PON Glossary
The following is a listing of words that are fairly specific to PON and referenced throughout this site and throughout the PON industry. If you feel that there is word missing or definition that need adjustment, feel free to contact us.
Term Definition
Access Network The method, time, circuit, or facility used to enter the network. The service provided by local exchange carriers or alternate access providers, which connect an interexchange carrier with its customers. The Access Network today is predominantly passive twisted pair copper wiring.
Add/Drop Multiplexer Add/Drop Multiplexer capable of extracting or inserting lower-bit-rate signal from a higher-bit-rate multiplexed signal without completely demultiplexing the signal.
APON An Asynchronous Transfer Mode (ATM) based Passive Optical Network (PON).
Asymmetric Digital Subscriber Line Asymmetric Digital Subscriber Line transmits data asymmetrically meaning the bandwidth usage is much higher in one direction than the other. Typical ADSL applications transmit 8 Mbps downstream and 768Kbps upstream, depending on the length of the local twisted pair loop. This is particularly beneficial for residential Internet access, remote access and video on demand because downstream usage far exceeds upstream usage.
Asynchronous Transfer Mode Asynchronous Transfer Mode is a connection-oriented service that segments data into a succession of small units called cells. Data transmitted from multiple sources is segmented into cells by the ATM network device, and the cells are then interleaved onto a single transmission media. It is asynchronous in the sense that the recurrence of cells depends upon the required or instantaneous bit rate. See also TDM and packet switching
Asynchronous Transfer Mode based Passive Optical Network An Asynchronous Transfer Mode (ATM) based Passive Optical Network (PON).
Backbone The part of a network used as the primary path for transporting traffic between network segments. A high-speed line - or series of connections - that forms a major pathway within a network.
Bandwidth The throughput, or ability to move information through or from a device, system or subsys tem, usually measured in quantities of data per second. A measure of the information-carrying capacity of a communications channel; range of usable frequencies that can be carried by a system, corresponding to the difference between the lowest and highest frequency signal that can be carried by the channel.
BLEC Building Local Exchange Carrier
BPON Broadband Passive Optical Network (PON)
CAC Connection Admission Control (CAC) - The set of actions taken by the network during the call setup phase (or during call renegotiation phase) in order to determine whether a connection request can be accepted or should be rejected (or whether a request for re-allocation can be accomplished).
CATV CATV (originally "community antenna television," now often "community access television") is more commonly known as "cable TV." In addition to bringing television programs to those millions of people throughout the world who are connected to a community antenna, cable TV is an increasingly popular way to interact with the World Wide Web and other new forms of multimedia information and entertainment services.
CBR Constant Bit Rate (CBR) - An ATM service category which supports a constant or guaranteed rate to transport services such as video or voice as well as circuit emulation which requires rigorous timing control and performance parameters. QoS Parameter typically used for voice traffic.
Cell A unit of transmission in ATM. A fixed-size frame consisting of a 5-octet header and a 48-octet payload.
Cell Delay Variation CDV is a component of cell transfer delay, induced by buffering and cell scheduling. Peak-to-peak CDV is a QoS delay parameter associated with CBR and VBR services. The peak-to-peak CDV is the ((1-a) quantile of the CTD) minus the fixed CTD that could be experienced by any delivered cell on a connection during the entire connection holding time. The parameter 揳?is the probability of a cell arriving late.
Central Office The Central Office is where communications common carriers terminate customer lines and locate switching equipment that interconnects those lines. Also, cons idered a location where Switching, Transmission and Power equipment that provide telephone service is centralized.
Coaxial Cable A type of cable with a center conductor, an insulator, a solid or braided shield around this insulator with a tough jacket on the outside. The inner insulation provides a constant distance between the center conductor and the shielding, providing a superior quality signal over longer distances, which gives higher bandwidth and better immunity to external interference than simple twisted pair cable provides.
Competitive Local Exchange Carrier In the United States, a CLEC (competitive local exchange carrier) is a company that competes with the already established local telephone business by providing its own network and switching.
