirical study for understanding the energy consumption characteristics of radio interfaces and typical composition of traffic in peer-to-peer networks, 2) a model for estimating the energy consumption of a mobile device with different traffic profiles, 3) a model for energy-aware load monitoring of mobile peer nodes, and 4) a mobile agent based virtual peers concept for energy-aware sharing of peer responsibilities between peer nodes in a subnet. The results give valuable insight into implementing energy-efficient peer-to-peer systems in mobile environments.

This paper presents an operator-assisted data offloading platform for 5G mobile networks by using Software Defined Networking (SDN). By enabling lateral communication between multiple SDN controllers, operators are able to perform the offloading process without the intervention of the user. Moreover, the offloading decision of proposed platform is based on accurate real time network conditions. The proposed mechanism is implemented on a testbed to verify feasibility and performance.

Software Defined Network (SDN) is an advanced approach to designing dynamic, manageable, cost-effective, and adaptable network architectures. SDN will play a key role as an enabler for 5G and future networks. Transferring network monitoring functions to a software entity working in conjunction with configurable hardware accelerators through a scheme called Software Defined Monitoring (SDM) is one promising way to attain the dynamism necessary for the monitoring of the next generation-networks. In this paper, we propose a novel SDM architecture for future mobile backhual networks. As an SDN solution, the proposed architecture provides more granular and dynamic network management functions through its programmable interface, centralized control, and virtualized abstractions. At the same time, the SDM framework intuitively seem prone to various challenges that come with the separation of the control and data planes of middleboxes. This paper collects specific opportunities, vulnerabilities as well as challenges related to SDM. It also highlights how SDM can be used to solve the current limitations in legacy monitoring systems. The feasibility of the proposed SDM architecture is verified by using a testbed implementation.

Virtual Private LAN Services (VPLS) is an Ethernet based VPN (Virtual Private Network) service which provides protocol independent and high speed multipoint-to-multipoint connectivity. In this article, we discuss the possibility to use emerging networks concepts such as Software Defined Networking (SDN) and Network Function Virtualization (NFV) to improve the performance, flexibility and adaptability of VPLS networks. SDN and NFV based VPLS (SoftVPLS) architectures offer new features such as centralized control, network programmability and abstraction to improve the performance, flexibility and automation of traffic, security and network management functions for future VPLS networks.

Secure VPLS (Virtual Private LAN Services) networks are becoming attractive in many Enterprise applications. However, the tunnel establishment mechanisms of legacy VPLS architectures are static, complex and inflexible in nature. As a result, secure VPLS architectures are suffering from limitations such as the limited scalability, over utilization of network resources, high tunnel establishment delay and high operational cost. In this article, we propose a novel SDN (Software Defined Networking) based VPLS (Virtual Private LAN Services) architecture to overcome tunnel management limitations in existing secure VPLS architectures. The proposed architecture utilizes IPsec enabled OpenFlow switches as PEs (Provider Edge Equipments) and OpenFlow protocol to install flow rules in PEs. A centralized controller is used to manage the tunnel establishment functions. We also propose a novel tunnel management mechanism which can estimate the tunnel duration based on real time session characteristics. Moreover, a novel tunnel resumption mechanism is proposed to reduce the tunnel establishment delay of subsequent tunnel establishments. Finally, the performance of proposed architecture is analyzed by using a simulation model and a testbed implementation.

In this demo we present an energy efficient motion detection mechanism for a high-resolution wireless (battery powered) surveillance camera node. We use Raspberry Pi (RPi) as a camera sensor node to demonstrate two scenarios. In the first scenario, the RPi performs motion detection using Pyro-electric InfraRed (PIR) sensor, while in the latter we use an external low-power node to keep the RPi in low power mode and at the same time detect motion using PIR sensor. The main contributions of this demo are the power management implementation, a surveillance application and the evaluation of power consumption between the two scenarios.

In this paper, we propose two secure virtual private network architectures for the long-term evolution backhaul network.They are layer 3 Internet protocol (IP) security virtual private network architectures based on Internet key exchange version 2 mobility and multihoming protocol and host identity protocol.Both architectures satisfy a complete set of 3GPP backhaul security requirements such as authentication, authorization, payload encryption, privacy protection, and IP-based attack prevention.The security analysis and simulation results verify that the proposed architectures are capable enough to protect long-term evolution backhaul traffic against various IP-based attacks.

