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Telecom Acronym Guide

Fourth Edition Telecom Acronym Guide Fourth Edition

Numerics ACAC Actual Call Admission Control 2F Two-fiber ACEG Alternating Current Equipment Ground 10 GbE 10 Gigabit Ethernet ACK Acknowledge 10 GFC 10 Gigabit Fibre Channel (Same as FC1200) ACL Active Control List; Access Control List 100G 100 Gigabits ACO Alarm Cutoff 16-QAM 16 (points) Quadrature Amplitude Modulation ACQ Acquire 3D Three-dimensional ACR Allowed Cell Rate 3G Third Generation ACS Automatic Channel Shutdown; Alarm Correlation and Suppression 3GPP Third Generation Partnership Project ACSE Association Control Service Element 40G 40 Gigabits ACSS Automatic Channel Shutdown Suppression; 4C Consortium of Intel, IBM, Matsushita, and Toshiba Automatic Channel Shutdown State 4F Four-fiber ACT Active 4G Fourth Generation ADC Analog-to-Digital Converter; Add/Drop Coupler 5C Consortium of Intel, Sony, Matsushita, Toshiba, ADI Asset Distribution Interface and Hitachi ADM Add/Drop Multiplexer 5G Fifth Generation ADP Actual Departure Potential; Automatic A Data Processing ADSL Asymmetric A/D Analog-to-digital ADT Actual Departure Time; Automatic AAL ATM Adaptation Layer Data Transmission AAL0 ATM Adaptation Layer Type 0 AE Automation Engine; Automation Environment A AL1 ATM Adaptation Layer Type 1 AES Advanced Encryption Standard; AAL2 ATM Adaptation Layer 2 Transport Application Environment Specific AAL3/4 ATM Adaptation Layer Types 3 and 4 AESA ATM End System Address; ATM End Station AAL5 ATM Adaptation Layer 5 Address ABR Available Bit Rate AF Application Function ABT Advanced BiCMOS Technology AFI Authority and Format Identifier AC Alternating Current; Administrative Complex; AFM APS Mode Mismatch Failure Atomic Clock AGC Automatic Gain Control; Access Group Controller AC-3 Audio Coding Revision 3

2 AGGR Aggregate ASE Amplified Spontaneous Emission; AID Access Identifier; Application Identifier Application Service Element AIM Auto Image Management; Active Inventory Map ASI Asynchronous Serial Interface; Asynchronous SCSI Interface AIN Advanced Intelligent Network ASIC Application-Specific Integrated Circuit AINI ATM Inter-Network Interface ASN.1 Abstract Syntax Notation One AINS Automatic in Service State ASP Applications Service Provider; AIR Additive Increase Rate Average Selling Price AIS Alarm Indication Signal ASYNC Asynchronous AISDP Alarm Indication Signal Decay Period AT Advanced Technology AISIP Alarm Indication Signal Integration Period AT&T American and Telegraph Company AIS-L Alarm Indication Signal - Line ATA Advanced Technology Attachment AIS-P Alarm Indication Signal - Path AIS-S Alarm Indication Signal - Section ATAF ATM Test Access Function AIS-V VT Alarm Indication Signal ATAG Autonomous Tag ALS Automatic Laser Shutdown; Application ATAGSEQ Autonomous Tag Sequence Layer Service ATC Alarm Traffic Controller AM Amplitude Modulation; Application Manager ATDMA Asynchronous Time Division Multiple Access AMF APS Mode Mismatch Failure A-TDMA Advanced Time Division Multiple Access AMI Access Method Interface; Alternate Mark ATM Asynchronous Transfer Mode Inversion ATM SAM ATM Service Access Multiplexer AMP ; Amperes ATMVCL ATM Virtual Channel Link AMS Asset Management System; Agent Management ATMVPL ATM Virtual Path Link System ATTN Attenuator AN Access Network AU/AU-x Administrative Unit ANSI American National Standards Institute AUG Administrative Unit Group AO Autonomous Output AUI Autonomous Unit Interface AOD Advertising on Demand AU-n Administrative Unit n APC Angled Physical Contact AUSF Authentication Server Function APD Avalanche PhotoDiode AUX Auxiliary API Application Program Interface AVC Attribute Value Change APS Automatic Protection Switching AVOD Advertising VOD APSBF Automatic Protection Switching Byte Failure AWG American Wire Gauge APSCM Automatic Protection Switching AWGN Additive White Gaussian Noise Channel Mismatch APSMM Automatic Protection Switching Mode Mismatch B AR Augmented Reality B/P Backplane ARC Alarm Reporting Control B3ZS Bipolar With 3-Zero Substitution ARP Address Resolution Protocol B6ZS Bipolar With 6-Zero Substitution ARPU Average Revenue per Unit (or User) B8ZS Bipolar With 8-Zero Substitution AS Autonomous System BA Booster Amplifier ASAP Alarm Severity Assignment Profile BB Broadband ASCII American Standard Code for BBE Background Block Error Information Interchange BBER Background Block Error Ratio ASD Access Security Device

3 BBE-RS Background Block Error Regenerator Section BPMN Business Process Modeling Notation (an SDH regenerator section error) B-PON Broadband BBU Base Band Unit BPP Backplane Protocol BC Business Continuity; Broadcast bps bits per second BCD Binary-Coded Decimal BPSR Bidirectional Path Switched Ring BCST Broadcast BPT Band Pass-Through B-DCS Broadband Digital Cross-connect System BPV BiPolar Violations BDFB Battery Distribution Fuse Bay; Battery Distribution B-RAS Broadband Remote Access Server Fuse Board BRI Basic Rate Interface BDR Broadband Digital Return BRM Backward RM BE Block Error; Best Effort BSC Board SC Connector BECN Backward Explicit Congestion Notification BSP Board Support Package BELLCORE BELL Communications Research, Inc. BSS Business Support System BER Bit Error Rate BT British Telecom; Burst Tolerance BE-RS Block Errors-Regenerative Section Btag Beginning Tag BER-SD-P Path Signal Degrade BER BTM Bits Termination Circuit Pack BER-SF-P Path Signal Failure BER BTO Build Transfer Operate BERT Bit Error Rate Test BTS Business Telecom Services BFP Back Facet Power; Basic Format Packet BTU/hr British Thermal Unit per hour BGP Border Gateway Protocol BW Bandwidth BGP4 Border Gateway Protocol, version 4 BWDM Band Wavelength Division Multiplexer BICI Broadband Inter-Carrier Interfaces; BYT Total Byte Count B-ISDN Inter-carrier Interface BICSI Building Industry Consulting Services International C BIOS Basic Input/Output System C Celsius; Critical BIP Bit Interleaved Parity; Breaker Interface Panel C/I Carrier-to-Interface Ratio B-ISDN Broadband ISDN C/N Carrier-to-Noise Ratio BIT Built-In Test; Binary Digit C2O Cable to Optic BITS Building Integrated Timing System CA Content Archived; Carrier Access bits/sym Bits per Symbol CAA Centralized Access Architecture BLSR Bidirectional Line Switched Ring CAB Conformity Assessment Body BML Business Management Layer CAC Connection Admission Control; BNC Bayonet Neill-Concelman British National Call Admission Control Connector CAD Aided Design BOC Bell Operating Company CALA Central America and Latin America BOD Bandwidth on Demand CAM Content Addressable Memory BOL Beginning of Life CANARIE Canadian Network for Advancement of Research BOM Bill of Materials CAP Competitive Access Provider BONDING Bandwidth On Demand Interoperability Group CAPEX Capital Expenditure BOOTP Bootstrap Protocol CAS Channel Associated Signaling BP Backplane CATV Community Antenna ; BPI Baseline Privacy Interface CB, C/B Circuit Breaker BPI+ Baseline Privacy Interface Plus C-Band Conventional Band BPM Business Process Modeling

4 CBDS Connectionless Broadband Data Service CID Circuit Identification; Craft Interface Device CBN Common Bonding Network CIF Client Interface CBR Constant Bit Rate CIFS Common File System CC Cross Connection; Clear Channel; Calling Centers CIM Client Interface Module CCAF Call Control Agent Function, IN block CIN Converged Interconnect Network CCAP Converged Cable Access Platform CINOT Ciena Optical Transport System CCB Configuration Control Board CIT Craft Interface Terminal; Craft Interface Tool CCC Cross Connect Controller CL Coupling Loss; Cleared CCC768 Cross Connect Fabric with 768x768 STS-1 capacity CLASS Custom Local Area Signalling Services CCCG Cross Connection and Control Group CLEC Competitive CCC-PC CCC Processor Card CLEI Common Language Equipment Identifier CCDF Complementary Cumulative Distribution Function CLFI Common Language Facility Identifier CCI Content Control Information CLI Command Line Interface CCITT Consultative Committee on International CLIP Calling Line Identification Presentation Telegraphy and CLIR Calling Line Identification Restriction CCK Complimentary Code Keying CLLI Common Language Location Identifier CCW Counterclockwise CLNP Connectionless Network Layer Protocol CDE Common Desktop Environment (UNIX) CLNS Connectionless Network Service CDMA Code Division Multiple Access CLP Cell Loss Priority CDN Content Delivery Network CLR Cell Loss Ratio CDP Contracted Deadline Potential CLTP Connectionless Transport Protocol CDR Call Detail Recording; Clock and Data Recovery cm centimeter CD-ROM Compact Disc Read Only Memory CM Control Module; Cable CDT Connection Dropping Threshold CMAP Converged Multiservice Access Platform CDTS Chromatic Dispersion Test Set CMC Coaxial Media Converter CDV Cell Delay Variation CM-CLI Control Module Command Line Interface CDVT Cell Delay Variation Tolerance CME Compressed Multiplication Equipment CD-WO Compact Disc - Write One CMF Channel Mismatch Failure; CE Consumer Electronics Client Management Frame CEA Consumer Electronics Association CMIP Common Management Information Protocol CELP Code Excited Linear Predictive CMIS Common Management Information Services CER Cell Error Ratio; Codeword Error Ration CMISE Common Management Information CES Circuit Emulation Service Service Element CESAR Converged Edge Services Access Router CMR Cell Misinsertion Rate CEV Controlled Environmental Vault CMS Call Management Server CFDM Command Frequency Division Multiplexer CMTS Cable Modem Termination System CFG Configuration CMU Clock Multiplier Unit CFM Cubic Feet per Minute C-n Container C-11=1,544 Mb/s; C-12=2,048 Mb/s; CFU Cooling Fan Unit C-2=6,312 Mb/s; C-3=34,368 Mb/s and 44,736 Mb/s; C-4=139,264 Mb/s CH Channel CN Core Network CHASEH Environmentally Hardened Chassis CNIPS Core Network Integrated Planning System CHASYNC Chassis with Sync CNIR Carrier-to-Noise/Ingress Ratio CI Compact Intelligence; Craft Interface; CNMP Customer Network Management Portal Customer Interface; Certified Integrator

