Reliable downloading algorithms for bittorrent-like systems

In this paper we study a reliable downloading algorithm for BitTorrent-like systems, and attest it in mathematics. BitTorrent-like systems have become immensely popular peer-to-peer file distribution tools in the internet in recent years. We analyze them in theory and point out some of their limitations especially in reliability, and propose an algorithm to resolve these problems by using the redundant copies in neighbors in P2P networks and can further optimize the downloading speed in some condition. Our preliminary simulations show that the proposed reliable algorithm works well; the improved BitTorrent-like systems are very stable and reliable.<br /

Automating the construction of replicated objects in a cluster of workstations

This paper describes a tool that mimics the design of the remote procedure call (RPC) system to support the building of replicated objects in a cluster of workstations (COW). The tool includes an interface definition language for describing a replica group, a language preprocessor and a runtime library system. The paper also presents one example and discusses some performance issues for replicated objects. <br /

An analysis of update ordering in a cluster of replicated servers

This paper analyses update ordering and its impact on the performance of a cluster of replicated servers. We propose a model for update orderings and constraints and develop a number of algorithms for implementing different ordering constraints. A performance study is then carried out to analyse the update ordering model.<br /

Getting the real-time precise round-trip time for stepping stone detection

Stepping stone attacks are often used by network intruders to hide their identities. The Round Trip Times (RTT) between the send packets and corresponding echo packets for the connection chains of stepping stones are critical for detecting such attacks. In this paper, we propose a novel real-time RTT getting algorithm for stepping stones which is based on the estimation of the current RTT value. Our experiments show that it is far more precise than the previous real-time RTT getting algorithms. We also present the probability analysis which shows that our algorithm has a high matching rate and a high accurate rate

S-Kcore : a social-aware Kcore decomposition algorithm in pocket switched networks

The key nodes in network play the critical role in system recovery and survival. Many traditional key nodes selection algorithms utilize the characters of the physical topology to find the key nodes. But they can hardly succeed in the mobile ad hoc network due to the mobility nature of the network. In this paper we propose a social-aware Kcore selection algorithm to work in the Pocket Switched Network. The social view of the network suggests the social position of the mobile nodes can help to find the key nodes in the Pocket Switched Network. The S-Kcore selection algorithm is designed to exploit the nodes\u27 social features to improve the performance in data communication. Experiments use the NS2 shows S-Kcore selection algorithm workable in the Pocket Switched Network. Furthermore, with the social behavior information, those key nodes are more suitable to represent and improve the whole network\u27s performance.<br /

OST : A transaction based online social trust model for social network and file sharing security

The continuous growth of the users pool of Social Networking web sites such as Facebook and MySpace, and their incessant augmentation of services and capabilities will in the future, meet and compare in contrast with today\u27s Content distribution Networks (CDN) and Peer-to-Peer File sharing applications such as Kazaa and BitTorrent, but how can these two main streams applications, that already encounter their own security problems cope with the combined issues, trust for Social Networks, content and index poisoning in CDN? We will address the problems of Social Trust and File Sharing with an overlay level of trust model based on social activity and transactions, this can be an answer to enable users to increase the reliability of their online social life and also enhance the content distribution and create a better file sharing example. The aim of this research is to lower the risk of malicious activity on a given Social Network by applying a correlated trust model, to guarantee the validity of someone\u27s identity, privacy and trustfulness in sharing content

A quick-response real-time stepping stone detection scheme

Stepping stone attacks are often used by network intruders to hide their identities. To detect and block stepping stone attacks, a stepping stone detection scheme should be able to correctly identify a stepping-stone in a very short time and in real-time. However, the majority of past research has failed to indicate how long or how many packets it takes for the monitor to detect a stepping stone. In this paper, we propose a novel quick-response real-time stepping stones detection scheme which is based on packet delay properties. Our experiments show that it can identify a stepping stone within 20 seconds which includes false positives and false negatives of less than 3%

Distinguishing DDoS attacks from flash crowds using probability metrics

Both Flash crowds and DDoS (Distributed Denial-of-Service) attacks have very similar properties in terms of internet traffic, however Flash crowds are legitimate flows and DDoS attacks are illegitimate flows, and DDoS attacks have been a serious threat to internet security and stability. In this paper we propose a set of novel methods using probability metrics to distinguish DDoS attacks from Flash crowds effectively, and our simulations show that the proposed methods work well. In particular, these mathods can not only distinguish DDoS attacks from Flash crowds clearly, but also can distinguish the anomaly flow being DDoS attacks flow or being Flash crowd flow from Normal network flow effectively. Furthermore, we show our proposed hybrid probability metrics can greatly reduce both false positive and false negative rates in detection.<br /

A parallel downloading algorithm for redundant networks

In this paper, we study the downloading mechanism of BitTorrent (or BT), a P2P based popular and convenient parallel downloading software tool, point out some of its limitations, and propose an algorithm to improve its performance. In particular, we address the limitations of BT by using neighbours in P2P networks to resolve the redundant copies problem and to optimise the downloading speed. Our preliminary experiments show that the proposed enhancement algorithm works well

A resource-search and routing algorithm within PCDN autonomy area

This paper studied a new type of network model; it is formed by the dynamic autonomy area, the structured source servers and the proxy servers. The new network model satisfies the dynamics within the autonomy area, where each node undertakes different tasks according to their different abilities, to ensure that each node has the load ability fit its own; it does not need to exchange information via the central servers, so it can carry out the efficient data transmission and routing search. According to the highly dynamics of the autonomy area, we established dynamic tree structure-proliferation system routing and resource-search algorithms and simulated these algorithms. Test results show the performance of the proposed network model and the algorithms are very stable. <br /