Search

The demand for mobile broadband services is increasing exponentially alongside with user expectations regarding the reachability of these services and their prices. This paper presents an integrated satellite and fifth generation (5G) network for providing inflight connectivity and evaluates the economic viability of offering broadband connectivity to passengers on commercial airplanes by the development of a techno-economic framework, which considers both capital and operational expenditures to compute the total cost of ownership (TCO) and an average cost per user and per Megabyte. Results show high operational costs mainly due to satellite bandwidth usage. Therefore, caching popular content on the network onboard is beneficial to reduce the traffic carried over the satellite link, thus lowering the operational costs as well. Furthermore, the framework is used to compare the identified business models for Inflight Entertainment and Connectivity offerings and their pricing strategies, alongside a benchmark against the current inflight connectivity pricing. Finally, a sensitivity analysis is elaborated in order to mitigate the uncertainty of inputs (e.g., rate of caching) used to feed the TCO model. Following concrete recommendations are the main result of this research: (1) Providing inflight broadband services with a 2-5 Mbps throughput per user is feasible if satellite communications is integrated into the 5G network. (2) Caching popular data reduces the operational costs and hence the average cost per user (from 25% to 32% depending on the caching rate adopted). (3) This framework allows to provide recommendations on the best suited business models and related pricing schemes.

Making decisions on capacity requirements in hospital environments has long-term consequences. Sound estimates of expected mid and long-term demand for hospital beds are required to avoid oversupply or deficits. Though in many cases, forecasts of admissions and Length of Stay evolutions for specific pathologies are available, current models rarely model hospital environments on the pathology level, rendering them useless. Additionally, existing models are most often unit type or facility-dependent. This work describes a model to estimate care demand and capacity needs per ward of a generic hospital, in which pathology-specific parameters can be used, and that supports patient stays structurally segmented across multiple wards. The methodology enables an increase in model complexity while explicitly guarding the accuracy of parameter estimates.

The Web is evolving more and more to a small set of walled gardens where a very small number of platforms determine the way that people get access to the Web (i.e. “log in via Facebook”). As a pushback against this ongoing centralization of data and services on the Web, decentralization efforts are taking place that move data into personal data vaults. This positioning paper discusses a potential personal data vault society and the required research steps in order to get there. Emphasis is given on the needed interplay between technological and business research perspectives. The focus is on the situation of Flanders, based on a recent announcement of the Flemish government to set up a Data Utility Company. The concepts as well as the suggested path for adoption can easily be extended, however, to other situations/regions as well.

Wireless solutions based on visible light communication (VLC) have been proposed for backhaul transmission in optical attocell networks. Perfect alignment of auxiliary transceivers is important for wireless backhaul links due to the requirement of direct line-of-sight (LOS) and the first-bounce specular reflection of mirror-aided non-LOS. However, the perfect alignment may not be guaranteed due to the limitation of the layout of BSs or installation mistakes. In this article, we investigate the impact of misalignment on the overall network performance. Two VLC backhaul link configurations have been considered and compared. Performance of using different frequency reuse schemes and channel allocation schemes are compared.

Hardware-accelerators in Network Function Virtualization (NFV) environments have aided telecommunications companies (telcos) to reduce their expenditures by offloading compute-intensive VNFs to hardware-accelerators. To fully utilize the benefits of hardware-accelerators, VNF-chain recovery models need to be adapted. In this paper, we present an ILP model for optimizing prioritized recovery of VNF-chains in heterogeneous NFV environments following node failures. We also propose an accelerator-aware heuristic for solving prioritized VNF-chain recovery problems of large-size in a reasonable time. Evaluation results show that the performance of heuristic matches with that of ILP in regard to restoration of high and medium priority VNF-chains and a small penalty occurs only for low-priority VNF-chains.

The performance of visible light communication (VLC)-based optical attocell networks degrades due to shadowing caused by opaque objects. In order to improve reliability, we propose a cross-layer algorithm to find the optimal routing and resource allocation schemes when shadowing occurs. Simulation results show that the optimal scheme found by the proposed algorithm significantly improves the performance of optical attocell networks with one randomly shadowed link.

International audience; One of the main incentives for deploying network functions on a virtualized or cloud-based infrastructure, is the ability for on-demand orchestration and elastic resource scaling following the workload demand. This can also be combined with a multi-party service creation cycle: the service provider sources various network functions from different vendors or developers, and combines them into a modular network service. This way, multiple virtual network functions (VNFs) are connected into more complex topologies called service chains. Deployment speed is important here, and it is therefore beneficial if the service provider can limit extra validation testing of the combined service chain, and rely on the provided profiling results of the supplied single VNFs. Our research shows that it is however not always evident to accurately predict the performance of a total service chain, from the isolated benchmark or profiling tests of its discrete network functions. To mitigate this, we propose a two-step deployment workflow: First, a general trend estimation for the chain performance is derived from the stand-alone VNF profiling results, together with an initial resource allocation. This information then optimizes the second phase, where online monitored data of the service chain is used to quickly adjust the estimated performance model where needed. Our tests show that this can lead to a more efficient VNF chain deployment, needing less scaling iterations to meet the chain performance specification, while avoiding the need for a complete proactive and time-consuming VNF chain validation.