5 CNR Carrier-to-Noise Ratio CRx Line Client Receive Line CO Central Office CS Control Sub-span; Convergence Sublayer; CoreStream COAX Coaxial Cable CSA Canadian Standards Association COBRA Copper and Optical Broadband Remote Access CSC Command Signal and Control CODEC Coder/Decoder CSD Core Switching Division COE Central Office Equipment CSES Consecutive Severely Errored Seconds COFA Change of Frame Alignment Csh C Shell COLD Central Office Layout Design CSH Common Signal Header COLL Collision Count CSI Convergence Sublayer Indicator CONDTYPE Condition Type CSM Core Switching Manager CONS Connection Oriented Network Service C-SMF Conventional Single Mode Fiber COO Chief Operating Officer CSO Composite Second Order COPS Common Open Policy Services CSP Customer Service Profile CORBA Common Object Request Broker Architecture CSR Customer Service Representative CORD Central Office Rearchitected as a Data Center CS-RZ Carrier-Suppressed Return-to-Zero COS Class of Service; Common Object Services; CORBA Object Services CST Central Standard Time CoS Class of Service CSU ; Customer Service Unit COT Central Office Terminal CSV Comma-Separated Value COTS Commercial off the Shelf CT Critical CP Circuit Pack; Control Processor; Connection CTAM Cable & Association Provisioner; Call Processing; Customer Premises for Marketing CPCI Compact Peripheral Component Interconnect CTB Composite Triple Beat CPD Common Path Distortion CTC Common Transmit Clock CPE Customer Premises Equipment; CTD Cell Transfer Delay Customer Provided Equipment CTG Cradle-To-Grave C-Plane Control Plane CTN Core Transmission Network CPLD Complex Programmable Logic Device CTP Connection Termination Point CPM Cross-Phase Modulation CTS Clear To Send CPRI Common Public Radio Interface CTx Line Client Transmit Line CPRM Content Protection for Recordable Media CU Centralized Unit CPT Channel Pass-Through CUG Closed User Group CPTTAG Connection Termination Point Tag CUPS Control and User Plane Split CPU Central Processing Unit CV Code Violation CR Circuit Reliability; Carriage Return; Critical Alarm CV-FE Code Violation - Far End C-RAN Centralized/Cloud-Radio Access Network CV-L Code Violation - Line CRC Cyclic Redundancy Check CV-P Code Violation - Path CRG Circuit Restoration Group CV-PFE Code Violation - Path Far End CR-LDP Constraint-based Routing Label Distribution CV-S, CVS Code Violation - Section; Protocol Code Violation - Seconds CRS Cross Connect CW Clockwise; Continuous Wave CRT Cathode Ray Tube CWDM Coarse Wavelength Division

6 D DE Discard Eligible DEC Digital Electrical Carrier D&C Drop and Continue D/A Digital-to-Analog DECT Digital European Cordless Telephone/ DAA Distributed Access Architecture DEG Degraded Signal DAC Digital to Analog Converter; Digital Addressable Controller DEMUX Demultiplexer DACS Digital Access and Cross-Connect System DENI Digital Entertainment Networking Initiative DAD Direct Access Device DENY Transaction Denier DADM Data Add/Drop Multiplexer DEPI DOCSIS External Downstream Interface DARPA Defense Advanced Research Projects DFB Distributed Feedback Agency (US) DG Disc Group DAS Direct Attached Storage DGD Differential Group Delay DATE Duly Authorised Telecommunications Entity DHCP Dynamic Host Configuration Protocol dB decibel DHWG Digital Home Working Group DB Database D/I Drop and Insert DB-9 Data Bus 9 Pin Connector DID Direct Inward Dialer DBA Database Administrator DiffServ Differentiated Services dBc Decibels referenced to the carrier DIO Digital Input/Output dBm Decibels reference to milliwatts DIP Dual In-line Package (switch) DBMS Database Management System DIR Direction DBPSK Differential Binary Phase Shift Keying Div Division DBS Direct Broadcast Satellite DLC dBW Decibels referenced to Watts DLCI Data Link Connection Identifier DC Direct Current; Data Connection DLL Dynamic Link Library; Data Link Layer (driver); DCC Data Communications Channel Downline Load DCE Data Communications Equipment; DLT Digital Linear Tape Drives Data Circuit Terminating Equipment DM Degraded Minute; Dispersion Mitigation DCF Dispersion-Compensating Fiber DMA Direct Memory Access DCG Dispersion Compensation Grating DMACS Distributed Monitoring and Control System DCI Data Center Interconnect DMB Digital Multipoint Bridge; DCM Dispersion Compensation Module Document Maintenance Bulletin DCME Digital Compressed Multiplication Equipment DMC Dual Modem Cards DCMS Digital Circuit Multiplication System DMH Degraded Modem Hours DCN Data Communication Network DMM Digital Multi-Meter DCOM Distributed Component Object Model DMOP Detailed Method of Procedure DCP Digital Communications Protocol; DMS Dispersion-Managed Solution Device Control Protocol DMUX [Optical] Demultiplexer DCS Digital Cross-connect System; DN Data Network Digital Connection System DNCS Digital Network Control System DCS 1800 Digital Cellular System, GSM variant at 1800 MHz D-NFVI Distributed Network Function Virtualization DCU Dial up Data Channel Unit Infrastructure DDI Direct Dialing Inward DNR Do Not Revert DDI DNS, DHCP, and IPAM DNS Domain Name Server; Domain Name System DDS Digital Data Storage; Digital Data Service; DOCSIS Data-Over-Cable Service Interface Specifications Digital Data System; Digital Data Stream

7 DOD Department of Defense DTL Designated Transit List DOS Disk Operating System DTMF Dual Tone Multiple Frequency DoS Denial of Service DTS Dynamic Transport System DP Distribution Point; Data Processing DTV DPDT Double-Pole, Double-Throw DU Distributed Unit DPFI Data Plane Fault Isolation DUART Dual Universal Asynchronous Receiver DPI Digital Program Insertion; Dots Per Inch Transmitter DPR Dedicated Protection Ring DUP Data User Part DPRAM Dual Port Random Access Memory DUS Don’t Use Synchronization DPT Dynamic Packet Transport DV Digital Video D-RAN Distributed Radio Access Network DVB-ASI Digital Video Broadcast Asynchronous Serial Interface DQ Degraded Quality Level DVC Dynamic Virtual Concatenation DQDB Distributed Queue Dual Bus DVD Digital Versatile Disc DQoS Dynamic Quality of Service DVD+R Recordable Digital Versatile Disc DQPSK Differential Quadrature Phase Shift Keying DVD+RW Rewritable Digital Versatile Disc DR Disaster Recovery DVI Display Visual Interface DRAM Dynamic Random Access Memory DVM Digital Voltmeter DRM Digital Rights Management DVOW Digital Voice Orderwire DS Digital Signal; Downstream DVR DS0 Digital Service, Level 0, 64kb/s DW Datawire DS1 Digital Service, Level 1, 1.544 Mb/s; Digital Signal Level DWDM Dense Wavelength Division Multiplexing DS3 Digital Signal Level 3 (T3 equivalent) DXC Digital Cross-Connect DSCP Differentiated Service Code Point DXI Data Exchange Interface DSCRDS Discard Count E DSF Dispersion Shifted Fiber E&M Ear & Mouth DSI Digital Speech Interpolation E1 European Equivalent of T1 (2.048 Mb/s signal speed) DSL Digital Subscriber Line; Digital Subscriber Loop E2E End-To-End DSLAM Digital Subscriber Line Access Multiplexer E2PROM Electrically Erasable Programmable Read DS-n Digital Signal, level n Only Memory DSP Digital Signal Processor E3 European data signal at a rate of 34.368 Mb/s DSS Direct Satellite Services EAI Enterprise Application Integration DSS2 Digital Subscriber Signaling 2 EAL Events, Alarms, and Logging DSTB Digital Set-top Box EAP Extensible Authentication Protocol DSX Digital Side Interface EAS Emergency Alert System DS-x Digital Signal where N denotes multiple EB Error Block; Eastbound of 51.84 Mb/s e-Band Extended Band DSX-1 Digital Signal Level 1 Cross Connect Eb/No Energy per Bit to Noise ratio DSX-3 Digital Signal Level 3 Cross Connect eBGP External BGP DT Decision Technology; Direct Termination EC Enhanced Capacity ; European Commission DTCP Digital Transmission Content Protection EC-1 Electrical Carrier Level 1 (STS1 Equivalent) DTE Data Terminal Equipment DTH Direct-to-Home, usually ECC Edge Card Control; broadcasting Embedded Communications Channel

