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This paper proposes a new paradigm for control plane in Time Sensitive Networks (TSN). An SDN controller proactively instructs network elements on the reconfigurations to perform locally if some specific events occur (e.g., failures, performance degradations). Instructions are given in the form of Finite State Machines (FSMs), which store information related to the actions that each network element should execute to react against a specific event. Thus, if such event occurs, the SDN controller is by-passed reducing reaction (e.g., recovery) time. Such an approach is here implemented for recovery upon failures in TSN. Experiments of failure recovery are carried out and measurements are presented comparing the FSM-based solution with a fully-centralized reactive restoration. Moreover, the proposed approach is compared through simulations against Frame Replication and Elimination for Reliability. Results will show how proactive FSM manipulation can strongly reduce recovery time in SDN-based TSN networks without overloading the network with frame replicas.

A heterogeneous 5G infrastructure includes physical and virtual computation, storage, and networking resources, exploiting different technologies and spanning across several administrative domains. These resources can be combined into end-to-end slices that can host different services. Services consist of virtual or physical elements and have different requirements, e.g., in terms of resource demands, latency, performance guarantees. The underlying resources need to be efficiently allocated to the slices and their corresponding services. To abstract away the complexities of the underlying 5G infrastructure and to provide the common functionalities required for efficient and flexible service and slice management and orchestration, we propose 5G Operating System (5G OS). We describe the requirements of such a system, present the high-level architecture of 5G OS, and describe the design challenges for different interfaces within 5G OS. Our proposed architecture includes scalable hierarchies of multi-domain and domain-specific slice and service orchestrators, software-defined network controllers, and network function virtualization management and orchestration frameworks.

Mobile computation offloading has been identified as a key-enabling technology to overcome the inherent processing power and storage constraints of mobile end devices. To satisfy the low-latency requirements of content-rich mobile applications, existing mobile cloud computing solutions allow mobile devices to access the required resources by accessing a nearby resource-rich cloudlet, suffering increased capital and operational expenditures. To address this issue, in this paper, we propose an infrastructure and architectural approach based on the orchestrated planning and operation of optical data center networks and wireless access networks. To this end, a novel formulation based on a multi-objective nonlinear programming model is presented that considers energy-efficient virtual infrastructure planning over the converged wireless, optical network interconnecting DCs with mobile devices, taking a holistic view of the infrastructure. Our modelling results identify trends and trade-offs relating to end-to-end service delay, mobility, resource requirements and energy consumption levels of the infrastructure across the various technology domains.

This work focuses on the design, analysis and evaluation of Dynamic Weighted Round Robin (DWRR) algorithms that can guarantee CPU service shares in clusters of servers. Our motivation comes from the need to provision multiple server CPUs in cloud-based data center environments. Using stochastic control theory we show that a class of DWRR policies provide the service differentiation objectives, without requiring any knowledge about the arrival and the service process statistics. The member policies provide the data center administrator with trade-off options, so that the communication and computation overhead of the policy can be adjusted. We further evaluate the proposed policies via simulations, using both synthetic and real traces obtained from a medium scale mobile computing application.

International audience; Ultra Dense Networks (UDNs) are a natural deployment evolution for handling the tremendous traffic increase related to the emerging 5G services, especially in urban environments. However, the associated infrastructure cost may become prohibitive. The evolving paradigm of network slicing can tackle such a challenge while optimizing the network resource usage, enabling multi-tenancy and facilitating resource sharing and efficient service-oriented communications. Indeed, network slicing in UDN deployments can offer the desired degree of customization in both vanilla Radio Access Network (RAN) designs, but also in the case of disaggregated multi-service RANs. In this article, we devise a novel multi-service RAN environment, i.e., RAN runtime, capable to support slice orchestration procedures and to enable flexible customization of slices as per tenant needs. Each network slice can exploit a number of services, which can either be dedicated or shared between multiple slices over a common RAN. The novel architecture we present concentrates on the orchestration and management systems. It interacts with the RAN modules, through the RAN runtime, via a number of new interfaces enabling a customized dedicated orchestration logic for each slice. We present results for a disaggregated UDN deployment where the RAN runtime is used to support slice-based multi-service chain creation and chain placement, with an auto-scaling mechanism to increase the performance.