OpenFlow provides a protocol to control a network from an external server called controller. Moreover, RouteFlow presents a framework to run Internet routing protocols in OpenFlow networks by running them in virtual machines or containers. The problem is that OpenFlow networks running RouteFlow do not recover fast from a port failure (e.g., port down event). The failure recovery time is dependent on user configurable parameters and is in seconds. To overcome this problem, we implement a solution in which a port failure of a physical OpenFlow node is detected immediately in its corresponding virtual machine and an immediate action is taken by the routing protocol. Therefore, once a routing protocol running on the corresponding virtual machine detects this failure, it broadcasts the failure in the network and a new failure free path is immediately configured over the OpenFlow network. We implement the proposed solution in an OpenFlow controller and test it over single autonomous and multiple autonomous system scenarios (including OpenFlow and non-Openflow scenarios) of the Internet emulated on the virtual wall testbed of the Fed4Fire facility in Europe. The results show that an OpenFlow network can recover from a failure in a short time interval using the proposed solution.

Many media services undergo a varying workload, showing periodic usage patterns or unexpected traffic surges. As cloud and NFV services are increasingly softwarized, they enable a fully dynamic deployment and scaling behaviour. At the same time, there is an increasing need for fast and efficient mechanisms to allocate sufficient resources with the same elasticity, only when they are needed. This requires adequate performance models of the involved services, as well as awareness of those models in the involved orchestration machinery. In this paper we present how a scalable content delivery service can be deployed in a resource- and time-efficient manner, using adaptive machine learning models for performance profiling. We include orchestration mechanisms which are able to act upon the profiled knowledge in a dynamic manner. Using an offline profiled performance model of the service, we are able to optimize the online service orchestration, requiring fewer scaling iterations.

Due to ever-increasing throughput demands, the lookup in conventional IP routers based on longest prefix matching is becoming a bottleneck. Additionally, the scalability of current routing protocols is limited by the size of the routing tables. Geometric greedy routing is an alternative to IP routing which replaces longest prefix matching with a simple calculation employing only local information for packet forwarding. For the first time, in this paper we propose a novel and truly all-optical geometric greedy router based on optical logic gates and optical flip-flops. The circuit of the router is constructed through the interconnection of SOAs and directional couplers. The successful functionality of the proposed router is verified through simulation. The circuit enables high data rate throughput.

In this paper we explore in details the framework ElasticO++, which is a simulation framework for Elastic Optical Networks using OMNeT++. ElasticO++ is the first software available capable of working with spectrum defragmentation in dynamic network scenarios. The flexibility offered by the discussed tool allows both academia and industry to develop and evaluate new algorithms and techniques for Elastic Optical Networks. In this paper, we focus on ElasticO++ architecture, algorithms, and the features which we consider makes our framework unique. Additionally, we present a simulation case study and the newer features we are currently developing.

Cooperative Intelligent Transportation Systems (C-ITS) enable vehicles to be aware of objects that are not in line of sight, by interacting directly with each other and the surrounding road infrastructure. C-ITS promise to reduce traffic congestion, lessen the environmental impact of transportation, and most importantly, significantly reduce the number of (lethal) traffic accidents. As C-ITS is subject to strong network effects, adoption of C-ITS is a key driver of its (societal) benefits. Therefore, this paper estimates penetration rates of C-ITS equipped cars in the car park of Flanders, Belgium. Based on the preferred policy option with mandatory adoption, as proposed in the recent new Delegated Regulation of the European Commission, full penetration of C-ITS in the Flemish car park is expected later than twenty years after the mandate enters into force. Determination of C-ITS adoption numbers is valuable for a number of stakeholders, such as national and local governments, road authorities, technology providers and network operators. Additionally, penetration numbers allow Member States to ascertain to what extent C-ITS can contribute to the goal of zero traffic mortalities by 2050, as envisioned by the European Commission.

Making cities smarter is the future. By bringing more technology into existing city infrastructure, smart city applications can arise. Whether these applications track devices e.g. public lightning, environmental measurements e.g. temperature or air quality, or analyze video streams e.g. for people density, it is expected that these will require a (near-) real time data connection. Upcoming 5G networks will be able to handle large amounts of connections at high speeds and low latencies and will therefor outperform current technologies such as 4G and low-power wide-area networks. In order to do so, these 5G networks fall back to numerous fiber connected small cells for up & downlink to the Internet. In this publication, we are looking into the additional fiber equipment and deployment cost to connect the required smart city network infrastructure, taking into account a Fiber-to-the-Home (FTTH) network is already available or will be installed as part of the smart city network rollout. More concretely, we are proposing a methodology comparing an anticipated and incremental planning approach for a number of different extensions upon the FTTH-network: connecting all electrical cabinets, connecting public lightning, and the connection of 5G using small cells. From this, we want to learn how much the total rollout cost can be reduced using a future-oriented smart city approach taking into account all future extensions, compared to an incremental short-time planning only planning additional fiber when required. In the meantime, we want to show the additional cost of creating a smart city network is limited when it is being combined with a FTTH rollout. Results of the proposed methodology and use case will be modeled planning and design software Comsof Fiber and will be published in a future work.