8 ECI Equipment Catalog Item EMS Element Management System ECLR Egress Cell Loss Ratio EMT Expiring Maintenance Tool ECn Electrical Carrier, level n; 0=64 kb/s, 2=6,312 Mb/s, eMTA Embedded Multimedia Terminal Adapter 3=44,736 Mb/s EMX ESCON MUX ECN Engineering Change Notice END Extended Management Domain ECO Engineering Change Order ENE End Network Element eCPRI enhanced Common Public Radio Interface ENUT Enhanced Non-preemptable Unprotected Traffic ECTRA European Committee for Telecommunications EO Equipment Order Regulatory Affairs EOC Embedded Operations Channel ED Equipment Degrade EoD Everything on Demand EDF Erbium-Doped Fiber EOF End of Frame EDFA Erbium-Doped Fiber Amplifier EOL End of Life EDI Electronic Data Interchange EOM End of Message eDOCSIS Embedded Data-Over-Cable Service Interface Specifications EoS Ethernet over SONET/SDH EEE Electronic Equipment Enclosure EOW Engineered Orderwire; Express Orderwire EEPROM Electrically Erasable Programmable Read EPA Environmental Protection Agency Only Memory EPCR Egress Peak Cell Rate EF Equipment Failure EPD Early Packet Discard EF&I Engineer, Furnish, and Install EPG Equipment Protection Group EFCI Explicit Forward Congestion Indication EPL Ethernet Private Line EFD Event Forwarding Discriminator EPLD Erasable Programmable Logic Device EFP Equipment Fault Protection E-PON Ethernet Passive Optical Network EH Environmentally Hardened EPR Engineering Progress Report EIA Electronic Industries Alliance; EPROM Erasable Programmable Read Only Memory Electronic Industries Association EQPT Equipment EID Equipment Identifier EQAM Edge Quadrature Amplitude Modulation EIDE Enhanced Integrated Drive Electronics ER Extended Reach EII European Information Infrastructure ERDI Enhanced Remote Defect Indicator EIR Excess Information Rate EREI-P Enhanced Path Remote Error Indication EIRP Effective Isotropic Radiated Power; ERMI Edge Resource Management Interface Equivalent Isotropic Radiated Power Errcde Error Code ™ EJB Enterprise Java Beans ES Errored Second ELAN Emulated Local Area Network ESA EDFA Saturation Algorithm; End System Address ELR Extra Long Reach ESCBND ESCON Bundle EM Element Manager ESCON Enterprise Systems Connection EMBS Egress Maximum Burst Size ESCR Egress Sustainable Cell Rate EMC ElectroMagnetic Compatibility ESD Electrostatic Discharge EMD Extended Management Domain ESDS Electrostatic Discharge Sensitive EMEA Europe, Middle East, and Africa ESF Extended Super Frame; Extended EMG Extended Management Gateway Superframe Format EMI Electromagnetic Interference ES-FE Errored Seconds - Far End EML Element Management Layer; ESI End System Identifier Electro-Absorptive Modulated Laser ES-IS End System to Intermediate System EMP Expiring Maintenance Process

9 ES-L Errored Seconds - Line FC100 Fibre Channel 1 Gb/s ES-LFE Errored Second-Line Far End FC10000 Fibre Channel 10 Gb/s (same as 10GFC) ESMOP Electronic Service Method of Procedure FC200 Fibre Channel 2 Gb/s ES-MS Errored Seconds at the Mulitplexor Section FC400 Fibre Channel 4 Gb/s ESN Extended Subnetwork FCAPS Fault, Configuration, Accounting, Performance ES-P Errored Seconds - Path (or Provisioning), Security management ES-PFE Errored Seconds - Path Far End FCC Federal Communications Commission ESR Errored Second Ratio FC-FE Failure Count - Far End ES-RS Errored Second Regenerator Section FCIP Fibre Channel over Internet Protocol ES-S Errored Seconds - Section FC-L Failure Count - Line EST Eastern Standard Time FC-LFE Failure Count - Line Far End ES-V Errored Second-Virtual Tributary (VT) Path; FCM Fan Control Module Errored Second-VT Path Far End FCP Fibre Channel Protocol ESx Errored Second Count FC-P Failure Count - Path ET End Terminal FC-PFE Failure Count - Path Far End Etag Ending Tag FCS Frame Check Sequence; Fibre Channel Standard ETH 10/100 Ethernet FCS32 Count of FCS-32 Error ETHBND Ethernet Bundle FC-V Failure Count - VT ETLMI ESCON Trib Laser Manager Interface FC-VFE Failure Count - VT Far End ETR External Timing Reference FDD Frequency Division Duplexed ETSI European Telecommunications Standards FDDI Fiber Distributed Data Interface Institute FDF Fiber Distributing Frame EU European Union FDL Facilities Data Link EVC Ethernet Virtual Circuit FDM Frequency Division Multiplexing; Fast Ethernet; EVM Error Vector Magnitude Frequency Division Modulation EVPL Ethernet Virtual Private Line FDMA Frequency Division Multiple Access EVPLAN Ethernet Virtual Private Local Area Network FDP Fiber Distribution Panel EWO Engineering Work Order FDRP Frame Drop EXER-R Exercise - Ring FE Far End; Fast Ethernet; Forward Error Correction EXER-S Exercise - Span (SONET) FEAC Far End Alarm Channel EXP Experimental FEACT Far-End Terminal Alarm Condition EXZ Excessive Zone FEALM Far-End Alarm FEB Fast Ethernet Bridging F FEBE Far End Block Error F Fahrenheit FEC Forward Error Correction; F&I Furnish and Install Forwarding Equivalence Class FA, F/A Fuse Alarm; Fault Alarm FECN Forward Explicit Congestion Notification FAB Field Alert Bulletin FECS Forward Error Correction Seconds FAD Functional Access Domain FEDS FICON Extended Storage over Distance FAF Facility Failure FEP Front End Processor; Far End Protection FAT Factory Acceptance Test FEPLF Far End Protection Line Failure FC Failure Code; Failure Count; Fiber Channel; FEPM Far End Performance Monitor Fibre Channel FERF Far End Receive Failure FC Switch Fibre Channel Switch FET Field-Effect Transistor

10 FF Fast Forward FRD Functional Requirements Document; FFA First Field Application Feature Requirements Definition FFP Facility Fault Protection FREQ Frequency FFT Fast Fourier Transform FRF Frame Relay Forum FIB Forwarding Information Base FRF.12 Frame Relay Forum Implementation Agreement 12 FIC Frame Identification Code FRF.13 Frame Relay Forum Implementation Agreement 13 FICON Fiber Connection FRF.5 Frame Relay Forum Implementation Agreement 5 FIL Fiber in the Loop FRF.8.1 Frame Relay Forum Implementation Agreement 8.1 FIT Failure in Time FRG Fragment Count FITB Fiber in the Building FRM Forward Resource Management; Frame Count FITL Fiber in the Loop FRMS Dropped Frames FITR Fiber in the Riser FRS Frame Relay Service FLAG Fiber Link Around the Globe FRU Field Replacement Unit FlexE Flexible Ethernet FS File System FlexO Flexible OTN FSA Field Service Application FM Fan Module; Fault Management; Forwarding FSAN Full Services Access Network (consortium) Module; Frequency Modulation FSB Field Service Bulletin FMA Failure Modes Analysis FSO Free Space Optical FMECA Failure Mode and Effects and Criticality Analyses FS-P Forced Switch - Protection FMS Fault Management System FS-R Forced Switch - Ring FNCS Foreign National Control System FSS Fixed Satellite Service FO Fiber Optics FS-S Forced Switch - Span FOADM Fixed Optical Add/Drop Multiplexer; FS-W Forced Switch - Working Flexible Optical Add/Drop Multiplexer FT France Telecom FOB Free On Board FT1 Fractional T1 FOC Final Operating Configuration FTA Fault Tree Analysis FOD Free on Demand FTAM File Transfer and Access Management FOS Follow on Satellite, Intelsat designation FTC Fabric and Timing Card FOSC Fiber Optic Splice Course FTM Fabric Timing Module FOTS Fiber Optic Transmission System FTP File Transfer Protocol FOW Forward Order Wire FTTB Fiber to the Building; Fiber to the Business FP Fabry-Perot (type of laser); Frame FTTC Fiber to the Curb (Kerb), linked to VDSL in Pulse (NEC) deployment FPG Facility Protection Group FTTD Fiber to the Desk FPGA Field Programmable Gate Array FTTH Fiber to the Home FPLMTS Future Public Land Mobile FTTP Fiber to the Premises; Maintenance Channel Telecommunications Systems Transparent Termination Point FPM Fan Power Module FTTx Fiber to the [endpoint] FPP Fast Pattern Processor FUNI Frame-based User-Network Interface FPS Frames Per Second FW Firmware; Firewall FR Frame Relay FWHM Full Width at Half Maximum FRAD Frame Relay Access Device FWM Four-Wave Mixing FRC Force FXO Foreign Exchange Office FXS Foreign Exchange Service

11 G GP Gateway Platform G/T Gain to System Noise Temperature Ratio GPI General Purpose Input GA General Availability GPIN General Purpose Input Gb Gigabit GPO General Purpose Output GB Gigabyte G-PON Gigabit Passive Optical Network GbE Gigabit Ethernet GPS Global Positioning System; Global Positioning Satellite GbE VFTP Gigabit Ethernet Virtual Facility Termination Point GR Generic Requirement; Geographic Redundancy GbE WAN Gigabit Ethernet GRDM Gigabit Rate Data Multiplexer GbE WIF Gigabit Ethernet Wide Area Network Interface gRPC gRPC Remote Procedure Call GBIC Gigabit Interface Converter GRTES General Requirements for Transmission Gbit Gigabit Equipment Specification Gbps, Gbits, Gb/s Gigabits per second GSM Global System for Mobile communications, originally: Groupe Spéciale Mobile Gbytes/s Gigabytes per second GSO Geostationary Earth Orbit GC Gateway Controller GT Gain Transfer; Grating Temperature GCAC Generic Connection Admission Control GTF Global Traffic Forecast (Intelsat) GCC0 General Communications Channel 0 (similar to SDH/SONET DCC) GTM Global Traffic Meeting (Intelsat) GCIT Graphical Craft Interface Terminal GTP Group Termination Point GCM General Control Module GTS General TeleSystems Group GCRA Generic Cell Rate Algorithm GUI Graphical User Interface GDMO Guidelines for the Definition of Managed Objects GW Gateway GE Gigabit Ethernet; Greater than or equal to; GWC Gateway Controller General Electric Corporation GEB Gigabit Ethernet Bridge H HA High Availability GEO Geostationary Earth Orbit HCSFI High-speed Central Switch Fabric Interface GESS General Electric Satellite Services HD High Definition GET Gigabit Ethernet Tunneling HDB3 High Density Bipolar 3 GFA Gain Flattened Amplifier HDCP High-bandwidth Digital Content Protection GFC Generic Flow Control HDLC High-speed/level Data Link Control GFF Gain Flattening Filter (used in EDFA) HDMI High Definition Multimedia Interface GFP Generic Framing Procedure HD-SDI High Definition Serial Digital Interface GFR Guaranteed Frame Rate HDSF High-speed Distributed Switch Fabric GHz Gigahertz (Billion hertz) HDSL High-speed Digital Subscriber Line GigE Gigabit Ethernet HDT Host Digital Terminal GII Global Information Infrastructure HDTV High Definition Television GMDSS Global Maritime Distress and Safety System HE Headend GMPLS Generalized Multi-Protocol Label Switching HEC Header Error Control; Headend Controller GMT Greenwich Mean Time; Grasshoppers Made for Telecommunications (GMT fuses) HEM Headend Modem GN Gateway Network Element HEPA High Efficiency Particulate Arrester GND Ground HERD Headends Re-architected as Data Center GNE Gateway Network Element HFC Hybrid Fiber Coax GOS Grade of Service HFM High-speed Forwarding Module

