An informal term generally applied to any transmission system capable of carrying a 44.736 Mbps DWS-3 signal (coax, fiber optic, digital microwave, etc.). There is no transmission standard called "T-3.".
Equipment used to adapt Integrated Services Digital Network (ISDN) Basic Rate Interface (BRI) channels to existing terminal equipment standards such as RS-232 and V.35. A Terminal Adaptor is typically packaged like a modem, either as a standalone unit or as an interface card that plugs into a computer or other communications equipment (such as a router or PBX). A Terminal Adaptor does not interoperate with a modem; it replaces it.
Element qui inclus dans un document (par exemple HTML) indique un formatage ou une commande à exécuter. En HTML, les balises vont souvent par paires et chaque balise est bornée par les signes < et >.
TASI systems represent an example of an ANALOG Statistical Time Division Multiplexing scheme. These systems enjoyed limited use in the 1980s, and were particularly adept at sharing voice circuits; specifically PBX trunks. A TASI multiplexer is interconnected between the PBX and the trunk facilities. Usually, one analog trunk circuit is used for signaling purposes between TASI units at each end of the link. The remaining voice trunks support analog TASI TDM voice conversations. In normal telephone conversations, a majority of time is spent in a latent (idle) state. TASI trunks will allocate "snippets" of voice from another channel during this idle time. If an individual were to monitor these TASI trunks, they would hear bits and pieces of various conversations. The signaling channel is used for the signaling conversion between End-Point PBX (Private Branch Exchange) units and also for the allocation of bandwidth once incoming speech energy has been detected.
As digital speech processing became more common, TASI systems were created that had analog inputs, and digital outputs. This type of multiplexing technique is more commonly known as "Digital Speech Interpolation" (DSI).
Unfortunately, TASI and DSI systems suffer from a few drawbacks. First, there can be a lot of voice "clipping" noticed by users. This occurs when a little bit of speech is lost while waiting for the TASI mux to detect valid speech and allocate bandwidth. Clipping also occurs when there just isn't bandwidth present at the moment. Also, TASI and DSI units are very susceptible to audio input levels and may have problems with the transport of voiceband data (e.g. VF modem) signals.(extract from An Overview of Multiplexing).
Physical layer specifications for the transmission of bit streams over multi-mode optic fiber at 100 Mbps using 4B/5B encoding. Same specifications as in FDDI. (see PHY).
Interface Physique optique multimode à 100 Mbits. Appelée aussi norme 4B/5B.
One of the two PHYsublayers that is responsible for adapting the ATM cellsinto a stream of bits to be carried over the physical medium (see also PM).
Une des deux sous-couches constituant la couche physique ATM, chargée de la convertion de la cellule ATM en un flot de bits pour sa transmission sur le support physique. (voir aussi PM).
Originally developed by the Department of Defense to support the interworking of dissimilar computers across a network. Provides end-to-end, connection-oriented, reliable transport layer (layer 4) functions over IP-controlled networks. Operating on top of IP(combined known as TCP/IP), it is responsible for multiplexing sessions, error recovery, end-to-end reliable delivery and flow control.
Encore appelé "notaire électronique". Organisme auprès duquel les utilisateurs de méthodes de cryptage doivent déposer leurs clés, afin que celles-ci puissent être données aux institutions officielles en cas de nécessité. Ces organismes sont imposés par un certain nombre de lois dans différents pays dont la France.
Set of protocols developed by the Department of Defense to develop ways to connect dissimilar computers across a network. Protocol family of the Internet network, that combines both TCP and IP.Widely used applications, such as Telnet, FTP and SMTPinterface to TCP/IP.
Pour accéder à un cours en PostScript sur TCP/IP : http://www.urec.fr/Ftp/publis_urec/93.04.cours.TCP_IP.1.ps.Z et http://www.urec.fr/Ftp/publis_urec/93.04.cours.TCP_IP.2.ps.Z.
See CDV.
A technique for splitting the total bandwidth (link capacity) into several channels to allow bit streams to be combined (multiplexed). The bandwidth allocation is done by dividing the time axis into fixed-length slots and a particular channel can then transmit only during a specific time slot. The transmission rate of the high-speed circuit must be equal to, or greater than, the aggregate speed of all of the channels.
