COMMUNICATIONS TERMS GLOSSARYRed terms refer to protocols – communications rules and procedures

A

AAL

ATM Adaptation Layer .The AAL is what gives ATM the flexibility to carry entirely different  types of services within the same format. It is important to understand that the AAL is not a network process but instead is performed by the network terminating equipment. Thus the networks task is only to route the cell from one point to another, depending on its header information.

AAL1 Transport for constant bit  rate data traffic as voice, video or other continous user data . Contains timing information, CRC for error detection and corection for AAL overhead.

AAL2 Variable bit rate as video or other interrupted user data.Uses MINI CELS that have 3 octets header and  payloads up to 64 bytes

AAL3 - 4 Merge of AAL3 & AAL4.Variable lenght frames and packets. Inefficient, is  replaced by AAL5

AAL5 ATM adaptation layer 5 -1 VCC per trunk. Passport trunks over ATM carry DPRS traffic using AAL5 to convert frames to ATM cells.

ABCATM buss controller

ABR avaible bit rate* ABR is an ATM layer service category for which the limiting ATM layer transfer characteristics provided by the network may change subsequent to connection establishment.

ABSATM bearer service

ACDAn Automatic Call Distributor (ACD) is a telephone facility that manages incoming calls and handles them based on the number called and an associated database of handling instructions. Many companies offering sales and service support use ACDs to validate callers, make outgoing responses or calls, forward calls to the right party, allow callers to record messages, gather usage statistics, balance the use of phone lines, and provide other services.

ACELPAlgebraic code excited linear prediction

ADPCMadaptive differential pulse code modulation

ADSL Asymmetric Digital Subscriber Line - is a technology for transmitting digital information at a high bandwidth on existing phone lines to homes and businesses.

ADTFAllowed cell rate decrease time factor

AFIAuthority and format identifier

AISalarm indication signal called Blue Alarm

AMaccess module

APIHigh-level application programming interfaces (APIs), for example, APPC

A_PCRActual peak cell rate

APPNadvanced peer-to peer networking

APSAutomatic protection switching

AQMATM queue manager

ARNAdvanced Router Nortel

ARPadress resolution protocol

ASICapplication specific integrated circuit

ATM asynchronous transfer mode * Trunking system transparency * ( Routing System ) Connection-oriented routing * ATM can forward traffic at much higher rates than VNS

ATMARPATM address of the ATMARP server to enable address resolution

ATMIFATM interface

ATM MPEMultiprotocol ATM encapsulation

ATUAsynchronous Telemetry Unit

AYTare-you-there packet of attributes such as remote node name

BBBC-IE

broadband bearer capability information element

BCbuss controller

BCIBackward Congestion Indication

BECNbackward explicit congestion notification

BER bit error rate is percentage of bits with errors in total bits received.

BERT bit error ratio (rate) testing.

BGP(4)border gateway protocol (version 4)

BNCBNC Option pt cablu coax The basic BNC connector is a male type mounted at each end of a cable. This connector has a center pin connected to the center cable conductor and a metal tube connected to the outer cable shield. A rotating ring outside the tube locks the cable to any female connector.

BoSSBayStack Operating System Switching Software

BooTPbootstrap protocol

BPDUsBridge Protocol Data Units

BTDSbit transparent data service

BTDSH bit transparent data service * It is required for signaling only in CCS( ts 24 for DS1, ts 16 for E1)

BUSbroadcast and unknown server

BWBandwidth

BWoDdynamic "Bandwidth on demand" to provide extra bandwidth for traffic peaks.

CCA

connection administrator

CACconnection admission control

Call Center

A call center is a physical place where customer and other telephone calls are handled by an organization, usually with some amount of computer automation. Typically, a call center has the ability to handle a considerable volume of calls at the same time, to screen calls and forward them to someone qualified to handle them, and to log calls. Call centers are used by mail-order catalog organizations, telemarketing companies, computer product help desks, and any large organization that uses the telephone to sell or service products and services.  Vi rtual call center is a call center in which the organization's representatives are geographically dispersed, rather than being situated at work stations in a building operated by the organization. Virtual call center employees may be situated in groups in a number of smaller centers, but most often they work from their own homes. This is an attractive arrangement for many employees: the hours are often flexible, and there's no dress code or commute. For the organization, the virtual call center model saves housing and equipment costs and can lead to lower employee turnover rates, which tend to be high for physical call centers.

CallPilot

CallPilot 4.0 provides a variety of new unified messaging features, as well as Cost of Ownership improvements designed to help reduce on-going management and maintenance costs. CallPilot is a unified messaging application for businesses using Meridian 1 PBX phone systems, Meridian SL-100, Communication Server 1000, and CPE Centrex systems. It combines voicemail, e-mail and fax messages into a single mailbox — accessible by phone, any desktop PC, or mobile e-mail enabled devices (PDAs). CallPilot Unified messaging provides a compelling solution for businesses that are looking at reducing costs, improving productivity, and staying connected to their customers and suppliers.

CAPcall accept packet

CAS Component Administration System or Channel associated signaling: signaling in same or in different channel permanent associated. CAS protocols : R1, R2, DTMF, MF

C-bit The 3th, 5th and 7th  overhead (bits in a frame, not in the payload , for signalling) bits in a DS3 signal's M-subframes (submultiframe, division of multiframe that contains multiple frames)

CbComited burst

CBCconnection bandwidth control

CBR constant bit rate * Differ from VBR; SAD (Speech activity detection) feature changes voice from CBR traffic to VBR traffic

CCRCustomer Call Routing

CCS Common channel signaling: one channel for all signaling functions of a group of voice channels CCS protocols : DPNSS, QSIG, CCS7. It requires BTDS for signaling- ts 24 for DS1, ts 16 for E1

CAMECDMA (code-division multiple access) refers to any of several protocols used in so-called second-generation (2G) and third-generation (3G) wireless communications. As the term implies, CDMA is a form of multiplexing, which allows numerous signals to occupy a single transmission channel, optimizing the use of available bandwidth. The technology is used in ultra-high-frequency (UHF) cellular telephone systems in the 800-MHz and 1.9-GHz bands

CDVcell delay variation

CDVTCell delay variation tolerance also known as network jitter (tolerance)

CELPCode excited linear prediction

CES circuit emulation service   Contivity Extranet Switch

CFPControl and function processor

Cgcongestion level

CIDCustomer identifier

CIF

Cost,Insurance and Freight(... named port of destination)  means that the seller delivers when the goods pass the ship's rail in the port of shipment. The seller must pay the costs and freight necessary to bring the goods to the named port of destination .The CIF term requires the seller to clear the goods for export. This term can be used only for sea and inland waterway transport. If the parties do not intend to deliver the goods across the ship's rail, the CIP term should be used. 