The Internet of Things (IoT) technologies interconnect wide ranges of network devices irrespective of their resource capabilities and local networks. The device constraints and the dynamic link creations make it challenging to use pre-shared keys for every secure end-to-end (E2E) communication scenario in IoT. Variants of Host Identity Protocol (HIP) are adopted for constructing dynamic and secure E2E connections among the heterogenous network devices with imbalanced resource profiles and less or no previous knowledge about each other. We propose a collaborative HIP solution with an efficient key establishment component for the high constrained devices in IoT, which delegates the expensive cryptographic operations to the resource rich devices in the local networks. Finally, we demonstrate the applicability of the key establishment in collaborative HIP solution for the constrained IoT devices rather than the existing HIP variants, by providing performance and security analysis.

Direct peer-to-peer connectivity between web browsers is becoming reality with the emerging and constantly developing WebRTC technology stack. This opens possibilities for new kind of plugin-free web applications, such as browser-to-browser file transfers and multi-party conferencing. In this paper, the performance of WebRTC on mobile devices is evaluated with different mobile device, wireless network connectivity and web browser configurations. The evaluation was conducted with a WebRTC test environment that was implemented based on PeerJS JavaScript library and PeerServer signaling server. The measurements include session establishment delay and overhead, session maintenance overhead, resource consumption of multiple simultaneous file transfers and efficiency of different file transfer approaches. Based on the results, the delay for establishing a WebRTC connection may in the worst cases exceed even 10 seconds making it a serious bottleneck. However, from the standpoints of memory consumption and CPU load, high-end mobile devices are very capable of running multiple simultaneous WebRTC connections for data transfers. The results of this paper provide new insight to researchers, application and browser developers and WebRTC standardization bodies.

Wireless Sensor Network (WSN) is a fundamental technology of the Internet of Things (IoT). Group communications in the form of broadcasting and multicasting incur efficient message deliveries among resource-constrained sensors in IoT-enabled WSNs. Secure and efficient key management is significant to protect the authenticity, integrity, and confidentiality of multicast messages. This paper develops two group key establishment protocols for secure multicast communications among resource-constrained devices in IoT. The applicability of the two protocols are analyzed and justified by performance and security analysis.

With the introduction of novel standardized web technologies such as WebGL, 3D virtual environments (VEs) are making their way into the web. Concurrently, resource rich mobile devices, such as smartphones and tablets, have become the primary access medium for the web. This paper introduces a method called RADE that enables resource-aware P2P-assisted 3D asset delivery in a web browser using WebRTC. Use of P2P technology in 3D asset delivery can (1) decrease the load on 3D asset servers; (2) decrease the application response times; and (3) reduce the operational costs of VE service providers. The performance and resource fairness of RADE was evaluated in real-life wireless networks using a prototype implementation. Based on the results, RADE can significantly reduce the server load and the 3D asset delivery times especially when 3D asset servers are under heavy load. For instance, with a scarce server bandwidth of 2Mbps, use of RADE resulted in 55% shorter 3D asset delivery times on average. Although RADE has been developed for 3D asset delivery, it is applicable for many types of web applications, including video delivery.

In this paper, we propose a novel architecture, called ADHT, that allows the participation of wireless and constrained-capacity M2M devices in a P2P overlay without compromising their battery life. The approach makes P2P-based networking feasible in scenarios where dedicated super-peer nodes are not available or not feasible to use, e.g. when all the participating nodes in a subnet are constrained devices. The concept is based on sharing the peer responsibilities among the nodes within the same subnet using mobile agent-based virtual peers. The mobile agent-based approach enables on-the-fly configurations to further reduce energy consumption in the subnet nodes during runtime. The presented mobile agent composition is both programming language- and platform-independent. Therefore it inherently enables heterogeneous platforms, from the low-power resource-constrained embedded networked devices to the cloud platforms, to operate as the P2P peer. We analyze the power consumption characteristics of the mobile agent-based approach by comparing it with alternative architectures with a numerical analysis.

