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Kademlia
Kademlia is a distributed hash table for decentralized peer-to-peer computer networks designed by Petar Maymounkov and David Mazières in 2002. It specifies the structure of the network and the exchange of information through node (networking), node lookups. Kademlia nodes communicate among themselves using User Datagram Protocol, UDP. A virtual or overlay network is formed by the participant nodes. Each node is identified by a number or ''node ID''. The ''node ID'' serves not only as identification, but the Kademlia algorithm uses the ''node ID'' to locate values (usually file Hash function, hashes or keywords). In order to look up the value associated with a given key, the algorithm explores the network in several steps. Each step will find nodes that are closer to the key until the contacted node returns the value or no more closer nodes are found. This is very efficient: like many other s, Kademlia contacts only Big O notation, O(\log n) nodes during the search out of a total o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Distributed Hash Table
A distributed hash table (DHT) is a Distributed computing, distributed system that provides a lookup service similar to a hash table. Key–value pairs are stored in a DHT, and any participating node (networking), node can efficiently retrieve the value associated with a given key. The main advantage of a DHT is that nodes can be added or removed with minimum work around re-distributing keys. ''Keys'' are unique identifiers which map to particular ''values'', which in turn can be anything from addresses, to Electronic document, documents, to arbitrary Data (computing), data. Responsibility for maintaining the mapping from keys to values is distributed among the nodes, in such a way that a change in the set of participants causes a minimal amount of disruption. This allows a DHT to scale (computing), scale to extremely large numbers of nodes and to handle continual node arrivals, departures, and failures. DHTs form an infrastructure that can be used to build more complex services, su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kad Network
The Kad network is a peer-to-peer (P2P) network which implements the Kademlia P2P overlay protocol. The majority of users on the Kad Network are also connected to servers on the eDonkey network, and Kad Network clients typically query known nodes on the eDonkey network in order to find an initial node on the Kad network. Usage The Kad network uses a UDP-based protocol to: * Find sources for eD2k hashes. * Search for eD2k hashes based on keywords in the file name. * Find comments and ratings for files (hashes). * Provide buddy services for firewalled ( Low ID) nodes. * Store locations, comments and (keywords out of) filenames. Note that the Kad network is not used to actually transfer files across the P2P network. Instead, when a file transfer is initiated, clients connect directly to each other (using the standard public IP network). This traffic is susceptible to blocking/shaping/tracking by an ISP or any other opportunistic middle-man. As with all decentralized networ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Overlay Network
An overlay network is a logical computer network that is protocol layering, layered on top of a physical network. The concept of overlay networking is distinct from the traditional model of OSI model, OSI layered networks, and almost always assumes that the underlay network is an IP network of some kind. Some examples of overlay networking technologies are, VXLAN, Border Gateway Protocol, BGP VPNs, and IP over IP technologies, such as Generic Routing Encapsulation, GRE, IPSEC tunnels, or SD-WAN. Structure Node (networking), Nodes in an overlay network can be thought of as being connected by virtual or logical links, each of which corresponds to a path, perhaps through many physical links, in the underlying network. For example, distributed systems such as peer-to-peer networks are overlay networks because their nodes form networks over existing network connections. The Internet was originally built as an overlay upon the telephone network, while today (through the advent of V ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kad Network
The Kad network is a peer-to-peer (P2P) network which implements the Kademlia P2P overlay protocol. The majority of users on the Kad Network are also connected to servers on the eDonkey network, and Kad Network clients typically query known nodes on the eDonkey network in order to find an initial node on the Kad network. Usage The Kad network uses a UDP-based protocol to: * Find sources for eD2k hashes. * Search for eD2k hashes based on keywords in the file name. * Find comments and ratings for files (hashes). * Provide buddy services for firewalled ( Low ID) nodes. * Store locations, comments and (keywords out of) filenames. Note that the Kad network is not used to actually transfer files across the P2P network. Instead, when a file transfer is initiated, clients connect directly to each other (using the standard public IP network). This traffic is susceptible to blocking/shaping/tracking by an ISP or any other opportunistic middle-man. As with all decentralized networ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peer-to-peer
Peer-to-peer (P2P) computing or networking is a distributed application architecture that partitions tasks or workloads between peers. Peers are equally privileged, equipotent participants in the network, forming a peer-to-peer network of Node (networking), nodes. In addition, a personal area network (PAN) is also in nature a type of Decentralized computing, decentralized peer-to-peer network typically between two devices. Peers make a portion of their resources, such as processing power, disk storage, or network bandwidth, directly available to other network participants, without the need for central coordination by servers or stable hosts. Peers are both suppliers and consumers of resources, in contrast to the traditional client–server model in which the consumption and supply of resources are divided. While P2P systems had previously been used in many application domains, the architecture was popularized by the Internet file sharing system Napster, originally released in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bootstrapping Node