Connection Admission Control Connection Admission Control (CAC) - The set of actions taken by the network during the call setup phase (or during call renegotiation phase) in order to determine whether a connection request can be accepted or should be rejected (or whether a request for re-allocation can be accomplished).
Constant Bit Rate Constant Bit Rate (CBR) - An ATM service category which supports a constant or guaranteed rate to transport services such as video or voice as well as circuit emulation which requires rigorous timing control and performance parameters. QoS Parameter typically used for voice traffic.
Core Network The part of a network used as the primary path for transporting traffic between network segments. A high-speed line - or series of connections - that forms a major pathway within a network.
Coupler Fused fiber device that optically splits and multiplexes signals. The couplers used in the PON outside plant network are basically power splitter wherein the power from the OLT is sent into different branches of the network to feed the ONTs based upon their distance from the OLT. Another type of coupler/splitter is used to separate the incoming and outgoing signals into their respective wavelengths at the OLT and ONT. This is a WDM coupler/splitter and is sometimes referred to as an optical multiplexer/deplexer.
CWDM Coarse Wave Division Multiplex
Cyclic Redundancy Check A mathematical algorithm commonly implemented as a cyclic shift register that computes a check field for a block of data. The sender transmits this check field along with the data so that the receiver can either detect errors, and in some cases even correct errors.
Dark Fiber Dark fiber refers to unused fiber-optic cable. Often times companies lay more lines than what's needed in order to curb costs of having to do it again and again. The dark strands can be leased to individuals or other companies who want to establish optical connections among their own locations. In this case, the fiber is neither controlled by nor connected to the phone company. Instead, the company or individual provides the necessary components to make it functional.
Dense Wave Division Multiplexing Dense Wave Division Multiplexing (DWDM) is an optical multiplexing technique used to increase the carrying capacity of a fiber network beyond what can currently be accomplished by time division multiplexing (TDM) techniques. Different wavelengths of light are used to transmit multiple streams of information along a single fiber with minimal interference.
Digital Subscriber Line Digital Subscriber Line (DSL) is a method of providing high-speed data services over the twisted pair copper wires traditionally used to provide POTS. Types of DSL include ADSL (asymmetric digital subscriber line), HDSL (high data rate digital subscriber line), SDSL (single line digital subscriber line), and VDSL (very high data rate digital subscriber line).
Digital Subscriber Line Access Multiplexer Digital Subscriber Line Access Multiplexer (DSLAM) - Provides high-speed Internet or Intranet access over traditional twisted-pair telephone wiring through the use of ADSL technology. Provides simultaneous high speed digital data access and POTS analog service over the same twisted-pair telephone line. Can be installed in the CO or at and ISP adjacent to the CO
DLC Digital Loop Carrier
DS0 Digital Signal level Zero: One 64 Kb channel
DS1 Digital Signal 1: 24 DS0s totalling 1.544 Mbps of bandwidth
DS3 Digital Signal level 3: 28 DS1s encapsulated; 44.736 Mbps data rate.
Dynamic Wave Slicing DWS (Dynamic Wave Slicing? extends WDM (Wave Division Multiplexing) by slicing each wavelength so that it can serve multiple end points (customers). This provides a division of available bandwidth over a PON by enabling a single fiber segment to allocate bandwidth to multiple customers according to their particular needs (from 1.7 to 100 Mbps in 1.7 Mbps increments). This provides effective utilization of the total capacity of the fiber optic media.
EPON Ethernet based Passive Optical Network (PON).
Erbium-Doped Fiber Amplifier Erbium-Doped Fiber Amplifier (EDFA) - A key enabling technology of DWDM, EDFAs allow the simultaneous amplification of multiple signals in the 15xx nanometer region, e.g. multiple 2.5 Gbps channels, in the optical domain. EDFAs drastically increase the spacings required between regenerators, which are costly network elements because they (1) require optical/electrical/optical conversion of a signal and (2) operate on a single digital signal, e.g. a single SONET or SDH optical signal. DWDM systems using EDFAs can increase regenerator spacing of transmissions to 500-800 km at 2.5 Gbps. EDFAs are far less expensive than regenerators and can typically be spaced 80-120 km apart at 2.5 Gbps , depending on the quality of the fiber plant and the design goals of the DWDM system.