Spanning Tree Protocol (STP) is a widely used protocol to maintain a loop free Layer 2 (L2) switching network. On the other hand, Virtual Private LAN Service (VPLS) is a L2 Virtual Private Network (VPN) service which is becoming very popular among many industrial enterprises. In a VPLS network, VPN connections through the provider network are invisible to L2 network devices and protocols. It causes to several issues while utilizing STP in a VPLS enabled Ethernet network. In this paper, we propose a novel Distributed STP (DSTP) to maintain a loop free Ethernet network over a VPLS network. DSTP proposes to run a modified STP instance in each remote network segment and evades the transportation of STP messages through the provider network. In addition, we propose two Redundancy Identification Mechanisms (RIMs) to mitigate the impact of invisible loops in the provider network. Simulation results verify that DSTP is capable of maintaining a loop free Ethernet network over a VPLS network. Furthermore, DSTP significantly reduces the convergence time of the spanning tree and STP overhead over the provider network.

In the centralized Wireless Sensor Network (WSN) architecture there exists a central entity, which acquires, processes and provides information from sensor nodes. Conversely, in the WSN applications in distributed Internet of Things (IoT) architecture, sensor nodes sense data, process, exchange information and perform collaboratively with other sensor nodes and endusers. In order to maintain the trustworthy connectivity and the accessibility of distributed IoT, it is important to establish secure links for end-to-end communication with proper authentication. The authors propose an implicit certificate-based authentication mechanism for WSNs in distributed IoT applications. The developed two-phase authentication protocol allows the sensor nodes and the end-users to authenticate each other and initiate secure connections. The proposed protocol supports the resource scarcity of the sensor nodes, heterogeneity and scalability of the network. The performance and security analysis justify that the proposed scheme is viable to deploy in resource constrained WSNs.

Software-Defined Mobile Networks (SDMNs) are becoming popular as the next generation of telecommunication networks due to the enhanced performance, flexibility and scalability. In this paper, we study the new security challenges of the control channel of SDMNs and propose a novel secure control channel architecture based on Host Identity Protocol (HIP). IPsec tunneling and security gateways are widely used in today's mobile networks. The proposed architecture utilized these technologies to protect the control channel of SDMNs. We implement the proposed architecture in a testbed and analyze the security features. Moreover, we measure the performance penalty of security of proposed architecture and analyze its ability to protect the control channel from various IP (Internet Protocol) based attacks.

The Internet of Things presents the user with a novel means of communicating with the Web world through ubiquitous object-enabled networks. Cloud Computing enables a convenient, on demand and scalable network access to a shared pool of configurable computing resources. This paper mainly focuses on a common approach to integrate the Internet of Things (IoT) and Cloud Computing under the name of CloudThings architecture. We review the state of the art for integrating Cloud Computing and the Internet of Things. We examine an IoT-enabled smart home scenario to analyze the IoT application requirements. We also propose the CloudThings architecture, a Cloud-based Internet of Things platform which accommodates CloudThings IaaS, PaaS, and SaaS for accelerating IoT application, development, and management. Moreover, we present our progress in developing the CloudThings architecture, followed by a conclusion.

Better tools for content-based access of video are needed to improve access to time-continuous video data. Particularly information about linear TV broadcast programs has been available in a form limited to program guides that provide short manually described overviews of the program content. Recent development in digitalization of TV broadcasting and emergence of web-based services for catch-up and on-demand viewing bring out new possibilities to access data. In this paper we introduce our data mining system and accompanying services for summarizing Finnish DVB broadcast streams from seven national channels. We describe how data mining of novelty concepts can be extracted from DVB subtitles to augment web-based "Catch-Up TV Guide" and "Novelty Cloud" TV services. Furthermore, our system allows accessing media fragments as Picture Quotes via generated word lists and provides content-based recommendations to find new programs that have content similar to the user selected programs. Our index consists of over 180 000 programs that are used to recommend relevant programs. The service has been under development and available online since 2010. It has registered over 5000 user sessions.

One challenging problem in Machine-to-Machine (M2M) applications is to efficiently discover the resources provided by a huge number of heterogeneous devices. This paper proposes distributed resource discovery architecture (DRD) for M2M applications. The DRD supports heterogeneous devices in resource description registration and discovery of resource value. It achieves interoperability among heterogeneous devices in disparate networks and enables resource access from the Internet. In the DRD, a resource registration component is designed for storing resource descriptions, a resource discovery component is designed to retrieve resource values on behalf of clients after getting address information by looking up resource descriptions. The DRD utilizes a peer-to-peer overlay to distribute workload and avoid single point of failure. A real-world prototype is implemented and verified with a simple demo. Preliminary evaluation on response time of resource discovery is provided.

