Ioanna Papafili

Interaction patterns between P2P content distribution systems and ISPs

Peer-to-peer (P2P) content distribution systems are a major source of traffic in the Internet, but the application layer protocols they use are mostly unaware of the underlying network in accordance with the layered structure of the Internets protocol stack. Nevertheless, the need for improved network efficiency and the business interests of Internet service providers (ISPs) are both strong drivers toward a cross-layer approach in peer-to-peer protocol design, calling for P2P systems that would in some way interact with the ISPs. Recent research shows that the interaction, which can rely on information provided by both parties, can be mutually beneficial. In this article we first give an overview of the kinds of information that could potentially be exchanged between the P2P systems and the ISPs, and discuss their usefulness and the ease of obtaining and exchanging them. We also present a classification of the possible approaches for interaction based on the level of involvement of the ISPs and the P2P systems, and we discuss the potential strengths and the weaknesses of these approaches.

A Framework of Economic Traffic Management Employing Self-Organization Overlay Mechanisms

Applications based on overlays have become very popular, due to the separation they provide and the improvement of perceived QoS by the end-user. Recent studies show that overlays have a significant impact on the traffic management and the expenditures of the underlying network operators. In this paper, we define a framework for Economic Traffic Management (ETM) mechanisms that optimize the traffic impact of overlay applications on ISP and telecommunication operator networks based on the interaction of network operators, overlay providers and users. We first provide a definition and an overview of Self-Organization Mechanisms (SOMs) and ETM for overlays. We then describe a basic framework for the interaction of components of SOMs and ETM, in terms of information and metrics provided, decisions made etc. Finally, we describe in detail how SOMs can be used to support ETM and we illustrate our approach and its implications by means of a specific example.

Service provider DevOps for large scale modern network services

Network service providers are facing challenges for deploying new services mainly due to the growing complexity of software architecture and development process. Moreover, the recent architectural innovation of network systems such as Network Function Virtualization (NFV), Software-defined Networking (SDN), and Cloud computing increases the development and operation complexity yet again. One of the emerging solutions to this problem is a novel software development concept, namely DevOps, that is widely employed by major Internet software companies. Although the goals of DevOps in data centers are well-suited for the demands of agile service creation, additional requirements specific to the virtualized and software-defined network environment are important to be addressed from the perspective of modern network carriers. In this paper, we thoroughly debate DevOps requirements for developing a modern service creation platform by taking EU FP7 project UNIFY as a reference architecture and suggest the corresponding extensions of UNIFY interfaces that meet the discovered requirements.

Design principles for the future internet architecture

Design principles play a central role in the architecture of the Internet as driving most engineering decisions at conception level and operational level. This paper is based on the EC Future Internet Architecture (FIArch) Group results and identifies some of the design principles that we expect to govern the future architecture of the Internet. We believe that it may serve as a starting point and comparison for most research and development projects that target the so-called Future Internet Architecture.

Socially-Aware Traffic Management

Socially-aware traffic management utilizes social information to optimize traffic management in the Internet in terms of traffic load, energy consumption, or end user satisfaction. Several use cases can benefit from socially-aware traffic management and the performance of overlay applications can be enhanced. We present existing use cases and their socially-aware approaches and solutions, but also raise discussions on additional benefits from the integration of social information into traffic management as well as practical aspects in this domain.

A tussle analysis for information-centric networking architectures

Current Future Internet (FI) research brings out the trend of designing information-oriented networks, in contrast to the current host-centric Internet. Information-centric Networking (ICN) focuses on finding and transmitting information to end-users, instead of connecting end hosts that exchange data. The key concepts of ICN are expected to have significant impact on the FI, and to create new challenges for all associated stakeholders. In order to investigate the motives as well as the arising conflicts between the stakeholders, we apply a tussle analysis methodology in a content delivery scenario incorporating socio-economic principles. Our analysis highlights the interests of the various stakeholders and the issues that should be taken into account by designers when deploying new content delivery schemes under the ICN paradigm.

Service Provider DevOps

Although there is consensus that software defined networking and network functions virtualization overhaul service provisioning and deployment, the community still lacks a definite answer on how carrier-grade operations praxis needs to evolve. This article presents what lies beyond the first evolutionary steps in network management, identifies the challenges in service verification, observability, and troubleshooting, and explains how to address them using our Service Provider DevOps (SP-DevOps) framework. We compendiously cover the entire process from design goals to tool realization and employ an elastic version of an industry-standard use case to show how on-the-fly verification, software-defined monitoring, and automated troubleshooting of services reduce the cost of fault management actions. We assess SP-DevOps with respect to key attributes of software-defined telecommunication infrastructures both qualitatively and quantitatively, and demonstrate that SP-DevOps paves the way toward carrier-grade operations and management in the network virtualization era.

A programmable, multi-format photonic transceiver platform enabling flexible optical networks

Development of programmable photonic devices for future flexible optical networks is ongoing. To this end, an innovative, multi-format QAM transmitter design is presented. It comprises a segmented-electrode InP IQ-MZM to be fabricated in InP, which can be directly driven by low-power CMOS logic. Arbitrary optical QAM format generation is made possible using only binary electrical signals, without the need for high-performance DACs and high-swing linear drivers. The concept enables a host of Tx-side DSP functionality, including the spectral shaping needed for Nyquist-WDM system concepts. In addition, we report on the development of an optical channel MUX/DEMUX, based on arrays of microresonator filters with reconfigurable bandwidths and center wavelengths. The device is intended for operation with multi-format flexible transceivers, enabling Dense (D)WDM superchannel aggregation and arbitrary spectral slicing in the context of a flexible grid environment.

A Markov model for the evaluation of cache insertion on peer-to-peer performance

Peer-to-peer file sharing applications generate huge volumes of the Internet traffic, thus leading to increased congestion and costs for the ISPs, particularly due to inter-domain traffic. Thus, analysis of peer-to-peer applications and related optimization approaches (such as locality awareness or caching techniques) has been the subject of extensive recent research. In this paper we introduce and analyze a probabilistic model that employs a Markov chain, aiming to approximate the transient evolution of a swarm with a fixed number of peers. This model estimates the distribution of the number of chunks already downloaded by a certain peer at any time. We also show how this model can serve as a tool to analyze certain properties of peer-to-peer applications, such as monotonicity of performance, and primarily to evaluate the effectiveness of cache insertion in a network serving peer-to-peer. For tractability reasons, the model employs certain simplifications of the original BitTorrent protocol, the impact of which is limited as validated experimentally.

Trade-Off between QoE and Operational Cost in Edge Resource Supported Video Streaming

The largest share of todays consumer Internet traffic is video streaming and its demand on content delivery networks is continuously growing. To cope with the increasing demand of video streaming, recent work proposes mitigating end-user equipment to support content delivery at the edge of the network. The throughput of end-user equipment supporting content delivery is limited by the uplink of the users Internet connection. Especially for video streaming insufficient throughput causes the video to stall and affects the Quality of Experience (QoE) of end-users. To prevent video streams from stalling, we consider a tiered caching architecture, which requests higher tier caches to support content delivery, if the uplink throughput drops below a certain threshold. We conduct a simulative performance evaluation of the mechanism to investigate its impact on the QoE of end-users. Our results show that especially if the upload bandwidth of end-user equipment is low the setting of the threshold has a high impact. This can be used by operators to achieve the desired trade-off between QoE and operational cost for cache resources.