HTTP Secure Hypertext Transfer Protocol Secure (HTTPS) is a communications protocol for secure communication over a computer network, with especially wide deployment on the Internet. Technically, it is not a protocol in and of itself; rather, it is the result of simply layering the Hypertext Transfer Protocol (HTTP) on top of the SSL/TLS protocol, thus adding the security capabilities of SSL/TLS to standard HTTP communications. The security of HTTPS is therefore that of the underlying TLS, which uses long term public and secret keys to exchange a short term session key to encrypt the data flow between client and server. To guarantee one is talking to the partner one wants to talk to, X.509 certificates are used. In its popular deployment on the internet, HTTPS provides authentication of the web site and associated web server that one is communicating with, which protects against man-in-the-middle attacks. Overview[edit] HTTPS creates a secure channel over an insecure network. Usage in websites[edit]
Transmission Control Protocol Web browsers use TCP when they connect to servers on the World Wide Web, and it is used to deliver email and transfer files from one location to another. HTTP, HTTPS, SMTP, POP3, IMAP, SSH, FTP, Telnet and a variety of other protocols are typically encapsulated in TCP. Historical origin[edit] In May 1974 the Institute of Electrical and Electronic Engineers (IEEE) published a paper titled "A Protocol for Packet Network Intercommunication."[1] The paper's authors, Vint Cerf and Bob Kahn, described an internetworking protocol for sharing resources using packet-switching among the nodes. Network function[edit] The protocol corresponds to the transport layer of TCP/IP suite. TCP is utilized extensively by many of the Internet's most popular applications, including the World Wide Web (WWW), E-mail, File Transfer Protocol, Secure Shell, peer-to-peer file sharing, and some streaming media applications. TCP segment structure[edit] A TCP segment consists of a segment header and a data section.
Magnet URI scheme Scheme that defines the format of magnet links Magnet is a URI scheme that defines the format of magnet links, a de facto standard for identifying files (URN) by their content, via cryptographic hash value rather than by their location. Although magnet links can be used in a number of contexts, they are particularly useful in peer-to-peer file sharing networks because they allow resources to be referred to without the need for a continuously available host, and can be generated by anyone who already has the file, without the need for a central authority to issue them. This makes them popular for use as "guaranteed" search terms within the file sharing community where anyone can distribute a magnet link to ensure that the resource retrieved by that link is the one intended, regardless of how it is retrieved. History[edit] Format [edit] The following parameters are supported:[2][3] The standard also allows for application-specific experimental parameters, which must begin with "x". magnet:? x.
Application layer Although both models use the same term for their respective highest level layer, the detailed definitions and purposes are different. In the OSI model, the definition of the application layer is narrower in scope. The OSI model defines the application layer as the user interface responsible for displaying received information to the user. TCP/IP protocols[edit] The IETF definition document for the application layer in the Internet Protocol Suite is RFC 1123. Remote login to hosts: TelnetFile transfer: File Transfer Protocol (FTP), Trivial File Transfer Protocol (TFTP)Electronic mail transport: Simple Mail Transfer Protocol (SMTP)Networking support: Domain Name System (DNS)Host initialization: BOOTPRemote host management: Simple Network Management Protocol (SNMP), Common Management Information Protocol over TCP (CMOT) Other protocol examples[edit] References[edit] External links[edit]
File Transfer Protocol FTP is built on a client-server architecture and uses separate control and data connections between the client and the server.[1] FTP users may authenticate themselves using a clear-text sign-in protocol, normally in the form of a username and password, but can connect anonymously if the server is configured to allow it. For secure transmission that hides (encrypts) the username and password, and encrypts the content, FTP is often secured with SSL/TLS ("FTPS"). SSH File Transfer Protocol ("SFTP") is sometimes also used instead, but is technologically different. History[edit] The original specification for the File Transfer Protocol was written by Abhay Bhushan and published as RFC 114 on 16 April 1971. Until 1980, FTP ran on NCP, the predecessor of TCP/IP.[2] The protocol was later replaced by a TCP/IP version, RFC 765 (June 1980) and RFC 959 (October 1985), the current specification. Protocol overview[edit] Communication and data transfer[edit] ASCII mode: used for text. Login[edit] or:
Transport layer Transport layer implementations are contained in both the TCP/IP model (RFC 1122),[2] which is the foundation of the Internet, and the Open Systems Interconnection (OSI) model of general networking, however, the definitions of details of the transport layer are different in these models. In the Open Systems Interconnection model the transport layer is most often referred to as Layer 4. The best-known transport protocol is the Transmission Control Protocol (TCP). Services[edit] Transport layer services are conveyed to an application via a programming interface to the transport layer protocols. Analysis[edit] The transport layer is responsible for delivering data to the appropriate application process on the host computers. Some transport layer protocols, for example TCP, but not UDP, support virtual circuits, i.e. provide connection oriented communication over an underlying packet oriented datagram network. TCP is used for many protocols, including HTTP web browsing and email transfer.