Content-based test video corpora usually builds on top of professional material or controlled settings. However, recent years have shown strong increase in user-generated content on the web. The increase in content volume creates challenges in accessibility and utility of the video content. In order to improve the utility of the user-generated videos, better automation for content-based descriptions are needed. Proper test sets are required to develop robust methods for content analysis. Detecting people from video is a common feature that is often seen in both in science and in commercial services. Unfortunately there is a lack of test data for person tracking from consumer videos. In this paper, we introduce a novel video dataset to accommodate this shortage. The dataset is done with two consumer-priced devices: a handheld camcorder and a mobile phone. Both devices were used to store material in indoor and outdoor settings with different attention levels from the people being filmed. The dataset comes with ground truth data that includes person head trajectories and other people marked in the background in MPEG-7-based metadata model. We give description of this metadata model and publish an annotation tool we used for creating the ground truth data. Also, we provide experimental results as a benchmark for all those who would like to use our dataset.

This paper introduces a scalable solution for distributing content-based video analysis tasks using the emerging MapReduce programming model. Scalable and efficient solutions are needed for this type of tasks, as the number of multimedia content is growing at an increasing rate. We present a novel implementation utilizing the popular Apache Hadoop MapReduce framework for both analysis job scheduling and video data distribution. We employ face detection as a case example because it represents a popular visual content analysis task. The main contribution of this paper is the performance evaluation of distribution models for video content processing in various configurations. In our experiments, we have compared the performance of our video data distribution method against two alternatives solutions on a seven node cluster. Hadoop's performance overhead in video content analysis was also evaluated. We found Hadoop to be a data efficient solution with minimal computational overhead for the face detection task.

Machine-to-Machine (M2M) communications emerge to achieve ubiquitous communications among all the networked devices. One challenging problem in M2M applications is to discover the resources provided by the devices efficiently. This challenge arises from two perspectives: (1) a large number of heterogeneous devices co-exist and most of them are constrained devices (e.g., limited processing capability), (2) different communication protocols are utilized to get access to different types of resources provided by the devices (e.g., humidity information provided by a sensor). This paper proposes distributed resource directory architecture for M2M applications, referred to as DRD4M. The DRD4M supports heterogeneous devices using HTTP and CoAP protocols for resource registration and lookup. This enables the interoperability among heterogeneous devices and resource access to constrained devices from disparate network including the Internet. The DRD4M introduces two components: a resource registration component for registering resources and a resource lookup component with caching functionality for handling resource lookup with filtering. A peer-to-peer (P2P) overlay is introduced in DRD4M to connect resource peers to avoid single point of failure. A real-world prototype is implemented and is verified with a demo application. Preliminary performance evaluation in terms of response time of resource lookup is provided.

In this paper, we propose an advanced model, called e-Aware, for estimating how application layer protocol properties affect the energy consumption of mobile devices, operating in 3G (WCDMA) and WLAN (802.11) networks. The main motivation for the model is to facilitate designing energy-efficient networking solutions, by reducing the need for time-consuming measurements with real-life networks and devices. The model makes a distinction between signaling and media transfers due to their different energy consumption characteristics, and takes into account the fundamentals of radio interface properties, such as different energy states and timers controlling them. The model is fine-tuned using device-specific coefficients that are defined according to real-world measurements with actual devices. We have implemented the model and simulated it in Matlab environment. The correct functionality is verified by comparing the results with real-life measurements in identical networking scenarios.

The popularity of community-centric applications has rapidly grown during the recent years. In this paper, we evaluate the robustness of a P2P community management system, where communities are established as autonomous DHT overlays that are advertised in a global DHT overlay. The evaluation is based on the experimental measurements conducted using a DHT-based protocol with two DHT algorithms called Kademlia and Chord. The robustness of the P2P community management system was evaluated with different levels of churn and node activity, in terms of nodes' look-up success ratio, network traffic load and average hop count. The P2P community management system was also compared against a flat DHT structure where all the community related activities are performed in a single DHT overlay. The evaluation results suggest that the P2P community management system performs very well in an environment with high level of churn, the performance improvement being especially significant with Chord.