12 HGW Home Gateway IAD Integrated Access Device; Interface Access HHP Households Passed Device HI Hardware/Software Interface; Hardware-Software IAS Service; Integration; High Speed Internet Internet Authentication Service HISSA High Speed Serial Application Specific Integrated IBCC In-Band Communication Channel Circuit (ASIC) iBGP Internal BGP HMS Hybrid Management Sub-layer IBS Intelsat Business Service HNv1 Home Networking Version 1 IBT International Business Traveller HO Higher Order IC Integrated Circuit HOD HBO on Demand ICB Independent Customer Builds HO-DSP High Order-Domain Specific Part ICD International Code Designator HO-DXC Higher Order Digital Cross Connect ICLR Ingress Cell Loss Ratio HOM High-Order Modulation ICMP Internet Control Message Protocol HomePNA Home Phoneline Networking Alliance ICNV Input- Command Not Valid HOP High Order Path ICP IMA Control Protocol HO-POH Higher Order - Path Overhead ICP Internet Content Provider HOVC Higher Order Virtual Concatenation ICPT Installed Circuit Pack Type HP Hairpin; Higher Order Path; Homes Passed ICR Initial Cell Rate HPA High Power Amplifier ID Identifier; Identification HPF High Pass Filter IDB International Development Bank HPNA Home Phoneline Networking Alliance IDE Integrated Device Electronics HPOV Hewlett Packard Open View IDF Intermediate Distribution Frame; Invalid Data Flag HPPI High Performance Parallel Interface IDH Identification High byte HP-UX Hewlett Packard’s UNIX-based OS that runs on IDI Initial Domain Identifier HP’s enterprise servers IDL Interactive Distance Learning; HRD Hardware Release Document; Interface Definition Language Hardware Requirements Document IDNV Input, Data Not Valid HS High Speed IDP Initial Domain Part HSB High Speed Bus IDR Intermediate Data Rate HSD High Speed Data IDS Intrusion Detection System HSSI High Speed Serial Interface IDT Inter-DXC Trunk HT High Threshold IDU Indoor Unit HTML Hyper Text Markup Language IE Information Element HTTP Hypertext Transfer Protocol IEC Incoming Error Count; InterExchange Carrier HVAC Heating, Ventilation, and Air-Conditioning IEEE Institute for Electrical and Electronics Engineers HVS Hospitality Voice Services IETF Internet Engineering Task Force HW Hardware IF Intermediate Frequency Hz Hertz IFC Initial First Cost IG Information Group I IGMP Internet Group Multicast Protocol I/B Inbound/Outroute (also known as the return link), IGP Interior Gateway Protocol from remote terminal to hub IIAC Input - Invalid Access Identifier I/O Input/Output IIOP CORBA Internet Inter-ORB Protocol IaaS Infrastructure as a Service IISP Interim Interface Signaling Protocol

13 ILA Intermediate Light Amplification; Integrated Line IPOA Internet Protocol over ATM Amplifier; In-Line Amplifier IPPV Impulse Pay Per View ILEC Incumbent Local Exchange Carrier IPR Intellectual Property Rights ILM Integrated Laser Module; Integrated Laser Modulator IPsec Internet Protocol Security ILMI Interim Link Management Interface; Interim Local IPSL Integrated IP Software License Management Interface IPTA Internet Protocol Transport Agreement ILOG Information Log; Incoming Log IPTV IP Television ILR Issues List Report IPX Internet Package Exchange IM Instant Messaging IR Intermediate Reach IMA Inverse Multiplexing over ATM IRD Integrated Receiver/Decoder IMBS Ingress Maximum Burst Size IRT Integrated Receiver/Transcoder IMD Intermodulation Distortion IS In Service; Intermediate System IME Interface Management Entity ISA Industry Standard Architecture IMT Inter Machine Trunk IS-ANR In Service - Abnormal IMT- IS-ANRST In Service - Abnormal and Restricted Advanced International Mobile Telecommunications- Advanced ISCC InterSwitch Communications Channel IN Intelligent Network ISCR Ingress Sustainable Cell Rate INAP Intelligent Network Application Part Protocol iSCSI Internet Small Computer System Interface; SCSI Protocol over TCP/IP I-NET Institutional Network ISD Idle Signal Detection INM Integrated Network Manager ISDN Integrated Services Digital Network Inroute see I/B IS-IS Intermediate System to Intermediate System INT Internal; Internal Clock ISM Industrial Scientific Medical INTAP Interoperability Technology Association for information Processing IS-NR In Service - Normal INTP Internodal Tunneling Protocol ISO International Standards Organization IntServ Integrated Services ISOC the Internet Society INVW Invalid Word Count ISP Internet Service Provider; Inside Plant IOA Input/Output Adapter IS-RST In Service - Restricted IOC Initial Operating Configuration ISTP Internet Signaling Transport Protocol IOF Inter-office Fiber ISV Independent Software Vendor IOR Interoperable Object Reference; IT Information Technology Indian Ocean Region ITA Installation, Test, and Acceptance IoT Internet of Things ITC Independent Transmit Clock IP Intelligent Peripheral, IN block; Internet Protocol ITE Information Technology Equipment IPAM IP Address Management ITL International Telecommunications Union IPC Inter-Process Communications; ITS Intelligent Transportation System; Institute for InterProcess or InterProcesser Control Telecommunications Sciences IPCR Ingress Peak Cell Rate ITT International Telephone and Telegraph IPCU DAMA IP Channel Unit ITU International Telecommunication Union IPG Inter-Packet Gap ITU-T ITU Telecommunications standards body IPM Interested Party Multicast IUC Interval Usage Code IPMI Internet Protocol Multicasting Initiative IVPN International VPN IPMS Interested Party Multicast Service IWF Interworking Function IXC Inter-exchange Carrier

14 J LANE Local Area Network Emulation J0 J Zero LAP Link Access Procedure; Link Access Protocol LAPB Link Access Procedure Balanced J2EE Java 2 Enterprise Edition LAPD Link Access Procedure-D Channel (X 25) JBR Jabber Count LAPF Link Access Procedure for Frame-Mode Bearer JDBC Java Database Connectivity Services JDK Java Development Kit LAPS Link Access Procedure JDMK Java Dynamic Management Kit LASER Light Amplification by Stimulated Emission JDS-HR Japan Digital Services - Half Rate of Radiation JEM Java Element Manager LATA Local Access and Transport Area JMS Java Messaging System LATM Local ATM JNDI Java Naming and Directory Interface L-Band Long Band JPEG Joint Photographic Experts Group LBC Laser Bias Current JRE Java Runtime Environment LBCL Laser Bias Current Level JTAG Joint Test Action Group LBCN Normalized Laser Bias Current JVM Java Virtual Machine LBO Line Build Out LC Lucent Connector; K LCAP Local Craft Access Panel k kilo (thousand) LCAS Link Capacity Adjustment Scheme K1 SONET or SDH overhead byte of MSP/MS-SPRing LCC Life-Cycle Cost; Link Control Channel (see K2) LCD Liquid Crystal Display K2 Used with K1-SONET or SDH overhead byte for MSP/MS-SPRing LCL Lower Confidence Limit Kb Kilobit LCN Local ; Logical Channel Number; Local Communications Network KB Kilobyte Kb/s, Kbit/s, LCR Least Cost Routing Kbps Kilobits per second LCT Large Capacity Terminal KB/s, KBps Kilobytes per second LD Laser Diode kBPS kilo Bits Per Second LDAP Lightweight Directory Access Protocol kft Kilofeet (USA cable length measurement) LDCC Line Data Communications Channel kHz kilohertz (thousand hertz) LDCELP Low Delay CELP Km Kilometer LDP Label Distribution Protocol Ksh Korn Shell LDS Local Digital Switch ksym/s Kilosymbols per second LEAF Large Effective Area Fiber ksym/sec Kilosymbols per second LEC Local Exchange Carrier kVA 1000 Volt Amperes LECS LAN Emulation Configuration Server kW Kilowatt LED Light Emitting Diode LEO Low Earth Orbit L LER Label Edge Router L2TP Layer 2 Tunneling Protocol LES LAN Emulation Server L3 Layer 3 LF Line Fail LA Line Adapter; Latin America LFE Line Far End LAC Local Access Concentrator LGN Logical Group LADM Linear Add/Drop Multiplexer LGX Light-Guide Crossconnects LAN Local Area Network LH Logical Host

15 LIC Line Interface Card LSL Lower Specification Limit LIF Line Interface LSM Loss of Sync Message LIM Line Interface Module LSN Logical Subnetwork LIP Local Information Packet LSP Label Switched Path; Local Service Provider LIU Line Interface Unit LSR Label Switch Router LLC Logical Link Control LSSGR LATA Switching System Generic Requirements LLSDCC Lower-Layer Section DCC LT Low Threshold; Laser Temperature LM Line Module LTE Line Terminating Equipment; LMDS Local Multipoint Distribution Service Long Terminal Evolution LMI Local Management Interface LTN Local Transport Network (fiber ring) LMP Link Management Protocol LTP Link Termination Point; Logical Termination Point LNA Low Noise Amplifier LTS Loop Testing System; Long Term Storage LNB Low Noise Block LU Line Unit LO Low Order LVD Low-Voltage Distribution LOADM Lightweight Optical Add/Drop Multiplexer LWP Low Water Peak LOC Loss of Clock LZS Lempel Ziv Stac Locn Location LO-DXC Low Order Digital Cross Connect M LOF Loss of Frame M&C Monitor and Control LOF-P Path Loss of Frame M12 MUX DS-1 into DS2 LOH Line Overhead M13 MUX DS-1 into DS3 LOM Loss of Multiframe; List of Materials M23 MUX DS-2 into DS3 LOP Loss of Pointer M2M Machine-to-Machine LOPDP Loss of Pointer Decay Period MAC Media Access Control; Medium Access Control LOPI Loss of Pointer Inhibit MAN Metropolitan Area Network LOPIP Loss of Pointer Integration Period MANO Management and Orchestration LOP-P Loss of Pointer - Path MAP Main Audio Program; Mobile Application Part Protocol LOP-V VT Loss of Pointer MAU Media Access Unit LOS Loss of Signal Mb Megabit LOSS Loss of Signal Seconds MB Megabyte LOVC Low Order VC Mbaud Megabaud LOW Local Orderwire MBH Mobile Back Haul LP Line Processor; Lockout of Protection; Low Order Mbits/s, Path Mb/s Megabits per second Lport Logical port MB/s Megabytes per second LP-S Lockout of Protection - Span Mb/s Million Bits Per Second LP-S/SF-P Lockout of Protection - Span/Signal Fail - MBS Maximum Burst Size Protection MCC Master Control Center/Computer LPWAN Low Power Wide Area Network M-CORD Mobile-CORD LR Long Reach (fiber); Line Regeneration Equipment MCP Management Control Processor LRDC Long Reach Daughter Card MCPC Multiple Channels Per Carrier LSA Low Speed ADM MCR Minimum Cell Rate; Minimum Cost Routing LSB Least Significant Bit MCS Master Control Station LSF Loss of Signal or Frame indication signal

