The table below lists current acronyms in common and current usage by members of the Information Technology community. These acronyms are used to discuss LAN, internet, WAN, routing and switching protocols, and their applicable organizations. The table contains only current, common, non-proprietary acronyms that are specific to Information Technology. Most of these acronyms appear in IT career certification

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Acronym	Meaning	Primary Applicability	Normative Reference
ACK Transmission Control Protocol The Transmission Control Protocol is one of the core protocols of the Internet Protocol Suite. TCP is one of the two original components of the suite, complementing the Internet Protocol , and therefore the entire suite is commonly referred to as TCP/IP...	Acknowledgement	Transport and other layers	TCP/IP Transmission Control Protocol The Transmission Control Protocol is one of the core protocols of the Internet Protocol Suite. TCP is one of the two original components of the suite, complementing the Internet Protocol , and therefore the entire suite is commonly referred to as TCP/IP... , for example. RFC 793
ACL Access control list An access control list , with respect to a computer file system, is a list of permissions attached to an object. An ACL specifies which users or system processes are granted access to objects, as well as what operations are allowed on given objects. Each entry in a typical ACL specifies a subject...	Access control list	Security, application layer	Access control list Access control list An access control list , with respect to a computer file system, is a list of permissions attached to an object. An ACL specifies which users or system processes are granted access to objects, as well as what operations are allowed on given objects. Each entry in a typical ACL specifies a subject... , Cisco overview
ADSL	Asymmetric digital subscriber line	Telecom	ITU-T G.992.5 Annex M, for example
AES Advanced Encryption Standard Advanced Encryption Standard is a specification for the encryption of electronic data. It has been adopted by the U.S. government and is now used worldwide. It supersedes DES...	Advanced Encryption Standard	Security	U.S. FIPS PUB 197
ANSI Ansi Ansi is a village in Kaarma Parish, Saare County, on the island of Saaremaa, Estonia....	American National Standards Institute	Organization	ANSI
ARP Address Resolution Protocol Address Resolution Protocol is a telecommunications protocol used for resolution of network layer addresses into link layer addresses, a critical function in multiple-access networks. ARP was defined by RFC 826 in 1982. It is Internet Standard STD 37...	Address Resolution Protocol	Link layer	RFC 1122
ATM Asynchronous Transfer Mode Asynchronous Transfer Mode is a standard switching technique designed to unify telecommunication and computer networks. It uses asynchronous time-division multiplexing, and it encodes data into small, fixed-sized cells. This differs from approaches such as the Internet Protocol or Ethernet that...	Asynchronous Transfer Mode	Telecom	ATM cell description
BGP	Border Gateway Protocol (routing protocol)	Application layer, Routers	RFC 4271
BSS	Basic service set (Wi-Fi)	Wireless	IEEE Std 802.11-2007
CAT Category 5 cable Category 5 cable is a twisted pair cable for carrying signals. This type of cable is used in structured cabling for computer networks such as Ethernet. It is also used to carry other signals such as telephony and video. The cable is commonly connected using punch down blocks and modular connectors...	Category (e.g. CAT-5 cable)	Physical layer	ANSI/TIA/EIA-568-B.1-2001
CCITT (obs.)	Standards organization that has been replaced by ITU-T	Organization	ITU-T
CHAP Challenge-handshake authentication protocol In computing, the Challenge-Handshake Authentication Protocol authenticates a user or network host to an authenticating entity. That entity may be, for example, an Internet service provider. CHAP is specified in RFC 1994....	Challenge-Handshake Authentication Protocol (PPP)	Security, telecom	RFC 1994
CIDR	Classless Inter-Domain Routing	Architecture	RFC 1518 RFC 1519
CIR Committed Information Rate Committed information rate or CIR in a Frame relay network is the average bandwidth for a virtual circuit guaranteed by an ISP to work under normal conditions. At any given time, the bandwidth should not fall below this committed figure...	Committed Information Rate (Frame Relay)	Telecom	RFC 1490 RFC 1973 RFC 2427
CLI	Command line interpreter	Hardware	Catalyst 6500 Series Command Reference, 7.6, for example
CPE	Customer premises equipment	Telecom	Telecom Glossary
CRC	Cyclical redundancy check	Link and other layers	24 References here.
CRC-16-CCITT	Cyclical redundancy check (X.25, HDLC)	Link layers	Reference on CRC page.