In this demonstration, we present dynamic allocation of accelerator resources to SSH tunnels in an NFV environment. In order to accelerate a VNF, its compute-intensive operations are offloaded to hardware cores running on an FPGA. The CPU utilization information of VNFs is continuously processed by a service management component to dynamically decide the suitable target to run VNF's crypto-operations. We also demonstrate switching between the non-accelerated and hardware-accelerated SSH-tunnels triggered by a change in the nature of the data traffic flowing through the tunnel and indicate throughput gains obtainable in dynamically switching contexts.

Although network functions virtualization redefined the role of the network service developer, existing concepts that are supposed to enable them are still limited, cumbersome, and time consuming in regard to the promised flexibility. This article describes how to move forward from these initial steps, identifies the challenges network service developers face during both development and runtime, and explains how to overcome them with our SCK and programmable MANO framework. We detail how our SCK facilitates the service creation process, resulting in two enhanced NFV DevOps cycles, test flexibility and quicker service development. We elaborate on our programmable MANO framework with both architectural considerations and a use case, to depict its customizability by network service developers, giving them fine-grained control over their service throughout its end-to-end operational life cycle.

The emerging cost-efficient visible light communication (VLC)-based indoor wireless network requires an economical solution for backhaul transmission. Non-line-of-sight (non-LOS) VLC links are generally applicable candidates to set up a backhaul network without rearrangement of existing lighting fixtures. Here, we describe non-LOS channels aided by the first-order specular reflection from mirrors, which can be used to overcome the multipath effect of purely diffuse non-LOS channels. Characterizations of purely diffuse and mirror-aided non-LOS channels are conducted with a time-efficient simulation model based on an iterative algorithm. Any bounce of reflections combined with specular and diffuse reflections can be simulated using the proposed iterative VLC model in polynomial time. Simulation results show that mirror-aided non-LOS channels outperform purely diffuse non-LOS links regardless of the link configuration. The effect of concentration and directionality of non-LOS VLC channels is also shown and discussed.

Recent developments in nanotechnology herald nanometer-sized devices expected to bring light to a number of groundbreaking applications. Communication with and among nanodevices will be needed for unlocking the full potential of such applications. As the traditional communication approaches cannot be directly applied in nanocommunication, several alternative paradigms have emerged. Among them, electromagnetic nanocommunication in the terahertz (THz) frequency band is particularly promising, mainly due to the breakthrough of novel materials such as graphene. For this reason, numerous research efforts are nowadays targeting THz band nanocommunication and consequently nanonetworking. As it is expected that these trends will continue in the future, we see it beneficial to summarize the current status in these research domains. In this survey, we therefore aim to provide an overview of the current THz nanocommunication and nanonetworking research. Specifically, we discuss the applications envisioned to be supported by nanonetworks operating in the THz band, together with the requirements such applications pose on the underlying nanonetworks. Subsequently, we provide an overview of the current contributions on the different layers of the protocol stack, as well as the available channel models and experimentation tools. As the final contribution, we identify a number of open research challenges and outline several potential future research directions., Comment: 37 pages, 11 figures, 7 tables

In this work, we present ElasticO++: an Elastic Optical Network Simulation Framework for OMNeT++. A tool created to enable testing in a whole range of routing, modulation, spectrum assignment, defragmentation algorithms, parameters, and topologies. To the best of our knowledge, the proposed framework is the first software available capable of working with fragmentation and defragmentation in dynamic network scenarios. The flexibility available on the proposed tool allows both academia and industry develop new algorithms and techniques for Elastic Optical Networks. The framework provides a set of instruments that allow rapid implementation, testing, and analysis of new algorithms; and enables a common and well-controlled environment for comparing existing algorithms. In its current version, the framework comes with ten traditional already implemented algorithms, which can be used standalone or in combination with new ones. This work describes the architecture and main features, which makes our framework unique. Additionally, we present a case study to demonstrate some of the proposed framework capabilities.

In this letter, we propose a novel protocol, inter-burst segregation protocol (IBSP), which guarantees zero packet loss in packet-switched networks. The protocol is implemented and evaluated in network simulator-3 and in the data plane development kit (DPDK) implemented by INTEL. The results confirm that a packet-switched network can achieve zero packet-loss using IBSP, although nearly all the bandwidth is consumed in the network. In addition, the jitter is significantly low and bounded using IBSP.

Virtualization is an enabling technology that improves scalability, reliability, and flexibility. Virtualized networking is tackled by emulating or paravirtualizing network interface cards. This approach, however, leads to complexities (implementation and management) and has to conform to some limitations imposed by the Ethernet standard. RINA turns the current approach to virtualized networking on its head: instead of emulating networks to perform inter-process communication on a single processing system, it sees networking as an extension to local inter-process communication. In this article, we show how RINA can leverage a paravirtualization approach to achieve a more manageable solution for virtualized networking. We also present experimental results performed on IRATI, the reference open source implementation of RINA, which shows the potential performance that can be achieved by deploying our solution.