A type of multiplexing where two or more channels of information are transmitted over the same link by allocating a different time interval ("slot" or "slice") for the transmission of each channel. I.e. the channels take turns to use the link. Some kind of periodic synchronising signal or distinguishing identifier is usually required so that the receiver can tell which channel is which.
TDM becomes inefficient when traffic is intermittent because the time slot is still allocated even when the channel has no data to transmit. Statistical time division multiplexing was developed to overcome this problem. See also TDMA.
Data multiplexing scheme used as the basis for all digital switching networks and Central Office switches. Each 8 kHz sample of an analog signal from a given phone line or channel is coded into 8 bits of digital information. These are then time multiplexed into successive bytes of data within a digital bus or channel of data. See also TDM
Voir AMRT.
Typically the regulated operating company. See also PTT, common carrier.
TERENA was formed in October 1994 by the merger of RARE and EARN to promote and participate in the development of a high quality international information and telecommunications infrastructure for the benefit of research and education. See also: Reseaux Associes pour la Recherche Europeenne, European Academic and Research Network.
Pour accéder au serveur de TERENA : http://www.earn.net.
Usually you will use terminal software in a personal computer. the software pretends to be (emulates) a physical terminal and allows you to type commands to a remote computer.
A partir d'un ordinateur ou d'un micro-ordinateur, il est nécessaire d'utiliser un logiciel d'émulation de terminal qui simule le fonctionnement d'un terminal physique et permet de saisir des commandes sur un ordinateur distant.
A common example is sending a message. If the receiver does not acknowledge the message within some preset timeout period, a transmission error is assumed to have occured. The resulting time-out usually results in a retransmission of information.
Délai/evénement qui se produit quant un équipement réseau ou un processus qui attend un message en provenance d'un autre équipement ou processus, ne le reçoit pas dans un délai donné fixé à l'avance. L'expiration de ce délai sans message se traduit généralement par la retransmission du message dont la réponse ou l'acquitement était attendu.
Utilisateur chargé de conserver les clés de cryptographie d'un ou plusieurs utilisateurs dans un cadre légal.
Voir le site http://www.telecom.gouv.fr/francais/activ/techno/crypto0698_1.htm pour des informations sur la réglementation française en matière de cryptographie.
Means for providing connection admission(CAC), congestion and flow control (i.e. UPC, traffic shaping).See also Congestion control.
2. An abstact concept passed between cooperating agents to ensure synchronised access to a shared resource.Such a token is never duplicated or destroyed (unless the resource is) and whoever has the token has exclusive access to the resource it controls. See for example token-ring. If several programmers are working on a program, one programmer will "have the token" at any time, meaning that only he can change theprogram whereas others can only read it. If someone else wants to modify it he must first obtain the token. Jeton (réseau)
Suite de bits particulière utilisée dans la méthode d'accès dite "Anneau à Jeton" (en anglais : token-ring). Ce jeton circule en permanence d'une station à l'autre, toujours dans le même sens. Si la station n'a rien à émettre, elle retransmet le jeton.
Technique et méthode d'accès popularisées par IBM pour une catégorie de réseaux locaux fonctionnant sur le principe du passage de jeton sur une liaison en forme d'anneau fermé.
Accord entre l'utilisateur et l'agent de gestion du réseau concernant la Qualité de Service que devra fournir le réseau et la satisfaction par l'utilisateur de paramètres de trafic prédéfinis (i.e. PCR, MBS, burstiness,débit cellule moyen).
Force le trafic de données à se conformer à un certain comportement. Habituellement correspond au cas le plus défavorable ou au cas le plus défavorable augmenté du taux moyen.
Dans un système de traitement par lots, les différents traitements soumis sont placés dans des files d'attente, et chaque traitement est extrait à son tour de la file d'attente quand le processeur est libre pour être exécuté. Cela veut donc dire qu'un traitement ne s'exécute que lorsque l'ordinateur dispose des ressources nécessaires pour l'exécuter. Un traitement par lots est un traitement qui outre son aspect non interactif a aussi un aspect différé.
Appareil diffusant une source de signaux vers plusieurs destinataires, et cela de manière passive (sans modifier ces signaux).
Le réseau Transpac est parmi les plus grands réseaux X.25 du monde.
A security authority or its agent, trusted by other entities with respect to security-related activities.
A terminal device that includes signal driving electronics.