CSMA/CA	Carrier sense multiple access / collision avoidance	Wireless	IEEE Std 802.11 Downloads
CSMA/CD	Carrier sense multiple access / collision detection	Physical layer	IEEE Std 802.3TM-2002
CSU/DSU CSU/DSU A CSU/DSU is a digital-interface device used to connect a Data Terminal Equipment device or DTE, such as a router, to a digital circuit, such as a T1 line. The CSU/DSU implements two different functions...	Channel service unit / data service unit	Telecom	Telecom Glossary
DCE DCE DCE may refer to:* Delhi College of Engineering, University of Delhi, India* Dalian Commodity Exchange* Data circuit-terminating equipment, also called Data Communications Equipment or Data Carrier Equipment* Cisco's DCE product portfolio...	Data communications equipment	Telecom	Telecom Glossary
DEC (obs.) Digital Equipment Corporation Digital Equipment Corporation was a major American company in the computer industry and a leading vendor of computer systems, software and peripherals from the 1960s to the 1990s...	Digital Equipment Corporation	Organization	Purchased by Compaq in 1998. Merged with Hewlett-Packard 2002.
DES Data Encryption Standard The Data Encryption Standard is a block cipher that uses shared secret encryption. It was selected by the National Bureau of Standards as an official Federal Information Processing Standard for the United States in 1976 and which has subsequently enjoyed widespread use internationally. It is...	Data Encryption Standard (obs. See AES)	Security	Federal Information Processing Standard (FIPS) FIPS-46-3
DHCP	Dynamic Host Configuration Protocol	Application layer, Internet Layer	RFC 2131 and others
DNS Domain name system The Domain Name System is a hierarchical distributed naming system for computers, services, or any resource connected to the Internet or a private network. It associates various information with domain names assigned to each of the participating entities...	Domain Name System	Application layer	Over 30 RFCs here. Domain name system The Domain Name System is a hierarchical distributed naming system for computers, services, or any resource connected to the Internet or a private network. It associates various information with domain names assigned to each of the participating entities...
DRAM Dram Dram or DRAM may refer to:As a unit of measure:* Dram , an imperial unit of mass and volume* Armenian dram, a monetary unit* Dirham, a unit of currency in several Arab nationsOther uses:...	Dynamic random-access memory	Hardware
DSL Digital Subscriber Line Digital subscriber line is a family of technologies that provides digital data transmission over the wires of a local telephone network. DSL originally stood for digital subscriber loop. In telecommunications marketing, the term DSL is widely understood to mean Asymmetric Digital Subscriber Line ,...	Digital Subscriber Line	Telecom	Telecom Glossary
DSLAM	Digital Subscriber Line Access Muliplexor	Telecom	Telecom Glossary (proposed)
DTE Data terminal equipment Data Terminal Equipment is an end instrument that converts user information into signals or reconverts received signals. These can also be called tail circuits. A DTE device communicates with the data circuit-terminating equipment...	Data Terminal Equipment	Telecom	Telecom Glossary
EHA	Ethernet Hardware Address (MAC address)	Link layer	IEEE Std 802 IEEE OUI Assignments
EIA Electronic Industries Alliance The Electronic Industries Alliance was a standards and trade organization composed as an alliance of trade associations for electronics manufacturers in the United States. They developed standards to ensure the equipment of different manufacturers was compatible and interchangeable...	Electronics Industry Alliance	Organization	EIA
EIGRP	Enhanced Interior Gateway Routing Protocol	Internet Layer	Cisco Doc ID: 16406
EOF EOF EOF may refer to:*End-of-file, the computing term for an end-of-file condition or its tangible indication*Empirical orthogonal functions, a statistical technique for simplifying a dataset*Enterprise Objects Framework, a product from Apple Computer...	End Of Frame (HDLC, etc.)	Link layer	HDLC framing
ESS	Extended service set (Wi-Fi group)	Wireless	IEEE Std 802.11-2007
