A report on Computer network

Fiber optic cables are used to transmit light from one computer/network node to another

2007 map showing submarine optical fiber telecommunication cables around the world.

Computers are very often connected to networks using wireless links

An ATM network interface in the form of an accessory card. A lot of network interfaces are built-in.

A typical home or small office router showing the ADSL telephone line and Ethernet network cable connections

The TCP/IP model and its relation to common protocols used at different layers of the model.

Message flows between two devices (A-B) at the four layers of the TCP/IP model in the presence of a router (R). Red flows are effective communication paths, black paths are across the actual network links.

Routing calculates good paths through a network for information to take. For example, from node 1 to node 6 the best routes are likely to be 1-8-7-6, 1-8-10-6 or 1-9-10-6, as these are the shortest routes.

Partial map of the Internet, based on the January 15, 2005 data found on opte.org . Each line is drawn between two nodes, representing two IP addresses. The length of the lines is indicative of the delay between those two nodes. This graph represents less than 30% of the Class C networks reachable.

Set of computers sharing resources located on or provided by network nodes.

- Computer network

119 related topics with Alpha

Internet

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ICANN headquarters in the Playa Vista neighborhood of Los Angeles, California, United States.

2007 map showing submarine fiberoptic telecommunication cables around the world.

Packet routing across the Internet involves several tiers of Internet service providers.

Number of mobile cellular subscriptions 2012–2016

As user data is processed through the protocol stack, each abstraction layer adds encapsulation information at the sending host. Data is transmitted over the wire at the link level between hosts and routers. Encapsulation is removed by the receiving host. Intermediate relays update link encapsulation at each hop, and inspect the IP layer for routing purposes.

Conceptual data flow in a simple network topology of two hosts (A and B) connected by a link between their respective routers. The application on each host executes read and write operations as if the processes were directly connected to each other by some kind of data pipe. After the establishment of this pipe, most details of the communication are hidden from each process, as the underlying principles of communication are implemented in the lower protocol layers. In analogy, at the transport layer the communication appears as host-to-host, without knowledge of the application data structures and the connecting routers, while at the internetworking layer, individual network boundaries are traversed at each router.

A DNS resolver consults three name servers to resolve the domain name user-visible "www.wikipedia.org" to determine the IPV4 Address 207.142.131.234

Creating a subnet by dividing the host identifier

This NeXT Computer was used by Tim Berners-Lee at CERN and became the world's first Web server.

Share of population using the Internet. See or edit source data.

Internet users per 100 population members and GDP per capita for selected countries.

Internet users per 100 inhabitants Source: International Telecommunication Union.

Internet users in 2015 as a percentage of a country's population Source: International Telecommunication Union.

'''Fixed broadband Internet subscriptions in 2012
as a percentage of a country's population''' Source: International Telecommunication Union.

'''Mobile broadband Internet subscriptions in 2012
as a percentage of a country's population''' Source: International Telecommunication Union.

Banner in Bangkok during the 2014 Thai coup d'état, informing the Thai public that 'like' or 'share' activities on social media could result in imprisonment (observed 30 June 2014).

Internet users by language<ref name=NIUBL-IWS>{{cite web|url=http://www.internetworldstats.com/stats7.htm|title=Number of Internet Users by Language|archive-url=https://web.archive.org/web/20120426122721/http://www.internetworldstats.com/stats7.htm|archive-date=26 April 2012|website=Internet World Stats, Miniwatts Marketing Group|date=31 May 2011|access-date=22 April 2012}}</ref>

$Website content languages<ref name=UofCLBWApril2013>{{cite web|title=Usage of content languages for websites|url=http://w3techs.com/technologies/overview/content_language/all|work=W3Techs.com|access-date=26 April 2013|archive-url=https://www.webcitation.org/66ZQzUXh6?url=http://w3techs.com/technologies/overview/content_language/all|archive-date=31 March 2012|url-status=live}}</ref>$

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.