BitTorrent Programmer Bram Cohen, a former University at Buffalo graduate student in Computer Science,[4] designed the protocol in April 2001 and released the first available version on July 2, 2001,[5] and the final version in 2008.[6] BitTorrent clients are available for a variety of computing platforms and operating systems including an official client released by Bittorrent, Inc. As of 2009, BitTorrent reportedly had about the same number of active users online as viewers of YouTube and Facebook combined.[7][8] As of January 2012[update], BitTorrent is utilized by 150 million active users (according to BitTorrent, Inc.). Based on this figure, the total number of monthly BitTorrent users can be estimated at more than a quarter of a billion.[9] Description[edit] The middle computer is acting as a seed to provide a file to the other computers which act as peers. The file being distributed is divided into segments called pieces. When a peer completely downloads a file, it becomes an additional seed.
Internet layer Internet-layer protocols use IP-based packets. The internet layer does not include the protocols that define communication between local (on-link) network nodes which fulfill the purpose of maintaining link states between the local nodes, such as the local network topology, and that usually use protocols that are based on the framing of packets specific to the link types. Such protocols belong to the link layer. A common design aspect in the internet layer is the robustness principle: "Be liberal in what you accept, and conservative in what you send"[1] as a misbehaving host can deny Internet service to many other users. Purpose[edit] The internet layer has three basic functions: In Version 4 of the Internet Protocol (IPv4), during both transmit and receive operations, IP is capable of automatic or intentional fragmentation or defragmentation of packets, based, for example, on the maximum transmission unit (MTU) of link elements. Core protocols[edit] Security[edit] IETF standards[edit]
eDonkey network The eDonkey Network (also known as the eDonkey2000 network or eD2k) is a decentralized, mostly server-based, peer-to-peer file sharing network best suited to share big files among users, and to provide long term availability of files. Like most sharing networks, it is decentralized, as there is not any central hub for the network; also, files are not stored on a central server but are exchanged directly between users based on the peer-to-peer principle. Currently, the eD2k network is not supported by any organization (in the past it was supported by the MetaMachine Corporation, its creator, which now is out of business) and development and maintenance is being fully provided by its community and client developers. There are many programs that act as the client part of the network. The original eD2k protocol has been extended by subsequent releases of both eserver and eMule programs, generally working together to decide what new features the eD2k protocol should support. Features[edit]
Point-to-point protocol PPP is used over many types of physical networks including serial cable, phone line, trunk line, cellular telephone, specialized radio links, and fiber optic links such as SONET. PPP is also used over Internet access connections. Internet service providers (ISPs) have used PPP for customer dial-up access to the Internet, since IP packets cannot be transmitted over a modem line on their own, without some data link protocol. Description[edit] PPP was designed somewhat after the original HDLC specifications. RFC 2516 describes Point-to-Point Protocol over Ethernet (PPPoE) as a method for transmitting PPP over Ethernet that is sometimes used with DSL. PPP is a layered protocol that has three components: PPP is specified in RFC 1661. Automatic self configuration[edit] Link Control Protocol (LCP) initiates and terminates connections gracefully, allowing hosts to negotiate connection options. After the link has been established, additional network (layer 3) configuration may take place. Link Dead
ed2k URI scheme In computing, eD2k links ( are hyperlinks used to denote files stored on computers connected to the eDonkey filesharing P2P network. General[edit] Many programs, such as eMule, MLDonkey and the original eDonkey2000 client by MetaMachine, which introduced the link type, as well as others using the eDonkey file sharing protocol, can be used to manage files stored in the filesharing network. eD2k links allow a file to be identified from a link in a web browser and to be downloaded thereafter by a client like eMule, Shareaza or any other compatible software. This linking feature was one of the first URIs to be introduced in peer-to-peer file sharing, and had a vast effect on the development of the eDonkey network, as it allowed external link sites to provide verified content within the network. Like other URI protocols, web browsers can be configured to automatically handle ed2k URIs. File link format[edit] eD2k hash algorithm[edit] Server links[edit] Example:
Internet Protocol This article is about the IP network protocol only. For Internet architecture or other protocols, see Internet protocol suite. The Internet Protocol (IP) is the principal communications protocol in the Internet protocol suite for relaying datagrams across network boundaries. Its routing function enables internetworking, and essentially establishes the Internet. Historically, IP was the connectionless datagram service in the original Transmission Control Program introduced by Vint Cerf and Bob Kahn in 1974; the other being the connection-oriented Transmission Control Protocol (TCP). The first major version of IP, Internet Protocol Version 4 (IPv4), is the dominant protocol of the Internet. Function[edit] The Internet Protocol is responsible for addressing hosts and for routing datagrams (packets) from a source host to a destination host across one or more IP networks. Datagram construction[edit] Sample encapsulation of application data from UDP to a Link protocol frame Reliability[edit]