RFC Editor Abbreviations List September 2013 ---------------------------------------------------------------------- It is common in technical writing to abbreviate complex technical terms by combining the first letters. The resulting abbreviations are often called acronyms. Editorial guidelines for the RFC series generally require expansion of these abbreviations on first occurrence in a title, in an abstract, or in the body of the document. The RFC Editor attempts to keep the use of abbreviations consistent and to point out conflicts to authors. For this purpose, we have built the abbreviation list below. This list contains abbreviations appearing in RFCs and sometimes reflects discussions with authors, WG chairs, and/or ADs. There is no claim of completeness. Note that some abbreviations have multiple expansions. Some abbreviations are so well known that expansion is probably unnecessary. The RFC Editor exercises editorial judgment about whether a particular use of one of the "well-known" abbreviations requires expansion. (For example, strict adherence to the expansion requirement can lead to impossibly ugly titles.) In the following list of abbreviations, those that are usually (but not necessarily) treated as "well known" are marked with asterisks. However, since there are so many different abbreviations and there is a range of knowledge among RFC readers, we tend to expand abbreviations in case of doubt. Finally, this list includes some terms that look like abbreviations but are actually fixed names for things, and hence cannot and should not be expanded. These are noted as "No expansion". ---------------------------------------------------------------------- 2G *- Second generation cellular (mobile) (2G) (RFC 3316) 2.5G *- Enhanced second generation cellular (mobile) (2.5G) (RFC 5194) 3G *- Third generation cellular (mobile) (3G) (RFC 3316) 3PCC - Third Party Call Control (3PCC) 3GPP IMS - Third Generation Partnership Project Internet Multimedia System or - Third Generation Partnership Project IP Multimedia Subsystem 4G *- 4th Generation Mobile network (mobile) (4G) (RFC 6965) 4rd - IPv4 Residual Deployment (4rd) (RFC 6346) 6CO - 6LoWPAN Context Option (6CO) (RFC 6775) 6LBR - 6LoWPAN Border Router (6LBR) (RFC 6345) 6LN - 6LoWPAN Node (6LN) (RFC 6775) 6LoWPANs - IPv6 over Low-Power Wireless Personal Area Networks (6LoWPANs) (RFC 4919) 6LR - 6LoWPAN Router (6LR) (RFC 6606) 6LSA - IPv6 Label Switching Architecture (6LSA) (RFC 6294) 6PE - IPv6 Provider Edge (6PE) (RFC 4798) 6rd - IPv6 Rapid Deployment on IPv4 Infrastructures (RFC 5969) 6to4-PMT - 6to4 Provider Managed Tunnel (6to4-PMT) (RFC 6732) A+P - Address plus Port (RFC 6346) AAA - Authentication, Authorization, and Accounting (AAA) AAC - Advanced Audio Coding (AAC) AAD - additional authenticated data (AAD) AAH - Abandoning All Hope (AAH) (RFC 6981) AAK - Authenticated Anticipatory Keying (AAK) (RFC 6630) AAL5 - ATM Adaptation Layer 5 (AAL5) ABI - application binary interface (ABI) (RFC 6458) ABNF *- Augmented Backus-Naur form ABR - Area Border Router (ABR) ABRO - Authoritative Border Router Option (ABRO) (RFC 6775) AC - Access Controller (AC) or - Attachment Circuit (AC) (RFCs 3985 and 4719) ACAP - Application Configuration Access Protocol (RFC 2244) ACE - Access Control Entry (ACE) (RFC 5661) ACH - Associated Channel Header ACK - No Expansion (not an abbreviation) ACL - Access Control List (ACL) AD - Authentic Data (bit or flag) (AD) (RFC 4035) ADISC - Address Discovery Extended Link Service (ADISC) Pronounced "ay-disk". ADM - Add-Drop Multiplexer (as in SONET ADM) ADMD - ADministrative Management Domain (RFCs 5451, 5585, 5598) ADS - Astrophysics Data System (ADS) ADSL - Asymmetric Digital Subscriber Line (ADSL) (RFC 5650) ADSP - Author Domain Signing Practices (ADSP) (RFC 5617) ADU - Application Data Unit (ADU) (RFC 5219) AEAD - Authenticated Encryption with Associated Data (AEAD) AES *- Advanced Encryption Standard (AES) AF - Assured Forwarding (as in "Diffserv AF" - RFC 5975) AFBR - Address Family Border Router (AFBR) (RFC 4925) AFI - Address Family Identifier (AFI) AfriNIC *- African Network Information Center AFS *- Authentication File System Typically not expanded Proper name is now AFS; expansion name dropped in the 1990s (RFC 5864) AFTR - Address Family Transition Router (AFTR) (RFC 6333) AH - Authentication Header (AH) AHS - Additional Header Segment (AHS) (RFC 3720) or - Adaptive HTTP Streaming (AHS) (RFC 6983) AIA - Authority Information Access (AIA) AIMD - Additive Increase Multiplicative Decrease (AIMD) AIS - Alarm Indication Signal (AIS) AKA - Authentication and Key Agreement (AKA) AMI - Advanced Metering Infrastructure (AMI) (RFC 6272) AKM - Authentication and Key Management (AKM) (RFC 5416) ALC - Asynchronous Layered Coding (ALC) (RFC 5775) ALG - Application Level Gateway (ALG) (RFC 5382) or - Application Layer Gateway (ALG) (RFCs 4966, 6052) ALOC - Area Locator (ALOC) (RFC 6306) ALT - Alternative Logical Topology (ALT) (RFC 6115) ALTO - Application-Layer Traffic Optimization (ALTO) (RFC 6029) AMEI - Association of Musical Electronics Industry (AMEI) AMID - Additive Increase Multiplicative Decrease (AMID) AMR - Adaptive Multi Rate (AMR) AMR-NB - Adaptive Multi Rate - NarrowBand (AMR-NB) AMR-WB - Adaptive Multi Rate - WideBand (AMR-WB) AMS - authoritative mapping server (AMS) (RFC 5582) AMSS - Advanced Mobile Station Software (AMSS) (RFC 6419) ANAT - Alternative Network Address Types (ANAT) (RFC 4091) ANDSF - Access Network Discovery and Selection Function (ANDSF) (RFC 6153) ANG - Access Network Gateway (ANG) (RFC 6342) ANSI *- American National Standards Institute AOR - address of record (AOR) (RFC 5109) AP - Access Point (AP) API *- Application Programming Interface APM - Application Performance Measurement (APM) APN - Access Point Name (APN) (RFC 6342) APNIC *- Asia Pacific Network Information Centre APP - Application-specific functions (RFC 3550) AQM - Active Queue Management (AQM) (RFC 3168) AR - Address Resolution (AR) or - Access Router (AR) (RFC 3753) ARF - Abuse Reporting Format (ARF) (RFC 5965) ARIN *- American Registry for Internet Numbers ARMv4 *- Advanced RISC Machine version 4 (RFC 6366) ARO - Access Router Option (ARO) (RFC 4889) or - Address Registration Option (ARO) (RFC 6775) ARP - Address Resolution Protocol (ARP) ARQ - Automatic Repeat reQuest AS - Autonomous System (AS) or - Applicability Statement (AS) or - Authentication Service (AS) (RFC 4120 or Kerberos) or - Application Specific (AS) (RFC 3890) ASBR - Autonomous System Border Router (ASBR) ASCII *- American Standard Code for Information Interchange ASE - Autonomous System External (ASE) or - amplifier spontaneous emission (ASE) ASIC - Application-specific Integrated Circuit (ASIC) ASM - Any-Source Multicast (ASM) or - address-sharing mechanism (ASM) (RFC 6864) ASN - Access Service Network (ASN) or - Autonomous System Number (ASN) (RFC 6382) ASN.1 *- Abstract Syntax Notation One ASNGW - Access Service Network Gateway (ASNGW) (RFC 6965) ASON - Automatically Switched Optical Network ASP - Application Service Provider (ASP) (RFC 5985) ASR - Automatic Speech Recognition (ASR) (RFC 6787) ATA - Analog Telephone Adaptor (ATA) (RFC 5194) ATD - Activation Time Delay (ATD) ATM *- Asynchronous Transfer Mode (ATM) or *- Automatic Teller Machine (ATM) ATU - ADSL Transceiver Unit (ATU) AU - Access Unit (AU) AUID - Agent or User Identifier (AUID) (RFC 6376) AVA - Attribute Value Assertion (AVA) (RFC 4514) AVP - attribute-value pair (AVP) *- Audio-Visual Profile (AVP) AVPF *- Audio-Visual Profile with Feedback (AVPF) AVT - Audio/Video Transport AXFR - Asynchronous Full Transfer (AXFR) or - Authoritative Transfer or - full zone transfer (AXFR) (RFC 6168) B-ISDN - Broadband Integrated Services Digital Network (B-ISDN) B2BUA - back-to-back user agent (B2BUA) B4 - Basic Bridging BroadBand (B4) (RFC 6333) BAB - Bundle Authentication Block (BAB) BACP - Bandwidth Allocation Control Protocol (BACP) (RFC 5000) or - Bonding Aggregation Control Protocol (BACP) (RFC 6767) BB - Bottleneck Bandwidth (BB) (RFC 6349) BCC - Bonding Communication Channel (BCC) (RFC 6766) BCE - Bonding Channel Entity (BCE) (RFC 6765) BCH *- Bose, Ray-Chaudhuri, Hocquenghem Typically not expanded; as in "BCH code" BCP *- Best Current Practice (should only be expanded for introductory docs, e.g., Tao of the IETF) or - Bridging Control Protocol (BCP) (RFC 3518) BDP - Bandwidth-Delay Product (BDP) (RFC 3481) BECN - Backward Explicit Congestion Notification (BECN) BEEP - Blocks Extensible Exchange Protocol (BEEP) BEK - bundle encryption key (BEK) BER *- Basic Encoding Rules - bit error rate (BER) (RFC 4837) BFCP - Binary Floor Control Protocol (BFCP) BFD - Bidirectional Forwarding Detection (BFD) BGP *- Border Gateway Protocol BIA - Bump-in-the-API (BIA) (RFC 3338) BIH - Bump-in-the-Host (BIH) (RFC 6535) BIS - Bump-in-the-Stack (BIS) (RFC 2767) BN - Bundle Node (BN) BNF *- Backus-Naur form BNG - Broadband Network Gateway (BNG) BOF *- Birds of a Feather BPDU - Bridge PDU (BPDU) (RFC 6325) BR - Border Router (BR) BRAS - Broadband Remote Access Server (BRAS) BRDP - Border Router Discovery Protocol (BRDP) (RFC 5887) BRI - Basic Rate Interface (BRI) BRPC - Backward Recursive PCE-Based Computation (BRPC) (RFC 5441) BS - Base Station (BS) (RFC 6342) BSC - Base Station Controller (BSC) (RFC 6459) BSD *- [name of operating system; better known by acronym] BSM - Bootstrap Message (BSM) BSO - Basic Security Option (BSO) BSP - Bundle Security Protocol (BSP) BSR - Bootstrap Router (BSR) BSSID - Basic Service Set Identifier (BSSID) BTMM - Back to My Mac (BTMM) BTS - Base Tranceiver Station (BTS) (RFC 6965) BTU - Bonding Transmission Unit (BTU) (RFC 6766) BW - Bandwidth (BW) (RFC 6928) CA - certification authority (CA) CA - cryptographic authentication (CA) (RFC 4813 update) CAA - Certification Authority Authorization (CAA) (RFC 6844) CAB - Converged Address Book (CAB) (RFC 6715) CAC - Connection Admission Control (CAC) CAdES - CMS Advanced Electronic Signatures (CAdES) CalDAV - Calendaring Extensions to WebDAV (CalDAV) (RFC 4791) CALS - Computer-Aided Acquisition and Life-Cycle Support (CALS) CAM - Content Addressable Memory (CAM) captcha - Completely Automated Public Turing test to tell Computers and Humans Apart (captcha) (RFC 5039) CAP - Candidate Access Point (CAP) (RFC 6630) CAPWAP - Control and Provisioning of Wireless Access Points (CAPWAP) CAR - Committed Access Rate (CAR) (RFC 6349) CARD - Candidate Access Router Discovery (CARD) CATNIP - Common Architecture for Next Generation Internet Protocol (CATNIP) (RFC 1707) CAVE - Cellular Authentication and Voice Encryption (CAVE) CBC - Cipher Block Chaining (CBC) CBC-MAC - Cipher Block Chaining