16 MCT Maintenance Channel Transparency Modem Modulator/Demodulator MCTF Motion Compensated Temporal Filtering MOF Managed Object Framework MDF Main Distribution Frame MOP Method of Procedure MDSO Multi-Domain Service Orchestration MOR Multi-wavelength Optical Repeater MDU Multiple Dwelling Unit MOS Mean Opinion Score mDVR Multi-TV Digital Video Recorder MP Management Portal ME Middle East MP3 MPEG-2 Layer 3 MEA Mismatch of Equipment and Attributes MPCKTS Multicast Packet Count MEC Multi-Access Edge Computing MPEG Moving Pictures Expert Group MEGACO Media Gateway Control Protocol MPI Multi-Path Interface; Multi-Path Interference MEO Medium Earth Orbit M-Plane Management Plane MER Modulation Error Ratio MPLmS Multi-Protocol Lambda Switching MFR Multilink Frame Relay MPLS Multi Protocol Label Switching MG Media Gateway MPLS-CP MPLS Control Plane MGC Media Gateway Controller MPN Mode Partition Noise MGCP Media Gateway Control Protocol MPOA Multi Protocol over Asynchronous Transfer Mode MGN Management Gateway Node MPS Multiple Priority System MHA Modular Headend Architecture MPT Pass-Through, Ministry of Posts and MHz Megahertz (million hertz) Telecommunications MIB Management Information Base MPTS Multiple Program Transport Stream MID Message Identifier MR Modification Request; Material Request; Medium Reach MIMO Multiple-Input Multiple-Output MRRB Maintenance Requirements Review Board; MIPS Millions of Instructions Per Second Material Release Review Board MIT Management Information Tree ms Milliseconds MiTTs Minutes of Telecommunications Traffic MS Multiplex Section MJ Major MSA Mediation Services Administrator ML Mediation Layer MS-AIS Multiplex Section - Alarm Indication Signal MLMD Multiplexer/Demultiplexer MSB Most Significant Bit MLPPP Multi-Link Point-to-Point Protocol MSC Metro Shelf Controller; Microsoft Cluster Server mm millimeter MSF Multiservice Switching Forum MM Multimode; Multimedia MSN Multi-Subnetwork MMCS Meridian Multi Media Center Switch MSNM Metro Switching Network Manager MME Multiwave Management Element MSNM ML Metro Switching Network Manager MMF Multi-Mode Fiber Mediation Layer MML Man Machine Language MSO Multiple System Operator MMO Main Material Order MSOH Multiplexer Section Overhead MMP Multiwave Management Element MSP Multiplex Section Protection; MN Minor Multiservice Switching Path MNO Mobile Network Operator MS-P Manual Switch-Protection MNC Multi-National Company MSPP Multiservice Provisioning Platform MO Managed Object MSPVC Management Soft Permanent Virtual Circuit MOD Module; Movies on Demand MS-R Manual Switch - Ring MODEM Modulator-Demodulator MS-RDI Multiplex Section - Remote Defect Indication

17 MS-REI Multiplex Section Remote Error Indication NCR Non-Conformance Report MSS Mobile Satellite Service NCS Network Computing System; Network Control MS-S Manual Switch - Span System; Network Call Signaling MS-Spring/ NCT Network Control Terminal MSPR Multiplex Section Shared Protection Ring NCTA National Cable & Telecommunications Association MST Mountain Standard Time; NDC National Destination Code Multiplex Section Termination NDF New Data Flag MSTE Multiplex Section Terminating Equipment NDIS Network Design and Inventory System MS-W Manual Switch - Working NDMH Non-Degraded Modem Hours MTA Multimedia Terminal Adapter NDP Network Discovery Protocol; MTBF Mean Time Between Failure Neighbor Discovery Protocol MTC Machine Type Communications NDSF Non-Dispersion Shifted Fiber MTIE Maximum Time Interval Error NDVR Network Digital Video Recording MTP Message Transfer Part NE Network Element MTTR Mean Time to Repair NE/FE Near End/Far End MTTU Mean Time to Understand NEBS Network Equipment Building Standards; MTU Maximum Transmission Unit Network Equipment Building Systems MUX Multiplexer NEC National Electric Code MUXCVR Muxceiver NEF Network Element Function mV Millivolt NEG Negative Terminal MVNO Mobile Virtual Network Operator NEID Network Element Identification MVOA Miniature Variable Optical Attenuator NEIR Network Element Information Request MZ Mach-Zehnder NEMA National Electrical Manufacturers Association NETCONF Network Configuration N NFS Networked File System NA No Alarm; Not Alarmed; Not Applicable; NFV Network Functions Virtualization Not Available; Numerical Aperture NFVO Network Functions Virtualization (NFV) NaaS Network as a Service Orchestration NAD Network Access Domain NGDLC Next Generation Digital Loop Carrier NAP Network Access Point NGFW Next Generation Firewall NAPT Network Address and Protocol |Translation NG-L1 Next Generation Layer 1 NAS Network Access Server; NGNA Next Generation Network Architecture Network Attached Storage NG-PON2 Next Generation PON2 NASA National Aeronautical and Space Agency (U.S.) NGSO Non-Geostationary Earth Orbit, used as a general NAT Network Address Translation descriptive for LEO and MEO systems. NBI Northbound Interface NGW National Gateway NBK No Backup NI Network Interface NC Nodal Controller; Normally Closed (contacts) NIC Network Interface Card NCB National Computer Board NID Network Interface Device NCC Network Control Center/Computer NIDU Network Interface Data Unit NCCC Network Control Coordination Channel NII National Information Infrastructure (for the U.S., NCCI Network Call Correlation Identification see also GII and EII) NCP Nodal Control Point; Nodal Control Processor NIS Network Infrastructure Solutions NCP&D Network Capacity Planning and Delivery NISC National Information Services Council

18 NIU Network Interface Unit NTSC National Television Standards Committee NLA Network Layer Address; Network Layer Agent NUT Non-preemptive Unprotected Traffic NLC Node Line Card NVM Non-Volatile Memory NLD Neighbor Link Discovery NVRAM Non-Volatile Random Access Memory NLPI Network Layer Protocol Identifier NZDSF Non-Zero Dispersion Shifted Fiber nm nanometer NM Network Management; Network Manager; O Network Management; Node Manager O&M Operations and Management NMA Network Monitoring and Analysis OA Optical Amplifier NME Network Management Ethernet OA&M Operations Administration and Management NMF Node-level Management Function OADM Optical Add/Drop Multiplexer NML Network Management Layer OAM Operations, Administration, and Maintenance NMS Network Management System OAMCell Operations, Administration, and Maintenance Cell NN N key on keyboard for a no response OAMP Operation, Administration, Maintenance, NNI Network to Network Interface; and Provisioning Network Node Interface O-Band Original Band NNIF Network to Network Interface O-BLSR Optical-Bidirectional Line Switched Ring NNM Network Node Manager OC Optical Carrier NNTP Network News Transfer Protocol OC-1 Optical Carrier level 1, SONET bit rate = 51.84 Mb/s NO Network Object; Normally Open (contacts) OC1 Optical Carrier level 1 (51.84 Mb/s) NOC Network Operations Center OC-12 Optical Carrier level 12, SONET bit rate = 622.08 Mb/s NOCC Network Operations Control Center OC-192 Optical Carrier level 192, SONET bit rate = 9.953 Gb/s NPC Network Parameter Control OC-3 Optical Carrier level 3, SONET bit rate = 155.52 Mb/s NPR Noise Power Ratio OC-48 Optical Carrier level 48, SONET bit rate = 2.488 Gb/s NR No Reply OCAP OpenCable Application Platform NRT Non-Real Time OCH Optical Channel NRTL Nationally Recognized Test Laboratory OCI Open Connection Indication NRTVBR Non Real-Time Variable Bit Rate OC-n Optical Carrier-number; Optical Carrier where N NRZ Non-Return to Zero denotes a multiple of 51.84 Mb/s ns Nanosecond OCT Octet Count NSA Non Service Affecting OCTU Optical Channel Transport Unit NSAP Network Service Access Point OCXO Oven-Controlled Crystal Oscillator NSF National Science Foundation (U.S.) ODA Outlet Digital Adapter NSI Network Side Interface ODBMS Object Database Management System NSN Nationally Significant Number ODF Optical Distribution Frame NSP Node Switch Provider; Node Switch Processor ODN Optical Distribution Network NT New Technology ODPR Optically Dedicated Protection Ring NTE Network Terminating Equipment ODU Outdoor Unit NTF No Trouble Found ODUk Optical channel Data Unit where k is 1 or 2 NTFCNCDE Notification Codes (TL1) OEM Original Equipment Manufacturer NTFS New Technology File System OEO Optical-to-Electronic-to-Optical OEPL Optical Ethernet Private Line NTP Network Time Protocol OEPLAN Optical Ethernet Private Local Area Network NTS Near Term Storage; Network Time Synchronization OEVPL Optical Ethernet Virtual Private Line

