Technical glossary

This page presents a list of words concerning computer science or the Internet and also their definition and/or explanation.

• Letter A
  

  Name	Definition
  ADSL (Asymetric Digital Subscriber Line)	Technology doping the capacity of the telephone lines to transmit data with a high flow, without losing the capacity and reception of a normal telephone call: the user can be connected permanently to Internet. It is necessary to have an Ethernet card, a specific modem, and especially, not to live too far from a ADSL telephone central.
  ARPANET (Advanced Research Project Administration Network)	Network developed by the American Departement of Defence in the sixties, and considered as the Internet's father.

  
  
• Letter B
  

  Name	Definition
  Backbone	Network having generally a high flow which is used to connect several sub-networks.
  Band Width	Data quantity that a communication channel can convey. The higher the flow, the faster the data can be transmitted. Expressed in bps.
  BGP (Border Gateway Protocol)	Protocol intended for the exchanges of routing information between automated systems.
  Bit rate	Amount of bits transmitted during a time interval brought back to the length of this interval. A binary rate is expressed in bit/s or multiple of this unit: kbit/s, Mbit/s, Gbit/s.

  
  
• Letter C
  

  Name	Definition
  Cable	Internet Broad band connection technology . Distributed in France by Noos for exemple.

  
  
• Letter D
  

  Name	Definition
  DHTML (Dynamic Hyper Text Markup Language)	Advanced programming language intended for Internet pages. This language distinguishes itself from HTML by enriched instructions, in particular for graphics and special effects.
  DNS (Domain Name Server)	Computer, which one calls Domain Name Server, whose role is to ensure the correspondence between addresses like www.sitename.extension having an IP address in order to correctly convey the sent messages.
  Domain name	Abbreviations used at the end of an electronic address in order to inform the user about the general contents of the site ex: com: commercial, fr: France, gouv:gouvernement, org:organisation, etc.

  
  
• Letter E
  

  Name	Definition
  Ebone	One of two main Europeans IP networks of continental size (with Europanet), which provides Internet access to the French universities (via an intermediary, RENATER).
  Ethernet	Communications protocol made up of cable, cards and software in order to allow computers to communicate on a local area network. Basic Ethernet allows a flow of 10 Mbit/s, Ethernet 100 allows a flow of 100 Mbit/s. Ethernet gigabit reaches 1 Gbit/s.
  Europanet	One of two main Europeans IP networks of continental size.

  
  
• Letter F
  

  Name	Definition
  Firewall	Computer and/or software which has the role of ensuring the safety of a local area network (in a company) connected to Internet.
  FTP	File transfer protocol. Allows the download all types of file between a distant machine and a local machine and vice a versa. The open public sites are it generally in anonymous mode.

  
  
• Letter G
  

  Name	Definition
  GIX (Global Internet eXchange)	Interconnexion node for operators and ISPs.

  
  
• Letter H
  

  Name	Definition
  Hosting	Reserved Space on a server’s hard disk for storing an Internet site. This space allows, depending on the cases, the possibility of using particular scripts (cgi) or languages: ASP, PHP etc.
  HTML	Common language of the Web's documents. Currently at version 4, HTML varies according to the navigators, which leads to compatibility problems.
  HTTP	Hyper Text Transfer Protocol: Protocol governing the Web.

  
  
• Letter I
  

  Name	Definition
  Internet	World network associating telecommunication resources and both client and server computers, intended for the exchange of electronic messages, multimedia information and files. It functions using a common protocol which allows the gradual routing of messages split up in independent packages.
  IP Address	Identifies the network and the station on a TCP/IP network. The address is normally on four bytes, separated by a point (for example, 87.34.53.12). Each number must lie between 0 and 255. According to the address class (A, B or C), 1, 2 or 3 bytes indicate the network, 3, 2 or 1 byte indicate the node. Thanks to the Hosts file, it is possible to make a correspondence between host names and IP addresses. IP addresses identifying peripherals on a network, must have a unique IP address. The networks connected to public Internet network must obtain an identifier from an network official from the InterNIC center or from one of its competitors (Internet Network Information Center) so that the uniqueness of the IP network identifiers is guaranteed.
  IP Multicast	routing system minimizing the number of data flows going from a server towards several clients by multiplying them only when closest to a recipients stations (the opposite of a broadcast).
  IPv4 (Internet Protocol version 4)	Current version of the IP protocol which codes the addresses on 32 bits and therefore managing 4 billion IP addresses.
  IPv6 (Internet Protocol version 6)	New Internet Protocol which will replace IPv4, it codes the addresses on 128 bits and manages the coding of the data using a method called ESP, the whole of Internet should have migrated to IPv6 by 2010.
  ISDN (Internet Service Digital Network)	Technology offering one or two specific lines trough which the voice, the data, the faxes can transit. It offers flows going from 64 to 128 kbit/s and requires a particular modem as well as a subscription invoiced according the duration of the connection at France Telecom.
  ISP (Internet Service Provider)	Internet Service Provider: Company that gives it customers the possibility to connect to a network.