Message Authentication Code (CBC-MAC) CBID - Crypto-Based Identifier (CBID) CBR - Constant Bitrate (CBR) CC - CSRC count (CC) (RFC 3550) or - Call Completion (CC) (RFC 6910) CC-V - Continuity Check and Connectivity Verification (CC-V) (RFC 6371) CCE - Call-Completion Entity (CCE) (RFC 6910) CCID - Congestion Control Identifier (CCID) (RFC 5238) or - Content Collection IDentifier (CCID) (RFC 6983) CCM - Counter with CBC-MAC (CCM) - Codec Control Messages (CCM) CCNL - Call Completion on Not Logged-in (CCNL) (RFC 6910) CCNR - Call Completion on No Reply (CCNR) (RFC 6910) CCMP - Counter Mode with CBC-MAC Protocol (CCMP) ccTLD - Country Code Top Level Domain (ccTLD) CCXML - Call Control XML (CCXML) CDF - Comma-Delimited Format or - cumulative distribution function (CDF) CDMA *- Code Division Multiple Access CDMA2000 - No Expansion It is a registered trademark of the Telecommunications Industry Association in the US. CDMI - Cloud Data Management Interface (CDMI) (RFC 6208) CDN - Call-Disconnect-Notify (CDN) or - Content Delivery Network (CDN) (RFC 5694) or - Content Distribution Network (CDN) (RFC 3914) CDNI - Content Distribution Network Interconnection (CDNI) (RFC 6707) CDP - Content Delivery Protocol (CDP) (RFC 5052) CDR - Call Data Record (CDR) (RFC 6707) CE - Congestion Experienced (CE) or - Customer Edge (CE) - Control Element (CE) (RFC 3746) CEID - Control Element ID (CEID) CEK - content-encryption key (CEK) (RFC 2630) CELP - Code-Excited Linear Prediction (CELP) CEMA - Connection Establishment for Media Anchoring (CEMA) (RFC 6714) CEP - Circuit Emulation over Packet (CEP) CERT *- Computer Emergency Response Team (CERT) (RFC 1147) CES - Circuit Emulation Service (CES) - Core-Edge Separation (CES) (RFC 6306) CESoPSN - Circuit Emulation Service over Packet Switched Network (CESoPSN) (RFC 5086) CFB - Cipher FeedBack (CFB) CFWS - comments and/or folding white space (CFWS) (RFC 5322) CGA - Cryptographically Generated Addresses (CGA) (RFC 3972) CGI - Common Gateway Interface (CGI) CGN - Carrier-Grade NAT (CGN) CHAP - Challenge Handshake Authentication Protocol (CHAP) CHbH - Critical Hop-by-Hop (CHbH) (RFC 6325) CIA - Confidentiality, Integrity, and Availability (CIA) (RFC 6272) CID - Carousel Instance Descriptor (CID) (RFC 6968) - Connection Identifier (CID) (RFC 5046) - Content Identifier (CID) (RFC 2392) - Context Identifier (CID) (RFC 3095) CIDR - Classless Inter-Domain Routing (CIDR) CIID - Carousel Instance IDentifier (CIID) (RFC 6968) CIPID - Contact Information in PIDF (CIPID) CIPSO - Common Internet Protocol Security Option (CIPSO) CIS - Cryptographic Interoperability Strategy (CIS) (RFC 6318) CISC - Complex Instruction Set Computer (or Computing) CIST - Common and Internal Spanning Tree (CIST) (RFC 6325) CItE - Critical Ingress-to-Egress (CItE) (RFC 6325) CLDR - Connectionless Data Response (CLDR) or - Common Locale Data Repository (CLDR) CLEI - Common Language Equipment Identifier (CLEI) CLI - command line interface (CLI) or - Call Level Interface (CLI) - Calling Line Identification (CLI) (RFC 5194) CLNP - Connectionless Network Protocol (CLNP) CLNS - Connectionless Network Service (CLNS) CLP - Cell Loss Priority (CLP) (RFC 4594) A flag in an ATM cell. CMAC - Cipher-Based Message Authentication Code (CMAC) (RFC 4494) CMC - Certificate Management over CMS (CMC) (RFC 2797) CMCC - Conference and Media Control Client (CMCC) (RFC 6504) CMS - Cryptographic Message Syntax (CMS) CMTS - cable modem termination system (CMTS) CN - Client Node (CN) or - correspondent node (CN) or - Common Name (CN) CNF - Cache-and-Forward (CNF) (RFC 6392) CNG - comfort noise generation (CNG) CoA - Care-of Address (CoA) or - Change-of-Authorization (CoA) (RFC 5176) CO - Central Office (CO) (RFC 5066) COM - Component Object Module (COM) (RFC 6355) COMEDIA - Connection-Oriented Media (COMEDIA) (RFC 4145) CONS - Content distribution Overlay Network Service (CONS) (RFC 6833) COPS - Common Open Policy Service (COPS) CORS - Cross-Origin Resource Sharing (CORS) (RFC 6202) Corba - common object request broker architecture (Corba) CoS - Class of Service (CoS) CoT - Care-of Test (CoT) (RFC 6275) CoTI - Care-of Test Init (CoTI) (RFC 6275) CP - Certificate Policy (CP) (RFC 6844) CPA - Certification Path Advertisement (CPA) (RFC 3971) CPE - Customer Premises Equipment (CPE) (RFC 4837) CPIM - Common Presence and Instant Messaging (CPIM) (RFC 3922) CPL - Call Processing Language (CPL) (RFC 3880) CPP - Common Profile for Presence (CPP) (RFC 3859) CPS - Certification Path Solicitation (CPS) (RFC 3971) -or- - Certification Practices Statement (CPS) (RFC 6844) CPU *- Central Processing Unit CR - carriage return (CR) or - Correspondent Router (CR) (RFC 4885) CRC - Cyclic Redundancy Check (CRC) CR-LDP - Constraint-based Routed Label Distribution Protocol (CR-LDP) CRIO - Core Router-Integrated Overlay (CRIO) (RFC 6832) CRISP - Cross Registry Internet Service Protocol (CRISP) CRL - Certificate Revocation List (CRL) CRLF *- Carriage-Return Line-Feed (ASCII control character sequence) CRMF - Certificate Request Message Format (CRMF) CRS - Coordinate Reference System (CRS) (RFC 5165) cRTP - compressed RTP (cRTP) CSAIL - Computer Science and Artificial Intelligence Laboratory (CSAIL) CSIRT - Computer Security Incident Response Team (CSIRT) (RFC 6274) CSMA/CD - Carrier Sense Multiple Access with Collision Detection (CSMA/CD) CSNP - Complete Sequence Number PDU (CSNP) CSP - Content Service Provider (CSP) (RFC 6707) CSPF - Constrained Shortest Path First (CSPF) CSRC - contributing source (CSRC) CSRF - cross-site request forgery (CSRF) (RFC 5849) CT_IU - Common Transport Information Unit (CT_IU) CTO - Congestion Timeout (CTO) (RFC 6817) CTM - Cellular Text Telephone Modem (CTM) (RFC 5194) CTR - Counter Mode (CTR) CTS - clear to send (CTS) CUG - Closed User Group (CUG) CW - Control Word (CW) DA - Destination Address (DA) - Datamover Architecture (DA) (for iSCSI) (RFC 5046) DAC - Dynamic Authorization Client (DAC) (RFC 5176) or - Duplicate Address Confirmation (DAC) (RFC 6775) DAD - Duplicate Address Detection (DAD) DAG - Directed Acyclic Graph (DAG) (RFC 6550) DANE - DNS-Based Authentication of Named Entities (DANE) (RFC 6394) DAO - Destination Advertisement Object (DAO) (RFC 6550) DAR - dynamic alternate routing (DAR) (RFC 3272) or - Duplicate Address Request (DAR) (RFC 6775) DARPA - Defense Advanced Research Projects Agency (DARPA) DASH - Dynamic Adaptive Streaming over HTTP (DASH) (RFC 6983) DASS2 - Digital Access Signaling System 2 (DASS2) DBA - Dynamic Bandwidth Allocation (DBA) DCCP - Datagram Congestion Control Protocol (DCCP) DCE - Data Communications Equipment (DCE) or - Distributed Computing Environment (DCE) DCOM - Distributed Component Object Model (DCOM) DCT - Discrete Cosine Transform (DCT) DD - Database Description (DD) (RFC 4813 update) DDDS - Dynamic Delegation Discovery System (DDDS) (RFC 6116) DDNS - Dynamic DNS (DDNS) (RFC6168) DDoS *- Distributed Denial of Service (DDoS) DDP - Device Discovery Protocol (DDP) DDUL - Dynamic DNS Update Lease (DDUL) DE - Discard Eligible (DE) [flag in a Frame Relay frame (RFC 4594)] DECADE - DECoupled Application Data Enroute (DECADE) (RFC 6392) DELT - Dual Ended Loop Test (DELT) DER *- Distinguished Encoding Rules DES *- Data Encryption Standard (DES) DF - Don't Fragment (DF) (RFC 5853) DFZ - Default-Free Zone (DFZ) DGIWG - Defence Geospatial Information Working Group (DGIWG) (RFC 6288) DHAAD - Dynamic Home Agent Address Discovery (DHAAD) (RFC 3775) DHCP *- Dynamic Host Configuration Protocol (DHCP) DHCPv6 *- Dynamic Host Configuration Protocol for IPv6 (DHCPv6) DID - Direct Inward Dialing (DID) DIFS - Distributed Interframe Space (DIFS) DIO - DODAG Information Object (DIO) (RFC 6550) DIS - DODAG Information Solicitation (DIS) (RFC 6550) DIT - Directory Information Tree (DIT) DKIM - DomainKeys Identified Mail (DKIM) (RFC 4686) DLCI - Data Link Connection Identifier (DLCI) DLSw - Data Link Switching (DLSw) (RFC 4594) [A forwarding mechanism for the IBM SNA (Systems Network Architecture). It places SNA NPDUs into a TCP connection between two routers, which tunnel them across an IP network.] DLV - DNSSEC Lookaside Validation (DLV) DN - Distinguished Name (DN) DNA - Detecting Network Attachment (DNA) (RFC 4436) DNS *- Domain Name System DNS-SD - DNS-based Service Discovery (DNS-SD) (RFC 6763) DNSSEC - DNS Security (DNSSEC) or - DNS Security Extensions (DNSSEC) (RFC 4033) DNT - Do Not Track (DNT) DOCSIS - Data Over Cable Service Interface Specification (DOCSIS) DODAG - Destination-Oriented Directed Acyclic Graph (DODAG) (RFC 6550) DOI - Domain of Interpretation (DOI) DOM - Document Object Model (DOM) (RFC 3075) DoS *- Denial of Service (DoS) different from DOS (operating system) DP - Data Plane (DP) (RFC 5852) -or- - distribution point (DP) (RFC 5280) -or- - DNSSEC Policy (DS) (RFC 6841) DPA - Destination Preference Attribute DPI - deep packet inspection (DPI) (RFC 5594) DPNSS - Digital Private Network Signaling System (DPNSS) DPS - Distributed Programming System (DPS) (RFC 694) -or- - Domain Pseudonym System (DPS) (RFC 6593) -or- - DNSSEC Practice Statement (DPS) (RFC 6841) DR - designated router (DR) DRB - Designated RBridge (DRB) (RFC 6325) DRBG - deterministic random-bit generator (DRBG) (RFC 6189) DRO - Discovery Reply Object (DRO) DRS - DGIWG Registry System (DRS) (RFC 6288) DRM - Digital Rights Management (DRM) (RFC 6129) DS - Diffserv (DS) - Differentiated Services (DS) (RFC 2474) - Delegation Signer (DS) (RFC 3755) DS-Lite - Dual-Stack Lite (DS-Lite) (RFC 6333) DSA - Digital Signature Algorithm (DSA) DSACK - Duplicate Selective Acknowledgement (DSACK) DSAP - Destination Service Access Point (DSAP) DSCP - Differentiated Services Code Point (DSCP) DSDL - Document Schema Definition Languages (DSDL) (RFC 6110) DSE - DSA-Specific Entry (DSE) DSL *- Digital Subscriber Line (DSL) DSLAM - Digital Subscriber Line Access Multiplexer DSM - Demand-Side Management (DSM) (RFC 5826) DSN - Delivery Status Notification (DSN) (RFC 3464) DSP - Digital Signal Processor (DSP) or - Digital Signal Processing (DSP) DSRK - Domain-Specific Root Key (DSRK) (RFC 5295) DSS - Digital Signature Standard (DSS) DSUSRK - Domain-Specific Usage-Specific Root Keys (DSUSRK) (RFC 5295) DTD *- Document Type Definition - Deactivation Time Delay (DTD) (RFC 5374) DTE - Data Terminal Equipment (DTE) DTLS - Datagram Transport Layer Security (DTLS) DTMF - dual-tone multi-frequency (DTMF) DTN - Delay-Tolerant Networking (DTN) DTS - decoding time stamp (DTS) (RFC 3640) or - decode time stamp (DTS) (RFC 6386) DTSN - Destination Advertisement Trigger Sequence Number (DTSN) (RFC 6550) DTX - Discontinuous Transmission (DTX) (RFC 5459) DUA - DASS 2 Extensions (DUA) DUID - DHCP