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Classful Network
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. ...
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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 interlinked hypertext documents and applications of the World Wide Web (WWW), electronic mail, internet telephony, streaming media and file sharing. The origins of the Internet date back to research that enabled the time-sharing of computer resources, the development of packet switching in the 1960s and the design of computer networks for data communication. The set of rules (communication protocols) to enable internetworking on the Internet arose from research and development commissioned in the 197 ...
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IP 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 1000000000 (number), 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 IPv6 deployment, 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 registry, regional Internet registries (RIRs) responsible in their designated territories for assignment to end users and local Internet registry, 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 ...
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List Of Assigned /8 IPv4 Address Blocks
Some large 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 block contains 256 = 2 = 16,777,216 addresses, which covers the whole range of the last three delimited segments of an IP address. This means that 256 /8 address blocks fit into the entire IPv4 space. As IPv4 address exhaustion has advanced to its final stages, some organizations, such as Stanford University, formerly using , 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 organizations List of assigned /8 blocks to the United States Department of Defense List of assigned /8 blocks to the regional Internet registries The reg ...
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IPv4 Subnetting Reference
Classless Inter-Domain Routing (CIDR ) is a method for allocating IP addresses 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 se ...
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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. Loopback can take the form of communication channels 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 test. Where a syst ...
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Broadcast Address
A broadcast address is a network address used to transmit to all devices connected to a multiple-access communications network. A message sent to a broadcast address may be received by all network-attached hosts. In contrast, a multicast address is used to address a specific group of devices, and a unicast address is used to address a single device. For network layer communications, a broadcast address may be a specific IP address. At the data link layer on Ethernet networks, it is a specific MAC address. IP networking In Internet Protocol version 4 (IPv4) networks, broadcast addresses are special values in the host-identification part of an IP address. The all-ones value was established as the standard broadcast address for networks that support broadcast. This method of using the all-ones address was first proposed by R. Gurwitz and R. Hinden in 1982. The later introduction of subnets and Classless Inter-Domain Routing changed this slightly, so that the all-ones value b ...
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General Electric
General Electric Company (GE) was an American Multinational corporation, multinational Conglomerate (company), conglomerate founded in 1892, incorporated in the New York (state), state of New York and headquartered in Boston. Over the years, the company had multiple divisions, including GE Aerospace, aerospace, GE Power, energy, GE HealthCare, healthcare, lighting, locomotives, appliances, and GE Capital, finance. In 2020, GE ranked among the Fortune 500, ''Fortune'' 500 as the 33rd largest firm in the United States by gross revenue. In 2023, the company was ranked 64th in the Forbes Global 2000, ''Forbes'' Global 2000. In 2011, GE ranked among the Fortune 20 as the 14th most profitable company, but later very severely underperformed the market (by about 75%) as its profitability collapsed. Two employees of GE—Irving Langmuir (1932) and Ivar Giaever (1973)—have been awarded the Nobel Prize. From 1986 until 2013, GE was the owner of the NBC television network through its ...
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Localhost
In computer networking, localhost is a hostname that refers to the current computer used to access it. The name ''localhost'' is reserved for loopback purposes. It is used to access the network services that are running on the host via the loopback network interface. Using the loopback interface bypasses any local network interface hardware. Loopback The local loopback mechanism may be used to run a network service on a host without requiring a physical network interface, or without making the service accessible from the networks the computer may be connected to. For example, a locally installed website may be accessed from a Web browser by the URL ''http://localhost'' to display its home page. IPv4 network standards reserve the entire address block (more than 16 million addresses) for loopback purposes. That means any packet sent to any of those addresses is looped back. The address is the standard address for IPv4 loopback traffic; the rest are not supported by ...
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CIDR Notation
Classless Inter-Domain Routing (CIDR ) is a method for allocating IP addresses 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 router (computing), routers across the Internet, and to help slow the rapid IPv4 address exhaustion, 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 bit, 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 ...
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Dot-decimal Notation
Dot-decimal notation is a presentation format for numerical data. It consists of a string of decimal numbers, using the full stop (''dot'') as a separation character. A common use of dot-decimal notation is in information technology where it is a method of writing numbers in octet-grouped base-10 (decimal) numbers. In computer networking, Internet Protocol Version 4 (IPv4) addresses are commonly written using the quad-dotted notation of four decimal integers, ranging from 0 to 255 each. IPv4 address In computer networking, the notation is associated with the specific use of ''quad-dotted notation'' to represent IPv4 addresses and used as a synonym for ''dotted-quad notation''. Dot-decimal notation is a presentation format for numerical data expressed as a string of decimal numbers each separated by a full stop. For example, the hexadecimal number ''0xFF000000'' may be expressed in dot-decimal notation as ''255.0.0.0''. An IPv4 address has 32 bits. For purposes of representati ...
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IETF
The Internet Engineering Task Force (IETF) is a standards organization for the Internet standard, Internet and is responsible for the technical standards that make up the Internet protocol suite (TCP/IP). It has no formal membership roster or requirements and all its participants are volunteers. Their work is usually funded by employers or other sponsors. The IETF was initially supported by the federal government of the United States but since 1993 has operated under the auspices of the Internet Society, a non-profit organization with local chapters around the world. Organization There is no membership in the IETF. Anyone can participate by signing up to a working group mailing list, or registering for an IETF meeting. The IETF operates in a bottom-up task creation mode, largely driven by working groups. Each working group normally has appointed two co-chairs (occasionally three); a charter that describes its focus; and what it is expected to produce, and when. It is open ...
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