Ethernet

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Symbol used by Apple on some devices to denote an Ethernet connection.

Accton Etherpocket-SP parallel port Ethernet adapter (circa 1990). Supports both coaxial (10BASE2) and twisted pair (10BASE-T) cables. Power is drawn from a PS/2 port passthrough cable.

An Intel 82574L Gigabit Ethernet NIC, PCI Express ×1 card

Older Ethernet equipment. Clockwise from top-left: An Ethernet transceiver with an in-line 10BASE2 adapter, a similar model transceiver with a 10BASE5 adapter, an AUI cable, a different style of transceiver with 10BASE2 BNC T-connector, two 10BASE5 end fittings (N connectors), an orange "vampire tap" installation tool (which includes a specialized drill bit at one end and a socket wrench at the other), and an early model 10BASE5 transceiver (h4000) manufactured by DEC. The short length of yellow 10BASE5 cable has one end fitted with an N connector and the other end prepared to have an N connector shell installed; the half-black, half-grey rectangular object through which the cable passes is an installed vampire tap.

A 1990s ISA network interface card supporting both coaxial-cable-based 10BASE2 (BNC connector, left) and twisted-pair-based 10BASE-T (8P8C connector, right)

Patch cables with patch fields of two Ethernet switches

A close-up of the SMSC LAN91C110 (SMSC 91x) chip, an embedded Ethernet chip

The original Ethernet implementation: shared medium, collision-prone. All computers trying to communicate share the same cable, and so compete with each other.

Modern Ethernet implementation: switched connection, collision-free. Each computer communicates only with its own switch, without competition for the cable with others.

Ethernet is a family of wired computer networking technologies commonly used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN).

Rack containing several enterprise class routers connected to multiple networks

Router (computing)

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A typical home or small office DSL router showing the telephone socket (left, white) to connect it to the internet using ADSL, and Ethernet jacks (right, yellow) to connect it to home computers and printers.

A screenshot of the LuCI web interface used by OpenWrt. This page configures Dynamic DNS.

The first ARPANET router, the Interface Message Processor was delivered to UCLA August 30, 1969, and went online October 29, 1969

A router is a networking device that forwards data packets between computer networks.

Packet switching

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Method of grouping data into packets that are transmitted over a digital network.

NSFNET Traffic 1991, NSFNET backbone nodes are shown at the top, regional networks below, traffic volume is depicted from purple (zero bytes) to white (100 billion bytes), visualization by NCSA using traffic data provided by the Merit Network.

Packet switching is the primary basis for data communications in computer networks worldwide.

Data link layer

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The data link layer, or layer 2, is the second layer of the seven-layer OSI model of computer networking.

Avaya ERS 2550T-PWR, a 50-port Ethernet switch

Network switch

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A modular network switch with three network modules (a total of 24 Ethernet and 14 Fast Ethernet ports) and one power supply.

A 5-port layer-2 switch without management functionality

A couple of managed D-Link Gigabit Ethernet rackmount switches, connected to the Ethernet ports on a few patch panels using Category 6 patch cables (all equipment is installed in a standard 19-inch rack)

A network switch (also called switching hub, bridging hub, and, by the IEEE, MAC bridge ) is networking hardware that connects devices on a computer network by using packet switching to receive and forward data to the destination device.

Local area network

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A local area network (LAN) is a computer network that interconnects computers within a limited area such as a residence, school, laboratory, university campus or office building.

Donald Davies

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Welsh computer scientist who was employed at the UK National Physical Laboratory (NPL).

In 1965 he conceived of packet switching, which is today the dominant basis for data communications in computer networks worldwide.

Internetworking

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Internetworking is the practice of interconnecting multiple computer networks, such that any pair of hosts in the connected networks can exchange messages irrespective of their hardware-level networking technology.

Quality of service

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Quality of service (QoS) is the description or measurement of the overall performance of a service, such as a telephony or computer network or a cloud computing service, particularly the performance seen by the users of the network.