A bootstrapping node, also known as a rendezvous host, is a node in an overlay network that provides initial configuration information to newly joining nodes so that they may successfully join the overlay network. Bootstrapping nodes are predominantly found in decentralized peer-to-peer (P2P) networks because of the dynamically changing identities and configurations of member nodes in these networks. Overview When attempting to join a P2P network, specific discovery or membership protocols (or other configuration information) may be required, and, if a newly joining node is unaware of these protocols, the newly established joining node will not be able to communicate with other nodes and ultimately join the network. Furthermore, these protocols and configuration requirements may dynamically change as the infrastructure and membership of the P2P network evolves. Therefore, there is a need to be able to dynamically inform a newly joining node of the required protocols and configur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sybil Attack
A Sybil attack is a type of attack on a computer network service in which an attacker subverts the service's reputation system by creating a large number of pseudonymous identities and uses them to gain a disproportionately large influence. It is named after the subject of the book '' Sybil'', a case study of a woman diagnosed with dissociative identity disorder. The name was suggested in or before 2002 by Brian Zill at Microsoft Research. The term pseudospoofing had previously been coined by L. Detweiler on the Cypherpunks mailing list and used in the literature on peer-to-peer systems for the same class of attacks prior to 2002, but this term did not gain as much influence as "Sybil attack". Description The Sybil attack in computer security is an attack wherein a reputation system is subverted by creating multiple identities. A reputation system's vulnerability to a Sybil attack depends on how cheaply identities can be generated, the degree to which the reputation system accept ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gnutella
Gnutella is a peer-to-peer network protocol. Founded in 2000, it was the first decentralized peer-to-peer network of its kind, leading to other, later networks adopting the model. In June 2005, Gnutella's population was 1.81 million computers increasing to over three million nodes by January 2006.On the Long-term Evolution of the Two-Tier Gnutella Overlay . Rasti, Stutzbach, Rejaie, 2006. See Figure 2a. In late 2007, it was the most popular file-sharing network on the Internet with an estimated market share of more than 40%. History The first client (also called Gnutella) from which the network got its name was developed by Justin Frankel and Tom Pepper of Nullsoft in early 2000, soon after the company's acquisition by AOL. On March 14, the program was ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bittorrent
BitTorrent is a Protocol (computing), communication protocol for peer-to-peer file sharing (P2P), which enables users to distribute data and electronic files over the Internet in a Decentralised system, decentralized manner. The protocol is developed and maintained by Rainberry, Inc., and was first released in 2001. To send or receive files, users use a Comparison of BitTorrent clients, BitTorrent client on their Internet-connected computer, which are available for a variety of computing platforms and Comparison of BitTorrent clients#Operating system support, operating systems, including BitTorrent (software), an official client. BitTorrent trackers provide a list of files available for transfer and allow the client to find peer users, known as "seeds", who may transfer the files. BitTorrent downloading is considered to be faster than HTTP ("direct downloading") and File Transfer Protocol, FTP due to the lack of a central server that could limit bandwidth. BitTorrent is one o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metric (mathematics)
In mathematics, a metric space is a set together with a notion of ''distance'' between its elements, usually called points. The distance is measured by a function called a metric or distance function. Metric spaces are a general setting for studying many of the concepts of mathematical analysis and geometry. The most familiar example of a metric space is 3-dimensional Euclidean space with its usual notion of distance. Other well-known examples are a sphere equipped with the angular distance and the hyperbolic plane. A metric may correspond to a metaphorical, rather than physical, notion of distance: for example, the set of 100-character Unicode strings can be equipped with the Hamming distance, which measures the number of characters that need to be changed to get from one string to another. Since they are very general, metric spaces are a tool used in many different branches of mathematics. Many types of mathematical objects have a natural notion of distance and th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Randomness
In common usage, randomness is the apparent or actual lack of definite pattern or predictability in information. A random sequence of events, symbols or steps often has no order and does not follow an intelligible pattern or combination. Individual random events are, by definition, unpredictable, but if there is a known probability distribution, the frequency of different outcomes over repeated events (or "trials") is predictable.Strictly speaking, the frequency of an outcome will converge almost surely to a predictable value as the number of trials becomes arbitrarily large. Non-convergence or convergence to a different value is possible, but has probability zero. Consistent non-convergence is thus evidence of the lack of a fixed probability distribution, as in many evolutionary processes. For example, when throwing two dice, the outcome of any particular roll is unpredictable, but a sum of 7 will tend to occur twice as often as 4. In this view, randomness is not haphaza ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IP Address
An Internet Protocol address (IP address) is a numerical label such as that is assigned to a device connected to a computer network that uses the Internet Protocol for communication. IP addresses serve two main functions: network interface identification, and location addressing. Internet Protocol version 4 (IPv4) was the first standalone specification for the IP address, and has been in use since 1983. IPv4 addresses are defined as a 32-bit number, which became too small to provide enough addresses as the internet grew, leading to IPv4 address exhaustion over the 2010s. Its designated successor, IPv6, uses 128 bits for the IP address, giving it a larger address space. Although IPv6 deployment has been ongoing since the mid-2000s, both IPv4 and IPv6 are still used side-by-side . IP addresses are usually displayed in a human-readable notation, but systems may use them in various different computer number formats. CIDR notation can also be used to designate how much ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
