Anargyros Sideris

Experimental Infrastructures for IP/DVB Convergence: an Actual Substantiation for Triple Play Services Provision at Remote Areas

This paper introduces and validates an experimental infrastructure of a fusion IP/DVB networking environment for the provision of triple play services at remote areas exploiting the synergy of Broadcasting, Internet and Telecommunication sectors technologies. This synergy constitutes a challenge for creating a networking platform which exploits the particularities and complementarities of these sectors for the support of ubiquitous services and always-on connectivity enabling passive rural citizens to become active Information Society participants. This paper describes important directions for exploiting the proposed unified platform alleviating the digital divide that currently exists not only among countries but also within most regions of the same country.

EXEGESIS: Extreme Edge Resource Harvesting for a Virtualized Fog Environment

Currently there is an active debate about how the existing cloud paradigm can cope with the volume, variety, and velocity of the data generated by end devices (e.g., Internet of Things sensors). It is expected that there will be over 50 billion of these devices by 2020, which will create more than two Exabytes worth of data each day. Additionally, the vast number of edge devices create a huge ocean of digital resources close to the data source, which, however, remain so far unexploited to their full extent. EXEGESIS proposes to harness these unutilized resources via a three-layer architecture that encompasses the mist, fog, and cloud. The mist network is located at the very bottom, where interconnected objects (Internet of Things devices, small servers, etc.) create neighborhoods of objects. This arrangement is enhanced by a virtual fog layer, which allows for dynamic, ad hoc interconnections among the various neighborhoods. At the top layer resides the cloud with its abundant resources that can also be included in one or more virtual fog neighborhoods. Thus, this article complements and leverages existing cloud architectures, enabling them to interact with this new edge-centric ecosystem of devices/resources, and benefit from the fact that critical data are available where they can add the most value.

Computing, Caching, and Communication at the Edge: The Cornerstone for Building a Versatile 5G Ecosystem

This article presents a unified computing, caching, and communication (3C) solution for the upcoming 5G environment that will allow service, content, and function providers to deploy their services/ content/functions near the end users (EUs); to allow network providers to virtually deploy their connectivity services over commodity hardware; and to enable end users to renounce their role as passive 5G stakeholders and become active ones by offering their 3C resources to the 5G ecosystem. In this direction, we foresee the exploitation of a peer-topeer- like middleware/app solution that upon installation will enhance the end user devices with the ability to form virtual fogs capable of providing their 3C resources to the 5G ecosystem. Additionally, we propose the introduction of heterogeneous nodes (e.g., FPGAs and GPUs) at the networks edge, which will boost the processing capabilities without paying a premium in power consumption. This will enable efficient and thorough filtering of the information that makes it all the way up to the cloud. In summary, this article proposes an architecture that exploits and advances the edge and extreme edge 3C paradigms toward enabling the 5G ecosystem to meet its own criterion for low end-to-end latencies and, as such, enable it to provide and sustain high QoS/QoE levels.

QoE fairness, HTTP Adaptive Streaming and IDVB-T: The AWM approach

In this paper, we show how Active Window Management (AWM) technique can be exploited for providing QoE fairness to the HTTP Adaptive Streaming users of an interactive digital broadcasting network. Furthermore, we test AWMs efficiency against another QoE fairness provision solution, presented in other research efforts, namely the Traffic Shaping. Towards these, we firstly describe the deployment of AWM and Traffic Shaping software modules in each intermediate node (Cell Main Node-CMN) of the broadcasting network and secondly we proceed with the experimental evaluation. The experimental results showed not only AWMs efficiency to achieve the set fairness goal but also revealed AWMs capacity, when compared to Traffic Shaping, to provide for much lower TCP Round Trip Times (88% less) and zero retransmissions; a result which could, in principle, lead to less TCP rate variations and thus less Quality Profile fluctuations.

Distributed NQoS provision in interactive DVB-T systems

This paper discusses a Distributed Network Quality of Service (NQoS) provision approach in decentralized interactive DVB-T systems (IDVB-T), enabling for scalable and fault tolerant operation. The paper describes the design and overall architecture of a regenerative IDVB-T infrastructure, where network resource allocation and service classification processes are performed at local level within each intermediate distribution node (Cell Main Node CMN), setting the basis for a CMN-to-CMN NQoS provision. Validity of the proposed approach is experimentally verified, and the test-results are compared against the aggregated and federated NQoS provision approaches, indicating similar performance but better scalability and fault-tolerant design.

A novel content-aware multipath routing concept exploiting random utility theory principles

This paper presents a novel multipath routing concept for content-aware networks, enabling better resource utilization and end-to-end QoS provision. Based on random utility theory and traffic identification techniques it delves into multinomial-type probability for efficient packet distribution among intra domain paths, by exploiting the capability of edge nodes to identify the content in transit, and proposes a network architecture where this concept may be applied. We focus on the methodology alterations that content-awareness will impose on the calculation of the utility that a corresponding packet will inherit in choosing a specific path, assuming that packets of “premium” content will have demanding QoS-centric network “taste” when they will have to choose a specific path.

IMS-enabled interactive broadcasting network utilizing peer to peer constellations

This paper propose an overlay interoperability technology for introducing the concept of Peer to peer (P2P) communications in the context of IP Multimedia Subsystem (IMS) enabled interactive broadcasting networks (iDVB-T), bearing the following: a) user initiated conception of communication applications paradigms and deployment, b) access of users on P2P applications from any rural-access network, and c) creation of a new ecosystem of users, emerging different behaviour from the traditional consumers, gearing-up new business and revenue prospects. The overall assessment of the proposed P2P-IMS architecture is evaluated by Real transmission reception experiments justifying the interoperability and validity of the iDVB-T environment proposed.

Content adaptation of IPTV services in Interactive DVB-T systems

This paper discusses how Content Adaptation of IPTV Services may enable decentralized Interactive DVB-T systems (IDVB-T) to optimize the utilization of their network resources, while offering End Users the higher possible QoE. The paper describes the design and overall architecture of a regenerative IDVB-T infrastructure, where content adaptation processes are performed following either a centralized or a distributed approach, setting the basis for a real time accommodation of IPTV services to the available network resources (i.e. bandwidth) and capabilities of End Users terminals (i.e. processing power, screen resolution, codec support). Validity of both Content Adaptation approaches is experimentally verified, with the initial test-results indicating similar performance.

Differentiated services provision in a converged DVB/IP networking environment

The paper discusses a converged DVB/IP environment capable to provide differentiated services at a guaranteed quality. Towards this the paper presents the design, implementation and integration of QoS aware mechanisms in the DVB/IP environment in order to enhance its capability as an IP networking infrastructure, optimizing the systems for the provision of IP heterogeneous services. The capability of the proposed QoS aware DVB/IP network environment is validated through experimental tests that were conducted under real transmission/reception conditions at a prototype infrastructure that conforms to the discussed architectural design issues.