Ethernet A LAN used to connect devices within a single building or campus at speeds up to10 Mbps. Within the OSI model, Ethernet is defined at layer one (physical) and layer two (data link). Based on Carrier Sense Multiple Access/Collision Detection(CSMA/CD), Ethernet works by simply checking the wire before sending data. Sometimes two stations send at precisely the same time in which case a collision is detected and retransmission is attempted.
Fiber Optic Cable A fiber optic cable consists of a bundle of glass threads, each of which is capable of transmitting messages modulated onto light waves.Fiber optics has several advantages over traditional metal communications lines: Fiber optic cables have a much greater bandwidth than metal cables. This means that they can carry more data. Fiber optic cables are less susceptible than metal cables to interference. Fiber optic cables are much thinner and lighter than metal wires. Data can be transmitted digitally (the natural form for computer data) rather than analogically
Fibre Channel Fibre Channel is an industry standard technology for transmitting data between computer devices at up to 1.0625 Gbps and over 10 km in distance. Fibre Channelis optimized for connecting servers to shared storage devices and for interconnecting storage controllers and drives. Fibre Channel utilizes either anoptical fiber or copper connection.
FTTB Fiber to the Business
FTTC Fiber to the Curb/Cabinet
FTTH Fiber To The Home
FTTX Fiber to the 'X' where x=(H)ome, (C)urb, (B)usiness or other locale
Full Service Access Network Full Service Access Network (FSAN). is a forum for the worlds leading telecommunications services providers and equipment suppliers to work towards a common goal of trulybroadband access networks. For more information visit http://www.fsanet.net
Gigabit Ethernet Another variation of the Ethernet protocol, is capable of transmitting data at one billion bits per second. This standard may eventually challenge ATM and FrameRelay as the high-speed LAN topology of choice, but, at present, ATM and FrameRelay still offer Quality of Service (QoS) guarantees that Gigabit Ethernet cannot match. Gigabit Ethernet can use high-quality copper wire at distances of less than 25 meters and optical fiber cabling for greater distances.
Gigabit PON An emerging standard from the FSAN defining the carrriers' requirements for PON networks in excess of 1Gbps.
Headend MSO (CATV) telecommunications office
Header Error Control Header Error Control (HEC) - A 1-octet field in the ATM cell header containing a CRC checksum on the cell header fields, HEC is capable of detecting multiple bit errors or correcting single bit errors.
High Bit Rate Digital Subscriber Line High Bit Rate Digital Subscriber Line (HDSL) - Unlike ADSL, High Bit Rate Digital Subscriber Line is a symmetric method of transmitting data at rates up to 1.5 Mbps in both directions. Because of the symmetric properties, the highest transmission rates can only be supported at lengths of 15,000-foot distances of two or more twisted pair lines.
IAD Integrated Access Device
Incumbent Local Exchange Carrier Incumbent Local Exchange Carrier (ILEC) - An ILEC is a telephone company in the U.S. that was providing local service when the Telecommunications Act of 1996 was enacted
IOT Intelligent Optical Terminal
IP A set of rules for how data gets transmitted from one place to another on the Internet. IP is a connectionless protocol, in which data gets broken down into a number of small bundles known as packets, and each packet gets transmitted to the destination separately, possibly along a different route than other packets from the same message.
ISP Internet Service Provider
ITU International Telecommunications Union
Lambda Greek symbol used to signify wavelength.
Last Mile The last mile is the local access network that extends from the Central Office (CO)to the end-user subscriber. Also called the local loop network, it is traditionally copper-based and suffers from the bandwidth limitations of that media.
Leased Line A physical line that a single subscriber leases from a carrier, giving the subscriber exclusive rights to the line's capacity.
Leased Line A physical line that a single subscriber leases from a carrier, giving the subscriber exclusive rights to the line's capacity.
Metro Network A network spanning a geographical area greater than a LAN but less than a WAN(Wide Area Network). IEEE 802.6 specifies the protocols and cabling for a MAN.
MTU/MDU Multiple Tenant Unit/Multiple Dwelling Unit - a building with more than one residence or business.