Distributed Hash Tables (DHTs) have been deployed in a wide variety of peer-to-peer (P2P) networks. While the traditional use of P2P technology is focused around content sharing, the current trend is in applying the P2P technology for new application areas, such as interpersonal communications. Despite active research and standardization efforts, such as the development of Peer-to-Peer Session Initiation Protocol (P2PSIP), there has been little effort to evaluate the suitability of different DHTs for interpersonal communications. As there are significant differences between the requirements of various application types, the task of selecting an appropriate DHT algorithm for a particular application type is not trivial. Therefore an evaluation is needed. In this paper, we compare the performance and efficiency of two popular DHT algorithms, Kademlia and Chord, in P2PSIP environment. We are particularly interested in their messaging overhead and routing performance in different sizes of overlay networks. The results reveal that in identical application scenarios, Kademlia outperforms Chord by shorter lookup path lengths, whereas Chord scales better to larger networks in the terms of messaging cost.

We analyze the performance of a DHT-based P2P overlay network in resource access and overlay maintenance activities. We use a cross-platform implementation of the protocol called P2PP. Mobile systems are the main target platform of our protocol implementation; due to practical reasons, we conduct large-scale evaluations using a server array. The performance metric is the request accomplishment success ratio in the overlay network. The evaluations are conducted in the presence of churn i.e. the peers' continuous activity of joining and leaving the overlay, which is crucial for realistic simulations. The online and offline time-periods of churning peers follow an exponential distribution. In addition to churn, we use overlay size and resource lookup activity as variable parameters. Measurements of request success ratio can be used to approximate the performance of a P2P overlay network and the load inflicted on it, when its number of peers and activity level are known.

In this paper, the user experience in added value location-based mobile music service called the City Night Life (CNL) is evaluated and analyzed. The CNL service provides recommendations about entertainment premises in the proximity by matching their music styles with the user's personal music preferences. Entertainment premises are shown on a map interface and are marked with colors according to their match. The paper presents the components of the CNL service, the music profile, matching algorithm and the map-based user interface in a web browser. The user evaluation with 53 test users assessed the feasibility and business potential of the CNL service. Data was collected with both quantitative questionnaires and short interviews. The results indicate that the CNL service will be most useful in relatively large, unfamiliar cities. Furthermore, the matching algorithm was perceived to perform quite well.

Peer-to-Peer (P2P) technologies have many advantages over traditional client/server technologies, including cost- effectiveness, scalability and robustness, due to their decentralized network structure. However, the performance has traditionally been an issue in P2P systems. Especially the higher lookup latencies, when compared with the traditional client/server systems, have been the bottleneck in many P2P systems. In this paper, we propose a truncated pyramid P2P architecture together with an enhanced model, Vertical Tunneling Model (VTM) for improving the lookup performance. The proposed architecture is built on Peer-to-Peer SIP (P2PSIP) network. VTM builds up vertical tunnels between the upper and lower sub-overlays to speed up the service lookup and decrease the session setup delay. Based on the performance analysis and results, it is shown that VTM has better performance compared with the existing systems in average lookup hops, which is about 1/3 of that of the existing systems, the predominance is more evident as the network scale increases.

Although mobile devices are rich sources of context information, the distribution of context in mobile environments is often hindered by the limited battery life, and wireless connections with low bandwidth. In this paper, we present two different implementations that enable context distribution in mobile environments. The first solution relies on a presence service architecture and publish-subscribe messaging, whereas the second solution is based on a mobile Web server architecture where the context information is fetched from the mobile device when needed. This paper evaluates the feasibility of the two implementations in mobile context distribution. The testing results show that the mobile server-based solution sets higher demands for the mobile device capabilities, but is able to provide more up-to-date context information. However, the solution based on the centralized context service provides higher interoperability as it utilizes the existing IETF standards.

We evaluate the battery life of mobile devices that act as full-fledged peer nodes in a Kademlia DHT based P2P overlay network. The motivation is to find out how long a mobile peer is able to function in a UMTS or WLAN access network, and how the different parameter settings affect this battery life; this is interesting as mobile access to P2P networks is expected to become common in the near future. The majority of the peers in an overlay are simulated on a server array, while the power measurements are conducted on actual mobile devices. The variable overlay parameters are the number of peers, resource lookup activity, and the level of churn. The chosen values of parameters represent a relatively high amount of activity. In UMTS the measured battery life is approximately 3 hours and in WLAN it is 5 to 10 (most often around 8) hours. We also provide power measurements on sending and receiving UDP packets in UMTS and WLAN, for approximating the power consumption of network protocols without protocol-specific measurements.