The power consumption in Information and Communication Technologies networks is growing year by year; this growth presents challenges from technical, economic, and environmental points of view. This has lead to a great number of research publications on “green” telecommunication networks. In response, a number of survey works have appeared as well. However, with respect to backbone networks, most survey works: 1) do not allow for an easy cross validation of the savings reported in the various works and 2) nor do they provide a clear overview of the individual and combined power saving potentials. Therefore, in this paper, we survey the reported saving potential in IP-over-WDM backbone telecommunication networks across the existing body of research in that area. We do this by mapping more than ten different approaches to a concise analytical model, which allows us to estimate the combined power reduction potential. Our estimates indicate that the power reduction potential of the once-only approaches is 2.3 $\times$ in a Moderate Effort scenario and 31 $\times$ in a Best Effort scenario. Factoring in the historic and projected yearly efficiency improvements (“Moore's law”) roughly doubles both values on a ten-year horizon. The large difference between the outcome of Moderate Effort and Best Effort scenarios is explained by the disparity and lack of clarity of the reported saving results and by our (partly) subjective assessment of the feasibility of the proposed approaches. The Moderate Effort scenario will not be sufficient to counter the projected traffic growth, although the Best Effort scenario indicates that sufficient potential is likely available. The largest isolated power reduction potential is available in improving the power associated with cooling and power provisioning and applying sleep modes to overdimensioned equipment.

Network virtualization and softwarizing network functions are trends aiming at higher network efficiency, cost reduction and agility. They are driven by the evolution in Software Defined Networking (SDN) and Network Function Virtualization (NFV). This shows that software will play an increasingly important role within telecommunication services, which were previously dominated by hardware appliances. Service providers can benefit from this, as it enables faster introduction of new telecom services, combined with an agile set of possibilities to optimize and fine-tune their operations. However, the provided telecom services can only evolve if the adequate software tools are available. In this article, we explain how the development, deployment and maintenance of such an SDN/NFV-based telecom service puts specific requirements on the platform providing it. A Software Development Kit (SDK) is introduced, allowing service providers to adequately design, test and evaluate services before they are deployed in production and also update them during their lifetime. This continuous cycle between development and operations, a concept known as DevOps, is a well known strategy in software development. To extend its context further to SDN/NFV-based services, the functionalities provided by traditional cloud platforms are not yet sufficient. By giving an overview of the currently available tools and their limitations, the gaps in DevOps for SDN/NFV services are highlighted. The benefit of such an SDK is illustrated by a secure content delivery network service (enhanced with deep packet inspection and elastic routing capabilities). With this use-case, the dynamics between developing and deploying a service are further illustrated.

The paper presents a topology-agnostic greedy protocol for network-on-chip routing. The proposed routing algorithm can tolerate any number of permanent faults, and is proven to be deadlock-free. We introduce a specialized variant of the algorithm, which is optimized for 2D mesh networks, both flat and wireless. The adaptiveness and minimality of several variants this algorithm are analyzed through graph-based simulations., Comment: Presented at 11th International Workshop on Network on Chip Architectures (NoCArc 2018)

This paper combines the concept of multi-sided platforms and the emerging market of the Internet of Things (IoT). At present, the IoT market is in an early stage, with an abundance of fragmented solutions targeting specific domains and/or specific types of applications. In this paper, we defend our position that software back-end IoT platforms offer considerable potential to become leading multi-sided platforms as the core of the complex IoT ecosystem and hence, a race for domination of the IoT platform market will appoint these platform leaders. Furthermore, some important trade-offs are discussed for platform providing companies that aspire to become leading multi-sided platforms in the Internet of Things industry.

Network architecture innovation has been driven by virtualization and centralization of network control based on software-defined networking SDN and by network functions moved to the cloud with network function virtualization NFV. These two principles are considered as promising enablers to reduce costs and spur innovation. In the first part of the paper, we argue that the evolved packet system EPS can be seen as a service function chain and an area in which service providers can capitalize on SDN and NFV capabilities. A multi-layer modular architecture for carrier networks based on SDN and NFV principles is provided. In the second part of the paper, we focus solely on SDN, and we argue that service providers can benefit from SDN to reach cost savings in their mobile network. Our work focuses on the cost savings that can be reached via the centralization of control and the operational paradigm of developing and operating the network management software in-house instead of buying a vendor solution only. We quantify the potential cost savings that can be reached in an Internet protocol/multi-protocol label switching-based transport service with SDN capabilities that interconnects the key functional elements in a mobile network. In the analysis, we evaluate the impact on capital expenditures and provide details on the impact on operational expenditures. The evaluation can serve as a blueprint for techno-economic analysis of the mobile network operator's processes in the transport network of a mobile network. Copyright © 2015 John Wiley & Sons, Ltd.

The rise of Software-Defined Networking (SDN) and Network Function Virtualization (NFV) introduce opportunities for service providers to reduce CAPEX/OPEX and to offer and quickly deploy novel network services. In particular, SDN and NFV enable the flexible composition of network functions, a generic service concept known as network service chaining (NSC).However, the control of resources, management and configuration of network service chains is challenging. In particular, there typically exist multiple options on how an abstract network service can be decomposed into more refined, inter-connected network functions. Moreover, efficient algorithms have to be devised to allocate the network functions. The underlying algorithmic problem can be seen as a novel generalization of the Virtual Network Embedding Problem (VNEP), where there exist multiple realization options. The joint optimization of decomposition and embedding has not been studied in the literature before.This paper studies the problem of how to optimally decompose and embed network services. In particular, we propose two novel algorithms to map NSCs to the network infrastructure while allowing possible decompositions of network functions. The first algorithm is based on Integer Linear Programming (ILP) which minimizes the cost of the mapping based on the NSCs requirements and infrastructure capabilities. The second one is a heuristic algorithm to solve the scalability issue of the ILP formulation. It targets to minimize the mapping cost by making a reasonable selection of the network function decompositions. The experimental results indicate that considering network function decompositions at the time of the embedding significantly improves the embedding performance in terms of acceptance ratio while decreasing the mapping cost in the long run in both optimal and heuristic solutions.