CIO Chief Information Officer (CIO) is a job title commonly given to the person in an enterprise responsible for the information technology and computer systems that support enterprise goals.

CIP Carriage and Insurance Paid To(... named place of destination) means that the seller delivers the goods to the carrier nominated by him but the seller must in addition pay the cost of carriage necessary to bring the goods to the named destination. This means that the buyer bears all risks and any additional costs occurring after the goods have been so

delivered. However, in CIP the seller also has to procure insurance against the buyer's risk of loss of or damage to the goods during the carriage. Consequently, the seller contracts for insurance and pays the insurance premium.If subsequent carriers are used for the carriage to the agreed destination, the risk passes when the goods have been delivered to the first carrier. The CIP term requires the seller to clear the goods for export. This term may be used irrespective of the mode of transport including multimodal transport.

CLConnectionless Data

CLPcell lost priority

CLRcell loss ratio

COConnection Oriented Data

COICommunity of interest

COMPANION WIRELESS

The name for the communication systems which use radio technology to transmit  and receive signals between its components and the Business Communications Manager.

CONTACT CENTER

A contact center (also referred to as a customer interaction center or e-contact center) is a central point in an enterprise from which all customer contacts are managed. The contact center typically includes one or more online call centers but may include other types of customer contact as well, including e-mail newsletters, postal mail catalogs, Web site inquiries and chats, and the collection of information from customers during in-store purchasing. A contact center is generally part of an enterprise's overall customer relationship management (CRM).A contact center would typically be provided with special software that would allow contact information to be routed to appropriate people, contacts to be tracked, and data to be gathered

CLP Cell Loss Priority

COPSCommon Open Policy Services

COSclass of service

CP control processor * Control processors manage the processor cards on the shelf and provide basic system capabilities.

CPCScommon part convergence sublayer

CPEcustomer premise equipment

CPNDCalling party name display

CQCcell queue control

CQMcell queue memory

CRcall route

CRCCRC-4 (Cyclic Redundancy Check 4) is a form of cyclic redundancy checking (a method of

checking for errors in transmitted data) that is used on E-1 trunk lines. CRC-4 is structured in a multiframe consisting of 16 frames numbered 0 to 15. The CRC-4 multiframe is then divided into two eight frame Sub-Multiframes (SMF) called SMF I and SMF II. Each SMF contains four CRC-4 bits designated C1, C2, C3, and C4. Through multiplication and division processes, the CRC-4 bits sent in each SMF are compared to each other and if they match, the frame is considered error free. Bit 1 is used for the CRC-4 bits. CRC-4 support is required for all network switches in Europe. However, some older switches including private branch exchanges (PBXs) do not support CRC-4.

CRMcustomer relationship management  analytics comprises all programming that analyzes data about an enterprise's customers and presents it so that better and quicker business decisions can be made.

CRPcall request packet

CRScall redirection server

C/RCommand/Response

CSE MXSuccession Communication Server for Enterprise Multimedia Xchange

CSMA/CD

The Ethernet carrier sense multiple access/collision detection (CSMA/CD) protocol operates in half-duplex mode, allowing either data transmission or reception, but never both at the same time. Point-to-point network connections, such as DTE-to-switch ports, do not need CSMA/CD to resolve media access contention from multiple devices; therefore, point-to-point network connections allow a file server to transmit frames to a switch while simultaneously receiving frames from the same switch. This two-way, non-CSMA/CD full-duplex communication provides an effective bandwidth of 200 Mb/s between two 100 Mb/s devices.

CSRMcall server resource modules

CS-ACELP Conjugated structure-algebraic coded excited linear prediction diff LD-CELP 80bytes-8kb/sec

CSV Comma Separated Values format

CTDCell Transfer Delay

CTE Computer Telephony Engine

CTICTI ( computer-telephony integration), or sometimes simply "computer telephony," is the use of computers to manage telephone calls. The term is used in describing the computerized services of call centers, such as those that direct your phone call to the right department at a business you're calling.

CTSClear To Send - modem

CUG Closed User Group facilitate folosita in X25 pentru cresterea sigurantei datelor din retea prin limitarea accesibilitatii

D

Ddestination

DCCData country code

DCEData circuit equipment (MASTER)  Data Communications Equipment (DCE) device. In practical terms, the DCE is usually a modem and the DTE is the computer itself, or more precisely, the computer's UART chip. For internal modems, the DCE and DTE are part of the same device.

DCMEDigital circuit multiplication equipment

DCRdestination call router

DCSdata collection system

DDSDigital Data Service

Deemission delay

DEdiscard eligible

DGCRADynamic generic cell rate algorithm

DIGlocal digital loopback test

DivX

DivX  (Digital Video Express) is a hacked MPEG4 codec allowing the encoding (and decoding) of high-quality MPEG4 video streams. MPEG4 is designed for low-bitrate applications and thus offers an excellent size/quality -ratio. As such DivX is ideal for very high quality DVD backups and other applications requiring high video quality at limited space.

Dmmeasured delay

DMLT Distributed Multi-LinkTrunking

Dppropagation delay

DLCIData Link Connection Identifier(I=ID) - Frame Relay protocol

DLRdata link routing

DDPDelivered Duty Paid means that the seller fulfils his obligation to deliver when the goods have been made available at the named place in the country of importation. The seller has to bear the risks and costs, including duties, taxes and other charges of delivering the goods thereto, cleared for importation. Whilst the EXW term represents the minimum obligation for the seller, DDP represents the maximum obligation. This term should not be used if the seller is unable directly or indirectly lo obtain the import licence. If the parties wish the buyer to clear the goods for importation and to pay the duty, the term DDU should be used. If the parties wish to exclude from the seller's obligations some of the costs payable upon importation of the goods (such as value added tax(VAT)), this should be made clear by adding words to this

effect:"Delivered duty paid, VAT unpaid named place of destination)"

DNDirectory number

DNAdynamic network address

DNS Domain Name System. DNS servers are strategically located on the Internet to convert domain names to IP addresses.