  
  
• Letter J
  

  Name	Definition
  No entry with this letter

  
  
• Letter K
  

  Name	Definition
  No entry with this letter

  
  
• Letter L
  

  Name	Definition
  LAN (Local Aera Network)	Local area network: Network located in a limited zone or a common environment, such as a building or a block of buildings. A local area network becomes a part of a wide area network when a connection is established (via distant modems, routers, telephone, satellite lines or a hertzian connection) with a large system, a public data network (Internet for example) or another local area network.

  
  
• Letter M
  

  Name	Definition
  MIME (Multi Purpose Internet Mail Extensions)	The most common Encoding system to attach digital files to electronic mails.
  Minitel	Ancestor of the Internet terminals which did not breakthrough worldwide because of its weak band-width, its lack of possible evolutions, its ridiculous graphic Definition, its very high user cost and its official management. France was the first country in the world to have a wide public network.
  Modem	MOdulator - DEModulator (of telephone signals...). Either internal or external to the computer, the modem is an electronic card specialized in the transformation and the emission/reception of data-processing signals into telephone signals and vice versa.

  
  
• Letter N
  

  Name	Definition
  NAP (Network Access Point)	American equivalent of the GIX.
  Network	A computer network can be local (its size is relatively reduced and it connects, generally through cables, several computers and peripherals inside a company) or widened (wide area network). It allows the transmission of any type of data, exchanged in a digital form and exploitable by the whole network. To manage a network, one or more computers have to be a server
  NSF (National Science Foundation)	American public organization which took care for a long time (amongst other things) of the maintenance of the American Internet backbone and prepared the emergence of Internet by laying out the first NAPs.
  NTP (Network Time Protocol)	Protocol for a temporal synchronization of the network.

  
  
• Letter O
  

  Name	Definition
  No entry with this letter

  
  
• Letter P
  

  Name	Definition
  Peering	Relation between two service providers who can, through a direct connection with each other, dispatch traffic mutually, save money and have a faster response time.
  PoP (Point of presence)	User Internet Access point. A service provider generally has several POPs thus allowing the communication tariffication to be at local cost.
  POP3 (Post Office Protocol version 3)	E-mail management protocol which allows mail consulting by all email management software.
  Protocol	Rules and defined code for data exchange (for the communication) between two connected machines (by a network, a telephone line, an infra-red connection, etc...)
  PSTN (Public switched telephone network)	It is the telephone network such as we all know it. Switched means here that the established connection is temporary and only lasts the time of the communication, in opposition to a permanent connection such as cable or the ADSL.

  
  
• Letter Q
  

  Name	Definition
  No entry with this letter

  
  
• Letter R
  

  Name	Definition
  Referencing	Once stored on a hosting server, an Internet site must be referred to the search engines. Referencing consists in contacting these engines and subjecting the presence and the contents of the site to them through ' Meta-Tags' markers which contain information relative to this site.
  RIPE NCC (Réseau IP Européen Network Organisation Centre)	Founded in 1989, RIPE NCC is a non-profit institution in charge of the management of IP addresses for Europe, the Middle East and some Asian and African countries. It is one of the three worldwide organizations in charge of the management of IP addresses. www.ripe.net
  Router	Software or hardware tool used to direct data through a network. It often acts as a bridge between several servers so that the users can easily reach all the resources available on the network. The router is also used as an interface between two networks using different protocols.

  
  
• Letter S
  

  Name	Definition
  Server	Consultable computer via another computer using a client software. The Web servers host Web pages, the mail servers store the messages, etc.
  SMTP (Simple Mail Transfert Protocol)	Electronic mails' management protocol.
  Switch	Interconnection element between 2 segments of local area networks of the same topology. Uses the MAC physical addresses.

  
  
• Letter T
  

  Name	Definition
  TCP/IP (Transmission Control Protocol/Ineternet protocol )	Communication protocol used on the Internet (particularly favourable with the networks interconnections) and more and more used for internal company networks (Intranet).

  
  
• Letter U
  

  Name	Definition
  URL (Uniform Ressource Locator)	Address of a HTML document. Each HTML document of a Web site has its own URL address. It indicates on which computer and in which folder the client's software will be able to find it.

  
  
• Letter V
  

  Name	Definition
  VLAN (Virtual LAN)	Logical regrouping (i.e. virtual) of some of the stations located on the same local area network.

  
  
• Letter W
  

  Name	Definition
  WAN (Wide Aera Network)	Opposite of a LAN. This type of network can be extend to the whole world.
  WWW (World Wide Web)	World Wide network also called Web. It is a grid of computers connected to each other by various ways: telephone, cable, fibre etc... The physical connection is ensured by the multitude of possible routes a bit like a cobweb. The temporary cut of one of the meshes of the net in general does not compromise the functioning of the network. In the same way, only one HTML page is split up into numbered packages which transit all by a different route before being given in the right order once delivered to the user's navigator.

  
  
• Letter X
  

  Name	Definition
  No entry with this letter

  
  
• Letter Y
  

  Name	Definition
  No entry with this letter

  
  
• Letter Z
  

  Name	Definition
  No entry with this letter