Energy efficiency and green communications have become well-established themes for next-generation communications systems, with specific regard to reducing carbon footprint, lowering environmental impact, and minimizing operational expenditures. Apart from conforming to the required societal green agenda, there are also many practical and financial advantages to creating solutions that exhibit such benefits. Extending the advantages of energy efficiency to access networks is paramount as it is the major contributor of energy consumption in the Internet. Among the various factors of energy consumption in access networks, optical network units (ONUs) at the customer's premises consume the bulk of energy: ONUs consume about 60-70% of the energy consumed in current fiber-to-the-home networks. In this paper, we propose a dynamic bandwidth allocation (DBA) algorithm for Ethernet passive optical networks (EPONs). The DBA algorithm exploits the sleep mode functionality, in which the optical network unit (ONU) is put into sleep according to the traffic load of the ONU. We explore the DBA paradigm for two kinds of ONUs: legacy (with large sleep overheads) and next generation (with small sleep overheads). We also extend the DBA algorithm with a variety of grant sizing (bandwidth allocation) schemes. The DBA algorithm achieves significant power savings in comparison to traditional power-ignore DBAs.

In recent years, rising energy prices and increasing environmental concerns have boosted research in the so called green ICT and green networking research tracks, aimed at improving the energy efficiency of communications while still offering maximal functionality. In this article we explore a future scenario in which low power networking is no longer optional, but instead becomes a necessity due to fluctuating energy availability. The contribution of this work is twofold. First, we argue why a so called post-peak future scenario, in which we can no longer rely on fossil fuels as our main resource for electricity production, is not unlikely, and what it might entail. Second, we explore the consequences of such a scenario for ICT: How well can current and future infrastructures cope with temporary energy limitations? As an illustration, we present a case study showing the impact of reduced energy availability on a wireless access network.

Telecom network operators face rapidly changing business needs. Due to their dependence on long product cycles they lack the ability to quickly respond to changing user demands. To spur innovation and stay competitive, network operators are investigating technological solutions with a proven track record in other application domains such as open source software projects. Open source software enables parties to learn, use, or contribute to technology from which they were previously excluded. OSS has reshaped many application areas including the landscape of operating systems and consumer software. The paradigm shift in telecommunication systems towards Software-Defined Networking introduces possibilities to benefit from open source projects. Implementing the control part of networks in software enables speedier adaption and innovation, and less dependencies on legacy protocols or algorithms hard-coded in the control part of network devices. The recently proposed concept of Network Function Virtualization pushes the softwarization of telecommunication functionalities even further down to the data plane. Within the NFV paradigm, functionality which was previously reserved for dedicated hardware implementations can now be implemented in software and deployed on generic Commercial Off-The Shelf (COTS) hardware. This paper provides an overview of existing open source initiatives for SDN/NFV-based network architectures, involving infrastructure to orchestration-related functionality. It situates them in a business process context and identifies the pros and cons for the market in general, as well as for individual actors.

Geometric routing is an alternative to traditional routing algorithms in which traffic is no longer forwarded using lookup tables, but using coordinates in an embedding of the underlying network. A major downside of current geometric routing algorithms is their inability to handle network failures in a graceful manner. Moreover, they cannot deal with dynamic graph topologies. This article presents a geometric routing scheme that uses an embedding based on a spanning forest. Allowing nodes to select the optimal spanning tree leads to both shorter paths and natural traffic redirection in case of network failures. By constructing the forest in such a way that its disconnected components have low redundancy, their coverage is maximized. Results show that this system is able to operate gracefully in severe failure scenarios, without any form of path protection or restoration. By means of an embedding regeneration procedure, the routing scheme is able to continuously adapt to an altering network topology. This geometric routing algorithm effectively combines two key objectives, namely low path stretch and high robustness. © 2015 Wiley Periodicals, Inc. NETWORKS, Vol. 664, 320-334 2015

Future Internet testbeds permit experiments not possible in today's public Net or commercial cloud services.

Geometric routing is an alternative for IP routing based on longest prefix matching. Using this routing paradigm, every node in the network is assigned a coordinate and packets are forwarded towards their intended destination following a distance-decreasing policy (greedy forwarding). This approach makes the routers significantly more memory-efficient compared to the current IP routers. In this routing, greedy embeddings are used to guarantee a 100% successful delivery to every destination in the network. Most of the existing proposals lack resiliency mechanisms to react efficiently to network changes. We propose a distributed algorithm to calculate a greedy embedding based on a spanning tree of the network. In this algorithm, nodes are triggered to re-calculate their coordinates upon a change in the topology such as link or node failures. The advantage of this approach is that it recovers from topology failures within a very short period of time. We further extend the algorithm to generate backups to apply protection in distributed setups. Different trade-offs and trends of re-convergence for geometric routing have been evaluated in an emulation environment. Realistic results are achieved through emulation as no model or abstraction is involved. The proposed routing scheme is implemented in Quagga routing software and new elements are developed in Click modular router to enable greedy forwarding. For the first time, the performance of this scheme is evaluated through emulation on a large topology of 1000 nodes and the results are compared with BGP. The experimental results indicate that the proposed scheme has interesting characteristics in terms of convergence time upon a change in the network topology.