DPdiscard priority (discard policy) Dialing plan

DPFDynamic Protocol Filtering (IBM)

DPNdynamic packet network / data packet network

DPNSS 1digital private network signaling system no.1

DPRS dynamic packet routing system * Connectionless routing ; is responsible for routing Passport traffic such as frame relay, APPN, and DPN-100. DPRS=FRframe relay+APPN(advanced peer to peer networking)+SLA DNR +DNA gateway

DQdestination queue indetifier

DS1

digital signal level 1

Digital Signal Designator Data Rate DS0 Multiple T-Carrier E-Carrier

DS0 64 Kbps 1 - -

DS1 1.544 Mbps 24 T-1 -

- 2.048 Mbps 32 - E1

DS1C 3.152 Mbps 48 - -

DS2 6.312 Mbps 96 T-2 -

- 8.448 Mbps 128 - E2

- 34.368 Mbps 512 - E3

DS3 44.736 Mbps 672 T-3 -

- 139.264 Mbps 2048 - E4

DS4/NA 139.264 Mbps 2176 - -

DS4 274.176 Mbps 4032 - -

- 565.148 Mbps 4 E4 channels - E5

DS1CA DS level and framing specification for digital signals in the North American digital transmission hierarchy. A DS1C signal uses 48 PCM channels and has a transmission rate of 3.15 Megabits per second, twice that of DS1.

DSL DSL (Digital Subscriber Line) is a technology for bringing high-bandwidth information to homes and small businesses over ordinary copper telephone lines. xDSL refers to different variations of DSL, such as ADSL, HDSL, and RADSL

DSxdigital signal level x

DS/DSCPThe Business Policy Switch includes the capability to enhance your network traffic management. For each packet, there is an octet in the packet header, the DiffServ (DS) field, that you can designate for specific service. For IP packets, six bits of the DS field is the DiffServ Code Point (DSCP). DSCP value defines how the packet is to be treated as it travels through the network.

DSPDigital signal processing

DSUData set unit

DTE

data terminating equipment {host)Short for Data Terminal Equipment, a device that controls data flowing to or from a computer. The term is most often used in reference to serial communications defined by the RS-232C standard. This standard defines the two ends of the communications channel as being a DTE and Data Communications Equipment (DCE) device. In practical terms, the DCE is usually a modem and the DTE is the computer itself, or more precisely, the computer's UART chip. For internal modems, the DCE and DTE are part of the same device.

DTMFdual tone multi frequency

DWDM Dense wavelength division multiplexing (DWDM) is a technology that puts data from different sources together on an optical fiber, with each signal carried at the same time on its own separate light wavelength.

EE1

european level 1

EAPexternal address plan

EAPMexternal address plan manager

EBRedge-based rerouting

ECRequivalent cell rate

EFCIexplicit forward congestion indication

EGHextended Gibbens-Hunt method

EGPexterior gateway protocol

EIRexcess information rate

EMEnterprise module

EOMend of message

Epend point

EPemission priority

EPDearly packet discard

ERExplicit rate

ESCON

Enterprise Systems Connection is a marketing name for a set of IBM and vendor products that interconnect S/390 computers with each other and with attached storage, locally attached workstations, and other devices using optical fiber technology and dynamically modifiable switches called ESCON Directors.

ESDthe ElectroStatic Discharge jack on the shelf assembly

ESFExtended superframe

ESIEnd system identifier

ExEuropean level x

EXWEx Works  conditia de livrare cea mai comoda pentru vanzator: trebuie sa puna marfa ambalata la dispozitia cumparatorului, care este obligat sa o incarce pe cheltuiala si riscul sau.

FFAST Flexible Advanced StackingTechnology

FBTDSframe aligned BTDS

FCIForward Congestion Indication

FCS Frame Check Sequence is utilized between the access device and the network to ensure bit integrity of the frame (FR)

FDCRfinal destination call router

FEAC Far End Alarm and Control

FEBE Far End Block Error

FERF Far End Receive Failure -Prima denumire (in documentatia mai veche ) pentru  RDI

FDDIFiber distributed data interface

FECNforward explicit congestion notification

FFPfast forwarder process

FISfax idle suppression

FPfunction processor * Function processors provide communication connections and services.

FPPfast packet processor

FR

Frame relay - a high-speed, packet switching WAN protocol designed to provide efficient, high-speed frame or packet transmission with minimum delay. Frame relay uses minimal error detection and relies on higher level protocols for error control.Frame relay is a telecommunication service designed for cost-efficient data transmission for intermittent traffic between local area networks LANs and between end-points in a wide area network WAN Frame relay puts data in a variable-size unit called a frame and leaves any necessary error correction (retransmission of data) up to the end-points, which speeds up overall data transmission. For most services, the network provides a permanent virtual circuit, which means that the customer sees a continous, dedicated connection without having to pay for a full-time leased line, while the service provider figures out the route each frame travels to its destination and can charge based on usage.

FR-ATMframe relay over ATM

FRDTEFrame relay DTE (Data termination equipment) access service interconnects a Passport 6400 node and other frame relay devices. You can use this service to connect private networks to public networks, private networks to private networks, private networks to private networks through public networks

FRFFrame relay forum

FRUNIFrame relay UNI (User to network)

FTPfile transfer protocol

FE1 fractional E1

FT1 fractional T1

FTTB FTTC

Fiber to the curb"(FTTC) refers to the installation and use of optical fiber cable directly to the curbs near homes or any business environment as a replacement for "plain old telephone service" (POTS). The term "fiber to the curb" recognizes that optical fiber is already used for most of the long-distance part of your telephone calls and Internet use. Unfortunately, the last part - installing fiber to the curb - is the most expensive. Fiber to the curb implies that coaxial cable or another medium might carry the signals the very short distance between the curb and the user inside the home or business. "Fiber to the building" (FTTB) refers to installing optical fiber from the telephone company central office to a specific building such as a business or apartment house. ". Hybrid Fiber Coax (HFC) is an example of a distribution concept in which optical fiber is used as the backbone medium in a given environment and coaxial cable is used between the backbone and individual users (such as those in a small corporation or a college environment).

GGAN

Global Area Network

gatewayLinks to other networks are called gateways a device (as a router ) serving as an entry A system that links two different types of networks and enables them to communicate with each other. The Business Communications Manager BCM can provide the gateway to an intranet or internet .into a network.

