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Classful Addressing
A classful network is an obsolete network addressing architecture used in the Internet from 1981 until the introduction of Classless Inter-Domain Routing (CIDR) in 1993. The method divides the IP address space for Internet Protocol version 4 (IPv4) into five address classes based on the leading four address bits. Classes A, B, and C provide unicast addresses for networks of three different network sizes. Class D is for multicast networking and the class E address range is reserved for future or experimental purposes. Since its discontinuation, remnants of classful network concepts have remained in practice only in limited scope in the default configuration parameters of some network software and hardware components, most notably in the default configuration of subnet masks. Background In the original address definition, the most significant eight bits of the 32-bit IPv4 address was the ''network number'' field which specified the particular network a host was attached to. The re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Internet Map In February 82
The Internet (or internet) is the global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to communicate between networks and devices. It is a '' network of networks'' that consists of private, public, academic, business, and government networks of local to global scope, linked by a broad array of electronic, wireless, and optical networking technologies. The Internet carries a vast range of information resources and services, such as the inter-linked hypertext documents and applications of the World Wide Web (WWW), electronic mail, telephony, and file sharing. The origins of the Internet date back to the development of packet switching and research commissioned by the United States Department of Defense in the 1960s to enable time-sharing of computers. The primary precursor network, the ARPANET, initially served as a backbone for interconnection of regional academic and military networks in the 1970s to enable resource sharing. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IPv4 Address Exhaustion
IPv4 address exhaustion is the depletion of the pool of unallocated IPv4 addresses. Because the original Internet architecture had fewer than 4.3 billion addresses available, depletion has been anticipated since the late 1980s, when the Internet started experiencing dramatic growth. This depletion is one of the reasons for the development and deployment of its successor protocol, IPv6. IPv4 and IPv6 coexist on the Internet. The IP address space is managed globally by the Internet Assigned Numbers Authority (IANA), and by five regional Internet registries (RIRs) responsible in their designated territories for assignment to end users and local Internet registries, such as Internet service providers. The main market forces that accelerated IPv4 address depletion included the rapidly growing number of Internet users, always-on devices, and mobile devices. The anticipated shortage has been the driving factor in creating and adopting several new technologies, including network a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Assigned /8 IPv4 Address Blocks
Some large /8 blocks of IPv4 addresses, the former Class A network blocks, are assigned in whole to single organizations or related groups of organizations, either by the Internet Corporation for Assigned Names and Numbers (ICANN), through the Internet Assigned Numbers Authority (IANA), or a regional Internet registry. Each /8 block contains 256 = 2 = 16,777,216 addresses, which covers the whole range of the last three delimited segments of an IP address. As IPv4 address exhaustion has advanced to its final stages, some organizations, such as Stanford University, formerly using 36.0.0.0/8, have returned their allocated blocks (in this case to APNIC) to assist in the delay of the exhaustion date. List of reserved /8 blocks List of assigned /8 blocks to commercial organisations List of assigned /8 blocks to the United States Department of Defense List of assigned /8 blocks to the regional Internet registries The regional Internet registries (RIR) allocate IPs within a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IPv4 Subnetting Reference
Classless Inter-Domain Routing (CIDR ) is a method for allocating IP addresses and for IP routing. The Internet Engineering Task Force introduced CIDR in 1993 to replace the previous classful network addressing architecture on the Internet. Its goal was to slow the growth of routing tables on routers across the Internet, and to help slow the rapid exhaustion of IPv4 addresses. IP addresses are described as consisting of two groups of bits in the address: the most significant bits are the network prefix, which identifies a whole network or subnet, and the least significant set forms the ''host identifier'', which specifies a particular interface of a host on that network. This division is used as the basis of traffic routing between IP networks and for address allocation policies. Whereas classful network design for IPv4 sized the network prefix as one or more 8-bit groups, resulting in the blocks of Class A, B, or C addresses, under CIDR address space is allocated to Internet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Loopback
Loopback (also written loop-back) is the routing of electronic signals or digital data streams back to their source without intentional processing or modification. It is primarily a means of testing the communications infrastructure. There are many example applications. It may be a communication channel with only one communication endpoint. Any message transmitted by such a channel is immediately and only received by that same channel. In telecommunications, loopback devices perform transmission tests of access lines from the serving switching center, which usually does not require the assistance of personnel at the served terminal. Loop around is a method of testing between stations that are not necessarily adjacent, wherein two lines are used, with the test being done at one station and the two lines are interconnected at the distant station. A patch cable may also function as loopback, when applied manually or automatically, remotely or locally, facilitating a loop-back ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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