An ever-increasing bandwidth demand is the main driver to investigate next-generation optical access (NGOA) networks. These networks, however, do not only have to comply with increasing data rates, but they should also meet the societal green agenda. As the access part consumes a major fraction of the energy consumption in today's fiber-to-the-home-based telecommunication networks, the energy efficiency of NGOA networks should be an important design parameter. In this paper, we present a detailed evaluation of the energy consumption in different NGOA technologies. Furthermore, we analyze the effects of (1) introducing low power modes (e.g., sleep and doze modes) in the various NGOA technologies and (2) using optimal split ratios adjusted to the traffic demands so that the energy consumption is optimized for the desired quality of service level.

While telecommunication networks have historically been dominated by a circuit-switched paradigm, the last decades have seen a clear trend towards packet-switched networks. In this paper we evaluate how both paradigms (which have also been referred to as optical bypass and non-bypass, respectively) perform in optical backbone networks from a power consumption point of view, and whether the general agreement of circuit switching being more power-efficient holds. We consider artificially generated topologies of various sizes, mesh degrees and - not yet previously explored in this context - transport linerates. We cross-validate our findings with a number of realistic topologies.Our results show that circuit switching is preferable when the average node-to-node demands are higher than half the transport linerates. However, packet switching can become preferable when the traffic demands are lower than half the transport linerate. We find that an increase in the network node count does not consistently increase the energy savings of circuit switching over packet switching, but the savings are heavily influenced by the mesh degree and (to a minor extent) by the average link length. Our results are consistent for uniform traffic demands and realistic traffic demands.A key take-away message for other research on power saving solutions in backbone networks is that the ratio between the average demand and the demand bitrate has considerable effect on the overall efficiency, and should be taken into account.

In OpenFlow, data and control plane are decoupled from switches or routers. While the data plane resides in the switches or routers, the control plane might be moved into one or more external servers (controllers). In this article, we propose verification mechanisms for the data plane functionality of switches. The latter consists of two parts: (1) Flow-Match Header part (to match a flow of incoming packets) and (2) action part (e.g., to forward incoming packets to an outgoing port). We propose a mechanism to verify the Flow-Match Header part of the data plane. The mechanism can be executed at the controller, or on an additional device or server (or virtual machines) attached to the network. Deploying a virtual machine (VM) or server for verification may decrease the load of the controller and/or consumed bandwidth between the controller and a switch. We propose a heuristic to place external verification devices or VMs in a network such that the verification time can be minimized. Verification time with respect to consumed resources are evaluated through emulation experiments. Results confirm that the verification time using the proposed heuristic is indeed shortened significantly, while requiring low bandwidth resources.

More often than not, maintaining a utility network requires opening up streets which results in traffic diversions and traffic jams in turn leading to additional nuisance for urban citizens. By aligning the planning of different utility providers, additional synergies can be achieved, which will not only result in fewer nuisances for the city in general, but may also lead to clear cost savings for the involved parties. Additionally, utility operators teaming up will also lead to safer work conditions, and less service interruptions due to unintentional damages. In this publication we present a multi-objective multi-actor approach to optimally reschedule the planning of a set of utility providers resulting in up to 32% more works executed in synergy and up to 46% more weeks of cooperation. Additionally, by verifying our approach with people with hands-on experience in utility network planning, we have managed to pinpoint a number of real-life implications; each of these issues have been discussed and when possible, approaches to tackle these issues have been proposed.

In this paper, we propose an OpenFlow enabled Internet infrastructure, using virtual path slicing in an end-to-end path, so that any user connected to an OpenFlow network is dynamically allocated a corresponding right of way. This approach allows an interference-free path, from other traffic, between any two endpoints, on multiple autonomous systems, for a given application flow (e.g., WebHD Video Streaming). Additionally, we propose and implement an end-to-end quality of service framework for the Future Internet and extend the virtual path slice engine to support future Internet technologies such as OpenFlow. The proposed framework is evaluated in distinct multiple autonomous scenarios for a city with a population of 1 million inhabitants, emulating xDSL (Digital Subscriber Line), LTE (Long-Term Evolution) and Fibre networking scenarios. The obtained results confirm the suitability of the proposed architecture between multiple autonomous systems, considering both data and control traffic scalability, as well as resilience and failure recovery. Furthermore, challenges and solutions for experimentation in a large-scale testbed are described.

Ongoing evolutions in the Network Function Virtualization (NFV) area show that software will play an increasingly important role within the telecommunication industry. It enables telco providers to faster introduce telecom services, combined with new possibilities to optimize and fine-tune operational performance. New virtualization and softwarization methods support fine-grained scaling of resources and highly-customizable configuration settings. Additionally, multi-datacenter topologies are available to deploy the Virtual Network Functions (VNFs) a service consists of. In this context, specialized tools are needed for debugging and validating the deployment, placement, chaining, configuration and scaling of network services, before the operator deploys the service in production. This demo showcases an open-source Software Development Kit (SDK), built to support NFV-based services throughout their whole lifecycle. During the demo, several example VNFs will be loaded into the SDK environment to demonstrate the features a service developer is envisioned to use, while either creating or updating NFV-based telecom services.