FCC Federal Communications Commission The Federal Communications Commission is an independent agency of the United States government, created, Congressional statute , and with the majority of its commissioners appointed by the current President. The FCC works towards six goals in the areas of broadband, competition, the spectrum, the...	Federal Communications Commission (US)	Organization	US FCC
FCS Frame Check Sequence A frame check sequence refers to the extra checksum characters added to a frame in a communication protocol for error detection and correction. Frames are used to send upper-layer data and ultimately the user application data from a source to a destination. The data package includes the message...	Frame check sequence (Ethernet)	Link layer	Ethernet Frame IEEE Std 802.3
FDDI	Fiber Distributed Data Interface	Link layer	American National Standards Institute X3T9.5 (now X3T12), ISO/IEC 9314-x
FTP	File Transfer Protocol	Application layer	RFC 959 and others
GBIC GBIC A gigabit interface converter is a standard for transceivers, commonly used with Gigabit Ethernet and fibre channel in the 1990s...	Gigabit interface converter	Hardware	[ftp://ftp.seagate.com/sff/INF-8053.PDF Seagate Specification]
Gbps	Gigabit per second	Physical layer	Gigabit per second
HDLC	High-level Data Link Control	Link layer	ISO 13239
http	HyperText Transfer Protocol	Application layer	W3C Change History for HTTP
https Https Hypertext Transfer Protocol Secure is a combination of the Hypertext Transfer Protocol with SSL/TLS protocol to provide encrypted communication and secure identification of a network web server...	HyperText Transfer Protocol Secure	Transport and other layers	SSL 3.0 Specification
IANA Internet Assigned Numbers Authority The Internet Assigned Numbers Authority is the entity that oversees global IP address allocation, autonomous system number allocation, root zone management in the Domain Name System , media types, and other Internet Protocol-related symbols and numbers...	Internet Assigned Number Authority	Organization	IANA
ICMP Internet Control Message Protocol The Internet Control Message Protocol is one of the core protocols of the Internet Protocol Suite. It is chiefly used by the operating systems of networked computers to send error messages indicating, for example, that a requested service is not available or that a host or router could not be...	Internet Control Message Protocol	Internet Layer	RFC 792
IDF Intermediate distribution frame Intermediate distribution frame : In a central office or customer premises, a frame that cross-connects the user cable media to individual user line circuits and may serve as a distribution point for multipair cables from the main distribution frame or combined distribution frame to individual...	Intermediate distribution frame	Physical layer	Structured cabling Structured cabling Structured cabling is building or campus telecommunications cabling infrastructure that consists of a number of standardized smaller elements called subsystems.Structured cabling falls into six subsystems:...  or Telecom Glossary
IDS	Intrusion Detection System	Security	Cisco Product Index
IEC International Organization for Standardization The International Organization for Standardization , widely known as ISO, is an international standard-setting body composed of representatives from various national standards organizations. Founded on February 23, 1947, the organization promulgates worldwide proprietary, industrial and commercial...	Commission Electrotechnique Internationale (French)	Organization	IEC
IEEE	Institute for Electrical and Electronic Engineers	Organization	IEEE
IETF	Internet Engineering Task Force	Organization	IETF
IMAP	Internet Message Access Protocol	Application layer	RFC 3501
IP Internet Protocol The Internet Protocol is the principal communications protocol used for relaying datagrams across an internetwork using the Internet Protocol Suite...	Internet Protocol	Internet Layer	RFC 791 RFC 1606
IPS	Intrusion prevention system	Security	"NIST - Guide to Intrusion Detection and Prevention Systems (IDPS)". 2007-02. Retrieved 2010-08-24.
