Kostas Katsalis

Network Store: Exploring Slicing in Future 5G Networks

In this paper, we provide a revolutionary vision of 5G networks, in which SDN technologies are used for the programmability of the wireless network, and where a NFV-ready network store is provided to Mobile Network Operators (MNO), Enterprises, and Over-The-Top (OTT) third parties. The proposed network serves as a digital distribution platform of programmable Virtualized Network Functions (VNFs) that enables 5G application use-cases. Currently existing application stores, such as Apples App Store for iOS applications, Googles Play Store for Android, or Ubuntus Software Center, deliver applications to user specific software platforms. Our vision is to provide a digital marketplace, gathering 5G enabling Network Applications and Network Functions, written to run on top of commodity cloud infrastructures, connected to remote radio heads (RRH). The 5G Network Store will be the same to the network provider as the application store is currently to a software platform.

5G Architectural Design Patterns

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.

MEC architectural implications for LTE/LTE-A networks

Towards 5G mobile networks, the low-latency and high-bandwidth services are highly anticipated; however, legacy 3G and 4G networks now suffers from the mobile data surge. In this sense, pushing network services to the network edge has the potential to improve the traffic latency, user experience, and offload Internet traffic. Although the LTE/LTE-A network can highly benefit from the Mobile Edge Computing (MEC) principle, a detailed MEC architecture is not currently in place. In this work, we propose a modular architecture for the Mobile Edge Host that is ETSI compliant and describe the functional mapping of the architecture to LTE systems. Proof-of-concept demonstrations based on the OpenAirInterface (OAI), a software implementation of LTE/LTE-A systems, present significant benefits of adopting the MEC concept in data caching use case.

NITOS testbed: A cloud based wireless experimentation facility

The NITOS wireless testbed, is one of the main building blocks in the wireless testbed experimentation, offered by the FIRE community, and a core Fed4Fire partner. Its main focus is on wireless accessed technologies and on all layers of the protocol stack. In the rapidly changing technological environment, a unique opportunity is provided to enhance the NITOS testbed with cloud computing experimentation capabilities and increase the heterogeneity and diversity of possible services that can be offered to experimenters/ developers. In this paper we describe the NITOS approach on adopting cloud technologies and SDN capabilities and how we upgrade the meaning of “delivered service” in testbed experimentation using SOA extensions.

Content Project: Considerations Towards a Cloud-Based Internetworking Paradigm

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.

A cloud-based content replication framework over multi-domain environments

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.

SLA-Driven VM Scheduling in Mobile Edge Computing

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.

Q4HEALTH: Quality of service and prioritisation for emergency services in the LTE RAN stack

Communications for emergency services have traditionally been provided by dedicated radio technologies, like the TETRA system. However the need for more efficient mobile communications is gaining popularity in these scenarios due to extreme requirements by means of availability, price and spectrum usage. This trend will be further accentuated in the coming years with the appearance of 5G systems that promise better figures in almost all the Key Performance Indicators (KPIs). LTE can provide many of the functionalities required by emergency services and is currently being evolved towards the 5G era by incorporating heterogeneous networking, over the top applications, network function virtualisation and more. The Q4Health project focuses on the preparatives for market introduction of eHealth video applications for first responders based on LTE technology. This preparation includes the investigation of advanced LTE programmability features and the design and execution of several novel experiments in order to optimise the communications for this platform.

Optical wireless network convergence in support of energy-efficient mobile cloud services

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.

CPU Provisioning Algorithms for Service Differentiation in Cloud-Based Environments

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.