Network slicing is the emerging paradigm in which operators use their resources to provide multiple logical networks and associated resources, with varying configurations and at the same time. More and more vertical industries need their machines and devices connected in networks with specific requirements. In order to provide networks fitted to these usecases, and not require that they adapt to the one-size-fits-all network as is currently the case with the mobile Internet, the telecom community vowed to include network slicing functionality within its next generation of mobile networking, 5G, as an end-to-end network solution. As the concept is new and still not fully grasped, we develop and refine the concept of a network slice both from a business and a technological point of view. We investigate how network slicing in the context of a vehicular network could be implemented and how it advances the state of the art. This involves a detailed study of the involved technologies across a range of infrastructures and network segments, as well as the resulting gaps in the existing technology landscape. Based on the lessons learned in this concrete usecase, network slicing is considered in a broader 5G landscape. We capture the main challenges and potential directions in order to make network slicing a true enabler of 5G-driven vertical industries.

A highly reliable set up of Management and Orchestration (MANO) functionality is crucial for telecom operators in order to support demanding NFV-powered telecom services such as elastic emergency or security services, or other applications requiring fast, dynamic and reliable (re-) provisioning processes. NFV MANO functionality controls the entire life cycle of such services, from instantiation and configuration to monitoring, migrating, scaling and terminating them. In this paper, we introduce tunable and scalable mechanisms that provide MANO with high availability and fault recovery, two reliability facets that are barely covered in the data plane dominated state-of-the-art. The mechanisms use state sharing and distributed load balancing in the context of both a centralised and distributed microservice-based architecture. The proposed mechanisms are unique as they are able to quantitatively characterise the trade-offs between both the degree of reliability and the associated cost in terms of bandwidth and computing power. This feature allows us to introduce a cost function to determine which configuration of the mechanism is optimal with respect to an operator's needs.

The growing demand for flexibility and cost reduction in the telecommunication landscape directs the focus of service development heavily to programmability and softwarization. In the domain of Network Function Virtualization (NFV), one of the goals is to replace dedicated hardware devices (such as switches, routers, firewalls) with software-based network functionalities, showing comparable performance when deployed on common servers. In this paper, we discuss how current VNF implementation and deployment strategies impact the efficient monitoring of their resources. In a multi-tenant, NFV-based ecosystem, different Service Providers deploy VNFs on a shared infrastructure, where the Infrastructure Provider exposes only VNF specific metrics and little information about the physical hosts where the VNFs are eventually orchestrated. Especially in the situation where datacenters are overcommitted, detecting the risk of e.g. CPU starvation is not straight-forward, when no information from the physical host is available. A new monitoring technique is introduced, based on the skewness of the measured probability distribution of the VNF resource consumption. Our measurements show that this metric is a good indicator for the (un)availability of the required CPU resources in the datacenter.

Traditional routing in the Internet is best-effort which makes it challenging for video streaming since no throughput, jitter, delay or loss rate is guaranteed. As different paths have different characteristics, path differentiation such as multipath routing is a promising technique to be used for meeting QoS requirements of media-intensive applications. Using overlay networks different paths are offered which enable more flexibility in QoS and congestion control while the reliability of the connections is enhanced. Software Defined Networking (SDN) is known to be a promising solution to the problems of routing as it provides fine-grained control over packet handling. Relying on SDN, we propose an adaptive multipath provisioning scheme ensuring maximal bandwidth and resiliency of media transfer in overlay networks. The scheme is a time slot-based approach which dynamically finds multipaths. It relies on both active probing and traffic prediction. The experimental results confirm that a more accurate prediction together with more frequent probing lead to fewer number of path re-calculation and also indicate that the proposed scheme enhances the reliability of connections while a more balanced load is achieved in the network compared to the shortest path-based scheme. (C) 2017 Elsevier B.V. All rights reserved.

As technology evolves and globalization continues, the need for reasonably priced roaming services has never been higher. In 2007, the European Commission (EC) introduced a first set of regulatory decisions to cap the maximal roaming fee end users have to pay for voice services. In the years after, additional price caps have been introduced for SMS and data, initially only for end users, in a later stage also for the wholesale tariff. The final step, Roaming Like at Home (RLAH), will start to take effect in June 2017; from then on end users will pay the same price (for voice, SMS and data) when roaming like in their domestic country. The effect of RLAH on the business case of each mobile operator is hard to predict, as the different national markets are extremely heterogeneous and operators face large discrepancies in terms of roaming usage and network costs due to different travelling patterns and various other reasons that cannot be harmonized (geography, economics, working force, usage history, etc.). Furthermore, competition in the telecom market will no longer be a purely national matter, as the decision to abolish roaming tariffs will fully open up cross-border competition. This paper aims at providing insights in the effect of RLAH for both the end user as well as the mobile operators. Following a literature survey approach, including an overview of the roaming regulation process from 2007 up to now, the paper discusses possible effects the RLAH initiative might trigger, going from lower wholesale prices for mobile operators to higher retail prices for end Users. Additionally, as the European Commission strives for a digital single market, this paper presents a number of technical solutions (carrier portability, software-based SIMs, cross-border IMSI, Roaming like a Local, Wi-Fi offloading) that may pose a - partial or full - alternative for roaming and explains how these may impact cross-border competition both positively and negatively. The solutions are assessed against two axes: (1) generating the best possible outcome for the end customers (in all countries) and (2) ensuring the best level playing field for (virtual) mobile operators in Europe, which will of course involve trade-offs on different levels.