IS-IS IS-IS Intermediate System To Intermediate System , is a routing protocol designed to move information efficiently within a computer network, a group of physically connected computers or similar devices....	Intermediate System to Intermediate System (routing protocol)	Internet Layer	ISO/IEC 10589:2002
ISDN	Integrated Services Digital Network	Telecom	IEC Area 716-xx
ISP Internet service provider An Internet service provider is a company that provides access to the Internet. Access ISPs directly connect customers to the Internet using copper wires, wireless or fiber-optic connections. Hosting ISPs lease server space for smaller businesses and host other people servers...	Internet service provider	Telecom	Telecom Glossary
ITU-T ITU-T The ITU Telecommunication Standardization Sector is one of the three sectors of the International Telecommunication Union ; it coordinates standards for telecommunications....	International Telecommunications Union	Organization	http://www.itu.int
kbps KBPS KBPS is a high school radio station run by Benson Polytechnic High School students enrolled in the radio broadcasting program. It is owned by Portland Public Schools...	Kilobit per second	Physical layer	Kilobit per second
LAN Local area network A local area network is a computer network that interconnects computers in a limited area such as a home, school, computer laboratory, or office building...	Local area network	Link and other layers	Telecom Glossary
LAPB LAPB Link Access Procedure, Balanced implements the data link layer as defined in the X.25 protocol suite. LAPB is a bit-oriented protocol derived from HDLC that ensures that frames are error free and in the right sequence. LAPB is specified in and ISO/IEC 7776...	Link Access Procedure, Balanced (x.25)	Telecom	ITU-T Recommendation X.222
LAPF Frame relay Frame Relay is a standardized wide area network technology that specifies the physical and logical link layers of digital telecommunications channels using a packet switching methodology...	Link-access procedure for frame relay	Telecom	RFC 1490
LLC Logical Link Control The logical link control data communication protocol layer is the upper sub-layer of the data link layer in the seven-layer OSI reference model...	Logical link control	Link layer	Telecom Glossary
MAC Media Access Control The media access control data communication protocol sub-layer, also known as the medium access control, is a sublayer of the data link layer specified in the seven-layer OSI model , and in the four-layer TCP/IP model...	Media access control	Link layer	IEEE Std 802.3 and 802.11, for example
MAN Metropolitan area network A metropolitan area network is a computer network that usually spans a city or a large campus. A MAN usually interconnects a number of local area networks using a high-capacity backbone technology, such as fiber-optical links, and provides up-link services to wide area networks and the...	Metropolitan area network	Telecom	Telecom Glossary
Mbps	Megabits per second	Physical layer	Megabit per second
MC	Multiple choice	IT Professional Certification	About certification exams
MDF Main distribution frame In telephony, a main distribution frame is a signal distribution frame for connecting equipment to cables and subscriber carrier equipment . The MDF is a termination point within the local telephone exchange where exchange equipment and terminations of local loops are connected by jumper wires...	Main distribution frame	Physical layer	Glossary See also Structured cabling Structured cabling Structured cabling is building or campus telecommunications cabling infrastructure that consists of a number of standardized smaller elements called subsystems.Structured cabling falls into six subsystems:...
MIB Management information base A management information base is a virtual database used for managing the entities in a communications network. Most often associated with the Simple Network Management Protocol , the term is also used more generically in contexts such as in OSI/ISO Network management model...	Management information base (SNMP)	Application layer	RFC 3418
MPLS Multiprotocol Label Switching Multiprotocol Label Switching is a mechanism in high-performance telecommunications networks that directs data from one network node to the next based on short path labels rather than long network addresses, avoiding complex lookups in a routing table. The labels identify virtual links between...	Multiprotocol Label Switching	network technology
MTU MTU MTU may refer to:Networks and Internet* Maximum transmission unit, the size of the largest packet that a network protocol can transmit* Multi tenant unit, a telecom term referring to a building with multiple offices or apartments...	Maximum Transmission Unit	Multiple layers
NAC Network Access Control Network Access Control is an approach to computer network security that attempts to unify endpoint security technology , user or system authentication and network security enforcement.-Background:Network Access Control is a computer networking solution that uses a set of protocols to define and...	Network access control	Link and other layers	IEEE 802.1x
NAT Nat Nat or NAT may refer to:* Nat., an abbreviation for Natural* Nat , a Burmese spirit worshipped in Myanmar in conjunction with Buddhism...	Network Address Translation	Internet Layer	Cisco Internet Protocol Journal: A look Inside Network Address Translators
NBMA	Non-Broadcast Multiple Access (e.g. Frame Relay ATM)	Telecom	See ATM Asynchronous Transfer Mode Asynchronous Transfer Mode is a standard switching technique designed to unify telecommunication and computer networks. It uses asynchronous time-division multiplexing, and it encodes data into small, fixed-sized cells. This differs from approaches such as the Internet Protocol or Ethernet that... , Frame Relay Frame relay Frame Relay is a standardized wide area network technology that specifies the physical and logical link layers of digital telecommunications channels using a packet switching methodology...  and X.25 X.25 X.25 is an ITU-T standard protocol suite for packet switched wide area network communication. An X.25 WAN consists of packet-switching exchange nodes as the networking hardware, and leased lines, Plain old telephone service connections or ISDN connections as physical links... , for examples.