19 OEVPLAN Optical Ethernet Virtual Private Local Area Network OpUk Optical channel payload Unit where k is 1 or 2 OFC Open Fiber Control; Communication OQPSK Offset Quaternary Phase-shift Keying OFDM Orthogonal Frequency Division Multiplexing ORB Object Request Broker OFS Out of Frame Second Orbital Slot Longitude position above the equator at which a OFTEL Office of Telecommunications (UK Regulator) satellite is located OID Object Identifier ORIG Original; Originating OIU Operator Interface Unit; Optical Interface Unit; ORL Optical Return Loss Office Interface Unit ORP Optical Routing Protocol OLA Optical Line Amplifier; Optical Link Analysis OS Operating System OLB Optical Link Budget OSA Optical Spectrum Analyzer OLM Optical Link Module OSC Optical Supervisory Channel; OLMP Optical Link Management Protocol Optical Service Channel OLS Optical Line System OSDS Operations Systems Data Server OLT Optical Line Termination; Optical Line Terminal OSGI Open Services Gateway Initiative OLTP OSRP Link Termination Point OSHA Occupational Safety and Health Act OM Optical Module OSI Open Systems Interconnection OMC Operation and Maintenance Center OSM OSC Splitter Module OMG Object Management Group OSMINE Operations Systems Modifications for the Integration of Network Elements OMT Orthogonal Mode Transducer OSNR Optical Signal-to-Noise Ratio; ON Optical Network Open Signal-to-Noise Ratio ONE Optical Network Element OSP Optical Signaling Protocol; Outside Plant ONP Open Network Provision OSPF Open Shortest Path First ONT Optical Network Terminal OSPR Optically Shared Protection Ring ONU Optical Network Unit OSRP Optical Signaling and Routing Protocols OO Optical-to-Optical OSS Operations Support System OOB Out of Band OSSAN Operations Support System Access Nodes OOF Out of Frame OSS-AU Out of Service-Autonomous OOK On-Off Keying OSS-AUMA Out of Service-Autonomous and Management OOM1 Out of Multi Frame Stage 1 OSS-AURST Out of Service-Autonomous and Restricted OOM2 Out of Multi Frame Stage 2 OSSI Operational Support System Interface OOO Optical - Optical - Optical OSWF On-site Work Force OOR Out of Range OTC Operations Technical Center; OOS Out of Service Optical Transport Card OOS-MA Out of Service-Management OTDR Optical Time Domain Reflectometer OOS- OTGR Operations Technology Generic Requirements MAANR Out of Service-Management and Abnormal OTN Optical Transport Network OpEx Operations Expenditure OTS Optical Transport System OPM Optical Performance Monitoring; Optical Power Meter OTS RPTR OTS Repeater OPR Optical Power Received OTT Over-The-Top OPS/INE Operations Provisioning System/Intelligent OTU Optical Transport Unit Network Element OUI Organizationally Unique Identifier OPT Optical Power Transmit OUNI Optical User Network Interface OPTORL Optical Return Loss O-UPSR Optical-Unidirectional Path Switched Ring

20 OUSM Optical Utility Services Manager PCP Primary Cross-connection Point, street OUSP Optical Utility Services Platform cabinet/flexibility point Outbound see O/B PCR Peak Cell Rate Outroute see O/B PCS Personal Communication System OW Order Wire PCS Probabilistic Constellation Shaping OXC Optical Cross Connect PDA Personal Digital Assistant PDAP Power Distribution and Alarm Panel P PDC Passive Dispersion Compensator P2P Peer to Peer PDF Portable Document Format P6 Pentium 6 PDH Plesiochronous Digital Hierarchy PA Port Adapter; Pre-Amplifier; Power Amplifier PDI Payload Defect Indication PaaS Platform as a Service PDL Polarization Dependent Loss PABX Private Automatic Branch Exchange PDP Policy Decision Point PAD Power Attenuation Device PDU Power Distribution Unit; Protocol Data Unit PAMA Permanent Assignment Multiple Access PEG Public, Education, Government PAN Personal Area Networking PEM Processor Enhancement Module; PARP Proxy ARP Processor Element Module PAS PanAmSat PEP Policy Enforcement Point PAT Program Association Table PESQ Perceptual Evaluation of Speech Quality PAX Path Adaptation and X-Connect PFE Path Far End PB Petabyte PFM Packet Forwarding Module PBOR Primary-Backup Object Replication PFO Premium Feature Open PPB-TE Provider Backbone Bridging - Traffic Engineering PG Peer Group; Protection Group PBT Provider Backbone Transport PGID Peer Group Identifier PBX Private Branch Exchange PGL Peer Group Leader PC Personal Computer; Physical Contact; PHY Physical Layer Device; Physical Processor Card PIC Programmable Interrupt Controller PCA Protection Channel Access PID Personally Identifiable Data; Protocol Identifier; PCB Printed Circuit Board Packet Identifier; Personal Identification PCC Processor Communication Channel PIF Packet Interface FPGA PCCA Pacific Century Corporate Access PIN Photo Intrinsic; Positive-Intrinsic Negative; PCE Path Computation Element Personal Identification Number PCF Policy Control Function PING Packet Internet Groper PCG Pacific Century Group PIP Plug-In Provisioning PCI Peripheral Component Interconnect PJ Pointer Justification PCM Pulse Code Modulation PL Packet Loss PCMCIA Personal Computer Memory Card PLC Packet Loss Concealment Interface Adaptor PLCN Pilot Line Change Notification PCMM PacketCable Multimedia PLCP Physical Layer Convergence Protocol PCN Program Change Notice; Product Change Notice; PLD Programmable Logic Device Personal Communications Network PLDT Philippines Long Distance PCO Pre-Conditioned Order PLL Phase Locked Loop P-Code Product Code PLM Payload Label Mismatch PLM-P Payload Label Mismatch - Path

21 PLM-V Payload Label Mismatch - VT PS Power Supply; Policy Server PLN PNNI Logical Node ps/nm-km Pico-second PLO Path Layer Overhead PSA Packetcable Service Agreement PM Performance Management; Performance PSBF Protection Switching Byte Failure Monitoring; Program Manager; Project Manager PSC Protection Switching Count; PMA Power Management Algorithm Project Steering Committee PMBB Performance Monitoring Building Block PSD Protection Switching Duration PMD Polarization Mode Dispersion PSEL Presentation Suite PMDC PMD Compensator PSI Program Specific Information PMM Power Management Module PSL Path Signal Label PMO Program Management Office PSM Persistent Stored Module PN Pseudo Noise; Physical Node PSN Packet Switch Node; Packet Switched Network PNC Physical Node Controller P-SNC Permanent SNC PNF Physical Network Function PSQM Perceptual Speech Quality Measurement PNNI Private Network-to-Network Interface; PSR Protection Side Regeneration; Path Switched Ring Private Network Node Interface PST Primary State; Pacific Standard Time PO Purchase Order PSTN Public Switched Telephone Network POC Point Of Contact PSU Power Supply Unit; Packet Switch Unit POH Path Overhead PT Pass-Through; Payload Type POM Project Office Manager PTE Path Terminating Equipment PON Passive Optical Network PTI Payload Type Indicator POP/PoP Point of Presence, usually referring to an Internet PTO Private Telecommunications Operator service provider/access point PTP Physical Termination Point; Point-To-Point; POR Power on Reset Path Termination Point POS Packet over SONET; Positive Terminal PTS Per Trunk Signaling POST Power on Self Test PTSE PNNI Topology State Element POTS Plain Old Telephone Service PTSP PNNI Topology State Packet PPC Power PC PTT Posts, Telegraph, and Telephone company (usually PPD Partial Packet Discard a government monopoly operator) PPJC Positive Pointer Justification Count PV Protocol Violation PPL Point-to-Point Link PVC Permanent Virtual Circuit; Poly Vinyl Chloride; PPM Parts per Minute; Parts Per Million; Pulses Per Million Private Virtual Circuit Pport Physical port PVR Personal Video Recorder PPP Point-to-Point Protocol PWB Printed Wire Board PPS Path Protection Switched; Pulses Per Second PWM Pulse Width Modulation PPT Power Passing Tap PWR Power PRB Project Review Board Q PRBS Pseudo Random Bit Sequence Q3 Telecommunications Management Network (TMN) PRC Primary Reference Clock Interface PRI Primary Rate Interface QAM Quadrature Amplitude Modulation PRNG Pseudo Random Number Generators QL Quality Level PROM Programmable Read Only Memory QMC QUICC Multichannel Controller PROT Protocol; Protection QoS Quality of Service PRS Primary Reference Source QPM Quarterly Progress Meeting

22 QPR Quarterly Progress Report RFP Request for Proposals QPSK Quadrature Phase Shift Keying RFT Radio Frequency Transmitter used to describe large antennas with associated QUICC Quad Integrated Communications Controller receive/transmit equipment R RG Residential Gateway R&D Research and Development; Research and Design RHC Regional Holding Company R.H. Relative Humidity RIB Routing Information Base R/W Read/Write RIN Relative Intensity Noise RA Resource Adapter RIP Routing Information Protocol RADIUS Remote Authentication Dial-In User Service RJ RAI Remote Alarm Indication RJ-11 Registered Jack –11 RAID Redundant Array of Inexpensive Disk; Redundant RKS Record Keeping Server Array of Independent Disk RMA Return Material Authorization; RAIG Resource Availability Information Group Replace Material Authorization RAITN Regional Arab Information Technology Network RMAN Recovery Manager RAM Random Access Memory RMI Remote Method Invocation RAN Regional Area Network; Radio Access Network RMS Root Mean Square RASCOM Regional African Satellite Communications RNR Not Ready to Receive; Remote Failure Indication Organisation ROADM Re-configurable Optical Add/Drop Multiplexer RBF Reconfigurable Blocking Filter ROC Regional Operations Center RBM Regional Business Manager ROI Return On Investment RBOC Regional Bell Operating Company ROM Read Only Memory RBW Resolution Bandwidth ROW Return OrderWire RCC Routing Control Channel RPM Revolutions Per Minute RCV Receiver RPR Resilient Packet Ring RCVR Receiver RR Ready to Receive; Reverse Request RDF Rate Decrease Factor RRB Reliability Review Board RDI Remote Defect Indication RRH Remote Radio Head RDI-L Remote Defect Indication - Line RRO Record Route Object RDI-P Remote Defect Indication - Path RR-R Reverse Request - Ring RED Random Early Detection; Random Early Discard RR-S Reverse Request - Span REF Reference RS Regenerator Section; Reed-Solomon REI Remote Error Indication RS232 Recommended Standard –232 REI-L Remote Error Indication - Line RS-E Ring Switch - East REI-P Remote Error Indication - Path RSOH Regenerator Section Overhead Rev. Revision RSP Route Switch Processor RF Radio Frequency RSTP Resilient Spanning Tree Protocol RFC Request for Comment RST Regenerator Section Terminating RSVP Resource Reservation Protocol RFFP Request For Final Proposals RFI Radio Frequency Interference; Remote Failure RSVP-TE Resource Reservation Protocol with Traffic Indication; Request for Information Engineering RFI-L Remote Failure Indication (detected at R/W Read/Write the line-layer) RS-W Ring Switch - West RFI-P Remote Failure Indication (detected at RT Remote Terminal; Real Time the path-layer)