There has been a large global effort to innovate and design optical access technologies that can accommodate the requirements emerging from a colossal increase in data rates. Currently TWDM-PONs and WDM-PONs have been foreseen as the main candidates for next-generation access systems. Due to current business modeling trends and possible regulatory obligations, these networks should also support open access, which refers to the sharing of a network infrastructure among different network entities in a non-discriminatory way. By sharing the (bottleneck) infrastructure facility, open access reduces the entry barrier for a network entity. This opens doors for a multi-provider scenario, which leads to competition among network players and can significantly reduce the price of services. Opening up the network, however, entails new architectures. In this article we propose novel architectures to support open access at the fiber and wavelength level for WDM-PON and TWDM-PON. These architectures differ significantly in terms of their cost (capital and operational expenditures). We compare the proposed architectures with regard to their cost and analyze the impact of adoption levels (percentage of users subscribed) and customer churn rate (how often the customers change network provider) on the cost of the architectures.

Fiber to the home networks are seen as the most future proof technology to offer increasing bandwidth to customers. The publication of the Digital Agenda has put forward challenging goals for the broadband connectivity in Europe, but the rollout of next generation fixed access networks is still lagging. One of the reasons is the high initial investment cost associated with the rollout of these networks. To decrease this cost, a cooperation model between utility operators during the deployment phase is proposed in this paper. A model has been developed, in order to optimize the position of the different infrastructures in the trench and to allow for a fair allocation of the different costs incurred between all cooperating parties. The combination of these models has shown that a synergetic deployment phase of new infrastructures, both in Greenfield and Brownfield installations, can decrease the deployment costs for fiber infrastructure up to 21%.

The paper introduces a novel architecture for optical access networks that simultaneously provides complete flexibility and security. At the same time, the distribution architecture is completely passive. Unlike the other architectures in literature, the proposed architecture does not possess a security-flexibility tradeoff. Complete flexibility allows to switch OFF appropriate number of active components at low network loads making this design a green technology. The discussed architecture has a long reach, which is independent of the number of users in the network.

Parking spot monitoring can be used for various smart parking applications. One particular use is detecting the city wide occupancy level of the parking spaces and redirecting cars accordingly to reduce congestion. The practice of monitoring parking spots is already widespread in modern off-street parking lots. However, a large fraction of a city's parking capacity still stems from on-street parking spots. These aren't yet monitored as commonly. This can be explained by higher deployment costs for on-street implementations.

In the early 2000s, a large number of companies thrived mainly due to the fast-paced evolution of network and Internet technologies. A similar trend is now emerging with the rise of the Internet of Things (IoT), using which almost every thing can be part of the Internet. Both groups of companies have important ICT networks as their core assets. In order to validate the feasibility of the business models of such companies, the relevant costs and revenues should be modeled. This publication focuses on the relevant costs, which can be divided into two categories: process costs and equipment costs, the latter being the focus here. For equipment costs, no formal standard exists. As a result, most studies make use of use case-specific ad hoc models (typically, a combination of visualization and spreadsheet modeling), which tend to be error-prone as well as hard to understand and reuse. To solve these issues, we developed the Equipment Coupling Modeling Notation (ECMN), which allows for both visualization and calculation while focusing on simplicity, flexibility, and reusability. ECMN is a flowchart-like notation based on a small number of building blocks, which allows for hierarchical modeling by means of nesting models (using submodels). In this study, ECMN was applied to an IoT use case to show its strengths, based on which a comparison was made with various ad hoc models using a set of requirements.

As large energy consumers, base stations need energy-efficient wireless access networks. This article compares the design of Long-Term Evolution (LTE) networks to energy-efficient LTE-Advanced networks. LIE-Advanced introduces three new functionalities - carrier aggregation, heterogeneous networks, and extended multiple-input, multiple-output (MIMO) support. The authors develop a power consumption model for LIE and LIE-Advanced macrocell and femtocell base stations, along with an energy efficiency measure. They show that LIE-Advanced's carrier aggregation and MIMO improve networks' energy efficiency up to 400 and 450 percent, respectively.

A change in network topology triggers the re-convergence process of routing protocols. The re-convergence time of current routing protocols (e.g. OSPF) is constrained by the possibility of having transient loops due to the independent calculation of shortest paths between routers affected by a network failure. Several IP Fast-ReRoute (IPFRR) schemes have been developed to pro-actively calculate and install alternate forwarding entries almost instantaneously once a topology update message is received, without causing temporary micro-loops. The IPFRR scheme which has been used most extensively so far makes use of Loop-Free Alternates (LFA). While these are easy to configure, LFAs still require manual configuration, and the resulting ratio of covered link failures is only about 60 to 70 percent. This paper presents a logical extension of the Loop-Free Alternate concept, proposes a self-configuring scheme to populate the corresponding alternate entries, and evaluates the performance of the scheme with respect to coverage, configuration time and path length in a simulation environment.