GBIC Gigabit Interface Converter

GbpsGigabits per second

GCACgeneric connection admission control

GCMglobal cache manager

GCRAgeneric cell rate algorithms

GFCgeneric flow control

.gif Graphical Interchange Format (.gif)

GIS

Geographic Information System ; an analytic framework for managing and integrating data. A GIS can be viewed in three ways: 1 The Database View: A GIS is a unique kind of database of the world—a geographic database (geodatabase); 2 The Map View: A GIS is a set of intelligent maps and other views; 3 The Model View: A GIS is a set of information transformation tools that derive new geographic datasets

GPRSgeneral packet radio services

GPS

Global Positioning System is a satellite-based navigation system made up of a network of 24 satellites placed into orbit by the U.S. Department of Defense. GPS satellites circle the earth twice a day in a very precise orbit and transmit signal information to earth. GPS receivers take this information and use triangulation to calculate the user's exact location. Essentially, the GPS receiver compares the time a signal was transmitted by a satellite with the time it was received. The time difference tells the GPS receiver how far away the satellite is. Now, with distance measurements from a few more satellites, the receiver can determine the user's position and display it on the unit's electronic map.

GREGeneric routing encapsulation

GSMGlobal System for Mobile communication

GUIA GUI is a graphical (rather than purely textual) user interface to a computer. As you read this, you are looking at the GUI or graphical user interface of your particular Web browser. The term came into existence because the first interactive user interfaces to computers were not graphical; they were text-and-keyboard oriented and usually consisted of commands you had to remember and computer responses that were infamously brief.

H

HDLC

high-level data link control Layer 2 of the OSI model is the data link layer. One of the most common layer 2 protocols is the HDLC protocol. In fact, many other common layer 2 protocols are heavily based on HDLC, particularly its framing structure: namely, SDLC, SS#7, LAPB ,LAPD and ADCCP. The basic framing structure of the HDLC protocol is shown below:HDLC uses zero insertion/deletion process (commonly known as bit stuffing) to ensure that the bit pattern of the delimiter flag does not occur in the fields between flags. The HDLC frame is synchronous and therefore relies on the physical layer to provide method of clocking and synchronizing the transmission and reception of frames.The HDLC protocol is defined by ISO for use on both point-to-point and multipoint (multidrop) data links. It supports full duplex transparent-mode operation and is now extensively used in both multipoint and computer networks.

HDSL

High-Data-Rate Digital Subscriber Line. One of four DSL technologies. HDSL delivers 1.544 Mbps of bandwidth each way over two copper twisted pairs. Because HDSL provides T1 speed, telephone companies have been using HDSL to provision local access to T1 services whenever possible. The operating range of HDSL is limited to 12,000 feet (3658.5 meters), so signal repeaters are installed to extend the service. HDSL requires two twisted pairs, so it is deployed primarily for PBX network connections, digital loop carrier systems, interexchange POPs, Internet servers, and private data networks.

HECheader error control

HgmFrUni Dna HuntGroupMember

HPHolding priority

HTDS HDLC transparent data service( HDLC = High level data link control ); see also BTDS (bit transparent data service) & VTDS(voice transparent data service)

HTMLHyperText Markup Language

HTTP Hypertext Transfer Protocol (HTTP)The set of rules used for exchanging text, graphic images, sound, video, and other multimedia files on the world wide web.

HUB

Hubs are devices with many ports (jacks into which network cables can plug in); a hub is simply a multi-port repeater. It takes data signals in through one port, and repeats everything out through all the other ports, hoping that one of the computers plugged into it is the destination computer.The disadvantage of this behavior is that it causes unnecessary traffic. By sending out the same signal to every computer, it clogs up the lines keeping them busy and preventing other data from being sent over them.

H323

Two standards have emerged for signaling and control of VoIP telephony: ITU-T H.323 and the IETF Session Initiated Protocol (SIP). These protocols, although resulting in the same end-user service (telephony), differ in the approach to providing signaling functions. H.323 is based more on a monolithic bloc derived from H.320 for traditional of the traditional circuit-switched ISDN multimedia, and SIP favors a more lightweight approach based on HTTP. The ITU-T Recommendation H.323 specification defines four different H.323 entities as the functional units of a complete H.323 network that can be packaged together into a co-located product. These include gatekeepers, multipoint control units (MCUs), gateways, and terminals.

I

ICDInternational code designator

ICMPinternet control message protocol

ICPIMA control protocol

ICRInitial cell rate

IDOL Intelligent Data Operating Layer (IDOL), platforma care formeaza o  intelegere conceptuala si contextuala a informatiilor

IDSAn IDS (Intrusion Detection System) is a network security system designed to identify intrusive or malicious behavior via monitoring of network activity. The IDS identifies suspicious patterns that may indicate an attempt to attack, break in to, or otherwise compromise a system. An IDS can be network-based or host-based, passive or reactive, and can rely on either misuse detection or anomaly detection

IDPinternet datagram protocol

IEInformation element

IGMP

Internet Group Management Protocol (IGMP) is used by IP Multicast routers to learn about the existence of host group members on their directly attached subnets (see RFC 2236). The IP Multicast routers get this information by broadcasting IGMP queries and listening for IP hosts reporting their host group memberships. This process is used to set up a client/server relationship between an IP Multicast source that provides data streams and the clients that want receive data.

IGRPInterior Gateway Routing Protocol

IISPinterim interswitch signaling protocol

ILSinterLAN switching ( Connectionless routing)

ILSIPILS routing stack

ILMIinterim(Integrated) local management interface

IMAinverse multiplexing for ATM

IMUXInverse multiplexing for frame-cell trunks

InARPinverse ARP

IPinternet protocol *Transmission control protocol/Internet protocol (TCP/IP) is a group of protocols that defines a common set of rules and standards that enable networks and hosts to communicate. IP isthe routed or network layer protocol of TCP/IP and is one of the most popular internetworking protocols.

IP addressing A system for assigning numbers to network subdivisions, domains, and nodes in TCP/IP

networks

IPIFRIP interface over frame relay

IPIVCIP interface over virtual circuit

IPNG IP Next Generation. A term used to describe the efforts of the Internet Engineering Task force to cope with the explosive growth of the Internet by defining the next generation of Internet Protocol

IPOAInternet Protocol over ATM

IPsec

Internet Protocol Security is a framework for a set of protocols for security at the network or packet processing layer of network communication. Earlier security approaches have inserted security at the application layer of the communications model. IPsec is said to be especially useful for implementing virtual private networks and for remote user access through dial-up connection to private networks. A big advantage of IPsec is that security arrangements can be handled without requiring changes to individual user computers.