23 RTC Real-Time Clock S-band frequency band RTI Real-Time Ingest SBG Session Boarder Controller RTN Return (voltage return) SBLK Errored Superblocks RTO Recovery Time Objective SBS Stimulated Brillouin Scattering RTOS Real-Time Operating System SBV Switched Broadcast Video RTP Routing Table Protocol; Real-Time Transport SBW Signal Bandwidth Protocol; Routine Task Procedure SC Service Channel; Square Connector; RTPS Real Time Streaming Protocol Shelf Controller RTRV Retrieve SCADA Supervisory Control and Data Acquisition RTS Ready to Send; Request to Send; SCC Serial Communications Controller; Real Time Operation System Serial Communications Channels RTSP Real Time Streaming Protocol SCCI Small Computer System Interface RTT Round-Trip Time SCCP Signalling Connection Control Part, part of SS7 RTU Right To Use S-CDMA Synchronous Code Division Multiple Access RTVBR Real-Time Variable Bit Rate Traffic SCE Service Creation Environment, IN block RU Rack Unit SCEP Service Creation Environment Point, IN block RW Rewind SCF Service Control Function, IN block RWA Routing and Wavelength Assignment SCM Service Channel Modem; Sub-Carrier Multiplexing RX Receive SCN Service Channel Network; Shared Content Network Rx Line Receive Line SCP Service Control Point, IN block RZ Return to Zero SCPC Single Channel Per Carrier RZ-DPSK Return to Zero Differential Phase Shift Keying SCR Sustainable Cell Rate; Silicon Controlled Rectifier SCSI Small Computer System Interface S SCTE Society of Cable Telecommunications Engineers s Second SD Signal Degrade; Signal Detect; Standard Definition s.f. Square Foot SDA System Design Authority S/IMP Signal to Impulse Ratio SDCC Section Data Communications Channel S/N Signal to Noise Ratio SDF Service Data Function, IN block SA Service-Affecting SDH Synchronous Digital Hierarchy SAAL Signaling ATM Adaptation Layer SDI Secure Digital Interface; Serial Digital Interface SaaS Software as a Service SDL Synchronous Data Link; Synchronous Delay Line SAAS Software As A Service SDLC Synchronous Data Link Control SABLIME Product Administration System (AT&T) SDMA Space Domain Multiple Access SAN Storage Area Network SDMH Severely Degraded Modem Hours SAP Secondary Audio Program SDN Software-Defined Networking SAR Segmentation and Reassembly SDP Service Data Point, IN block SARP Switching Address Resolution Protocol SD-P Signal Degrade - Path SAS Severely Errored Frame and AIS Seconds SD-R Signal Degrade - Ring SASE Standalone Synchronization SDRAM Synchronized Dynamic Random Access Memory SATA Serial AT Attachment SD-S Signal Degrade-Span SATCOM Satellite Communications Satellite Capacity SDTV Standard Definition Television SATT Synchronization, Alarms, and Telemetry SDU Service Data Unit Termination SDV Switched Digital Video SAW Surface Acoustic Wave

24 SE Systems Engineer SLA Service Level Agreement SEAL Simple and Efficient Adaptation Layer SLIP Serial Line Internet Protocol SEC Secondary SLM Service Layer Manager SEF Severely Errored Framing SLOSS Synchronization Loss SEFS Severely Errored Frame Seconds SLR Service Level Report SEFS-S Severely Errored Framing Seconds - Section SLTE Submarine Line Terminating Equipment SEM Service Entitlement Manager SM Single Mode; Switching Module; Shelf Manager SEMS Severely Errored Multi-frame Seconds SMAP Service Management Access Point, IN block SerDes Serializer/DeSerializer SMB Small and Medium Business SES Severely Errored Seconds SMC Serial Management Controllers; Standard SES-L Severely Errored Seconds - Line Management Committee SES-LFE Severely Errored Seconds - Line Far End SMCS Short Message Service Center SES-P Severely Errored Seconds - Path SMDS Switched Multimegabit Data Service SES-PFE Severely Errored Seconds - Path Far End SME Small and Medium Enterprise; Short Message Entity SESR Severely Errored Second Ratio SMF Session Management Function SES-RS Severely Errored Seconds - Regenerator Section SMF Single Mode Fiber SES-S Severely Errored Seconds - Section SMIR Single Mode Intermediate Reach SES-V Severely Errored Seconds - VT SML Service Management Layer SES-VFE Severely Errored Seconds - VT Far End SMLR Single Mode Long Reach SETS Synchronous Equipment Timing Source SMM Service Mediation Module SF Signal Failure; Super Frame SMON Switch Monitor SFD Start of Frame Delimiter SMOP Service Method of Procedure SFF Small Form Factor (connector) SMP Service Management Point, IN block SFO Sync Frequency Offset SMS Service Management System, IN block; Service SFP Small Form-factor Pluggable Management Suite; Short Message Service SF-R Signal Failure - Ring SMSC Short Message Service Centre, part of GSM SF-S Signal Failure - Span messaging system SG Signaling Gateway SMT Surface Mount Technology; Self-Monitoring Task SGC Signaling Gateway Controller S-MTA Standalone Multimedia Terminal Adaptor S-GW Serving Gateway SN Service Node, IN block sh Bourne Shell SNA Systems Network Architecture SHx Shelf Number SNC Subnetwork Connection; Subnetwork Controller SI Serial Interface; Service Independent ; SNCP Subnetwork Connection Protection System Integrator SNCP/I Subnetwork Connection Protection/Inherent SIB Service Independent Building Block, IN block monitoring SIC System Integrity Control; Standard Industrial SNCP/N Subnetwork Connection Protection/Non-intrusive Classification monitoring SID System Identification number; Source Identifier SNG Satellite News Gathering SIF SONET Interoperability Forum; Switch Interface FPGA SNM Switching Network Manager SIM Service Interface Module SNMP Simple Network Management Protocol SIP Session Initiation Protocol SNP Sequence Number Protection SITA Société Internationale de Télécommunications SNR Signal-to-Noise Ratio Aéronautique SNTP Simple Network Time Protocol

25 SOA Semiconductor Optical Amplifier SST Secondary Service State SOAP Simple Object Access Protocol SSTUR Site-Specific Turn-Up Report SOF Start of Frame SSU Synchronization Supply Unit; Subscriber Terminals SOH Section Overhead; State of Health ST Straight Terminus; Straight Tip SOHO Small Office/Home Office ST1 Stratum 1; Switched T1 SONET Synchronous Optical Network, U.S. equivalent to SDH ST2 Stratum 2 SOP Standard Operating Procedure; Service Provider ST3 Stratum 3 SP Shelf Processor; Shelf Pump; Service Provider ST3E Stratum 3 Enhanced SPC SONET Permanent Circuit ST4 Stratum 4 (Asynchronous) SPCN Satellite Personal Communications Network STB Set-Top Box SPE Synchronous Payload Envelope STC Stacking and Timing Card SPF Shortest Path First STE Section Terminating Equipment; Section SPI Serial Peripheral Interface; Service Provider Interface Terminating Element SPM Self-Phase Modulation STII (2) Type of optical connector SPR/SPRing Shared Protection Ring STM Synchronous Transfer Mode, or Module SPTP Service Path Termination Point STM-0 Synchronous Transfer Mode level 0, SDH bit rate = 51.84 Mb/s SPVC Soft Permanent Virtual Connection; Soft Permanent Virtual Circuit STM-1 Synchronous Transfer Mode level 1, SDH bit rate = 155.52 Mb/s SQL Structured Query Language STM-16 Synchronous Transfer Mode level 16, SDH bit rate = SR Short Reach (fiber) 2488.32 Mb/s SRAM Static Random Access Memory STM-4 Synchronous Transfer Mode level 4, SDH bit rate = SRC/DST Source/Destination 622.08 Mb/s SRD Software Release Document STM-64 Synchronous Transfer Mode level 64, SDH bit rate = SRF Specialised Resource Function, IN block 9953.28 Mb/s SRN Software Release Notice STM-n Synchronous Transport Module n SRS Stimulated Raman Scattering STM-nC Synchronous Transport Module of level n SRTS Synchronous Residual Time Stamp concatenated SRVEFF Service Affecting (TL1) STMX SONET/SDH Thin Multiplexer SS/TDMA Satellite Switched Time Division Multiple Access, STP Spanning Tree Protocol; Shielded Twisted Pair Intelsat service STS Synchronous Transport Signal SS5 Signaling System 5 STS-1 Synchronous Transport Signal Level 1 SS7 Signalling System 7, supported by the ITU-T, STS-3 Synchronous Transport Signal Level 3 also known as CCITT 7 STS-3c Synchronous Transport Signal Level 3, concatenated SSB Single Sideband STS-n Synchronous Transport Signal n SSCOP Service-Specific Connection Oriented Protocol STS-Nc Contiguous Concatenation of N STS-1 SPEs SSCS Service-Specific Convergence Sublayer STS-N-Xv Virtual Concatenation of X STS-N SPEs SSEL Session Selector STU Secure Telephone Unit; Synchronized, Traceability SSF Server Signal Failure; Service Switching Function Unknown; Stratum Traceability Unknown SSH Security Shell STU-P Stratum Traceability Unknown-Provisioned SSL Secure Sockets Layer SVC Switched Virtual Circuit SSM Synchronization-Status Messages SVCC Switched Virtual Channel Connection SSMF Standard Single Mode Fiber SVOD Subscription SSP Service Switching Point, IN block SVP Secure Video Processor SSPA Solid State Power Amplifier SVPC Switched Virtual Path Connection