Network slicing is expected to be the main pillar around which virtualization technologies together with SDN control and NFV, will provide on-demand network and cloud infrastructures and facilitate rapid service deployment. In this paper we present JOX, an event-driven orchestrator for the virtu- alized network, operating on top of the Juju management system, that inherently supports network slicing. JOX is a python-based generic network slicing orchestrator, with a plugins architecture that is able to support different segments of a modern mobile edge network. We present a concrete prototype implementation of JOX for LTE, with experimental results considering footprint analysis, performance metrics, and implementation experience for slicing and orchestrating of an operational LTE network.

Mobile-Edge Computing (MEC) is about offering application developers and service providers cloud-computing capabilities and an IT service environment at the edge of the mobile network. However, although cloud computing can be used to meet traditional challenges, like scalability concerns and provide for fast resource provisioning times, a multifaceted analysis is required when it comes in multi-operator environments with time-critical applications and services. In this work, we claim that the service importance must be at the epicenter when it comes to the scheduling and placement decision of whether to deploy the service at the edge network or not. Virtual machine (VM) scheduling decisions should avoid SLA violations for popular or time-critical services, and be fair between the service providers. A Lyapunov optimization framework is derived to solve this stochastic optimization problem that aims to maximize the revenue of the physical infrastructure owner in a multi-network operator-sharing environment with time-critical SLAs. A series of simulation experiments validate the high effectiveness of the proposed approach over benchmarking ones.

Together with recent advancements in Radio Access Network (RAN) technologies, Wi-Fi is expected to be at the center of research on the subject of ubiquitous wireless connectivity, towards building the new 5G ecosystem. Nevertheless, the necessary testbed infrastructure to support large scale experimentally driven research seems to be missing. In this work we present the design and implementation of a novel Virtual Wi-Fi Testbed. We present how a traditional Wireless Testbed can support hundreds of virtual Wi-Fi nodes that are open to experimenters. We discuss the design and implementation of the virtualization tools. We demonstrate the accuracy and the overhead analysis of the approach in the face of actual testbed conditions. Implementation experience is also reported on the benefits of using the proposed virtualization approach for a simple association algorithm.

In this work, we present novel Architectural Design Patterns towards open, cloud-based 5G communications. We provide a brief classification of technologies that cannot be ignored in the design process of 5G systems and illustrate how a new technological added value can be created, when current methodologies, design paradigms, as well as design patterns and their extensions are properly exploited in efficient Radio Access Network (RAN) architectures. We believe that in many cases, the required technology is already there; nevertheless the correct approach has to be worked out and placed within an appropriate context, especially in the case of the integration of complex RAN systems. The enhancements in RF optimization, the progress in cloud computing, Software Defined Networks (SDN) and Network Function Virtualization (NFV), new design concepts such as Network Slicing have to become part of the RAN design methodology. Diverse architectural concepts should break existing stereotypes to pave the way towards the true 5G system integration.

In this work, we present how programmable data-plane technology (software routers) offers an easy-to-apply mechanism to create virtual wireless networks and support buffering and scheduling decisions. Furthermore, we present a feedback-based buffering mechanism that is able to provide throughput ratio guarantees per virtual network, without requiring any modifications in the 802.11 driver and without relying on statistical knowledge of the workload per virtual network or knowledge regarding the channel conditions. We implement the proposed mechanism in a software router in a 802.11 Access Point and we evaluate its performance in a wireless testbed environment. The methodology and the mechanics developed are generic and with some modifications can be applied to differentiating services for other types of guarantees like delay.

One of the distinctive features of the new virtualized ecosystem, is the multi-stakeholder participation in the way cloud services are designed, deployed and offered. In this work, we address the emerging content replication problem a Content Delivery Network (CDN) provider needs to consider, when deploying its network over multi-domain, heterogeneous environments, where virtual network operators utilize both the CDN services and the virtualized infrastructures. In our model, the benefit that the CDN provider enjoys may be different per network operator for the same request, while our model takes into account the replication cost to every domain, as well as the user mobility, besides physical storage limitations. Since the optimal placement of the objects at the caches of the various domains resembles the multiple knapsack problem, which is NP-complete, we provide two approximate solutions to the emerging content placement problem. We evaluate the proposed policies through extensive simulations and we compare them against a myopic method, where a domain is unaware of the caching strategy of the other domains that is connected to.