IPX

internetwork packet exchange * A Novell LAN protocol that creates maintains and terminates connections between network devices* The Passport 6400 internetwork packet exchange (IPX) service is a connectionless network layer protocol that delivers datagram packets on a best-effort basis. IPX uses the information in the routing information protocol packets to determine current information about the network topology. The service advertisement protocol (SAP) allows printers, file servers, and gateways to announce their availability to nodes on the network. IPX also allows direction or control of services provided on the network by filtering the packets.

ISAC ISDN Subscriber Access Controller (ISAC)

ISCsInternational switching centers

ISDLCIntegrated Services Digital Line Card

ISDN

ISDN (Integrated Services Digital Network) is a set of CCITT/ITU standards for digital transmission over ordinary telephone copper wire as well as over other media. Home and business users who install an ISDN ADAPTER (in place of a telephone modem) receive Web pages at up to 128 Kbps compared with the maximum 56 Kbps rate of a modem connection. ISDN requires adapters at both ends of the transmission so your access provider also needs an ISDN adapter

ISPInternet service provider

ISVNInteroperability Software Version Numbers

IVDintegrated voice and data

IVR

Interactive Voice Response (IVR) is a software application that accepts a combination of voice telephone input and touch-tone keypad selection and provides appropriate responses in the form of voice, fax, callback, e-mail and perhaps other media. IVR is usually part of a larger application that includes database access

J

jabber In local area networks, transmission by a data station beyond the time interval allowed by the protocol.

JIT

just-in-time - compiler in the Java programming language and environment, a just-in-time (JIT) compiler is a program that turns Java bytecode (a program that contains instructions that must be interpreted) into instructions that can be sent directly to the processor

 

.jpeg, .jpg Joint Photographic Experts Group (.jpeg, .jpg)

JTIDS Joint Tactical Information Distribution System

JTRB Joint Telecommunications Resources Board

K

KTSkey telephone system  In a local environment, obstacle such as a mountain range or the edge of a terminals and equipment that provide immediate building. Note: The knife-edge effect is access from all terminals to a variety of telephone explained by Huygens’ principle, which states that a services without attendant assistance.  Note: A well-defined obstruction to an electromagnetic wave KTS may interface with the public switched telephone

L

LACP

Link Aggregation (LA) allows you to create and manage a trunk group. You can control and configure a trunk group automatically through the use of the Link Aggregation Control Protocol (LACP). 802.3ad provides an industry standard method for bundling multiple links together to form a single trunk between two networking devices. Trunks that conform to the 802.3ad standard are Link Aggregation Groups (LAGs). BoSS 3.1 supports 2 types of trunks•Dynamic LAG•MLTA trunk group that is formed by Link Aggregation is called a Link Aggregation group (LAG), and a trunk group that is formed by BayStack Multilink Trunking is called a Multilink trunk (MLT) group.

LAPD Link Access Protocol Dlink layer protocol specified by CCITT ( used by FR)

LAN local area network

LANE LAN emulation over ATM Parti din reteaua ATM se comporta ca o retea LAN Virtuala (devices ATM interactioneaza transparent cu devices LAN)

LCLogical channel ; A logical channel (LCh) is the instance of a path on a trunk.LCh components existsonly on the receiving side of a trunk

LCD loss of cell delineation

LCN logical channel number

LCM local cache manager

LCo logical connection

LDAP

Lightweight Directory Access Protocol, is an Internet protocol that email and other programs use to look up information from a server. Ex .Search for all people located in Chicago whose name contains "Fred" that have an email address. Please return their full name, email, title, and description."

LD-CELP Low delay- code excited linear prediction diff CS-ACELP 5bytes-16kb/sec

LDM Legacy data module

LDS link delay synchronization

LEC LAN emulation client

leased dedicated

LES LAN emulation server

LG link group

LGT Link group table

LIS logical IP subnet

LLB Local Analog Loopback -modem

LLc Logical link control

LMI Link management interface

LMID logical module identifier

LN Logical network

LNNI LAN emulation network-to-network interface specification

LNN logical network number

LOC Location code

LODS loss of delay synchronization

LP Logical Processor

LPD late packet discartd

LPT Logical Processor type

LRC Longitudinal redundancy check

LSA link state advertisement

LSAP Multiple link service access points

LSB Least significant bit

LTP Light-weight trunk protocol

MMAC media access control

MAG Magellan access switch

MAS Master

MBG Minimum bandwidith guarantee

M-bit Bit 1 of 5th, 6th,7th Msubframes in a DS3 signal

MBS maximum burst size

MCDN Network Signaling Protocol -Meridian 1 ISDN primary rate interface protocol * Meridian 1 customer defined network

MCR minimum cell rate

MCS Multiservice cut-through switching

MD Management device

MDA

Media Dependent Adapters. An independent module, generally featuring an input and/or output port that interfaces to some style of media connector. <!--[if ppt]--> –<!--[endif]-->

MDM Preside Multiservice Data Manager

MDP Management Data Provider

MIB management information bases

MID module identifier - second module level in the DPRS addressing hierarchy

MLTMultiLink Trunk (MLT) is a point-to-point connection that aggregates multiple ports so that they logically act as a single port with the aggregated bandwidth. Grouping multiple ports into a logical link allows you to achieve higher aggregate throughput on a switch-to-switch or switch-to-server application. MultiLink Trunking provides media and module redundancy.

MP3 Motion Picture Experts Group, Audio Layer 3“ sau MPEG Layer III

MPANL Multiservice Passport Access Network Link

MPE multiprotocol encapsulation

MPE -ATM multiprotocol encapsulation service

MPEG4

MPEG-4 is an ISO/IEC standard developed by MPEG (Moving Picture Experts Group), the committee that also developed the Emmy Award winning standards known as MPEG-1 and MPEG-2. These standards made interactive video on CD-ROM and Digital Television possible.