NIC	Network Interface Card	Physical layer	Telecom Glossary
NRZ Non-return-to-zero In telecommunication, a non-return-to-zero line code is a binary code in which 1's are represented by one significant condition and 0's are represented by some other significant condition , with no other neutral or rest condition. The pulses have more energy than a RZ code...	Non-return-to-zero	Physical layer	Federal Standard 1037C
NRZI	Non-return to zero inverted	Physical layer	Federal Standard 1037C
NVRAM NVRAM Non-volatile random-access memory is random-access memory that retains its information when power is turned off, which is described technically as being non-volatile...	Non-volatile RAM	Hardware	Sample vendor data here
OSI Open Systems Interconnection Open Systems Interconnection is an effort to standardize networking that was started in 1977 by the International Organization for Standardization , along with the ITU-T.-History:...	Open System Interconnect (joint ISO and ITU standard)	Organization	ISO/IEC 9594-5:2005 Open Systems Interconnection Protocol Specifications
OSPF	Open Shortest Path First (routing protocol)	Internet Layer	RFC 2238
OUI Organizationally Unique Identifier An Organizationally Unique Identifier is a 24-bit number that is purchased from the Institute of Electrical and Electronics Engineers, Incorporated Registration Authority...	Organization Unique Identifier	Link and other layers	IEEE OUI Assignments
PAP Password authentication protocol A password authentication protocol is an authentication protocol that uses a password.PAP is used by Point to Point Protocol to validate users before allowing them access to server resources. Almost all network operating system remote servers support PAP.PAP transmits unencrypted ASCII passwords...	Password authentication protocol	Security	RFC 1334
PAT	Port address translation	Internet Layer	RFC 1918
PC Personal computer A personal computer is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end-user with no intervening computer operator...	Personal computer (host)	Hardware
PCM	Pulse-code modulation	Physical layer	ITU-T G.711
PDU Protocol data unit In telecommunications, the term protocol data unit has the following meanings:#Information that is delivered as a unit among peer entities of a network and that may contain control information, address information, or data....	Protocol data unit (such as segment, packet, frame, etc.)	Multiple layers	Fed Std 1037C
POP3	Post Office Protocol, version 3	Application layer	RFC 1939
POP Point of presence A point of presence is an artificial demarcation point or interface point between communications entities. It may include a meet-me-room.In the US, this term became important during the court-ordered breakup of the Bell Telephone system...	Point of presence	Telecom	Telecom Glossary
POST Post -Mail:* Mail, the postal system, especially in Commonwealth of Nations countries* Post, an entry in a blog or internet forum - see posting style-Newspapers and magazines:* New York Post, USA* The Washington Post, USA...	Power-on self test	Hardware	Cisco Catalyst 2800 User Guide, for example
POTS POTS POTS may refer to:* Plain old telephone service, basic wireline telecommunication connection** POTS codec, a digital audio device** DSL filter, also known as a POTS filter* Postural orthostatic tachycardia syndrome, a medical condition...	Plain old telephone service	Telecom	Telecom Glossary
PPP	Point-to-point Protocol	Telecom	RFC 1661
PPTP	Point-to-Point Tunneling Protocol	Telecom	RFC 2637
PTT PTT PTT may refer to:Chemistry and medicine:* Partial thromboplastin time, a performance indicator in medicine for coagulation status* Photothermal Therapy, A method of using light and photosensitizers for medical treatments...	Public Telephone and Telegraph	Telecom	Telecom Glossary or Free Dictionary
PVST	Per-VLAN Spanning Tree	Link layer	Cisco's introduction to Spanning Tree Protocol
RADIUS RADIUS Remote Authentication Dial In User Service is a networking protocol that provides centralized Authentication, Authorization, and Accounting management for computers to connect and use a network service...	Remote Authentication Dial-In User Service	Security	RFC 2865
RAM Ram -Animals:*Ram, an uncastrated male sheep*Ram cichlid, a species of freshwater fish endemic to Colombia and Venezuela-Military:*Battering ram*Ramming, a military tactic in which one vehicle runs into another...	Random Access Memory	Physical layer	Telecom Glossary
RARP	Reverse ARP	Link layer	RFC 903
RFC Request for Comments In computer network engineering, a Request for Comments is a memorandum published by the Internet Engineering Task Force describing methods, behaviors, research, or innovations applicable to the working of the Internet and Internet-connected systems.Through the Internet Society, engineers and...	Request for Comments	Multiple layers	IETF's RFC Index
RIP Routing Information Protocol The Routing Information Protocol is a distance-vector routing protocol, which employs the hop count as a routing metric. RIP prevents routing loops by implementing a limit on the number of hops allowed in a path from the source to a destination. The maximum number of hops allowed for RIP is 15....	Routing Information Protocol	Internet Layer	RFC 2453, for RIP version 2
RLL Run Length Limited Run length limited or RLL coding is a line coding technique that is used to send arbitrary data over a communications channel with bandwidth limits. This is used in both telecommunication and storage systems which move a medium past a fixed head. Specifically, RLL bounds the length of stretches ...	Run-Length Limited	Physical layer	RLL Run Length Limited Run length limited or RLL coding is a line coding technique that is used to send arbitrary data over a communications channel with bandwidth limits. This is used in both telecommunication and storage systems which move a medium past a fixed head. Specifically, RLL bounds the length of stretches ...  is used in a wide range of encodings.