We present the effects of different churn models on the performance of structured peer-to-peer (P2P) networks in this paper. Specifically, Exponential distribution (ED), Pareto distribution (PD), and Weibull distribution (WD) are evaluated to provide a comparative analysis. Kademlia-based Peer-to-Peer Protocol (P2PP) is utilized as the underlying signaling protocol. Through simulations, we conclude that the simulated different churn models do not have a significant effect on the performance of the simulated structured P2P network. Quantitatively, ED and PD result in better performance compared to WD from the viewpoints of lookup success rate, mean network traffic load, and mean number of messages.

Peer-to-peer service-oriented community coordinated multimedia (SCCM) is envisioned as a novel paradigm in which the user consumes multiple media through requesting multimedia-intensive Web services via diversity display devices, converged networks, and heterogeneous platforms within a virtual, open and collaborative community in context of a novel concept of multimedia applications as Web services. A generic P2P SCCM scenario is created and examined first. The SCCM model is designed with respect to service architecture, a tunneled hierarchical P2P model and metamodel framework. The progress with the development of content annotation services is presented.

The need for efficient and scalable data management has increased in the contemporary distributed mobile and fixed networks. Sharing growing amounts of multimedia data stored in autonomous, heterogeneous and distributed equipment such as mobile devices, personal computers, enterprise servers etc. is a trend, especially considering peer-to-peer networking scenarios. In this paper we describe a simple yet extendable analytical model to enable comparison of various aspects of the existing and emerging distributed data management systems. We introduce an abstract model for analyzing service enabler efficiency indicating operational costs for system external and internal parameters. Model is applied to benchmark distributed data management techniques to support optimal design choices, especially considering the design guidelines for data management in mobile P2P environments.

Community coordinated multimedia (CCM) envisions the paradigm of consuming multiple media via diversity display devices, converged networks, and heterogeneous platforms within a virtual, open and collaborative community. This paper applies service orientation approach and Web services technology to establish a Service-oriented CCM architecture (SCCM) for tackling requirements of scalability, discoverability, composibility, layered abstraction, QoS and agility in distributed collaborative multimedia management. A generic CCM scenario is examined. CCM service model is designed with service-orientation principles. A prototype of CCM is implemented with supporting multimedia publish, streaming, and viewing within SCCM.

Human experience is being extended and enhanced by collaboratively consuming electronic and networked content and multimedia-intensive services. This technical phenomenon is addressed by our generalized Community Coordinated Multimedia model in this paper. Content-driven and service-driven models are identified and a converged CCM model is introduced. Characteristics of Community Coordinated Multimedia are specified and challenges for developing a technological framework are presented.

This paper evaluates the feasibility of mobile nodes as peers in a structured peer-to-peer overlay network. Our performance analysis is based on the Peer-to-Peer Protocol (P2PP), which is a peer protocol candidate for the Peer-to-Peer Session Initiation Protocol (P2PSIP). We use both, live-network measurements and simulations, to evaluate two performance metrics: resource lookup success rate and mobile battery duration. While lookup success rate measures P2PP performance in general, battery duration is crucial for mobile use of P2PP. Restricted battery life limits the feasibility of mobile peers. We reveal the tradeoff between lookup success rate and battery duration. Based on the findings it is possible to find more suitable protocol parameters for mobile peers. The battery duration measurements, made with UDP in UMTS and WLAN access networks, are also applicable in the wireless usage of other application-layer protocols.

Abstract—Selection of optimal network connectivity in mobile telecommunications is an important field of study. There are more parameters to consider than mere selection of physical connectivities. For optimal vertical connectivity selections, a cross-layer approach is needed. This paper presents a formulation for the Holistic Connectivity framework, which, when applied in a mobile middleware solution, enables seamless top-down connectivity management in mobile consumer products. The solution has emphasis on peer-to-peer networking. Connectivity policy management extends the context-aware connectivity management framework developed earlier at the University of Oulu, Finland. Technical and functional scenarios for the proposed framework are discussed, and preliminary experimental results with realtime traffic are provided for supporting further design and requirement specification. Keywords-connectivity management; mobile middleware; crosslayer optimization I.