MPID module process identifier- third and lowest level in the DPRS so RID (Routing), MID(module), MPID (module process) addressing hierarchy

MPLS

Multiprotocol Label Switching is a standards-approved technology for speeding up network traffic flow and making it easier to manage. MPLS involves setting up a specific path for a given sequence of packets, identified by a label put in each packet, thus saving the time needed for a router to look up the address to the next node to forward the packet to. MPLS is called multiprotocol because it works with the Internet Protocol , Asynchronous Transport Mode (ATM), and frame relay network protocols

MPOA Multiprotocol over atm

MPS Multiple Priority System

MTU maximum transmission unit

music on hold

in a state of interruption during a telephone call when one party switches to another line without totally disconnecting the other party

MVP Multi purpose voice platform - processor

MVP-E MVP enhanced (echo cancellation)

MVR multiple virtual router

M13 A DS3 framing format or the multiplex between DS1 and DS3 levels

NNBMA non broadcast multi acces

NCS Network Clock Synchronization

Nep nailed up end point

NFAS non-facility associated signaling or multiple links per D-channel (nB+D)

NHRP next hop resolution protocol

NHS next hop server

NIS Network interface specification

NMIS Network management interfaces

NMM network management MIB ( MIB= management information bases)

NMS Network Management System

NN Network node

NNINetwork network (or node) interface * The Passport 6400 frame relay network-to-network interface (NNI) service provides a communication interface between two frame relay networks. This service receives, processes, and transmits the network status signaling information through the network. The end user receives accurate information about the network

NPVC Nailed up permanent virtual connection ( opus SVPC)

NRP nailed-up relay point

nrtVBR non-real-time VBR

NS NetworkSynchronization

NSAP Network service access point

NTP Network time protocol

NUI Network User Identification

OOAM Operational administration maintenance 

OC Optical Carrier, specifies the speed of fiber optic networks conforming to the SONET standard OC-3 = 155.52 Mbps

OEM

Original Equipment Manufacturer, which is a misleading term for a company that has a special relationship with computer producers. OEMs buy computers in bulk and customize them for a particular application. They then sell the customized computer under their own name. The term is really a misnomer because OEMs are not the original manufacturers -- they are the customizers.

OM-P Open management system for Passport

OSI Open system interconnection

OSPF open shortest path first

PP bit priority bit

PA (trunk) Path administrator

PABX

A PBX (private branch exchange) is a telephone system within an enterprise that switches calls between enterprise users on local lines while allowing all users to share a certain number of external phone lines. The main purpose of a PBX is to save the cost of requiring a line for each user to the telephone company's central office. The PBX is owned and operated by the enterprise rather than the telephone company (which may be a supplier or service provider, however)

PANL Passport access network link

payload The information bits of a frame or cell, are not part in overhead

PBRSde ex 2^15-1 A 215- 1 pseudorandom bit sequence PRBS n=15

PCM Pulse code modulation

PCMCIA Personal Computer Memory Card International Association

PCRpeack cell rate * The unit of measurement for PCR is cells per second (cells/s) but the Passport trunk and topology systems work in bandwidth units of bits per second (bps). The AtmAccess component converts the PCR value to a bandwidth value measured in bits/s using the conversion formula of 1 cell/s = 384 bit/s.The ACR is the minimum of the PCR, CCR, and

actual shaping rate (ASR).     * Passport Carrier release

PDC processor daughter card * Processor data card

PDH Plesiochronous digital hierarchy

PDU protocol data unit

PHY Physical Layer Entity

PID process identifier

PLC permanent logical connection

PLCP Physical Layer Convergence Protocol

PNCS passport network clock synchronization

PNNI private network network(node) interface

POMS Port management system

PORSpath-oriented routing system * (Connection-oriented routing  voice transport &voice networking) PORS is the routing system used by the voice networking service.PORS=VOICE+BTDS+HTDS

PORSvc Path-Oriented Routing System virtual circuit

Port Mirroring

method of monitoring network traffic that forwards a copy of each incoming and outgoing packet from one port of a network switch to another port where the packet can be studied. A network administrator uses port mirroring as a diagnostic tool or debbuging feature, especially when fending off an attack. Port mirroring can be managed locally or remotely.

PNCS Passport Network Clock Synchronization

PNNI Private network network (or node) interface

PPD partial packet discard

PPP

Point to point protocol service is a data link layer protocol service that provides packet transfer between two dedicated WAN peers. Packet transfers are full duplex and sequential.A protocol for  creating a TCP/IP connection over both synchronous and asynchronous systems.  PPP provides connections for host to network or between two routers, It also has a security mechanism. PPP is well known as a protocol for connections over regular telephone lines using  modems on both ends. This protocol is widely used for connecting personal computers to the internet.

PQC Passport queue controller

PRBS Pseudorandom bit sequence, a test pattern for live random traffic

PRI primary rate interface

PROTOCOL

The special set of rules that end points in a telecommunication connection use when they communicate. Protocols exist at several levels in a telecommunication connection. For example, there are protocols for the data interchange at the hardware device level and protocols for data interchange at the application program level. In the standard model known as Open Systems Interconnection OSI there are one or more protocols at each layer in the telecommunication exchange that both ends of the exchange must recognize and observe. Protocols are often described in an industry or international standard

PSTN public switched telephone network

PTI payload type indicator

PTS Passport trace system

PVID Port VLAN Identifier

PVC Permanent virtual connecton

PVG Packet Voice Gateway

QQDU quantization distortion unit

QoS

quality of service defined by: PCR peack cell rate &  SCR sustained cell rateCDV & CDVT cell delay variation & cell delay variation toleranceCTD cell transfer ratio &CLR cell loss ratio

QRSSA quasi random signal source 2 ^20  pattern cu 14 octeti sigur 0 din 20

QSIG Q interface signaling PROTOCOL;

RRADIUS Remote Authentication Dial In User Services

RAI Remote Alarm Indication - Yellow

RARP reverse address resolution protocol

RCOS routing class of service

RDI remote defect indication  FERF Far End Receive Failure -Prima denumire (in documentatia mai veche ) pentru  RDI

RFC Request for Comment

Rg Remote Group

RID routing identifier - first level in the DPRS addressing hierarchy. In the DPRS, RID (Routing id), MID(module id.), MPID (module process id. ) addressing hierarchy

RIP routing information protocol

RISC reduced instruction set computer

RLB Remote Digital Loopback -modem

RM resource module

RMON Remote Monitoring

ROIReturn of Invesment - how much profit or cost saving is realized. An ROI calculation is sometimes used along with other approaches to develop a business case for a given proposal.

ROUTER

The router, like the switch, is a smart hub. However, while the switch only concerns itself with MAC addresses, the router only concerns itself with IP addresses. And it doesn’t concern itself with the individual IP address, but only the form of the IP address.If a computer within one network tried to communicate with another computer in its own network, the router would notice that the form of the destination IP address is the same as that of the network from which the message originated. So the router would not allow this packet to pass through it to the other network. It would make sure that information remained isolated within that network only. But if a computer in one network wanted to communicate with a computer in the other network, the router would allow the package to be sent into the other network. This way it allows two networks to communicate with each other, while at the same time limiting traffic to a bare minimum.