Unique Identifier (DUID) DUNS - Data Universal Numbering System (DUNS) DUT - Device Under Test (DUT) DVB - Digital Video Broadcasting (DVB) (RFC 5328) DVI - No Expansion DVMRP - Distance Vector Multicast Routing Protocol (DVMRP) (RFC 1075) DWDM - Dense Wavelength Division Multiplexing (DWDM) (RFC 6898) E.164 - No Expansion Refers to a telephone numbering plan as specified by the ITU-T E.164 specification E-LAN - Bidirectional Logical Connectivity between >2 UNIs (E-LAN) (RFC 6329) - Ethernet LAN, provides multipoint connectivity (RFC 6965) E-LINE - Ethernet point-to-point connectivity E-LSP - Explicitly TC-encoded-PSC LSP (E-LSP) (note: expansion in RFC 3270 was updated by RFC 5462) E-VLAN - Ethernet Virtual Private LAN (E-VLAN) (RFC 6965) EAP - Extensible Authentication Protocol (EAP) EAP-GSPK - Extensible Authentication Protocol - Generalized Pre-Shared Key (EAP-GPSK) (RFC 5433) EAP-TTLS - Extensible Authentication Protocol Tunneled Transport Layer Security (EAP-TTLS) (RFC 5281) EBCDIC *- Extended Binary Coded Decimal Interchange Code (EBCDIC) EBGP - External Border Gateway Protocol (EBGP) EBM - Equipped Bit Mask (EBM) EC - Elliptic Curve (EC) ECAM - European Committee for Academic Middleware (ECAM) (RFC 6338) EC2N - elliptic curve group over GF[2^N] (as in EC2N group) ECC - Elliptic Curve Cryptography (ECC) ECC CDH - Elliptic Curve Cryptography Cofactor Diffie-Hellman (ECC CDH) (RFC 6278) ECCSI - Elliptic Curve-Based Certificateless Signatures for Identity-Based Encryption (ECCSI) (RFC 6507) ECDH - Elliptic Curve Diffie-Hellman (RFC 6239) ECDSA - Elliptic Curve Digital Signature Algorithm (ECDSA) ECM - Error Correction Mode (ECM) ECMP - Equal-Cost Multipath (ECMP) or - Electronic Commerce Messaging Protocol (ECMP) EC2N - Elliptic Curve Group over GF[2^N] (as in EC2N group) ECN - Explicit Congestion Notification (ECN) ECP - Elliptic Curve Group over GF[P] (as in ECP group) or - Electronic CodeBook (ECP) or - Encryption Control Protocol (ECP) (RFC 1968) ECRTP - Enhanced Compressed RTP (ECRTP) (RFC 3545) ECT - ECN-Capable Transport (ECT) EDCA - Enhanced Distributed Channel Access (EDCA) (RFC 5416) EDF - empirical distribution function (EDF) (RFC 2330) EDGE - Enhanced Data rates for GSM Evolution (EDGE) EDI - Electronic Data Interchange (EDI) EDIINT - Electronic Data Interchange - Internet Integration (WG name) EDNS(0) - Extension Mechanisms for DNS (EDNS(0)) (RFC 6891) EE - End Entity (EE) or EF - Expedited Forwarding (as in "Diffserv EF" - RFC 5975) EFCI - Explicit Forward Congestion Indication (EFCI) EFM - Ethernet First Mile (EFM) (RFC 4837) EFR - Enhanced Full Rate (EFR) EGP *- Exterior Gateway Protocol EHLO *- Extended Hello (RFC 5321) For the template in RFC 5321, "EHLO" is specified a term of art, not an abbreviation. EID - Endpoint Identifier (EID) (RFC 6260) EIP - Extended Internet Protocol (EIP) (RFC 6306) EISS - Extended Internal Sublayer Service (EISS) (RFC 6325) EIRP - Equivalent Isotropic Radiated Power (EIRP) EKU - extended key usage (EKU) ELOC - Endpoint Locator (ELOC) (RFC 6306) EMA - External Measurement Agent (EMA) (RFC 6813) EMS - Energy Management Systems (EMS) (RFC 6272 - Smart Grid) EMSK - Extended Master Session Key (EMSK) (RFC 5295) eNB - Evolved Node B (eNB) (RFC 6965) ENUM - No Expansion Refers generally to a telephone numbering plan. However, the term ENUM is universal, whereas Telephone Number Mapping is not. There are ENUM activities and organizations all over the world. The "long name" of the ENUM WG long name is the anomaly, because ENUM is not an abbreviation, despite appearances. EOF *- End of File (EOF) EOF - Extended Options and Flags (EOF) (RFC 4813 update) EOR *- exclusive or [In logical operations, the exclusive disjunction, also called exclusive or, (symbolized XOR or EOR), is a type of logical disjunction on two operands that results in a value of "true" if and only if exactly one of the operands has a value of "true." (wikipedia)] EPC - Electronic Product Code (EPC) (RFC 5143) - Evolved Packet Core (EPC) (RFC 5448) EPI - Educational Policy Institute (EPI) (RFC 6338) EPON - Ethernet Passive Optical Network (EPON) (RFC 4837) EPP - Extensible Provisioning Protocol (EPP) EPS - Evolved Packet System (EPS) (RFC 6342) EPUB *- electronic publication (EPUB) ER - EAP Re-authentication (ER) (RFC 6697) ERE - Extended Regular Expressions (ERE) ERO - Explicit Route Object (ERO) ERP - EAP Re-authentication Protocol (ERP) (RFC 5296) - Enterprise Resource Provision (ERP) (RFC 3505) - Enterprise Resource Planning (ERP) (RFC 5413) ERT - Expected Residual Time (ERT) (RFC 5651) ERU - Effective Request URI (ERU) (RFC 6797) ERX - EAP Re-authentication Extension (ERX) (RFC 6696) ES - Errored Seconds (ES) ESADI - End-Station Address Distribution Information (ESADI) (RFC 6325) ESB - Extension Security Block (ESB) ESI - Error Source Identifier (ESI) (RFC 5974) or - Entity Status Inquiry (RFC 4171) or - Encoding Symbol ID (RFC 5053) - Energy Services Interface (ESI) (RFC 6272 - Smart Grid) ESMTP *- Extended Simple Mail Transfer Protocol ESN - Electronic Serial Number (ESN) or - Extended Sequence Number (RFC 4302) Per Errata 3615, the N (of ESN) can also be "Numbers", but the abbreviation should not be plural (i.e., the abbreviation shoul still be ESN). ESO - Extended Security Option (ESO) ESP - Encapsulating Security Payload (ESP) ESRP - Emergency Service Routing Proxy (ESRP) (RFC 5012) ESS - Extended Service Set (ESS) ETR - Egress Tunnel Router (ETR) (RFC 6834) ETS - Emergency Telecommunications Service (ETS) (RFC 5115) ETSI *- European Telecommunications Standards Institute (ETSI) ETX - Expected Transmission Count (ETX) (RFC 6551) EUI - Extended Unique Identifier (EUI) EVDO - Evolution-Data Optimized (EVDO) (RFC 6965) EVRC - Enhanced Variable Rate CODEC (EVRC) EVRC-NW - Enhanced Variable Rate Narrowband-Wideband Codec (EVRC-NW) (RFC 6884) EVS - Extended-Vendor-Specific (EVS) (RFC 6929) EWMA - exponentially weighted moving average (EWMA) (RFC 5559) FA - forwarding adjacency (FA) - Foreign Agent (FA) FAD - feature and attribute data (FAD) (RFC 6288) FAN ELS - Fabric Address Notification Extended Link Service (FAN ELS) Pronounced "fan ee el es" FARP - Fibre Channel Address Resolution Protocol (FARP) Pronounced "farp" FBL - Feedback Loop (FBL) (RFC 6377) FCAPS - Fault, Configuration, Accounting, Performance, and Security (FCAPS) FCFS - First come, first served (FCFS) (RFC6709) FCI - Feedback Control Information (FCI) FCIP - Fibre Channel Over TCP/IP (FCIP) FCP - Fibre Channel Protocol (FCP) FCS - Frame Check Sequence (FCS) FDB - Filtering Database (FDB) (RFC 6329) FDDI - Fiber Distributed Data Interface (FDDI) (RFC 4297) FDT - File Delivery Table (FDT) (RFC 3926) FE - Forwarding Element (FE) (RFC 3746) FEC - Forward Error Correction (FEC) or - Forwarding Equivalence Class (FEC) (MPLS; RFC 3031) FECN - Forward Explicit Congestion Notification (FECN) FF - Fixed-Filter (FF) FFD - Full Function Device (FFD) (RFC 4919) ffs - for further study FFT - Fast Fourier Transform (FFT) FG - forest guide (FG) (RFC 5582) FI - Forwarding Indicator (FI) (RFC 6306) FIA - form interpretation algorithm (FIA) (W3C VoiceXML 2.0) FIB - Forwarding Information Base (FIB) (RFC 1322) FID - Flow ID (FID) [RFC6801] FIFO *- First In, First Out [This is listed in Merriam Websters Dictionary.] FII - Forked Instance Identifier (FII) (RFC 5533) FIN - Not expanded TCP flag bit name; see SYN. FIPS *- Federal Information Processing Standards (FIPS) FLUTE - File Delivery over Unidirectional Transport (FLUTE) (RFC 3926) FMIPv6 - Fast Handovers for Mobile IPv6 (FMIPv6) (RFC 5568) FMT - feedback message type (FMT) (RFC 6284) ForCES - Forwarding and Control Element Separation (ForCES) (RFC 3746) FPGA - Field-Programmable Gate Array (FPGA) FPS - Frames Per Second (FPS) (RFC 6349) FQDN - Fully Qualified Domain Name (FQDN) FR - Frame Relay (FR) FRAND - fair, reasonable, and non-discriminatory (FRAND) (RFC 6852) FRR - Fast Reroute (FRR) FSM - Finite State Machine (FSM) FSPF - Fabric Shortest Path First (FSPF) FSSI - FEC-Scheme-Specific Information (FSSI) (RFC 6363) FT - feedback target (FT) FTN - FEC-to-NHLFE (FTN) (RFC 3031) FTP *- File Transfer Protocol FTTH - fiber to the home (FTTH) FWS - folding white space (FWS) (RFC 5322) G-ACh - Generic Associated Channel (G-Ach) (RFC 6965) GAL - Generic Associated Channel Label (GAL) (RFC 5586) or G-ACh Label (GAL) (RFC 5586) GARP - Generic Attribute Registration Protocol (GARP) GAS - Generic Advertisement Service (GAS) GbE - Gigabit Ethernet (GbE) GBS - Generic Bonding Sub-layer (GBS) (RFC 6765) GCKS - Group Controller/Key Server (GCKS) GCM - Galois/Counter Mode (GCM) GCO - Global Concurrent Optimization (GCO) GDOI - Group Domain of Interpretation (GDOI) GERAN - GSM/EDGE Radio Access Network (GERAN) (RFC 3314) GFP - Generic Framing Procedure (GFP) (RFC 6001) GGSN - Gateway GPRS Support Node (GGSN) GIST - General Internet Signaling Transport (GIST) (RFC 5971) GLB - Global Locator Block (GLO) (RFC 6306) GLOP - No Expansion (RFCs 2770 and 3180) GMAC - Galois Message Authentication Code (GMAC) (RFC 4543) GMII - Gigabit Media Independent Interface (GMII) (RFC 4837) GML - Geography Markup Language (GML) GMPLS *- Generalized Multiprotocol Label Switching GMRP - GARP Multicast Registration Protocol (GMRP) GNSS - Global Navigation Satellite System (RFC 6280) GPL - General Public License (GPL) GPMD - General-Purpose Media Descriptor (GPMD) (RFC 6498) GPRS - General Packet Radio Service (GPRS) GPS *- Global Positioning System (GPS) GPU - Graphics Processing Unit (GPU) (RFC 6917) GRE - Generic Routing Encapsulation (GRE) GRUU - Globally Routable User Agent URI (GRUU) GSAKMP - Group Secure Association Key Management Protocol (GSAKMP) GSE - Generalized Structure Element (GSE) GSI - Grid Security Infrastructure (GSI) GSLB - Global Server Load Balancing (GSLB) (RFC 6589) GSM - Global System for Mobile Communications (GSM) GSPD - Group Security Policy Database (GSPD) GSPM - Generic Secure Password Method (GSPM) (RFC 6467) GSS-API - Generic Security Service Application Program Interface (GSS-API) GSTN - General Switched Telephone Network (GSTN) (RFC 2305) or - Global Switched Telephone Network (GSTN) (RFC 2846) GTK - Group Temporal Key (GTK) gTLD - Generic Top Level Domain (gTLD) GTP - Generic Tunneling Protocol (GTP) - GPRS Tunnelling Protocol (GTP) (RFC5847) GTSM - Generalized TTL Security Mechanism (GTSM) GUI *- Graphical User Interface GUID - Globally Unique Identifier (GUID) GVRP - Generic VLAN Registration Protocol (GVRP) HA - Home Agent (HA) (RFC 6245) HAC - Home Agen Controller (HAC) (RFC 6618) HAS - HTTP Adaptive Streaming (HAS) (RFC 6983) HBA - Host Bus Adapter (HBA) or - Host-Based Authentication (HBA) or - Hash-Based