In this paper, we analyze the results of the end-user evaluation of a wellness-related mobile application for Symbian OS, the Wellness. With the application, users were able to plan their physical exercise beforehand, keep track of their performed exercise, and share that information to a peer group in real-time or after the exercise. The evaluation was carried out with 15 volunteer test users. Each of them used the application for 6 to 8 days, doing some physical exercise during that period. During the exercise, the users would wear a sports computer and a heart rate meter that communicated with the application in the phone. After the testing period, the users answered a questionnaire about their experiences. The users appreciated the application's basic idea, although the instability of the application deteriorated the quality of the user experience. Moreover, persons who had used similar wireless devices or applications before found the application more usable than those who had little experience of such technology.

In mobile networking, the use of context information in a versatile manner is emerging. Context information, which characterizes the situation of an entity, provides ease of use in mobile devices with limited input and output capabilities. A mobile peer-to-peer navigation application uses context information to verify this statement. It acts as a graphical user interface for group-based context-aware communication and as an enabler of inter-application cooperation. It uses an intelligent application platform for distributing context information. The analytical results consist of quantitative evaluation, involving functional testing and delay analysis, and a qualitative evaluation, involving user testing. The concepts of group-based context distribution and inter- application cooperation were found functional and useful.

The seamless and flexible interconnection of the existing and emerging protocols and networks is essential to the success of the new generation mobile applications and services. For exploiting the functional diversity, we have developed a middleware for mobile devices called the Plug-and-Play Application Platform (PnPAP). We have previously studied the Session Initiation Protocol (SIP) as an interconnecting protocol for the PnPAP nodes. In this paper, we analyze the usage of a new variant of SIP called Peer-to-Peer SIP (P2P SIP) for this purpose. Our interconnection architecture utilizes layered (hierarchical) P2P SIP to establish a self-organizing, failure tolerant overlay signaling network between PnPAP nodes. Signaling latency and scalability of the layered P2P SIP signaling is compared in a simulation environment with both the traditional client-server SIP and fully distributed P2P SIP. Simulation results illustrate the benefits of the layered P2P SIP solution where only the supernodes participate to the DHT management, enabling light-weight peer node implementation for mobile nodes.

This paper presents a novel mobile application interaction concept using application supernetworking. With efficient use of middleware, the use of resources can be optimized through so called Supersessions, which is an important factor especially in mobile devices. By implementing application co-operation, the user's awareness of available services can be increased while decreasing the amount of needed user input. Measurement results based on our plug-and-play application platform prototype with application supernetworking show the feasibility of the approach

Contemporary ubiquitous information systems combine efficiently context-aware and peer-to-peer communication concepts. This paper introduces a novel mobile peer-to-peer (P2P) navigation application, NaviP2P. In addition to basic navigation functionalities such as GPS positioning, showing the user location on the map, scrolling and zooming of the map view, the application leverages P2P group communication to portray peer group members' availability information on the map for starting supported application sessions. In this feasibility study, the current status of the application prototype is presented with a quantitative latency and cost analysis. End-to-end latency budget is outlined and different map storage and distribution solutions are compared to analyse communications and implementation feasibility

There are several non-interoperable peer-to-peer (P2P) protocols available today with different functionalities. In order to exploit this functional diversity on mobile devices, we have developed a plug-and-play application platform (PnPAP). PnPAP provides autonomous, dynamic selection between multiple P2P protocols while ensuring the best available network connectivity. In this paper, we introduce methods for utilizing session initiation protocol (SIP) in inter-PnPAP communications. This communication may include downloads of distributed P2P resources such as polymorphic protocol libraries or dynamic state-machine control modules. These components are then used to optimize connectivity management between heterogeneous wireless access networks. In addition, context information may be exchanged between mobile nodes in order to facilitate extended service availability, operability and quality. We analyze the feasibility of merged P2P and All-IP (including SIP) architecture through the novel use of a specialized SIP server and the leveraging of the emerging instant messaging capabilities of SIP. Preliminary measurement results from the prototype implementation on a Symbian platform and test-bed, with overhead and latency analysis, illustrate the feasibility of this approach.