Rp relay point

RPI routing protocol interface

RS Rout selector

RSA Remote server agent

RSI Remote server interface

RSR requested shaping rate

RSVP Resource ReSerVation Protocol

RTD round trip delay

RTS Request To Send

rtVBR real-time VBR * Real time variable bit rate

SS source

SAD speech activity detection * fast <200 msec ; slow>10 sec

SAP service advertisement protocol

SAR segmentation and reassembly

SBIC shared bus interface controller

SCCS Symposium Call Center Server

SCN state change notification ( data to update the network model )

SCR source call router

SCR sustained cell rate

SDD Passport service data description

SDH Synchronous Digital Hierarchy - European Standard

SDLC Synchronous Data Link Control

SDS software distribution site

Server Farm

A group of servers usually located in a secure area, and sometimes collocated at an ISP. These servers all serve a single purpose (such as serving Web pages, for example) and have some sort of load balanced across them. If one server in the farm dies, business carries on as usual. If performance is slow, you add more servers. This term is popular when dealing with Web-based applications, where a group of web servers all serve up the same content or pull data from a database server or group of database servers.

SFPsmall form factor The Passport 1600 Routing Switch series is a fixed port Layer 3 solution set. It is available in three models: the Passport 1648T with 48 ports of 10/100 plus 4 connections for small form factor (SFP) - Small Form factor Pluggable

SFQ shaped fair queuing

SHDSL Symetric High bit-rate Digital Subscriber Line

Sig signalling

SIP

The Session Initiation Protocol (SIP) is an Internet Engineering Task Force (IETF) standard protocol for initiating an interactive user session that involves multimedia elements such as video, voice, chat, gaming, and virtual reality.Like HTTP or SMTP, SIP works in the Application layer of the Open Systems Interconnection  communications model. The Application layer is the level responsible for ensuring that communication is possible. SIP can establish multimedia sessions or Internet telephony calls, and modify, or terminate them. The protocol can also invite participants to unicast or multicast sessions that do not necessarily involve the initiator.Two standards have emerged for signaling and control of VoIP telephony: ITU-T H.323 and the IETF Session Initiated Protocol (SIP). These protocols, although resulting in the same end-user service (telephony), differ in the approach to providing signaling functions. H.323 is based more on a monolithic bloc derived from H.320 for traditional of the traditional circuit-switched ISDN multimedia, and SIP favors a more lightweight approach based on HTTP.

SLC switched logical connection

SMLT Split Multi-Link Trunking

SNA systems network architecture

SNMPsimple network management protocol SNMP is the standard for network management that uses a common software agent to manage local and wide area network equipment from different vendors; part of the Transmission Control Protocol/Internet Protocol (TCP/IP) suite and defined in RFC1157. SNMPv1 is version one, or the original standard protocol. SNMPv3 is a combination of proposal updates to SNMP, most of which deal with security.

SONET Synchronous optical network -North American Standard

SP Setup priority

SPF shortest path first

Spanning Tree

Where two bridges are used to interconnect the same two computer network segments, spanning tree is a protocol that allows the bridges to exchange information so that only one of them will handle a given message that is being sent between two computers within the network. The spanning tree protocol prevents the condition known as a bridge loop.

SPO short path oriented

SPVC Soft permanent virtual circuit

SRB source route bridging is a process of relaying MAC packets along a route specified by the source end system.

SQL Structured Query Language (SQL), a programming structure that is used to process and retrieve queried information from a database.

Src Source PVC

Sres source route end station

SRT source route transparent bridging

SRTS Synchronous residual time stamp

SSH

SSH is a protocol that uses public key cryptography to transfer data securely over insecure networks. At the core of most SSH implementations are the "ssh" and "scp" commands."ssh" and "scp" are "secure" versions of the UNIX "rsh" and "rcp" commands, (which in turn are a bit like the more familiar "telnet" and "ftp" programs). The "ssh" command provides command-line, (non-GUI), access to a remote server. "scp" allows files to be copied to/from a remote server. Both programs use the SSH protocol to establish a secure connection and to encrypt all data passing between the client and the server.

SSL

The Secure Sockets Layer (SSL) is a commonly-used protocol for managing the security of a message transmission on the Internet. SSL has recently been succeeded by Transport Layer Security (TLS), which is based on SSL. SSL uses a program layer located between the Internet's Hypertext Transfer Protocol (HTTP) and Transport Control Protocol (TCP) layers. SSL is included as part of both the Microsoft and Netscape browsers and most Web server products. Developed by Netscape, SSL also gained the support of Microsoft and other Internet client/server developers as well and became the de facto standard until evolving into Transport Layer Security.

STG ID for spanning tree group

STM Synchronous Transfer Mode (mod de transport sincron European) operates with same rate as STS 3 (155.52 Mbs)

STM1 Synchronous Transport Mode; SDH standard for OC33 optical fiber at 155.52 Mbs

STP shield twisted pair- cable

STS nivelul de transport sincron -standard Nord American; compatibil SDH

SVC Switched virtual connection

SVC switched virtual circuit (Used in Voice networking)

SVPC Soft permanent virtual circuit (or connection)

SVS switched voice service

SWITCH

A switch is as a smart hub. It’s a hub that understands MAC addresses (but not IP addresses). A switch automatically learns the MAC addresses of all the computers plugged into it by communicating with them. It stores these in a little table. When it receives the packet from computer A, it reads the MAC address of the destination computer off the packet. And it proceeds to send that packet out through that port, and no other. So the packet goes only to computer C and not to computer B and D. This way the only cables being used are the ones that need to be, and the rest of the network is free to transfer other data.

TTAPI Telephony Applications Programming Interface

TCO Total Cost of Ownership

TCP transmission control protocol.

TCP-IP

Transmission control protocol/Internet protocol (TCP/IP) is a group of protocols that defines a common set of rules and standards that enable networks and hosts to communicate. IP is the routed or network layer protocol of TCP/IP and is one of the most popular internetworking protocols.TCP is responsible for breaking data down into IP packets before they are sent, and for assembling the packets when they arrive. IP is responsible for the sending and receiving data packets over the Internet.

