Mining Unclassified Traffic Using Automatic Clustering Techniques

In this paper we present a fully unsupervised algorithm to identify classes of traffic inside an aggregate. The algorithm leverages on the K-means clustering algorithm, augmented with a mechanism to automatically determine the number of traffic clusters. The signatures used for clustering are statistical representations of the application layer protocols. The proposed technique is extensively tested considering UDP traffic traces collected from operative networks. Performance tests show that it can clusterize the traffic in few tens of pure clusters, achieving an accuracy above 95%. Results are promising and suggest that the proposed approach might effectively be used for automatic traffic monitoring, e.g., to identify the birth of new applications and protocols, or the presence of anomalous or unexpected traffi

Evidences Behind Skype Outage

Skype is one of the most successful VoIP application in the current Internet spectrum. One of the most peculiar characteristics of Skype is that it relies on a P2P infrastructure for the exchange of signaling information amongst active peers. During August 2007, an unexpected outage hit the Skype overlay, yielding to a service blackout that lasted for more than two days: this paper aims at throwing light to this event. Leveraging on the use of an accurate Skype classification engine, we carry on an experimental study of Skype signaling during the outage. In particular, we focus on the signaling traffic before, during and after the outage, in the attempt to quantify interesting properties of the event. While it is very difficult to gather clear insights concerning the root causes of the breakdown itself, the collected measurement allow nevertheless to quantify several interesting aspects of the outage: for instance, measurements show that the outage caused, on average, a 3-fold increase of signaling traffic and a 10-fold increase of number of contacted peers, topping to more than 11 million connections for the most active node in our network - which immediately gives the feeling of the extent of the phenomeno

Passive characterization of sopcast usage in residential ISPs

Abstract—In this paper we present an extensive analysis of traffic generated by SopCast users and collected from operative networks of three national ISPs in Europe. After more than a year of continuous monitoring, we present results about the popularity of SopCast which is the largely preferred application in the studied networks. We focus on analysis of (i) application and bandwidth usage at different time scales, (ii) peer lifetime, arrival and departure processes, (iii) peer localization in the world. Results provide useful insights into users ’ behavior, including their attitude towards P2P-TV application usage and the conse-quent generated load on the network, that is quite variable based on the access technology and geographical location. Our findings are interesting to Researchers interested in the investigation of users ’ attitude towards P2P-TV services, to foresee new trends in the future usage of the Internet, and to augment the design of their application. I

OUTSOURCING STRATEGIES. HOW TO FORMALIZE AND NEGOTIATE THE OUTSOURCING CONTRACT.

In the globalized economy multinational firms have given rise to local firms able to produce at a low cost and at acceptable quality levels. A growing number of firms have outsourced production and manufacturing activities of all types to these firms, not only to reduce production costs but also to make their organizational structures more streamlined and flexible. Outsourcing decisions, which originally were limited to production which had a modest technological content and was of marginal importance for the business in question, is increasingly adopted for activities which, requiring core competencies or belonging to the core business, were considered inseparable from the organization and thus not outsourceable. Gradually an outsourcing strategy has developed which has found it convenient to outsource even core competencies and functions, such as specialized manufacturing, which require a particular technology, marketing, product design, and the search for know-how (Prahalad and Hamel 1990: 79-91).\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\r\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\nSuch an outsourcing strategy has a number of advantages, among which quality improvement, a greater focus on managing other core competencies, a greater flexibility and leverage regarding resources, along with the possibility of entering new markets, even ones with a high rate of development.\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\r\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\nThis article analyzes the fundamental stages for an outsourcing strategy. It will demonstrate how, in order to achieve an outsourcing strategy, it is necessary to include outsourcing in the general strategy, gather suitable information for choosing the outsourcer, negotiate the contract with the supplier, choose the type of relationship to have with the supplier, and, finally, plan the transfer of activities and functions from the outsourcee to one or more outsourcers or providers.\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\r\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\noutsourcing, outourcing decision, strategic perspective, outsourcing contract, contract negotiation, outside information, organizational culture

Towards sustainable ICT

While information and communication technologies (ICT) can play a crucial role in tackling issues related to sustainability, and reducing resource consumption in every sector, they also consume huge amounts of energy, andthis, combined with the predicted rapid growth of demand for communication services, is expected to make the whole sector more and more energy-hungry in the coming years. The sustainability of ICT itself is also becoming an urgent challenge. Actions can be taken in several directions: i) introducing a massive and pervasive use of renewable energy sources, a step that requires the design of communication services to be revised; ii) enforcing rules and policies that induce the provisioning of sustainable services and promote the adoption of proper attitudes; and iii) involving the users who will become conscious consumers and participate in crowdsourcing projects tomonitor consumption and foster energy-aware behaviours

TCP smart framing: a segmentation algorithm to reduce TCP latency

TCP Smart Framing, or TCP-SF for short, enables the Fast Retransmit/Recovery algorithms even when the congestion window is small. Without modifying the TCP congestion control based on the additive-increase/multiplicative-decrease paradigm, TCP-SF adopts a novel segmentation algorithm: while Classic TCP always tries to send full-sized segments, a TCP-SF source adopts a more flexible segmentation algorithm to try and always have a number of in-flight segments larger than 3 so as to enable Fast Recovery. We motivate this choice by real traffic measurements, which indicate that today's traffic is populated by short-lived flows, whose only means to recover from a packet loss is by triggering a Retransmission Timeout. The key idea of TCP-SF can be implemented on top of any TCP flavor, from Tahoe to SACK, and requires modifications to the server TCP stack only, and can be easily coupled with recent TCP enhancements. The performance of the proposed TCP modification were studied by means of simulations, live measurements and an analytical model. In addition, the analytical model we have devised has a general scope, making it a valid tool for TCP performance evaluation in the small window region. Improvements are remarkable under several buffer management schemes, and maximized by byte-oriented schemes

Modeling the interaction between TCP and Rate Adaptation

In this paper, we model and investigate the interaction between the TCP protocol and rate adaptation at intermediate routers. Rate adaptation aims at saving energy by controlling the offered capacity of links and adapting it to the amount of traffic. However, when TCP is used at the transport layer, the control loop of rate adaptation and one of the TCP congestion control mechanism might interact and disturb each other, compromising throughput and Quality of Service (QoS). Our investigation is lead through mathematical modeling consisting in depicting the behavior of TCP and of rate adaption through a set of Delay Differential Equations (DDEs). The model is validated against simulation results and it is shown to be accurate. The results of the sensitivity analysis of the system performance to control parameters show that rate adaptation can be effective but a careful parameter setting is needed to avoid undesired disruptive interaction among controllers at different levels, that impair QoS

KISS: Stochastic Packet Inspection Classifier for UDP Traffic

This paper proposes KISS, a novel Internet classifica- tion engine. Motivated by the expected raise of UDP traffic, which stems from the momentum of Peer-to-Peer (P2P) streaming appli- cations, we propose a novel classification framework that leverages on statistical characterization of payload. Statistical signatures are derived by the means of a Chi-Square-like test, which extracts the protocol "format," but ignores the protocol "semantic" and "synchronization" rules. The signatures feed a decision process based either on the geometric distance among samples, or on Sup- port Vector Machines. KISS is very accurate, and its signatures are intrinsically robust to packet sampling, reordering, and flow asym- metry, so that it can be used on almost any network. KISS is tested in different scenarios, considering traditional client-server proto- cols, VoIP, and both traditional and new P2P Internet applications. Results are astonishing. The average True Positive percentage is 99.6%, with the worst case equal to 98.1,% while results are al- most perfect when dealing with new P2P streaming applications