Addresses (HBA) (RFC 5535) HC - high capacity (HC) HDLC - High-Level Data Link Control (HDLC) HELD - HTTP-Enabled Location Delivery (HELD) (RFC 5985) HET - Header Extension Type (HET) (RFC 3450) HFC - Hybrid Fiber Coaxial (HFC) HG - home gateway (HG) HIP - Host Identity Protocol (HIP) (RFC 5201) hIPv4 - hierarchical IPv4 (RFC 6306) HIT - Host Identity Tag (HIT) HKDF - HMAC-based Key Derivation Function (HKDF) (RFC 5869) HLR - Home Location Register (HLR) (RFC 6342) HMAC - Hashed Message Authentication Code (HMAC) - Hash-Based Message Authentication Code (HMAC) (RFC 6039) HMIPv6 - Hierarchical Mobile IPv6 (HMIPv6) (RFC 5380) HoA - Home Address (HoA) HoT - Home Test (HoT) (RFC 6275) HoTI - Home Test Init (HoTI) (RFC 6275) HOKEY - Handover Keying (HOKEY) (RFC 5169) HPTP - HTTP-based Peer to Peer (HPTP) (RFC 6392) or - HTTP-based Peer-to-Peer (HPTP) (adj.) HSM - Hardware Security Module (HSM) (RFC 5485) HSPA - High-Speed Packet Access (HSPA) (RFC 6965) (No hyphen; not our term to define) HSS - Home Subscriber Server (HSS) (RFC 6342) HSTS - HTTP Strict Transport Security (HSTS) (RFC 6797) HTTP *- HyperText Transfer Protocol HTTPS *- Hypertext Transfer Protocol Secure HTML *- HypterText Markup Language IA-RWA - Impairment-Aware Routing and Wavelength Assignment (IA-RWA) (RFC 6566) IA_PD - Identity Association for Prefix Delegation (IA_PD) (RFC 3633) IAB *- Internet Architecture Board (should only be expanded for introductory docs, e.g., Tao of the IETF) IAID - Identity Association IDentifier (IAID) (RFC 3315) IAMM - In-line Aware MRB Mode (IAMM) (RFC 6917) IANA *- Internet Assigned Numbers Authority (should only be expanded for introductory docs, e.g., Tao of the IETF) IAP - Intercept Access Point (IAP) (RFC 3924) - Internet Access Provider (IAP) (RFC 5012) - Intermediate Anonymization Process (IAP) (RFC 6235) IAX - Inter-Asterisk eXchange (IAX) (RFC 5456) IBAKE - Identity-Based Authenticated Key Exchange (IBAKE) (RFC 6267) IBCF - Interconnection Border Control Function (IBCF) (3GPP term) IBE - Identity-Based Encryption (IBE) (RFC 5091) IBGP - Internal BGP (IBGP) (RFC 4456) ICC - ITU-T Carrier Code (ICC) (RFC 5580) ICE - Interactive Connectivity Establishment (ICE) ICMP *- Internet Control Message Protocol ICP - Internet Content Provider (ICP) (RFC 6883) ICRP - Incoming-Call-Reply (ICRP) ICRQ - Incoming-Call-Request (ICRQ) ICSA - International Computer Security Association (ICSA) ICV - Integrity Check Value (ICV) I-D - Internet-Draft (I-D) IDEA - International Data Encryption Algorithm (IDEA) (RFC 5469) IDN - Internationalized Domain Name (IDN) (RFC 5891) IDNA - Internationalizing Domain Names in Applications (IDNA) (RFC 5891) - Internationalized Domain Names for Applications (IDNA) (RFC 5890) IdP - Identity Provider (IdP) (RFC 6448) IDRP - Inter-Domain Routing Protocol (IDRP) (ISO/IEC 10747) IDS - Intrusion Detection System (IDS) IE - Information Element (IE) IEC *- International Electronical Commission IEEE *- Institute of Electrical & Electronics Engineers IESG *- Internet Engineering Steering Group (should only be expanded for introductory docs, e.g., Tao of the IETF) IETF *- Internet Engineering Task Force (should only be expanded for introductory docs, e.g., Tao of the IETF) IF - intermediate frequency (IF) iff *- if and only if (from mathematical logic) IFG - Inter-Frame Gap (IFG) (RFC 5066) IGD - Internet Gateway Device (IGD) IGP *- Interior Gateway Protocol (IGP) IGMP *- Internet Group Management Protocol IHL - Internet Header Length (IHL) IID - Instance ID (IID) (RFC 6822) - Interface Identifier (IID) IIH - IS-IS Hello (IIH) (RFC 3373) IKE - Internet Key Exchange Protocol (IKE) IKEv2 - Internet Key Exchange Protocol Version 2 (IKEv2) ILM - Incoming Label Map ILMI - Integrated Local Management Interface (ILMI) ILNP - Identifier-Locator Network Protocol (ILNP) (RFC 6740) - Interim LNP (ILNP) (RFC 3482) ILV - Index-Length-Value (ILV) (RFC 6369) IMA - Inverse Multiplexing for ATM (IMA) (RFC 6765) IMAP *- Internet Message Access Protocol IMEI - International Mobile Equipment Identity (IMEI) (RFC 5563) iMIP - iCalendar Message-Based Interoperability Protocol (iMIP) (RFC 6047) IMPP - Instant Messaging and Presence Protocol (IMPP) IMS - IP Multimedia Subsystems (IMS) IMSI - International Mobile Subscriber Identity (IMSI) INCITS - INternational Committee for Information Technology Standards IO - information object (IO) (RFC 6392) IOI - Item of Interest (IOI) (RFC 6973) ION - IETF Operational Notes (ION) (RFC 4693) IOS - Internetwork Operating System (IOS); as in Cisco IOS IP *- Internet Protocol IPBX - IP Private Branch Exchange (IPBX) IPCP - IP Control Protocol (IPCP) IPDV - IP Packet Delay Variation (IPDV) (RFC 6412) IPFIX - IP Flow Information Export (RFC 3917) IPFRR - IP Fast Reroute (IPFRR) (RFC 5286) IPHC - IP Header Compression (IPHC) IPP - Internet Printing Protocol (IPP) (RFC 2910) IPPM - IP Performance Metrics (IPPM) IPR *- Intellectual Property Rights (IPR) IPsec *- IP Security (IPsec) IPTV - No Expansion A service that delivers television signals over an RTP/UDP/IP video stream. It is read "IP TV". IPv4 *- Internet Protocol version 4 (RFC 791) IPv6 *- Internet Protocol version 6 IPX - Internetwork Packet Exchange (IPX) IQN - iSCSI Qualified Name (IQN) (RFC 6716) IR - Initiation and Refresh (IR) - Internet Registry (IR) IRI - Internationalized Resource Identifier (IRI) IRTF *- Internet Research Task Force (should only be expanded for introductory docs, e.g., Tao of the IETF) IS - Information Service (IS) or *- Intermediate System (IS) ISC - Internet Systems Consortium (ISC) ISID - Initiator Session Identifier (ISID) (RFC 5048) IS-IS *- Intermediate System to Intermediate System (routing protocol) ISAKMP - Internet Security Association and Key Management Protocol (ISAKMP) ISATAP - Intra-Site Automatic Tunnel Addressing Protocol (ISATAP) (RFC 5579) iSCSI - Internet Small Computer System Interface (iSCSI) ISDN *- Integrated Services Digital Network (ISDN) iSNS - Internet Storage Name Service (iSNS) (RFC 5046) ISO *- International Organization for Standardization ISOC *- Internet Society ISP *- Internet Service Provider iSPF - incremental Shortest Path First (iSPF) RFC 6981) ISS - Internal Sublayer Service (RFC 6325) ISUP - ISDN User Part (ISUP) iTIP - iCalendar Transport-independent Interoperability Protocol (iTIP) (RFC 5546) ITR - Ingress Tunnel Router (ITR) (RFC 6834) ITU *- International Telecommunication Union ITU-T *- ITU Telecommunication standardization sector IU - Information Unit (IU) IUA - ISDN Q.921-User Adaptations Layer (IUA) IUMM - In-line Unaware MRB Mode (IUMM) (RFC 6917) IV - Initialization Vector (IV) or - Impairment Validation (IV) (RFC 6566) IVL - Independent VLAN Learning (IVL) IVR - Interactive Voice Response (IVR) IW - Initial Window (IW) (RFC 6928) IWF - Interworking Function (IWF) (RFC 5604) IXFR - Incremental Zone Transfer (IXFR) JID - Jabber Identifier (JID) (RFC 6121) JRD - JSON Resource Descriptor (JRD) (RFC 6415) JSON - JavaScript Object Notation (JSON) (RFC 4627) JWT - Joint Working Team (JWT) (RFC 5317) or - JavaScript Object Notation Web Token (JWT) (RFC 6819) KARP - Keying and Authentication for Routing Protocols (KARP) (RFC 6862) KDC - Key Distribution Center (KDC) KDF - Key Derivation Function (KDF) (RFC 5295) KE - key establishment (KE) (RFC 6318) KEK - key encryption key (or key-encryption key) (KEK) KEM - Key Encapsulation Mechanism (RFC 5990) KINK - Kerberized Internet Negotiation of Keys (KINK) KLV - Key-Length-Value (KLV) (RFC 5119) KMP - Key Management Protocol (KMP) (RFC 6862) KMS - Key Management Service (KMS) KPAK - Key Management Service Public Authentication Key (KPAK) (RFC 6507) KPML - Key Press Markup Language (KPML) (RFC 4730) KSAK - Key Management Service Secret Authentication Key (KSAK) (RFC 6507) KSK - Key Signing Key (KSK) (RFC 4033) L2F - Layer 2 Forwarding (L2F) L2TP - Layer 2 Tunneling Protocol (L2TP) L2VPN - Layer 2 Virtual Private Network (L2VPN) L3VPN - Layer 3 Virtual Private Network (L3VPN) L-LSP - Label-Only-Inferred-PSC LSP (L-LSP)(RFC 3270) LACNIC *- Latin American and the Caribbean Internet Addresses Registry LACP - Link Aggregation Control Protocol (LACP) (RFC 6959) LAG - Link Aggregation Group (LAG) (RFC 6391) LAN *- Local Area Network (LAN) LATM - Low-overhead MPEG-4 Audio Transport Multiplex (LATM) (RFC 3016) LBR - LLN Border Router (LBR) (RFC 5548) LC - Local Controller (LC) or - Link Connection (LC) LCAF - LISP Canonical Address Format (LCAF) (RFC 6830) LCAS - Link Capacity Adjustment Scheme (LCAS) (RFC 6344) LCCE - Logical Cluster Computing Environment (LCCE) or - L2TP Control Connection Endpoint (RFCs 3931 and 4719) LCI - Location Configuration Information (LCI) (RFC 4676) LCP - Location Configuration Protocol (RFC 5687) or - large content providers (LCP) (RFC 6306) - Link Control Protocol (LCP) (RFC 1661) LCT - Layered Coding Transport (LCT) (RFC 5651) LDAP - Lightweight Directory Access Protocol (LDAP) LDH - letter-digit-hyphen (LDH) (RFC 4713) LDI - Link Down Indication (LDI) (RFC 6965) LDML - Locale Data Markup Language (LDML) (RFC 6067) LDN - Local Domain Name (LDN) (RFC 6440) LDP *- Label Distribution Protocol (LDP) LDPC - Low-Density Parity Check (LDPC) (RFC 6816) LDR - Link Delivery Ratio (LDR) (RFC 6606) LEDBAT - Low Extra Delay Background Transport (LEDBAT) (RFC 6057) LER - Label Edge Router (LER) LFA - Loop-Free Alternate (LFA) (RFC 5286) LFB - Logical Functional Block (LFB) (RFC 5811)(RFC 5812) - Logical Function Block (LFB) (RFC 5810) LFIB - Label Forwarding Information Base (LFIB) (RFC 5439) LFN - Long Fat Network (LFN) (RFC 2757) or - Local Fixed Node (LFN) (RFC 3963) LFSR - linear feedback shift register (LFSR) (RFC 6027) LIFO - last-in-first-out (LIFO) LIP - Loop Initialization Primitive Sequence (LIP) Pronounced "lip". LIR - Local Internet Registry (LIR) LIS - Location Information Server (LIS) (RFC 5687) LISP - Locator-Identifier Split Protocol (LISP) (RFC 5720) or Locator/ID Separation Protocol (LISP) (RFC 5887) LKH - Logical Key Hierarchy (LKH) LLC/SNAP - Logical Link Control/Subnetwork Access Protocol (LLC/SNAP) Pronounced "el el see snap". LLDP - Link Layer Discovery Protocol (LLDP) (ANSI/TIA-1057) LLDP-MED - Link Layer Discovery Protocol - Media Endpoint Discovery (LLDP-MED) (RFC 6443) LLID - Logical Link Identifier (LLID) (RFC 4837) LLN - Low-Power and Lossy Network (plural LLNs) (RFC 5867) LLQC - Last Listener Query Count (LLQC) (RFC 6636) LLQI - Last Listener Query Interval (LLQI) (RFC 6636) LLQT - Last Listener Query Timer (LLQT) (RFC 3810) LLS - Link-Local Signaling (LLS) (RFC 4813 update) LMA - Local Mobility Anchor (LMA) (RFC 6058) LMDS - Local Multipoint Distribution Service (LMDS) LMP - Link Management Protocol (LMP) LMQC - Last Member Query Count (LMQC) (RFC 6636) LMQI - Last Member Query Interval (LMQI) (RFC 6636) LMQT - Last Member Query Timer (LMQT) (RFC 6636) LOPS - Loss of Packet Synchronization (LOPS) LoST - Location-to-Service Translation (LoST) (RFC 5222) LMTP - Local Mail Transfer Protocol (LMTP) (RFC 2033) LoWPAN - Low-Power Wireless Personal Area Network (LoWPAN) (RFC 4919) LQI - Link Quality Indication (LQI) (RFC 6606) LRDD - Link-based Resource Descriptor Document (LRDD) (RFC 6415) LRM - Link Resource Manager (LRM) (RFC 5787) LRU - Least Recently Used (LRU) LSA - Link State Advertisement (LSA) LSAP - Link Service Access Point (LSAP) LSB - least significant bit (LSB) or - Locator-Status-Bit (LSB) (RFC 6830) LSC - Link State Control (LSC) - Lambda Switch Capable (LSC) (RFC 5549) - Lambda Switching Capable (LSC) (RFC 5787) LSDB - Link State Database (LSDB) LSE - Label Stack Entry (LSE) (RFC 5960) LSI - Local Scope Identifier (LSI) (RFC 4423) LSP - Label Switched Path (LSP) or - Label Switching Path (LSP) -- RARELY USED - Link State Packet (LSP) or - Link State PDU (LSP) (or Link State Protocol Data Unit) LSR - Label Switching Router (LSR) - Loose Source Routing (LSR) (RFC 6301) LSRR - Loose Source and Record Route (LSRR) LSW - Least Significant Word (LSW) LTE - Long-Term Evolution (LTE) (RFC 6342) (No hyphen; not our term to define) LUN - Logical Unit Number (LUN) LW-IGMPv3 - Lightweight IGMPv3 (LW-IGMPv3) (RFC 5790) LW-MLDv2 - Lightweight MLDv2 (LW-MLDv2) (RFC 5790) LWSP - linear whitespace (LWSP) (RFC 6376) MA - Multicast Acquisition (MA) (RFC 6332) or - multiple attachment (MA) (RFC 6362) MA/RA - Maintenance Agency/Registration Authority (MA/RA) MAC - Message Authentication Code (MAC) or - Medium Access Control (MAC) or - Media Access Control (MAC) Caution when expanding these. Alfred provides the following info: a) IEEE 802.2 (et al.) : MAC == Media Access Control -- Sublayer of the Link Layer; most frequently used in combination with "address". I pose the rule of thumb: Whenever "MAC" appears in context with "address", it has to be expanded in the IEEE sense. b) Legacy cryptographic terminology : MAC == Message Authentication Code c) Media/Medium dependent upon plural/singular. Per Dan Romascanu for RFCs 5412-5418. MACE - Middleware Architecture Committee for Education (MACE) (RFC 3613) MAE - Metropolitan Area Ethernet (MAE) (RFC 2901) MAG - Mobile Access Gateway (MAG) (RFC 5213) *MAN - Metropolitan Area Network MANET - Mobile Ad Hoc Network (MANET) (RFC 6139) MAP - Mobility Anchor Point (MAP) (RFC 4140) - Mobile Application Part (MAP) (RFC 3482) MAS - Mobile Access Station (MAS) (RFC 6301) MBMS - Multimedia Broadcast/Multicast Service (MBMS) (RFC 4352) MC - Motion Compensation (MC) MCC - Mobile Country Code (MCC) (RFC 4186) - Management Communication Channel (MCC) (RFC 5586) MCU - Multipoint Control Unit (MCU) MCMS - Multimedia Cable Network System (MCNS) MDA - Mail Delivery Agent (MDA) (RFC 4496) MDC - Modification Detection Code (MDC) (RFC 4880) MDL - maximum datagram lifetime (MDL) (RFC 6864) mDNS - Multicast DNS (mDNS) (RFC 6762) MDS - Maximal Separable Distance (MDS) (RFC 5401) MD5 *- Message Digest 5 (Typically not expanded (RFC 4635)) MED - Multi-Exit Discriminator (MED) MEDIACTRL *- Media Server Control MEG - Maintenance Entity Group (MEG) (RFC 5921) MEP - Maintenance Entity Group End Point (MEP) (RFC 5921) MF - More Fragments (MF) (RFC 5931) MFIB - Multicast Forwarding Information Base (MFIB) MG - Media Gateway (MG) (RFC 2719) MGC - Media Gateway Controller (MGC) MGCP - Media Gateway Control Protocol (MGCP) MHAE - Mobile-Home Authentication Extension (MHAE) MHP - Multimedia Home Platform (MHP) (RFC 4259) or - Multi-Homed Prefix (MHP) (RFC 5286) MIB *- Management Information Base MIC - Message Integrity Check (MIC) or - Message Integrity Code (MIC) MIDCOM - Middlebox Communications (midcom) MIDI - MIDI (Musical Instrument Digital Interface) Typically not expanded. If expand, make MIDI primary, that is, use "MIDI (Musical Instrument Digital Interface)", not "Musical Instrument Digital Interface (MIDI)". (per RFC Editor note for RFCs 4695 and 4696) MIF - multiple interfaces (MIF) (RFC 6418) MIKEY - Multimedia Internet KEYing (MIKEY) MIME *- Multipurpose Internet Mail Extensions MIN - Mobile Identification Number (MIN) MINC - multicast inference of network characteristics (MINC) (RFC 3611) MINE - Minimal Encapsulation in IP (MINE) (RFC 5225) MIP - Mobile IP - Maintenance Entity Group Intermediate Point (RFC 5921) MIP6 - Mobile IPv6 (MIP6) (RFC 4887) MITM - man in the middle (MITM) [typically hyphenated as adj. before "attack"] MKI - Master Key Identifier (MKI) MKT - Master Key Tuple (MKT) (RFC 5925) MLDv2 - Multicast Listener Discovery Version 2 (MLDv2) mLDP - Multipoint LDP (mLDP) (RFC 6826) not as defined in RFC 6388 (mLDP: Multipoint extensions for LDP) confirmed by WG chair and AD MLM - Mailing List Manager (MLM) (RFC 6377) MLPP - Multilevel Precedence and Preemption (MLPP) MMA - MIDI Manufacturers Association MME - Mobile Management Entity (MME) MMS - Multimedia Messaging Service (MMS) MN - Mobile Node (MN) (RFC 5213) MN-FA - Mobile Node - Foreign Agent (MN-FA) MNC - Mobile Network Code (MNC) (RFC 4186) MNG - Mobile Network Gateway (MNG) (RFC 6342) MO - Measurement Object (MO) MOBIKE - IKEv2 Mobility and Multihoming (MOBIKE) MODP - modular exponentiation group (as in MODP group) MOP - Mode of Operation (MOP) (RFC 6550) MOS - mean opinion score (MOS) (RFC 3611) MOSPF - Multicast Extensions to OSPF (MOSPF) (RFC 1075) MP-BGP - Multiprotocol BGP (RFC 4760) MP2PE - Multi-Point to Point Emulation (MP2PE) (RFC 4837) MP2MP - Multipoint-to-Multipoint (MP2MP) MPD - Media Presentation Description (MPD) (RFC 6983) MPEG *- Motion Picture Experts Group Typically not expanded MPI - Minimum Picture Interval (MPI) (RFC 5631) or Multiprecision Integer (MPI) (RFC 4880) MPLS *- Multiprotocol Label Switching Use "Multiprotocol" wherever "Multi Protocol" or "MultiProtocol" occur (RFC 3031, et al.) MPLS-TP - MPLS Transport Profile (MPLS-TP) (RFC 5654) MPTCP - Multipath TCP (MPTCP) (RFC 6824) MR - Mobile Router (MR) (RFC 3753) or - Map Resolver (MR) (RFC 6115) MRB - Media Resource Broker (MRB) (RFC 5567) MRD - Multicast Router Discovery (MRD) (RFC 4286) MRIB - Multicast Routing Information Base (MRIB) MRRU - Maximum Reconstructed Reception Unit (MRRU) (RFC 4995) MRT - Multi-threaded Routing Toolkit (MRT) (RFC 6396) MRTG - Multi Router Traffic Grapher (MRTG) MRU - Maximum Receive Unit (MRU) MS - Media Server (MS) (RFC 5707) - Mobile Station (MS) (RFC 2604) - Message Store (MS) (RFC 1506) - Manual Switch (MS) (RFC 2892) MS-PW - Multi-Segment Pseudowire (MS-PW) (RFC 5254) MSA - Mail Submission Agent (MSA) (RFCs 4871, 5068) - Message Submission Agent (MSA) - Mobility Service Authorizer (MSA) (RFC 5026) MSB - most significant bit (MSB) (RFC 5225) MSCML - Media Server Control Markup Language (MSCML) (RFC 5022) MSDP - Multicast Source Discovery Protocol (MSDP) MSL - maximum segment lifetime (MSL) MSM - Mobile Station Modem (MSM) (RFC 6419) MSML - Media Server Markup Language (MSML) (RFC 5707) MSN - Master Sequence Number (MSN) (RFC 5225) MSRP - Message Session Relay Protocol (MSRP) (RFC 5631) MSS - Maximum Segment Size (MSS) or - Mobile Support Station (MSS) (RFC 6301) MSTP - Multiple Spanning Tree Protocol (MSTP) or - Mobility Service Transport Protocol (MSTP) (RFC 5164) MSW - Most Significant Word (MSW) MT - Message Transfer (MT) (RFC 1138) - Mobile Terminal (MT) (RFC 3726) - Multiplier (MT) (RFC 3946) - Multi-Topology (MT) (RFC 4915) MTA - Mail Transport Agent (MTA) or - Mail Transfer Agent (MTA) MTU *- Maximum Transmission Unit MUA - Mail User Agent (MUA) or - Message User Agent (MUA) MVRP - Multiple VLAN Registration Protocol (MVRP) (IEEE 802.1ak) MWI - Message-Waiting Indicator (MWI) (RFC 5551) MXF - Material Exchange Format (MXF) (RFC 4539) NA - Neighbor Advertisement (NA) (RFC 6434) NACK *- Negative ACKnowledgement NAI - Network Access Identifier (NAI) NAL - Network Abstraction Layer (NAL) (RFC 3984) NAPT - Network Address Port Translator (NAPT) or - Network Address and Port Translator (NAPT) (can use Translator or Translation - both are fine) NAPTR - Naming Authority Pointer (NAPTR) NAR - New Access Router (NAR) (RFC 5270) NAS - Network Access Server (NAS) - Network-Attached Storage (NAS) (RFC 5532) NAT *- Network Address Translation (NAT) or - Network Address Translator (NAT) NAT-PMP - NAT Port Mapping Protocol (NAT-PMP) (RFC 6886) NAT-PT - Network Address Translation - Protocol Translation (NAT-PT) (RFC 2766) NAT-T - Network Address Translation Traversal (NAT-T) NBMA - Non-Broadcast Multi-Access (NBMA) NCE - Network Connection Endpoint (NCE) (RFC 2238) or - Neighbor Cache Entry (NCE) (RFC 6583) NCP - Network Control Protocol (NCP) NCS - Network Control Signaling (NCS) ND - Neighbor Discovery (ND) (RFC 3756) NDN - Named Data Networking (NDN) (RFC 6392) NDP - Neighbor Discovery Protocol (NDP) (RFC 3971) - Neighbor Discovery Process (NDP) (RFC 6583) NE - Network Element (NE) (RFC 3746) NEA - Network Endpoint Assessment (NEA) (RFC 6813) NEMO - Network Mobility (NEMO)(RFC 3963) NENA - National Emergency Number Association (NENA) NETCONF - Network Configuration Protocol (NETCONF) [Not typically expanded in titles, but expand in abstract] NetInf - Network of Information (NetInf) (RFC 6392) NEWPRED - No Expansion Refers to error resilience in MPEG-4 version 2 regarding which frame should be used as the reference for the next prediction. NFC - Normalization Form C (NFC) (RFC 5646) -- Unicode Normalization Form C NFKC - Normalization Form KC (NFKC) (RFC 5894) NFS *- Network File System (RFC 1094) NHLFE - Next Hop Label Forwarding Entry NI - Named Information (NI) (RFC 6920) NIC - Network Interface card (NIC) - Network Information Center (NIC) (as in AfriNIC, APNIC, LACNIC) NID - Network Interface device (NID) or - Network Identifier (NID) - Namespace Identifier (NID) (RFC 6061) NIDS - Network Intrusion Detection System (RFC 6274) NIH - Named Information for Humans (NIH) (RFC 6920) NIR - National Internet Registry (NIR) (RFC 6308) NIS - Network Information Service (NIS) NIST *- National Institute of Standards and Technology (NIST) NLM - Network Lock Manager (NLM) (RFC 3010) NLPID - Network Layer Protocol Identifier (NLPID) NLRI - Network Layer Reachability Information (NLRI) (RFC 5512) nMAG - new Mobility Access Gateway (nMAG) (RFC 6058) NMP - Network Musical Performance (NMP) NMS - Network Management System (NMS) NNI - Network-Network Interface (NNI) NNTP - Network News Transfer Protocol (NNTP) NORM - NACK-Oriented Reliable Multicast (NORM) (RFC 5740) NOS/OLS - Not_Operational Primitive Sequence / Offline Primitive Sequence (NOS/OLS) N-PE - Network-facing PE (RFC 4026) NREN - National Research and Education Network (NREN) (RFC 6137) NRPN - Non-Registered Parameter Numbers (NRPN) (RFC 6295) Note: the plural is used in MIDI documents NRS - Name Resolution Service (NRS) (RFC 6392) NRZ - Non-Return-to-Zero (NRZ) NS - No Expansion as in "NS simulator" is network simulator, but should not be expanded or - Neighbor Solicitation (NS) (RFC 3971) NSAP - Network Service Access Protocol (NSAP) or - Network Service Access Point (NSAP) (RFC 6325) NSC - Network Simulation Cradle (NSC) (RFC 6928) NSCP - Name Server Control Protocol (NSCP) (RFC 5887) NSE - Named Signaling Event (NSE) NSEC - NextSECure (NSEC) NSF *- National Science Foundation NSIS - Next Steps in Signaling (NSIS) NSLP - NSIS Signaling Layer Protocol (NSLP) NSP - native service processing (NSP) (RFCs 3985 and 4719) or - Network-Specific Prefix (NSP) or - Network Service Provider (NSP) (RFC 6707) NSS - Namespace Specific String (NSS) (RFC 5119) NSSA - Not-So-Stubby Area (NSSA) (RFC 3101) NTFS - New Technology File System (NTFS) NTP *- Network Time Protocol NTSC *- National Television Standards Committee NUD - Neighbor Unreachability Discovery (RFC 5887) NUT - Network Under Test (NUT) (RFC 6349) NVC - Number of Virtual Components (NVC) (RFC 4606) NVT - Network Virtual Terminal (NVT) (RFC 4335) OA - Ordered Aggregate (OA) OAM - Operations, Administration, and Maintenance (OAM) per Adrian Farrell (RFC 6291) OASIS - Organization for the Advancement of Structured Information Standards (OASIS) (RFC 3121) OATC - Open Authentication Technology Committee (OATC) (RFC 6750) OAuth *- [seems to be more of a name rather than an abbreviation] O&M - OAM and Management (O&M) per Adrian Farrell (RFC 6291) OCP - Objective Code Point (OCP) (RFC 6550) OCR - optical character recognition (OCR) OCSP - Online Certificate Status Protocol (OCSP) ODU - Optical Data Unit (ODU) (RFC 4328) OEM - original equipment manufacturer (OEM) OEO - optical-electronic-optical (OEO) (RFC 6566) OF - Objective Function (OF) (RFC 6550) OFB - Output FeedBack (OFB) OFDM - Orthogonal Frequency Division Multiplexing (OFDM) (RFC 5416) oFIB - ordered forwarding information base (oFIB) (RFC 5715) OGC - Open Geospatial Consortium (OGC) (RFC 6288) OGF - Open Grid Forum (OGF) (RFC 5388) OID *- Object Identifier oif - outgoing interface OIPF - Open IPTV Forum (OIPF) (RFC 6893) OLS - Optical Line System (OLS) (RFC 6898) OLSR - Optimized Link State Routing (OLSR) (RFC 3626) OLT - Optical Line Terminal (OLT) (Server unit of the EPON) (RFC 4837) OMA - Open Mobile Alliance (OMA) OMAP - Online Multimedia Authorization Protocol (OMAP) (RFC 6750) OMP - Optical Multi-Point (OMP) (RFC 4837) ONC - Open Network Computing (ONC) (RFC 1831) OPES - Open Pluggable Edge Services (OPES) OPEX - Operating Expenses (OPEX) (RFC 6965) - Operational Expediture (OPEX) (RFC 5851) ORCHID - Overlay Routable Cryptographic Hash Identifiers (ORCHID) (RFC 4843) ORO - Option Request Option (ORO) (RFC 4242) OS *- Operating System OS - Outbound Streams (OS) (RFC 2960) OSI *- Open Systems Interconnection OSN - Original Sequence Number (OSN) OSPF *- Open Shortest Path First (routing protocol) OSS - Operational Support System (OSS) (RFC 5851) OSSI - Open Source Software Institute (OSSI) OTAF - Over-the-Air Functionality (OTAF) OTASP - Over-the-Air Service Provisioning (OTASP) OTI - Object Transmission Information (OTI) (RFC 5052) OTN - Optical Transport Network (OTN) (RFC 3474) OTP - One-Time Password (OTP) OU - Organizational Unit (OU) OUI - Organizationally Unique Identifier (OUI) (RFC 1294) OXC - Optical Cross-Connect (OXC) OWAMP - One-Way Active Measurement Protocol (RFC 4656) P2MP - Point-to-Multipoint (P2MP) (RFC 4837) P2P - peer-to-peer (P2P) or - point-to-point (P2P) P2PE - Point-to-Point Emulation (P2PE) (RFC 4837) P3P - Platform for Privacy Preferences (P3P) (RFC 3505) PA - provider-aggregated (PA) (RFC 5887) or provider assigned (PA) (RFC 5375) PAA - PANA Authentication Agent (RFC 5191) PAC *- Proxy Auto-Configuration (PAC) Not typically expanded; e.g., "the PAC file" or "Microsoft PAC" PACE - Password Authenticated Connection Establishment (PACE) (RFC 6631) PAD - Peer Authorization Database (PAD) PAI - P-Asserted-Identity (PAI) (RFC 5947) PAKE - password-authenticated key exchange (PAKE) (RFC 6113) PAL *- Phase Alternation Line PANA - Protocol for Carrying Authentication for Network Access (RFC 5193) PAR - previous access router (PAR) (RFC 6301) PAT - Port Address Translation (PAT) PB - Provider Bridge (PB) (IEEE 802.1ad) or - Posture Broker (RFC 6813) PBA - Proxy Binding Acknowledgement (PBA) (RFC 6058) PBB - Provider Backbone Bridge (PBB) (IEEE 802.1ah) PBKDF2 - Password-Based Key Derivation Function 2 (PBKDF2) PBU - Proxy Binding Update (PBU) (RFC 6058) PBX - Private Branch Exchange (PBX) PC - Protocol Controller (PC) (RFC 5787) PCB - Payload Confidentiality Block (PCB) PCC - Path Computation Client (PCC) (RFC 6805) PCE *- Path Computation Element (PCE) (RFC 4655) PCEP - Path Computation Element (PCE) Communication Protocol (PCEP) (RFC 5440) PCM - Pulse Code Modulation (PCM) PCMU *- Pulse Coded Modulation Pronounced 'mu-law' Not typically expanded (RFCs 4733 and 4734) PCN - Pre-Congestion Notification (RFC 5559) PCP - Port Control Protocol (PCP) (RFC 6887) PCRF - Policy and Charging Rule Function (PCRF) (RFC 6342) PD - Prefix Delegation (RFC 3633) PDA *- Personal Digital Assistant PDC *- Personal Digital Cellular (mobile phone standard) Similar to CDMA; should not be expanded. PDF *- Portable Document Format (PDF) PDH - Plesiochronous Digital Hierarchy (PDH) PDN - Packet Data Network (PDN) PDN GW - Packet Data Network Gateway (PDN GW) (RFC 6965) PDP - Packet Data Protocol (PDP) (RFC 6342) PDS - Parameter Data Structure (PDS) (RFC 5534) PDSN - Packet Data Serving Node (PDSN) (RFC 4787) PDU *- Packet Data Unit or - Protocol Data Unit PDV - Packet Delay Variation (PDV) (RFC 5087) PE - Provider Edge (PE) PEP - Policy Enforcement Point (PEP) PEM1 - No Expansion PEM-1 is not an abbreviation, it is an acronym, and cannot be expanded. (RFC 5224) PEN - Private Enterprise Number (PEN) PETR - Proxy Egress Tunnel Router (PETR) (RFC 6834) PGM - Pragmatic General Multicast (PGM) (RFC 3208) PGP - Pretty Good Privacy (PGP) PHB - Per Hop Behavior (PHB) PHIB - Previous Hop Insertion Block (PHIB) PHOP - previous hop (PHOP) PHP - Penultimate Hop Popping (PHP) (RFC 5994) PHR - Per Hop Reservation (PHR) PHY - Physical Layer (PHY) PI - Provider Independent (PI) (RFC 5887) or - Protocol Instantiation (PI) (RFC 5651) PIB - Payload Integrity Block (PIB) PIDF - Presence Information Data Format (PIDF) PIDF-LO - Presence Information Data Format Location Object (PIDF-LO) PII - Personally Identifiable Information (PII) (RFC 6117) *PIM - Protocol Independent Multicast PIM-SM - Protocol Independent Multicast - Sparse Mode (PIM-SM) PIO - Prefix Information Option (PIO) (RFC 6550) PITR - Proxy Ingress Tunnel Router (PITR) (RFC 6834) PKCS - Public-Key Cryptography Standards (PKCS) PKG - Private Key Generator (PKG) (RFC 5091) PKI *- Public Key Infrastructure (PKI) PKINIT - Public Key Cryptography for Initial Authentication in Kerberos (PKINIT) (RFC 4556) PKIX *- Public Key Infrastructure using X.509 PL - Protocol Layer (RFC 5811) PLC - Packet Loss Concealment (PLC) (RFC 3951) or - Policy (Rule) Lifetime Change (PLC) (RFC 4540) or - Power Line Communication (PLC) (RFC 4779) (Communication can be singular or plural) PLCP - Physical Layer Convergence Procedure (PLCP) PLR - Point of Local Repair (PLR) or - Packet Loss Rate (PLR) (RFC 6035) PLMN - Public Land-based Mobile Network (PLMN) PLPMTUD - Packetization Layer Path MTU Discovery (RFC 4821) pMAG - previous Mobility Access Gateway (pMAG) (RFC 6058) PMD - Physical Medium Dependent (PMD) (RFC 4069) PMIPv6 - Proxy Mobile IPv6 (RFC 5213) PMS - Physical Media Specific (PMS) (RFC 6765) PMSI - P-Multicast Service Interface (PMSI) (RFC 6513) or - Provider Multicast Service Interface (RFC 6625) PMTU - Path MTU (PMTU) PMTUD - Path MTU Discovery (PMTUD) (RFC 4459) PNG *- Portable Network Graphics (PNG) PNNI - Private Network-Network Interface (PNNI) POI - Purge Originator Identification (RFC 6233) PON - Passive Optical Network (PON) (RFC 4837) POP - Point of Presence (POP) or - Post Office Protocol (POP) or - proof of possession (PoP) (RFC 6484) POS - PPP over SONET (POS) (RFC 2615) POSIX - Portable Operating System Interface (POSIX) (RFC 5022) POTS - Plain Old Telephone Service PPP *- Point-to-Point Protocol PPPoA - Point-to-Point Protocol over ATM (PPPoA) PPPoE - Point-to-Point Protocol over Ethernet (PPPoE) PPS - Packets Per Second (PPS) PPSP - Peer-to-Peer Streaming Portocol (PPSP) (RFC 6707) PPTP - Point to Point Tunneling Protocol (PPTP) PR-SCTP - Partially Reliable-Stream Control Transmission Protocol (PR-SCTP) (RFC 5472) PRF - Pseudorandom Function (PRF) PRL - Potential Router List (PRL) (RFC 5214) PRNG - Pseudorandom Number Generator (PRNG) PRR - Port-Range Router (PRR) (RFC 6346) or - Policy Reserve Rule (PRR) (RFC 3989) PS - Parametric Stereo (PS) (RFC 6416) or - Proxy Signature PSAMP - Packet Sampling (PSAMP) PSAP - Public Safety Answering Point (PSAP) (RFC 5031) PSC - Packet Switch Capable (PSC) - Packet Switching Capable (PSC) or - PHB Scheduling Class (PSC) or - Protection State Coordination (PSC) (RFC 5654) PSD - Power Spectral Density (PSD) (RFC 5851) PSK - Pre-Shared Key (PSK) (RFC 4764) PSN *- Public Switched Network or - Packet Switched Network PSS - Packet-switched Streaming Service (PSS) (3GPP) or - Probabilistic Signature Scheme (PSS) (as in RSASSA-PSS) PSTN - Public Switched Telephone Network (PSTN) PT - payload type (PT) - posture transport (RFC 5209) PTI - Payload Type Identifier (PTI) PTK - Pairwise Transient Key (PTK) PTM - Packet Transfer Mode (PTM) or - Pulse-Time Modulation (PTM) PTS - presentation time stamp (PTS) (RFC 2038) PTSW - payload type switch (PTSW) (RFC 6498) PtM - Point to Multipoint (PtM) PtP - Point to Point (PtP) PVC - Permanent Virtual Circuit (PVC) PVP - Permanent Virtual Path (PVP) PVT - Public Validation Token (PVT) (RFC 6507) PW - pseudowire PWE3 - Pseudowire Emulation Edge-to-Edge (PWE3) QoE - Quality of Experience (QoE) QoP - Quality of Protection (QoP) QoS *- Quality of Service (QoS) QQIC - Querier's Query Interval Code (QQIC) (RFC 3376) QRV - Querier's Robustness Variable (QRV) (RFC 3376) QSIG - Q-signaling protocol [No expansion] R2T - request-to-transmit (R2T) RA - Router Advertisement (RA) (RFC 5887) - Routing Area (RA) (RFC 5787) RADIUS *- Remote Authentication Dial-In User Service (RADIUS) Year 2006+ docs don't expand RADIUS in title RAID - Redundant Array of Independent Disks (RAID) RAMS - Rapid Acquisition of Multicast Sessions (RAMS) (RFC 6285) RAMS-R - RAMS Request (RAMS-R) (RFC 6285) RAMS-T - RAMS Termination (RAMS-T) (RFC 6285) RAN - Radio Access Network (RAN) RANAP - Radio Access Network Application Protocol (RANAP) (RFC 3868) RANGER - Routing and Addressing in Networks with Global Enterprise Recursion RAO - Router Alert Option (RAO) (RFC 5350) RAQMON - Real-time Application Quality-of-Service Monitoring (RAQMON) (RFC 4710) RBR - Realm Border Router (RBR) (RFC 6306) RBridge - Routing Bridge (RBridge) (RFC 6325) RC - Routing Controller (RC) RFC 5787) RCODE - No Expansion (RFC 4635) RD - Route Distinguisher (RD) (RFC 2547) - Router Discovery (RD) (RFC 3756) RDDP - Remote Direct Data Placement Protocol (RDDP) RDF - Resource Description Framework (RDF) RDI - Remote Defect Indicator (RDI) - Remote Defect Indication (RDI) (RFC 4842) RDMA - Remote Direct Memory Access (RDMA) RDN - Relative Distinguished Name (RDN) RDO - Route Discovery Option (RDO) RDS - Resolution Discovery System (RDS) RE - Redundancy Elimination (RE) (RFC 6392) REAP - Reachability Protocol (REAP) (RFC 5534) RED - Random Early Detection (RED) (RFC 2309) RELAX NG - Regular Language for XML Next Generation (better known by RELAX NG) REST - Representational State Transfer (REST) (RFC 6120) RF - radio frequency (RF) RFC *- Request for Comments (RFC) RFD - Reduced Function Device (RFD) (RFC 4919) RIB - Routing Information Base (RIB) RIID - Rendezvous Point Interface ID (RFC 3956) RIP *- Routing Information Protocol RIPE NCC *- Reseaux IP Europeens Network Coordination Centre RIPng - Routing Information Protocol Next Generation (RIPng) RIR - Regional Internet Registry (RIR) RISC - Reduced Instruction Set Computer (or Computing) RJRS - Recovery Journal Receiver Structure (RJRS) RJSS - Recovery Journal Sending Structure (RJSS) RLE *- Run Length Encoding (RFCs 5762 and 3611) RLMI - Resource List Meta-Information (RLMI) (RFC 4662) RLOC - Routing Locator (RLOC) (RFC 6306) RLS - Resource List Server (RLS) (RFC 4662) RMON - remote (network) monitoring (RMON) (RFC 4710) RMS - root mean square (RMS) (RFC 5686) RMT - Reliable Multicast Transport (RMT) (RFC 3269) RNC - Radio Network Controller (RNC) (RFC 1986) ROA - Route Origin Authorization (ROA) (RFC 6482) ROADM - Reconfigurable Optical Add/Drop Multiplexer (ROADM) (RFC 6566) ROHC - RObust Header Compression (ROHC) ROLL - Routing Over Low-Power and Lossy (ROLL) (RFC 5867) RP - Rendezvous Point (RP) (RFC 5887) or - Relying Party (RP) (RFC 4158) RPC - remote procedure call (RPC) (Remote Procedure Call protocol -- RFC 1831) RPF - Reverse Path Forwarding (RPF) RPL - Routing Protocol for Low-Power and Lossy Networks (RPL) (RFC 6206) RPN - Registered Parameter Numbers (RPN) (RFC 6295) Note: the plural is used in MIDI documents RPKI - Resource Public Key Infrastructure (RPKI) (RFC 6382) RPSL - Routing Policy Specification Language (RPSL) RR - Resource Record (RR) or - receiver report (RR) or - Route Reflector (RR) (as used by BGP) RRO - Record Route Object (RRO) RRT - Return Routability Test (RRT) RS - Retransmission Server (RS) or - Router Solicitation (RS) (RFC 4380) RSA *- Rivest, Shamir and Adleman RSAES-OAEP - RSA Encryption Scheme - Optimal Asymmetric Encryption Padding (RSAES-OAEP) RSASSA-PSS - RSA Probabilistic Signature Scheme (RSASSA-PSS) RSIP - Realm Specific IP (RSIP) (RFC 3103) RSOO - Relay-Supplied Options option (RSOO) (RFC 6422) RSSI - Received Signal Strength Indication (RSSI) RSTP - Rapid Spanning Tree Protocol (RSTP) (IEEE 802.1t) RSVP *- Resource Reservation Protocol RSVP-TE - RSVP - Traffic Engineering (RFC 5420) RTBH - Remote Triggered Black Hole (RTBH) (RFC 5635) RTCP - RTP Control Protocol (RTCP) if RTP in RTCP needs to be expanded, should be expanded as: RTCP - Real-time Transport Control Protocol (RTCP) RTMP - Real Time Messaging Protocol (RTMP) (RFC 6707) RTO - retransmission timeout (RTO) RTP *- Real-time Transport Protocol RTS - request to send (RTS) RTSP - Real Time Streaming Protocol (RTSP) RTT *- round-trip time RTX *- Retransmission RVS - Rendezvous Server (RVS) (RFC 6301) RW - Restart Window (RW) (RFC 6928) RZ - Return-to-Zero (RZ) S-BGP - Secure Border Gateway Protocol (S-BGP) S-GW - Serving Gateway (S-GW) (RFC 6653) S-NAPTR - Straightforward-Naming Authority Pointer (S-NAPTR) (RFC 3958) S-PE - Switching Provider Edge (RFC 5254) S-PMSI - Selective PMSI (S-PMSI) (RFC 6037) S2L - source-to-leaf (S2L) (RFC 5862) SA - security association (SA) or - Source-Active (SA) or - Source Address (SA) SACK - selective acknowledgment (SACK) (RFC 2581) SAD - Security Association Database (SAD) (RFC 5202) SAFI - Subsequent Address Family Identifier (SAFI) SAID - Security Association ID (RFC 4131) Historically (back to early drafts "SAId" is being used in MIB object Names, also in enumeration values like "Said" are being used; can leave them as is mainly because: a) NMS vendors and operators are familiar with that syntax for OBJECT names involving SAIDs b) It is risky to make global replace that could lead to SNMP syntax errors on deployment (e.g., global replace of SAId for SAID Fix in DESCRIPTION Clauses ONLY: "(SAID)" instead of "(SAId)" "SAID" instead of "SAId" SALT - Speech Application Language Tags (SALT) (RFC 5629) SAML - Security Assertion Markup Language (SAML) SAN - System Area Network (SAN) - Subject Alternative Name (SAN) (RFC 6251) SAOL - Structured Audio Orchestra Language (SAOL) (RFC 6295) SAP - Session Announcement Protocol (SAP) or - Service Access Point (SAP) or - Serving Access Point (SAP) (RFC 5836) SAR - Segmentation and Reassembly (SAR) SASL - Simple Authentication and Security Layer (SASL) SAToP - Structure-Agnostic Time Division Multiplexing over Packet (SAToP) (RFC 4553) SAVI - Source Address Validation Improvement (SAVI) (RFC 6343) SAVP *- Secure Audio-Visual Profile (SAVP) (RFC 3711) SAVPF *- Secure Audio-Visual Profile with Feedback (SAVPF) (RFC 5124) SB - Source Block (SB) (RFC 6801) SBC - Session Border Controller (SBC) (RFC 5853) SBM - Subnet Bandwidth Manager (SBM) SBN - Source Block Number (SBN) (RFC 5053) SBR - Spectral Band Replication (SBR) (RFC 5691) SC - Softwire Concentrator (SC) (RFC 5571) SCCRP - Start-Control-Connection-Reply (SCCRP) SCCRQ - Start-Control-Connection-Request (SCCRQ) SCHAC - Schema for Academia (SCHAC) (RFC 6338) SCRAM - Salted Challenge Response Authentication Mechanism (SCRAM) (RFC 5802) SCS - Secure Cookie Sessions (SCS) (RFC 6896) SCSI - Small Computer System Interface (SCSI) (RFC 4455) SCT - Sender Current Time (SCT) (RFC 5651) SCTP - Stream Control Transmission Protocol (SCTP) SCVP - Simple Certificate Validation Protocol (SCVP) - Server-Based Certificate Validation Protocol (SCVP) (RFC 5055) S/D - Source/Destination (S/D) SDAT - Simple DNA address table (SDAT) (RFC 6059) SDES - source description (SDES) SDID - Signing Domain Identifier (SDID) (RFC 6376) SDH - Synchronous Digital Hierarchy (SDH) SDNV - Self-Delimiting Numeric Value (SDNV) SDO - Standards Development Organization (SDO) (RFC 4052) SDP - Session Description Protocol (SDP) SDU - service data unit (SDU) SEAL - Subnetwork Encapsulation and Adaptation Layer (SEAL) (RFC 5320) SECG - Standards for Efficient Cryptography Group (SECG) SEND - Secure Neighbor Discovery (SEND) (RFC 5887) SES - Severely Errored Seconds (SES) SFGMP - Source Filtering Group Management Protocol (SFGMP) SFMT - sub-feedback message type (SFMT) SGW - Serving Gateway (SGW) (RFC 6965) SHA *- Secure Hash Algorithm SHDSL - Single-pair High-speed Digital Subscriber Line (SHDSL) (RFC 5066) SHIM - Stanza Headers and Internet Metadata (SHIM) SI - softwire initiator (SI) (RFC5571) SID - session ID or server ID or sender ID or - Silence Insertion Descriptor (SID) (RFC 5459) or - Silence Descriptor (SID) (RFC 5993) From Ingemar Johansson (author) There seems to be two definitions: "Silence Descriptor" and "Silence Insertion Description". The 3GPP and ETSI definition seems to be "Silence Descriptor" SIDR - Secure Inter-Domain Routing (SIDR) (RFC 6382) SIFS - Short Interframe Space (SIFS) SIMCO - Simple Middlebox Configuration (SIMCO) (RFC 4540) SIMD - single instruction, multiple data (SIMD) (RFC 6386) SIMPLE - SIP for Instant Messaging and Presence Leveraging Extensions (SIMPLE) SIP *- Session Initiation Protocol SIPP - Simple Internet Protocol plus (SIPP) (RFC 1710) SIPS - Session Initiation Protocol Secure (SIPS) SLA - Service Level Agreement (SLA) SLAAC - Stateless Address Autoconfiguration (SLAAC) (RFC 4429) SLI - Set-Link-Info (SLI) (RFC 3931 - includes hyphens) SLLA - Source Link-Layer Address (SLLA) SLLAO - Source Link-Layer Address Option (SLLAO) SLP - Service Location Protocol (SLP) SMB - Session Management Broker (SMB) (RFC 6108) SMDS - Switched Multimegabit Data Service (SMDS) SMF - Standard MIDI File (SMF) (RFC 4695, RFC 6295) S/MIME *- Secure/Multipurpose Internet Mail Extensions SMI - Structure of Management Information (SMI) (RFC 1095) SMIL - Synchronized Multimedia Integration Language (SMIL) SMIv2 - Structure of Management Information Version 2 (SMIv2) SMPTE - Society of Motion Picture and Television Engineers (SMPTE) (RFC 3497) SMR - Solicit-Map-Request (SMR) (RFC 6834) SMS *- Short Message Service SMSS - Sender Maximum Segment Size (SMSS) (RFC 5681) SMTP *- Simple Mail Transfer Protocol SMUX - SNMP Multiplex (SMUX) SN - Sequence Number (SN) Sn - No Expansion number value Sn in mathematical equations (RFC 5109) SNA - Systems Network Architecture (SNA) (RFC 4594) SNAP - Subnetwork Access Protocol (SNAP) (RFC 5157) - Simple Notification and Alarm Protocol (SNAP) (RFC 4416) SNI - Server Name Indication (SNI) (RFC 6125) SNIA - Storage Networking Industry Association (SNIA) (RFC 6208) SNID - subnamespace identifier (SNID) (RFC 6453) SNMP - Simple Network Management Protocol (SNMP) SNP - Subnetwork Point (SNP) or - Sequence Number Packet (SNP) SNR - Signal-to-Noise Ratio (SNR) SNTP - Simple Network Time Protocol (SNTP) SOA - Start of Authority (RFC 4697) SOAP *- Simple Object Access Protocol But "a Web services messaging protocol; originally the acronym for Simple Object Access Protocol, the term is no longer defined in common use" -IEEE Computer Society "In previous versions of this specification the SOAP name was an acronym. This is no longer the case." - W3C (http://www.w3.org/TR/2007/REC-soap12-part1-20070427/) SOCKS - no expansion. name of protocol. (RFC 1928, RFC 3089) SOHO - Small Office, Home Office (SOHO) (RFC 3022) SONET - Synchronous Optical Network (SONET) SOP - Start of Packet (SOP) (RFC 5371) or - Same-Origin Policy (SOP) (RFC 6797) SPD - Security Policy Database (SPD) (RFC 5202) SPE - Synchronous Payload Envelope (SPE) SPF - Sender Policy Framework (SPF) - Shortest Path First (SPF) (RFC 5305) 9/8/08 - SPF should be expanded in most if