Multimode Fiber Optical fiber supporting propagation of multiple modes of light. Multimode fibers have a larger core diameter than single mode fibers.
Multiple Systems Operator Multiple Systems Operator (i.e., CATV company)
Multiplex A general concept that refers to combining independent sources of information into a form that can be transmitted over a single communication channel. Multiplexing can occur both in hardware (i.e., electrical signals can be multiplexed) and in software (i.e., protocol software can accept messages sent by multiple application programs and send them over a single network to different destinations).
NGDLC Next Generation Digital Loop Carrier
OAM Operations Administration and Maintenance (OAM) - A group of network management functions that provide network fault indications, performance information and data and diagnosis functions.
OAN Optical Access Networking
OAS Optical Access Switch
OC-# Short for Optical Carrier, used to specify the speed of fiber optic networks conforming to the SONET standard. The table shows the speeds for common OC levels.|OC-1 = 51.85 Mbps|OC-3 = 155.52 Mbps|OC-12 = 622.08 Mbps|OC-24 = 1.244 Gbps|OC-48 = 2.488 Gbps
ODSI Optical Domain Service Interconnect (ODSI) - This is an open, informal initiative comprised of service providers and networking vendors. ODSI represents a coalition ofnetworking professionals with a common interest in selecting, applying and promoting the open interfaces and protocols that will allow higher-layer service networks to effectively interoperate with the intelligent optical network core.http://www.odsi-coalition.com. ||Open Systems Interconnection (OSI) A logical structure for network operations standardized by the International Standards Organization (ISO). The OSI model organizes the communications process into seven different categories and places the categories in a layered sequence based on their relationship to other users. Layers, seven through four, deal with end-to-end communications between the message source and the message destination, while layers three through one deal with network access
OLT Optical Line Terminal (OLT) - This is the PON controller card or unit it is located at the CO and the FSAN spec this is the optical line terminal. The terminal at the subscriber抯 end of the network is theONT or optical network terminal. Several OLTs may be located in a single chassis. The laser at the OLT is frequently a DFB (distributed-feedback laser) transmitting at1550nm and is always on. Signals from the OLT tell the ONTs when to send upstream traffic to it.
ONT Optical Network Terminal (ONT) - The optical network terminal resides at the subscriber抯 end of the PON. It provides the interface between the network and the subscriber抯 equipment. Frequently the laser used at the ONT is a Fabry Perot type and operates at 1310nm and only transmits when given permission by the OLT.
Passive Optical Network A Passive Optical Network (PON) is made up of fiber optic cabling and passive splitters and couplers that distribute an optical signal through a branched "tree" topology to connectors that terminate each fiber segment. Compared to other access technologies, PON eliminates much of the installation, maintenance, andmanagement expenses needed to connect to customer premises. Per the FSAN specifications PON is a point to multipoint system with one OLT at the central office servicing up to 32 ONTs. The system is single fiber with downstream traffic sent inthe 1550 nm wavelength window and upstream traffic being sent in the 1310wavelength window. This is an example of Bi-directional transmission on a single fiber. Sometimes the PON is called B-PON, which indicates it is a Broadband PON. Also it can be an APON, which is an ATM based PON or an EPON, which is an Ethernet based PON.
path A path at a given bit rate is a logical connection between the point at which a standard frame format for the signal is assembled, and the point at which the standard frame format for the signal is disassembled.
Payload The data in an ATM cell or IP packets that subscribers want to access (the message, conversation, file, etc.). The term payload is used to distinguish the subscriber's data from the "overhead," which is data in an ATM cell or IP packet that network equipment tacks on to the payload to help guide its transmission across the network.
PBX Private Branch Exchange
Point of Presence Point of Presence (POP) - A facility used by a network access provider to house physical equipment that enables subscribers to access the network. The term is used to describe the location where a long distance carrier connects to a local service carrier, and also the location where an Internet service provider houses equipment that enables dialupsubscribers to access the Internet.
Public Switched Telephone Network Public Switched Telephone Network (PSTN) - The traditional voice network infrastructure, including both local service and long distance service, that has been in use in various parts of the world for up to a century or so.
