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Zero-configuration networking (zeroconf) is a set of technologies that automatically creates a usable computer network based on the Internet Protocol Suite (TCP/IP) when computers or network peripherals are interconnected. It does not require manual operator intervention or special configuration servers. Zeroconf is built on three core technologies: assignment of numeric network addresses for networked devices, automatic distribution and resolution of computer hostnames, and automatic location of network services, such as printing devices. Without zeroconf, a network administrator must set up services, such as Dynamic Host Configuration Protocol (DHCP) and Domain Name System (DNS), or configure each computer's network settings manually. ==Background== Computer networks use numerical addresses to identify communications endpoints in a network of participating devices. This is similar to the telephone network, which assigns a string of digits to identify each telephone. In modern networking protocols, information to be transmitted is divided into a series of network packets. Every packet contains the source and destination addresses. Network routers examine these addresses to determine the best network path in forwarding the data packet at each step toward its destination. Similarly to telephones displaying a number card, it was a common practice in early networks to attach an address label to networked devices. The dynamic nature of modern networks, especially residential networks in which devices are power up only when needed, requires ad-hoc, dynamic address assignment mechanisms that do not require user involvement for initialization and management. These systems automatically assign addresses to common names chosen either by the equipment manufacturer, such as a brand and model number, or chosen by users for identifying their equipment. The names and addresses are automatically entered into a directory service. The early history of computer networking built upon technologies of the telecommunications networks and thus, protocols tended to fall into two groups, those intended to connect local devices into a local area network (LAN), and those intended primarily for long-distance communications. Wide area network (WAN) systems tended to have centralized setup, where an authority would assign addresses and names, often using manual means. LAN systems tended to provide more automation of these tasks, so that new equipment could be added to a LAN with a minimum of operator intervention. An early example of a zero-configuration LAN system is AppleTalk, a protocol introduced by Apple Inc. for the early Macintosh computers in the 1980s. Macs, as well as other devices supporting the protocol like the Apple IIGS and a variety of printers and file servers, could be added to the network by plugging them in, all further configuration was automated. Network addresses were automatically selected by each device using a protocol known as AARP, while each machine built its own local directory service using a protocol known as NBP. NBP included not only a name, but the type of device and any additional user-provided information like its physical location or device status. Users could look up any device on the network with the application Chooser, which filtered names based on the device type. On Internet Protocol networks, the Domain Name System was typically maintained manually by a network administrator. This led to the introduction of a number of new protocols providing automated services, such as the Dynamic Host Configuration Protocol (DHCP). 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Zero-configuration networking」の詳細全文を読む スポンサード リンク
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