ROM Read-only memory Read-only memory is a class of storage medium used in computers and other electronic devices. Data stored in ROM cannot be modified, or can be modified only slowly or with difficulty, so it is mainly used to distribute firmware .In its strictest sense, ROM refers only...	Read-Only Memory	Hardware	Telecom Glossary
RSTP	Rapid Spanning Tree Protocol	Link layer	IEEE 802.1w - Rapid Reconfiguration of Spanning Tree
RTP Real-time Transport Protocol The Real-time Transport Protocol defines a standardized packet format for delivering audio and video over IP networks. RTP is used extensively in communication and entertainment systems that involve streaming media, such as telephony, video teleconference applications, television services and...	Real-time Transport Protocol	Application layer	RFC 3550
SDLC Synchronous Data Link Control Synchronous Data Link Control is a computer communications protocol. It is the layer 2 protocol for IBM's Systems Network Architecture . SDLC supports multipoint links as well as error correction. It also runs under the assumption that an SNA header is present after the SDLC header...	Synchronous Data Link Control	Link layer	Cisco Technology Handbook: SDLC and Derivatives
SFD	Start-of-frame delimiter (Ethernet, HDLC, etc.)	Link layer	IEEE 802.3 (Ethernet), or RFC 2687 (HDLC), for examples
SFP	Small form-factor pluggable	Hardware	[ftp://ftp.seagate.com/sff/INF-8074.PDFS Seagate Specification]
S-HTTP	Secure HTTP (rarely used)	Transport and other layers	RFC 2660 See also https Https Hypertext Transfer Protocol Secure is a combination of the Hypertext Transfer Protocol with SSL/TLS protocol to provide encrypted communication and secure identification of a network web server...
SLARP	Serial Line ARP (Address Resolution Protocol)	Link and other layers	Archived Cisco Serial Line Encapulation extension
SLIP Serial Line Internet Protocol The Serial Line Internet Protocol is an encapsulation of the Internet Protocol designed to work over serial ports and modem connections. It is documented in RFC 1055...	Serial Line Internet Protocol (obs.)	Telecom	RFC 1055
SMTP	Simple Mail Transfer Protocol	Application layer	RFC 5321
SNA	Systems Network Architecture (IBM)	Multiple layers	SNA Protocol Suite
SNAP Subnetwork Access Protocol The Subnetwork Access Protocol is a mechanism for multiplexing, on networks using IEEE 802.2 LLC, more protocols than can be distinguished by the 8-bit 802.2 Service Access Point fields. SNAP supports identifying protocols by Ethernet type field values; it also supports vendor-private protocol...	SubNet Access Protocol	Link layer	IEEE 802 Overview and Architecture
SNMP	Simple Network Management Protocol	Application layer	RFC 1155, RFC 3410 thru RFC 3418 and others
SOF	Start of frame	Link layer	IEEE 802.3 (Ethernet), or RFC 2687 (HDLC), for examples
SRAM Static random access memory Static random-access memory is a type of semiconductor memory where the word static indicates that, unlike dynamic RAM , it does not need to be periodically refreshed, as SRAM uses bistable latching circuitry to store each bit...	Static random access memory	Hardware	PC Guide's Definition
SSH Secure Shell Secure Shell is a network protocol for secure data communication, remote shell services or command execution and other secure network services between two networked computers that it connects via a secure channel over an insecure network: a server and a client...	Secure shell	Application layer	RFC 4252
SSID	Service set identifier (Wi-Fi)	Wireless	IEEE 802.11
STP Spanning tree protocol The Spanning Tree Protocol is a network protocol that ensures a loop-free topology for any bridged Ethernet local area network. The basic function of STP is to prevent bridge loops and ensuing broadcast radiation...	Spanning Tree Protocol	Link layer	Cisco's Introduction to Spanning Tree Protocol
SYN (TCP)	Synchronization	Link and other layers	RFC 793 and many others