Quality of Service Quality of service (QoS) - The concept of applying and ensuring specific, quantifiable performance levels on a shared network. Performance can be assessed based on physical measurements of the network, the methods by which network traffic is prioritized, and on how the network is managed.
Regional Bell Operating Company Regional Bell Operating Company (RBOC) - One of six telephone companies created after AT&T divestiture. Also, the acronym for the local telephone companies created in 1984 as part of the break-up of AT&T.(The six RBOCs are Ameritech, Bell Atlantic, Bell South, NYNEX, Southwestern Belland U.S.West. Some of the six have and/or are merging.)
Router A computer that directs bundles of data being transmitted between nodes on different networks
RT Remote Terminal
Scalable The ability to add power and capability to an existing system without significant expense or overhead.
Simple Network Management Protocol Simple Network Management Protocol (SNMP) - A set of protocols for managing complex networks. SNMP works by sending messages, called protocol data units (PDUs), to different parts of a network. SNMP compliant devices called agents, store data about themselves in Management Information Bases (MIBs) and return this data to the SNMP requesters.
Single Mode Fiber Used to describe optical fiber that allows only one mode of light signal transmission
SONET Synchronous Optical Network (SONET) - Standards for transmitting digital information over optical networks. It defines a physical interface, optical line rates known as Optical Carrier (OC) signals, frame formats and a OAM& (Operations, Administration, Maintenance and Provisioning) protocol. The base rate is known as OC-1 and runs at 51.84 Mbps. Higher rates area multiple of this such that OC-12 is equal to 622 Mbps (12 times 51.84 Mbps)
Synchronous Transport Signal 1 Synchronous Transport Signal 1(STS-1) - electrical SONET signal at 51.84 Mbps.
T1 Refers to a networking standard capable of transmitting data at a rate of 1.54-Mbps.This protocol is commonly employed by very large enterprises such as telecommunications companies, the Internet backbone and connections from Internet service providers to the Internet backbone
T3 A faster implementation of T1. Using coaxial cable, T3 allows for data transmission rates of 45 Mbps and is used for WAN backbones , the Internet backbone and connections from Internet service providers to the Internet backbone.
TDMA Time Division Multiple Access
Time Division Multiplex Time Division Multiplex (TDM) - A method for transmitting multiple calls over a single line; each call is assigned a recurring timeslot on the line, and a small portion of that call gets transmitted over the line each time its assigned timeslot is available.
Twisted Pair Cable A form of wiring in which a pair of wires are wrapped around one another again and again. Twisting two wires reduces their susceptibility to electrical interference.
Unspecified Bit Rate Unspecified Bit Rate (UBR) - a QoS parameter used typically used for data transmission.
Variable Bit Rate Variable Bit Rate (VBR) - An ATM Forum defined service category which supports variable bit rate data traffic with average and peak traffic parameters. A generic term for sources that transmit data intermittently. The ATM Forum divides VBR into real-time and non-real-time service categories in terms of support for constrained Cell Delay Variation (CDV)and Cell Transfer Delay (CTD).
Very high-speed Digital Subscriber Line Very high-speed Digital Subscriber Line (VDSL) - A scheme to boost transmission speeds to as much as 52 Mbps for very short distances (up to 1000 ft.) on copper wire, or longer distances in fiber-optic networks.
Virtual Private Network Virtual Private Network (VPN) - A network service that employs encryption and tunneling to provide a subscriber with a secure private network that runs over public network infrastructure.Wavelength. A measure of the color of the light for which the performance of the fiber has been optimized. It is a length stated in nanometers (nm) or in micrometers (um).
Wavelength Division Multiplexing Wavelength Division Multiplexing(WDM) - A type of multiplexing developed for use on optical fiber. WDM modulates each of several data streams onto a different part of the light spectrum.
发表于 2003-4-12 13:36:00
(Operations, Administration, Maintenance and Provisioning) protocol. The base rate is known as OC-1 and runs at 51.84 Mbps. Higher rates area multiple of this such that OC-12 is equal to 622 Mbps (12 times 51.84 Mbps)