26 SW Software TE Terminal Equipment SWCA Split Working Channel Access TEC Thermo-Electric Cooler SWID Software Identifier TED Traffic Engineering Database SWOD Software ODACS TEI Terminal Endpoint Identifier; SX Short Reach as in 1000Base-SX Terminal Equipment Identifier SYNC Synchronization Telco Telephone Company SYNCIO Synchronized Input/Output TELR Talker Echo Loudness Rating SYSLOG System Log TEO Telephone Equipment Order TERM Termination T TFT Thin Film Transistor T1 Service or line operation at the DS-1 rate TFTP Trivial File Transfer Protocol T1 1.544 Mb/s (US orientated) TG Timing Generator T3 Digital Carrier System for DS3 Signals TGCP Trunking Gateway Control Protocol TAC Transport Aggregated Circuit; TGS Time Generation System Technical Assistance Center THEC Corrected Type Header Error Correction Code TACACS Terminal Access Controller Access THz TeraHertz (1012 hertz) Control Systems TI Terrestrial Interference TACS Total Access Communications Systems TIA Telecommunications Industry Association (Analogue) TID Target Identification; Terminal Identification TADR Target Address TIE Time Interval Error TADRMAP Target Address Map TIM Trace Identifier Mismatch; TAM Total Available Market Transmit Intermediate Multiplexer TAP Test Access Port; Technician Access Port TIM-S Trace Identifier Mismatch - Section TARP Target Identifier Address Resolution Protocol TIRKS Trunk Integrated Record Keeping System TAS Telecommunications Authority of Singapore TISSA Time Space Switch Application-Specific TB Terabyte Integrated Circuit TBD To Be Determined TKIP Temporal Key Integrity Protocol TBOS Telemetry Byte Oriented Serial Protocol TL-1 Transaction Language 1 TBUS Timing Bus TL-1 CLI Transaction Language One, Command Line TC Transmission Convergence; Transport Complex; Interface Transport Channel TLC Transport Logical Connection TCA Threshold Crossing Alert; TLI Transaction Language Command Line Interface Timing Control and Access TLS Transparent LAN Services, Transport Layer TCBE Total Corrected Bit Error Security TCM Trellis Coded Modulation; Transport Channel TLSR Transoceanic Line Switched Ring Members TLV Type-Length-Value TCMO Transport Complex Managed Object TM Timing Module; Transaction Manager TCP Transmission Control Protocol; Trouble Cleaning Procedure TMC Terminal Monitor and Control TCP/IP Transmission Control Protocol/Internet Protocol TML Telephony Markup Language TCTP Transparent Connection Termination Point TMN Telecommunications Management Network TD Traffic Director TMO Trans Metro Optical (platform) TDEV Time Deviation tmout Time Out TDM Time Division Multiplexing tmper Time Period TDMA Time Division Multiple Access TMUX Terminal Multiplexer

27 TNL Ethernet Tunneling UART Universal Asynchronous Receiver/Transmitter TNM Transport Network Management UAS Unavailable Seconds TOD Television on Demand UASL Unavailable Second Count-Line ToD Time of Day UAS-L Unavailable Seconds - Line TOH Transport Overhead UAS-LFE Unavailable Seconds - Line Far End TOP Task Oriented Practice; Task Oriented Procedure UASP Unavailable Second Count-Path TOS Type of Service UAS-P Unavailable Seconds - Path TP Termination Point UAS-PFE Unavailable Seconds - Path Far End TPFI Timing Plane Fault Isolation UAS-RS Unavailable Seconds - Regenerator Section TQM Total Quality Management UAS-S Unavailable Seconds - Section TR Technical Reference UAS-V Unavailable Seconds - VT TRIB Tributary UAS-VFE Unavailable Seconds - VT Far End TRM Technical Review Meeting UAT Unavailable Time tRTO TCP Retransmit Timeout UB Uncorrected Block TrTOH Transparent Transport Overhead U-Band Ultra-long Band TS Time Slot; Time Stamp; Time Synchronization UBR Undefined Bit Rate; Unspecified Bit Rate TSA Time Slot Assignment UBRVBR Unspecified Bit Rate Variable Bit Rate TSD Transport System Division UC User Channel TSE Topology State Element UCBE Uncorrectable Block Error TSEL Transport Selector UCD Upstream Channel Descriptor TSF Transport Signal Failure UD Unconditional Disconnect TSG Timing Signal Generator UDLR Unidirectional Link Routing TSI Time Slot Interchange; Time Switch Interchange UDP User Datagram Protocol TSN Time Sensitive Networking UDR Unconditional Disconnect Response TSR Technical Service Representative UDM Unified Data Management TSX Time-Space Switch ASIC UE User Equipment TTE Transparent Terminal Equipment UEM Universal Equipment Modules TTL Transistor Transistor Logic; Time to Live UEQ Unequipped TTP Trail Termination Point UGC Universal Gateway Carrier TTTP Transparent Trail Termination Point UGS Unsolicited Grant Service TU Tributary Unit; Transmission Unit UHD Ultra High Density TUG Tributary Unit Group UHF Ultra High Frequency TUG-n Tributary Unit Group, level n UI User Interface TU-n Tributary Unit, level n UIC User Interface Client TV Television UID User Identifier TVRO Television Receive Only earth station UITS Unacknowledged Information Transfer Service TW TrueWave – fiber brand UL Underwriters Laboratories TWC TrueWave Classic – fiber brand ULH Ultra Long Haul TX Transmit ULSDCC Upper Layer Section Data Communications Tx Line Transmit Line Channel UMTS Universal Mobile Telecommunications System UNEQ Unequipped Path; Unequipped U UNEQ-P Unequipped Path UAE United Arab Emirates

28 UNEQ-V Unequipped VT VCL Virtual Channel Link UNEs Unbundled Network Elements VCM Virtual Concatenation-group Member UNI User Network Interface VC-N Virtual Container Level N (N=11, 12, 2, 3, 4) UNI/UNIF User Network Interface VC-N-Xc Contiguous Concatenation of X Virtual Containers UNII Unlicensed National Information Infrastructure at Level N UOG Universal OSS Gateway VC-N-Xv Virtual Concatenation of X Virtual containers at Level N UPC Ultra Physical Contact; Universal Packet Carrier; Usage Parameter Control VCO Voltage Controlled Oscillator UPF User Plane Function VCR Video Cassette Recorder UPN Universal Personal Number VCSEL Vertical Cavity Surface-Emitting Laser UPnP Universal Plug and Play VCXO Voltage Controlled Crystal Oscillator UPS Uninterrupted Power Supply VDC Volts Direct Current UPSR Unidirectional Path Switched Ring VDSL Very-high-bit-rate Digital Subscriber Line UPT Universal Personal Telecommunications VEC Voice Equivalent Circuit URI Universal Resource Identifier VF Virtual Fiber; Virtual Facility URL Universal Resource Locator VFCU Voice/FAX Channel Unit US Upstream VFTP Virtual Facility Termination Point USB Universal Serial Bus VG Virtual Group USEPA United States Environmental Protection Agency VGA Variable Gain Amplifier UTC Universal Time Coordinated; Universal Transport VHF Very High Frequency Carrier VIM Virtual Infrastructure Manager UTOPIA Universal Test and Operations Physical Interface VLAN Virtual Local Area Network for ATM VLR Very Long Reach UTP Unprotected Termination Point; VM Voice Mail; Virtual Memory; Virtual Machine Unshielded Twisted Pair VME Versa Module Eurocard UV Ultraviolet VMM Voice/Modem Module UVC Universal Voice Carrier; Universal Video Carrier VNF Virtual Network Function V VNFI Virtual Network Function Infrastructure VOA Variable Optical Attenuator V Voltage VOD Video on Demand V/A Video/Audio VoIP Voice over Internet Protocol VAC Voltage Alternating Current VOM Volt-Ohm Meter VAD Voice Activity Detection VOQ Virtual Output Queuing VADSL Very high speed (Asymmetric) Digital Subscriber Line VOW Voice Order Wire VAP Virtual Access Partitioning VP Virtual Path V-band 50/40 GHz VPC Virtual Path Connection VBI Vertical Blanking Interval VPCI Virtual Path Connection Identifier VBR Variable Bit Rate VPG Virtual Path Group VC Virtual Circuit; Virtual Channel; Virtual Container; VPI Virtual Path Identifier Virtual Concatenation VPI/VCI Combined, VPI and VCI identify a connection VCAT Virtual Concatenation on an ATM Network VCC Virtual Channel Connection VPL Virtual Path Link VCG Virtual Concatenation Group VPLS Virtual Private LAN Service VCI Virtual Channel Identifier VPN Virtual Private Network

29 V-pole Vertical-pole WIF Wide Area Network Interface VPS Voice Processing System WiFi Wireless Fidelity VPSP Virtual Path Switch Protection WiMedia An alliance for Wireless Multimedia VR Virtual Reality WLAN Wireless Local Area Network vRouter Virtual Router WLL/WiLL Wireless , WiLL is also Motorola’s VRRP Virtual Router Redundancy Protocol WLL product line name VSA Virtual-Scheduling Algorithm; Vector WM9 Windows Media Player Version 9 Signal Analyzer WPA Wireless (WiFi) Protected Access VSAT Very Small Aperture Terminal WPS Working/Protect Splitter VSI Vendor-Specific Information WRED Weighted Random Early Discard; Weighted VSR Very Short Reach Random Early Detection VSSP Virtual Service Switching Point WSS Wavelength Selective Switch VT Virtual Tributary WTO World Trade Organisation VT-100 Terminal Emulation System WTR Wait to Restore VTG Virtual Tributary Group WWN World Wide Name V-UNI Virtual User Network Interface WWW World Wide Web

W X W Watt; Working X.25 Packet Switched Communications Interface WAD Wavelength Add and Drop XC Cross Connect WAN Wide Area Network XCVR Transceiver WB Working Band; Westbound XDSL See DSL (Digital Subscriber Line) WBS Work Breakdown Structure XFP 10 Gb/s small form-factor pluggable transceiver WC Watts per Channel XML Extensible Markup Language WCA Working Channel Access XMTR Transmitter WCSS WDM Capable Switching System XPM Cross-Phase Modulation W-DCS Wideband Digital Cross-Connect System Y WDM Wavelength Division Multiplexing YANG Yet Another Next Generation WDT Watchdog timer WE Western Europe Z WECA Wireless Ethernet Compatibility Alliance ZAC Zero Administration Client WEP Wired Equivalency Privacy ZWP Zero Water Peak WFA Workforce Automation WFM Workforce Management WFQ Weighted Fair Queuing

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