Undoubtedly, SDN has the potential to fundamentally change the way end-to-end networks are provisioned and designed. By introducing programmability into networking, the handling of network changes and network provisioning via open software interfaces has become a reality; together with the hardware/software virtualization advances in server systems and software platforms, cloud services can now be rapidly deployed and efficiently managed. The CONTENT project is an EU funded effort for network and infrastructure virtualization over heterogeneous, wireless and metro optical networks, that can be used to provide end-to-end cloud services. In this work we present the wireless network virtualization solution, in the light of the CONTENT technical approach, where a convergent LTE/Wi-Fi network is virtualized and interconnected with an optical TSON metro network. We present our approach in designing and implementing converged virtual 802.11 and LTE wireless networks and the corresponding efficient wireless data-plane mechanisms required, in order to satisfy strict QoS requirements.

This paper proposes a next generation ubiquitous converged infrastructure to support Cloud and mobile Cloud computing services. The proposed infrastructure facilitates interconnection of fixed and mobile end users with computational resources through a heterogeneous network integrating optical metro and wireless access networks. To satisfy the low-latency requirements of content-rich mobile applications, a novel stochastic virtual infrastructure planning model that takes a holistic approach considering jointly the network and computational resources is presented. Our modelling results identify trends and trade-offs related to end-to-end service delay, resource requirements and energy consumption levels of the infrastructure across the various technology domains under traffic uncertainty.

Cloud service provisioning on top of virtual infrastructures is of major importance in modern ICT, since it is directly correlated to the way business models are designed and revenue is generated from the cloud service providers. In this work we examine an end-to-end content replication problem over cloud-based multi-technology infrastructures. We extend the classical model where every network node is a potential replica carrier and the link weights represent hops/delay and we examine replication schemes for content that a) is requested by customers belonging in different virtual networks and b) depending on the requester there is different impact on the system operational cost. We examine both centralized and distributed content replication management policies and we evaluate their performance through extended simulations, by means of total cost, the number of object replacements and the number of iterations required. © 2014 IEEE.

Although cloud computing and the Software Defined Network (SDN) framework are fundamentally changing the way we think about network services, multi-domain and multi-technology problems are not sufficiently investigated. These multi-domain, end-to-end problems concern communication paths that span from the wireless access and the wireless backhaul networks to the IT resources through optical networks. In this paper we present the CONTENT project approach to network and infrastructure virtualization over heterogeneous, wireless and metro optical networks, that can be used to provide end-to-end cloud services. The project goal is to drive innovation across multi-technology infrastructures and allow ICT to be delivered and consumed as a service by Virtual Network Operators. The communication mechanics between wireless and optical domains and the physical layer abstractions of a CONTENT Virtual Network are presented and the relation of the proposed approach with the SDN framework is investigated.

In this paper, we study the problem of resource allocation in the setting of multitier data centers. Our main motivation and objective is to provide applications hosted in the data center with different service levels. In such centers, there are several mechanisms the designer can use to achieve such objectives. We restrict our attention to CPU time at the service tier as the resource; the objective we consider is service differentiation, expressed as allocating prespecified percentages of this resource to applications. Then, mechanisms at the designer's disposal to provide desired service differentiation include the triplet of load balancing through the switch fabric, enqueueing at a server and scheduling at a server. We focus on the enqueueing component of control mechanisms. We provide, through analysis and simulations “rules of thumb” for situations where simple enqueueing policies can provide service differentiation.

Flexibility is a key capability to allow future 5G networks to support varying service offerings over a common infrastructure. 5G-PICTURE investigates the design of programmable compute and transport network infrastructures, able to instantiate third-party 5G connectivity services on demand. This paper introduces the 5G-PICTURE vision on an integrated compute, RAN and transport architecture, and describes a set of innovative functions in the RAN, Transport and Synchronization domains that 5G-PICTURE has developed to fulfill its vision. Initial evaluation results are presented for the aforementioned functions.

In this paper we focus on the problem of multidomain orchestration for Network Function Virtualization (NFV), over multi-technology environments. In order to facilitate service deployment in end-to-end setups, new orchestration designs are required that exploit and advance existing methodologies. We examine in detail the challenges on multi-domain NFV orchestration for the general case and we provide the current landscape and existing technologies. We also describe a reference architecture for the problem of multi-domain NFV orchestration, that also supports the concept of Network Slicing. Finally, we present a realization of the architecture proposed for the LTE network and we describe a use case with LTE-specific considerations.