TCP/IP Transmission Control Protocol The Transmission Control Protocol is one of the core protocols of the Internet Protocol Suite. TCP is one of the two original components of the suite, complementing the Internet Protocol , and therefore the entire suite is commonly referred to as TCP/IP...	Transmission Control Protocol/Internet Protocol	Transport layer	RFC 793 and many others
TDM Time-division multiplexing Time-division multiplexing is a type of digital multiplexing in which two or more bit streams or signals are transferred apparently simultaneously as sub-channels in one communication channel, but are physically taking turns on the channel. The time domain is divided into several recurrent...	Time-division multiplexing	Physical layer	Fed Std 1037C
TFTP Trivial File Transfer Protocol Trivial File Transfer Protocol is a file transfer protocol known for its simplicity. It is generally used forautomated transfer of configuration or boot files between machines in a local environment....	Trivial File Transfer Protocol	Application layer	RFC 1350
TIA TIA TIA may refer to:Aviation:* Tirana International Airport Nënë Tereza, , Tirana, Albania* Tampa International Airport, , commonly abbreviated as "TIA"...	Telecommunications Industry Alliance	Organization	Telecommunications Industry Association
UDP User Datagram Protocol The User Datagram Protocol is one of the core members of the Internet Protocol Suite, the set of network protocols used for the Internet. With UDP, computer applications can send messages, in this case referred to as datagrams, to other hosts on an Internet Protocol network without requiring...	User Datagram Protocol	Transport layer	RFC 768
USB	Universal Serial Bus	Physical and other layers	USB 3.0 Specification
UTP Twisted pair Twisted pair cabling is a type of wiring in which two conductors are twisted together for the purposes of canceling out electromagnetic interference from external sources; for instance, electromagnetic radiation from unshielded twisted pair cables, and crosstalk between neighboring pairs...	Unshielded twisted pair	Physical	Many versions are defined by TIA, such as: TIA-568-B
VC Virtual circuit In telecommunications and computer networks, a virtual circuit , synonymous with virtual connection and virtual channel, is a connection oriented communication service that is delivered by means of packet mode communication...	Virtual circuit	Transport and other layers	Telecom Glossary
VLAN	Virtual local area network	Link layer	IEEE 802.1Q
VLSM	Variable-length subnet masking	Architecture	RFC 1518 RFC 1519
VPN	Virtual private network	Application layer	Virtual Private Network Consortium
W3C	World Wide Web Consortium	Organization	W3C
WAN Wide area network A wide area network is a telecommunication network that covers a broad area . Business and government entities utilize WANs to relay data among employees, clients, buyers, and suppliers from various geographical locations...	Wide-area network	Telecom	Telecom Glossary
WEP Wired Equivalent Privacy Wired Equivalent Privacy is a weak security algorithm for IEEE 802.11 wireless networks. Introduced as part of the original 802.11 standard ratified in September 1999, its intention was to provide data confidentiality comparable to that of a traditional wired network...	Wired Equivalent Privacy	Wireless	IEEE 802.11
Wi-Fi Wi-Fi Wi-Fi or Wifi, is a mechanism for wirelessly connecting electronic devices. A device enabled with Wi-Fi, such as a personal computer, video game console, smartphone, or digital audio player, can connect to the Internet via a wireless network access point. An access point has a range of about 20...	IEEE 802.11 (Wi-Fi Alliance)	Wireless	Wi-Fi Alliance
WPA Wi-Fi Protected Access Wi-Fi Protected Access and Wi-Fi Protected Access II are two security protocols and security certification programs developed by the Wi-Fi Alliance to secure wireless computer networks...	Wi-Fi Protected Access	Security	IEEE 802.11i
www	World Wide Web	Architecture	W3C Consortium