not all IS-IS documents as "Shortest Path First" rather than "Sender Policy Framework" SPI - Security Parameter Index (SPI) SPIT - Spam over Internet Telephony (SPIT) (RFC 5278) SPKI - Simple Public Key Infrastructure (SPKI) (RFC 2692) - SubjectPublicKeyInfo (SPKI) (per author of RFC 6698) SPKM - Simple Public-Key GSS-API Mechanism (SPKM) (RFC 2025) SPM - Secure Password Method (SPM) (RFC 6467) SPME - Sub-Path Maintenance Element (SPME) (RFC 5921) SPND - Secure Proxy Neighbor Discovery (SPND) SPNEGO - Simple and Protected GSS-API Negotiation (RFC 4178) SPT - shortest path tree (SPT) SPVC - Switched Permanent Virtual Circuit (SPVC) SQL *- Structured Query Language SR - sender report (SR) SRH - Source Routing Header (SRH) (RFC 6554) SRLG - Shared Risk Link Group (SRLG) SRP - Secure Routing Protocol (SRP) - Secure Remote Password (SRP) (RFC 5054) SRR - status report request (SRR) SRTP - Secure Realtime Transport Protocol (SRTP) or - Secure Real-time Transport Protocol (SRTP) (RFC 3711) SRTCP - Secure Realtime Transport Control Protocol (SRTCP) SRV - Service Record (SRV) SS7 - Signaling System 7 (SS7) (RFC 6076) SS-FSSI - Sender-Side FEC-Scheme-Specific Information (SS-FSSI) (RFC 6363) SS-PW - Single-Segment Pseudowire (SS-PW) (RFC 5254) SSAP - Source Service Access Point (SSAP) SSE - Server Session End (SSE) or - State Signaling Event (SSE) SSH - Secure SHell (SSH) Protocol SSID - Service Set Identifier (SSID) SSK - Secret Signing Key (SSK) (RFC 6507) SSL/TLS - Secure Socket Layer/Transport Layer Security (SSL/TLS) SSM - source-specific multicast (SSM) or - Single Source Multicast (SSM) (RFC 5740) SSN - Server Sequence Number (SSN) or - subsystem number (SSN) or - Stream Sequence Number (SSN) or - Station Serial Number (SSN) SSO - Single Sign-On (SSO) (RFC 6595) SSP - scheme-specifc part (SSP) or - SIP Service Provider (SSP) (RFC 5486) SSPI - Security Support Provider Interface (SSPI) SSRC - synchronization source (SSRC) SSRR - Strict Source and Record Route (SSRR) SSV - Shared Secret Value (SSV) or - Secret State Verifier (SSV) STB - Set-Top Box (STB) (RFC 6972) STP - Spanning Tree Protocol (STP) or - Secure Transfer Protocol (STP) STS - Synchronous Transport Signal (STS) STUN - Session Traversal Utilities for NAT (STUN) (RFC 5389) - Simple Traversal of the UDP Protocol through NAT (STUN) (RFC 3489 -- obsolete) SUT - System Under Test (SUT) SVC - Switched Virtual Circuit (SVC) *SVG - Scalable Vector Graphics (SVG) SVL - Shared VLAN Learning (SVL) SYN - No Expansion TCP flag bit name. See FIN. T-MPLS - Transport MPLS (T-MPLS) (RFC 5704) T-PE - Terminating Provider Edge (T-PE) (RFC 5254) TAMP - Trust Anchor Management Protocol (RFC 5934) TCAM - Ternary Content-Addressable Memory (TCAM) TCN - Topology Change Notification (TCN) (RFC 2643) TCP *- Transmission Control Protocol TDD - Telecommunication Device for the Deaf (TDD) (RFC 5194) TDIM - Time-Division Inverse Multiplexing (TDIM) (RFC 6765) TDM - Time Division Multiplexer (TDM) or - Time-Division Multiplexing (TDM) TDMA *- Time-Division Multiple Access See also CDMA TDMoIP - Time Division Multiplexing over IP (TDMoIP) (RFC 5087) TE - Traffic Engineering (TE) or - Traffic Engineered (TE) TED - Traffic Engineering Database (TED) TEI - Terminal Endpoint Identifier (TEI) TEP - tunnel endpoint (TEP) (RFC 6438) TERENA - Trans-European Research and Education Networking Association (TERENA) (RFC 1983) TESLA - Timed Efficient Stream Loss-Tolerant Authentication (TESLA) TF-EMC2 - Task Force on European Middleware Coordination and Collaboration (TF-EMC2) (RFC 6338) TFRC - TCP Friendly Rate Control (TFRC) TFS - Time and Frequency Synchronization (TFS) (RFC 6965) *TFTP - Trivial File Transfer Protocol (RFC 1350) TGS - Ticket-Granting Server (TGS) or - Ticket-Granting Service (TGS) TGT - Ticket-Granting Ticket (TGT) TIAS - Transport Independent Application Specific (Maximum) (TIAS) (RFC 3890) TIMIP - Terminal Independent Mobile IP (TIMIP) (RFC 6301) TKIP - Temporal Key Integrity Protocol (TKIP) (RFC 5416) TLD - Top-Level Domain (TLD) tLDP - Targeted LDP (tLDP) (RFC 6826) TLLA - Target Link-Layer Address (TLLA) TLLAO - Target Link-Layer Address Option (TLLAO) TLS - Transport Layer Security (TLS) TLSA - No exp -- RRtype per RFC 6698 TLSP - TRILL Link State Protocol (TLSP) (RFC 6361) TLV *- Type-Length-Value (self-describing data) TML - Transport Mapping Layer (RFC 5811) TNC - Trusted Network Connect (TNC) (RFC 6813) TNCP - TRILL Network Control Protocol (TNCP) (RFC 6361) TNP - TRILL Network Protocol (TNP) (RFC 6361) ToIP - Real-time Text over Internet Protocol (ToIP) (RFC 5194) TOE - TCP Offload Engine (TOE) (RFC 5532) or - target of evaluation (TOE) (RFC 4949) TOI - Transmission Object Identifier (TOI) (RFC 5775) TPGT - Target Portal Group Tag (TPGT) TPDU - Transport Protocol Data Unit (TPDU) TPM - Transport Performance Metrics (TPM) TPS - Transport Protocol Specific (TPS) (RFC 6765) TRILL - Transparent Interconnection of Lots of Links (TRILL) (RFC 5556) TS - Traffic Selector (TS) or - Transport Stream (TS) (RFC 5458) TSI - Transport Session Identifier (TSI) (RFC 5651) TSM - Transport Security Model TSN - Trunk Switched Network (TSN) or - Test Support Network (TSN) or - Transmission Sequence Number (TSN) (RFC 3708) TTD - Throughput Test Device (TTD) (RFC 6349) TTL *- Time to Live TTSI - Text-To-Speech Interface (TTSI) TU - Time Unit (TU) TUG - Tributary Unit Group (TUG) TURN - Traversal Using Relay NAT (TURN) (RFC 5245) or - Traversal Using Relays around NAT (TURN) (RFC 5766) TV - Type/Value (TV) (RFC 5857) TWAMP - Two-Way Active Measurement Protocol (TWAMP) (RFC 5357) TX *- Transmission UA - User Agent (UA) UAC - User Agent Client (UAC) UAM - Universal Access Method (UAM) UAS - User Agent Server (UAS) - Unavailable Seconds (UAS) UDDI - Universal Description, Discovery, and Integration (UDDI) UDP *- User Datagram Protocol UDP-Lite *- User Datagram Protocol Lite UDPTL - UDP Transport Layer (UDPTL) UDVM - Universal Data/Voice Multiplexer (UDVM) UE - User Equipment (UE) (RFC 3314) UI *- User Interface UID - Unique Identifier (UID) or - User Identifier (UID) ULA - Unique Local Addressing (ULA) (RFC 5887) - Unique Local Address (ULA) ULID - Upper-Layer Identifier (ULID) (RFC 5533) ULP - Unequal Loss Protection (ULP) UMA - Unlicensed Mobile Access (UMA) UMB - Ultra Mobile Broadband UML - Unified Modeling Language (UML) UMTS - Universal Mobile Telecommunications System (UMTS) (RFC 3310) UNI - User-Network Interface (UNI) U-NII - Unlicensed National Information Infrastructure (U-NII) (RFC 5416) UNSAF - UNilateral Self-Address Fixing (UNSAF) (RFC 3424) U-PE - User-facing PE (RFC 4026) UPnP - Universal Plug and Play (UPnP) URI *- Uniform Resource Identifier URL *- Uniform Resource Locator URN *- Uniform Resource Name uRPF - unicast reverse path forwarding (uRPF) (RFC 6343) USB *- Universal Serial Bus US-CERT - US Computer Emergency Readiness Team (CERT) USM - User-based Security Model USRK - Usage Specific Root Keys (USRK) (RFC 5295) UTC *- Coordinated Universal Time UTF-8 *- Unicode transformation format 8. UTI - Universal Transport Interface (UTI) - note: Cisco UTRAN - Universal Terrestrial Radio Access Network (UTRAN) (RFC 3113) UUID - Universally Unique Identifier (UUID) VACM - View-based Access Control Model (VACM) VAD - Voice Activity Detection (VAD) (RFC 5459) VBD - Voiceband Data (VBD) (RFC 6498) VBR-NRT - Variable Bit Rate - Non Real Time (RFC 3496) VBR-RT - Variable Bit Rate - Real Time (RFC 3496) VC - Virtual Circuit (VC) vCard *- No expansion VCAT - Virtual Concatenation (VCAT) (RFC 6344) VCC - Virtual Channel Connection (VCC) VCCV - Virtual Circuit Connectivity Verification (VCCV) VCI - Virtual Channel Identifier (VCI) or - Virtual Circuit Identifier (VCI) VDL - Valid Data Length (VDL) VDSL - Very high bit-rate Digital Subscriber Line (VDSL) or - Very high speed Digital Subscriber Line (VDSL) VET - Virtual Enterprise Traversal (VET) VLAN *- Virtual Local Area Network VLB - Valiant Load-Balancing (VLB) (RFC 6306) VMR - Variable Multi Rate (VMR) VMR-WB - Variable Multi Rate WideBand (VMR-WB) VoD - Video on Demand (VoD) (RFC 5851) VoIP - Voice over IP (VoIP) VOP - Video Object Plane (VOP) (RFC 3016) VPC - Virtual Path Connection (VPC) VPI - Virtual Path Identifier (VPI) VPIM - Voice Profile for Internet Mail (VPIM) VPN *- Virtual Private Network (VPN) VPLS - Virtual Private LAN Service (VPLS) VPWS - Virtual Private Wire Service (VPWS) (RFC 4026) VRF - VPN Routing and Forwarding (VRF) (RFC 4026) or - Virtual Routing and Forwarding (VRF) (RFC 4382) VRP - VLAN Registration Protocol (VRP) (RFC 6325) VRRP - Virtual Router Redundancy Protocol (VRRP) VSA - Vendor-Specific Attribute (VSA) (RFC 6158) VSP - Voice Service Provider (VSP) (RFC 5582) VSS - Virtual Subnet Selection (VSS) (RFC 6607) VT - Virtual Tributary (VT) VXML - VoiceXML (VXML) W3C *- World Wide Web Consortium (W3C) WAN *- Wide Area Networks WAP - Wireless Application Protocol (WAP) (RFC 2406) W-CDMA - Wideband Code Division Multiple Access (W-CDMA) WDM - Wavelength Division Multiplexing (WDM) WebDAV - Web Distributed Authoring and Versioning (WebDAV) WEBRC - Wave and Equation Based Rate Control (WEBRC) (RFC 3738) WEP - Wired Equivalent Privacy (WEP) WF - Wildcard-Filter (WF) WFQ - Weighted Fair Queuing (WFQ) (RFC 4594) WG *- Working Group WGS 84 - World Geodetic System 1894 (WGS 84) (RFC 6397) WHT - Walsh-Hadamard transform (WHT) (RFC 6386) WiMAX - Worldwide Interoperability for Microwave Access (WiMAX) WLAN *- Wireless Local Area Network (WLAN) WM - Wireless Medium (WM) WRAP - Web Resource Authorization Profiles (WRAP) (RFC 6750) WRR - Weighted Round Robin (WRR) (RFC 3594) WS - White Space (WS) WSON - Wavelength Switched Optical Network (WSON) (RFC 6566) WSP - whitespace (RFC 5617) WWN - World Wide Name (WWN) WWNN - World Wide Node Name (WWNN) WWPN - World Wide Port Name (WWPN) XCAP - Extensible Markup Language (XML) Configuration Access Protocol (XCAP) (RFC 4825) XCON - Centralized Conferencing (XCON) (RFC 5239) XDR - External Data Representation protocol (XDR) (RFC 4506) XLAT - translator (XLAT) (RFC 6145) XML *- EXtensible Markup Language XML-RPC - Extensible Markup Language-Remote Procedure Calling (XML-RPC) (RFC 6537) XMLDSIG - XML Digital Signatures (XMLDSIG) XMLSIG - XML-Signature Syntax and Processing (XMLSIG) XMPP - Extensible Messaging and Presence Protocol (XMPP) (RFC 6120) XNQ - eXtended Network Quality (XNQ) XOR *- exclusive or (see EOR above) XR - Extended Report (XR) XRD - Extensible Resource Descriptor (XRD) (RFC 6415) XRI - Extensible Resource Identifier (XRI) XSD - XML Schema Definition (XSD) XUI - XCAP User Identifier (XUI) ZKPP - Zero-Knowledge Password Proof (ZKPP) (RFC 6113) ZSK - Zone Signing Key (ZSK) (RFC 4033)