This paper proposes an intelligent mobile middleware utilizing group-based content push with dynamic session startup and plug-and-play features. Solution enhances the distribution of mobile content, such as game applications or multimedia files, within a peer group community. It exploits the social relationships of the user community to enable instant application downloading, installation, and licensing upon incoming connection attempt initiated by another peer group member. In the core of the middleware functionality are dynamic application identification and immediate session startup. This paper presents a use case scenario for a content push procedure. Functional and technical analysis of the novel middleware component are provided. Observations from experimental signaling system setup are mapped with estimates of end-to-end delay budget.

While peer-to-peer (P2P) has emerged as a new hot communication concept among the Internet users, mobile usage of P2P applications is still taking its first steps. This article first elaborates the evolutionary process that P2P architectures are going through. Challenges and requirements for mobile P2P are then identified, followed by a definition of a novel Plug-and-Play Application Platform (PnPAP). This platform enables dynamic selections between diverse P2P and session management protocols while preserving the best available network connectivity through Holistic Connectivity (HCon) management. On-the-fly reconfiguration and run-time parameter optimization can be done with a lightweight interpretable state machine. The concept enables flexible and seamless communications for mobile devices in P2P networks.

Vertical handoff means mobility between heterogeneous wireless access network technologies. Hierarchical radio access networks with overlapping cells gives an opportunity to handoff between local area high bandwidth networks and wide coverage cellular data. Vertical mobility combines the capacity of local area networks and the coverage of wide area cellular networks. Resource allocation in this kind of environment has not been yet fully addressed in the current research work. Clearly, additional bandwidth offered by wide-band local area wireless networks opens a new area for network performance optimization. For that, it is needed to understand the processes that have an effect on the system performance. In particular, vertical mobility is usually characterized by handoffs between systems having different data rates. The most critical area for system performance is at the very edge of the cell, where the received signal strength (RSS) varies around the sensitivity threshold of the receiver. Simulation results show the estimates of the delay and general performance in a multiple radio network environment. Generalization of handoff performance between multiple radio networks with different data rates is given with analysis.

Managing QoS of VoIP is a challenge especially in a heterogeneous network environment such as Internet where often exists limitations or bottlenecks for the bandwidth. As the Internet protocol is evolving to a new version (v6) that offers a bigger address space at the cost of a bigger header size, there has been unawareness and worry how the increased header size affects real-time traffic, especially in bandwidth-limited wireless systems. In practice there will always be subnetworks and applications in the Internet that does not support the header compression and QoS methods available. Therefore there is a needed to analyze how VoIPv6 works in a bandwidth-limited wireless environment that does not support e.g. header compression, in comparison to VoIPv4. This was studied in a bandwidth-limited wireless LAN testbed. This paper presents the measurement results with analysis.

Mobility between dissimilar networks is one of the future trends in network design towards fourth generation of telecommunication systems. A cellular network can be overlaid with a spottish high data-rate WLAN network in areas such as business centers, hotels and airports. To avoid unnecessary search of WLAN beacon the terminal must be aware of the whereabouts of the overlay system to be visited. We suggest the usage of geolocation information in mobility management via distributed location databases to enable a moving host to prepare for handoff. Three scenarios and the related problems are presented, and the requirements for the system architecture and terminal are outlined. Considerations on the algorithm are given and preliminary simulation results of a fuzzy logic handoff algorithm are presented.

With the finalization of new series of IEEE 802.11 and ETSI HIPERLAN standards, it becomes very important and interesting to study the methods to integrate geolocation functionalities into the next generation wireless LANs. We investigate geolocation methods and system architectures using OFDM signals in HIPERLAN/2 wireless LANs. We propose a novel method to measure geolocation metrics by exploiting the HIPERLAN/2 MAC frame structure. Computer simulation results are presented to show the performance of the geolocation systems using OFDM signals.

The fourth generation of telecommunication networks will be a mix of existing and emerging wireless and wired networks. They will provide a framework for multi-service usage cases, such as Internet access, geolocation and real-time applications (such as voice and video). In this paper we refer this collection of interoperating networks as multi-service networks and elaborate the aspects of system architecture and mobility management in this heterogeneous environment. First, requirements for system architecture are outlined. A novel multi-service architecture is defined based on fully integration of location based services and IP mobility approach. Handoff decision policies for multi-service network scenarios are then considered and simulation results for the handoff algorithm are presented. The suitability of the fuzzy logic algorithm is discussed in this context.