TD-IE traffic descriptor information element

TDM Time-division-multiplexed network

TDMA TDMA (time division multiple access) is a technology used in digital cellular telephone communication that divides each cellular channel into three time slots in order to increase the amount of data that can be carried.

TDS Transparent data service

TIE (Ear & Mouth) terminal interface equipment

TIMS Transmission Impairment Measurement Set for testing &power spectrum measurement

TODA time-of-day accounting

TOP topology manager

TPT tandem pass through-tandem node detection for routing compressed voice calls through an intermediate PBX by way of tandemPassport nodes. Only MVP/MVP-E FPs support tandem pass through (TPT).

TRM transport resource manager

TRS Target shaping rate

ts time slot

UUBR unspecified bit rate

UDP user datagram protocol   "Packet" and "datagram" are similar in meaning. A protocol similar to

TCP, the User Datagram Protocol (UDP) uses the term datagram. Also port for the RADIUS server.

UMTS Universal Mobile Telecommunication Service

UNACK Unacknowledged trunks

ULP upper layer protocols

UNI user network interface

UPC usage parameter control - the set of actions taken by the network to monitor and control traffic

UPS Uninterruptible Power Supply

USB Universal Serial Bus

UTC Universal Coordinated Time

UTP - universal trunk protocol- unshilded twisted pair for cable

URL Uniform Resource Locator is a pointer to a specific bit of information on the Internet.

VVBR variable bit rate

VBRrt variable bit rate real time

VBRnrt variable bit rate non real time

VC virtual circuit * Virtual channel * virtual connection . Identifica un tip de trafic, mai multe VC identifica un VP

VCC virtual channel connection-circuit * VCC is an association established between two ATM layer users that communicate through a virtual channel

Vcd virtual channel descriptor

VCI virtual channel identifier

VF voice frequency

VFF very fast forwarder

VFP Voice function processor

VLAN

Virtual LAN. Shared VLAN (SVL) and individual VLAN (IVL) learning is supported. SVL is the same as the VLAN implementation on the BayStack 450 Switch, in which all VLANs in the switch share the same forwarding database. IVL is a new feature on the Business Policy Switch and lets individual VLANs have separate forwarding databases within the switch. IVL allows the switch to handle duplicate MAC addresses if they are in different VLANs

VLSM Variable Length Subnet Masks

VNCVNC stands for Virtual Network Computing. It is, in essence, a remote display system which allows you to view a computing 'desktop' environment not only on the machine where it is running, but from anywhere on the Internet and from a wide variety of machine architectures

VNCS Voice networking call server

VNS

virtual networking system(Connectionless routing). A connectionless routing system used by Passport to transport data traffic for connectionless services The virtual networking system (VNS) routes connectionless packets across a Passport logical network. This is done by encapsulating the packets in a Passport VNS header as it enters the network and using the data in the header to route the packet across the Passport network. This allows encapsulated WAN traffic to consolidate with other Passport traffic (such as DPN and PORS traffic) on common trunks.

VoFR Voice over frame relay

VoIP

VoIP (voice over IP - that is, voice delivered using the Internet Protocol) is a term used in IP telephony for a set of facilities for managing the delivery of voice information using the Internet Protocol (IP). In general, this means sending voice information in digital form in discrete packets rather than in the traditional circuit-committed protocols of the public switched telephone network (PSTN). A major advantage of VoIP and Internet telephony is that it avoids the tolls charged by ordinary telephone service. In addition to IP, VoIP uses the real-time protocol (RTP) to help ensure that packets get delivered in a timely way. Using public networks, it is currently difficult to guarantee Quality of Service (QoS). Better service is possible with private networks managed by an enterprise or by an Internet telephony service provider (ITSP).

VP Voice profile sau Virtual Path (mai multe Virtual Channels identifica un VP)

VPC virtual path connection A VPC is an association established between two ATM layer users that communicate through a virtual PATH

Vpd virtual path descriptor

VPI virtual path indentifier/intranet

VPI ID virtual private intranet identifier

VPN Virtual Private Networks

VR virtual router

VPS Voice Processing Series 

VPT Virtual path terminators- consolidates multiple VCCs into a singleVPC for ease of handling through the network backbone.

VRoute Voice route

VRRP virtual router redundancy protocol

VS Voice service

VSR (Vsr) Voice subroute

VSS Passport 15000-Variable Speed Switch

VTDS voice transparent data service

VTDS voice transparent data service

WWAN wide area network

WAP Wireless Application Protocol

WFQ Weighted fair queuing

WRED Weighted random early detection

XXDLC eXtended Digital Line Card

xDSL

xDSL x-type digital subscriber line; refers to different services  of DSL, such as ADSL, HDSL, and RADSL x2/DSL is a modem from 3Com that supports 56 Kbps modem communication but is upgradeable through new software installation to ADSL when it becomes available in the user's area. 3Com calls it "the last modem you will ever need."

Y

YIA Yes- I -am If the local end does not receive a Yes I Am (YIA) packet , then the Passport trunk disables. If the local end receives a YIA packet, then the local end validates the remote node identification and continues to provide service.

Yellow alarm

DS1 also called a remote alarm or RAI , indicates a near-to-far transmission failure

Z0TLP zero transmission level point ;zero dBm transmission level point.

Z Time Zulu Time(Coordinated Universal Time) Time scale based on the second (SI) Synonyms World Time, Z Time, Zulu

#

802.3

802.3 - (Ethernet) - este o retea magistrala care poate transmite date la 10Mbps. Datele sunt transmise prin fir fiecarui calculator, insa numai cele indreptatite sa le receptioneze confirma primirea. Protocolul CSMA/CD regularizeaza traficul prin retea, permitand transmisia doar atunci cand cablul este liber si nici un alt calculator nu transmite. 

802.4

 

802.4 - (Transferul jetonului) - este o retea inel care se bazeaza pe o schema de transfer al jetonului. Fiecare calculator receptioneaza toate datele, insa raspunde numai cel a carui adresa este mentionata explicit. Jetonul care, circula pe cablu determina calculatorul care poate emite.

802.5

802.5 - (Token Ring) - este o retea inel care poate transmite date la 4 sau la 16Mbps, Chiar daca in denumire apare cuvantul inel, aceasta topologie are; forma de stea, fiecare calculator fiind conectat la un concentrator (hub) central. Inelul (inchiderea buclei) se realizeaza in cadrul concentratorului. Jetonul care circula in inel determina calculatorul care poate transmite date.