AAL: ATM Adaptation Layer
The ATM Adaptation Layer (AAL) relays ATM cells between the ATM Layer and higher layers. When relaying information received from the higher layers, it segments the data into ATM cells. When relaying information received from the ATM Layer, it must reassemble the payloads into a format the higher layers can understand. This operation, which is called Segmentation and Reassembly (SAR), is the main task of AAL. Different AALs (AAL0, AAL1, AAL2, AAL3/4 and AAL5) were defined in supporting different traffic or services expected to be used.
Standard Organization: ATM Forum and ITU-T
Reference Document: ITU-T I.363

AAL0: ATM Adaptation Layer Type 0
ATM Adaptation Layer Type 0 (AAL0) refers to raw ATM cells. AAL0 payload consists of 48 bytes without a special field.
Standard Organization: ATM Forum and ITU-T
Reference Document: ITU-T I.366.2

AAL1: ATM Adaptation Layer Type 1
ATM Adaptation Layer Type 1 (AAL1) supports constant bit rates, time-dependent traffic such as voice and video. AAL1 is used for connection-oriented, delay-sensitive services requiring constant bit rates (CBR), such as video and voice traffic.
Standard Organization: ATM Forum and ITU-T
Reference Document: ITU-T I.366.2

AAL2: ATM Adaptation Layer Type 2
ATM Adaptation Layer Type 2 (AAL2) is designed for variable bit rate video transfer. AAL2 is perfect for low-rate voice traffic, with compression, silent and idle channel suppression. AAL type 2 is subdivided into the Common Part Sublayer (CPS ) and the Service Specific Convergence Sublayer (SSCS ).
Standard Organization: ATM Forum and ITU-T
Reference Document: ITU-T I.366.2

AAL3/4: ATM Adaptation Layer Type 3/4
ATM Adaptation Layer Type 3/4 (AAL3/4) is designed for variable bit rate, delay-tolerant data traffic requiring some sequencing and/or error detection support. AAL 3/4 supports both connectionless and connection-oriented links, but is primarily used for the transmission of SMDS packets over ATM networks.
Standard Organization: ATM Forum and ITU-T
Reference Document: ITU-T I.366.2

AAL5: ATM Adaptation Layer Type 5
ATM Adaptation Layer Type 5 (AAL5) is designed for variable bit rate, delay-tolerant connection-oriented data traffic requiring minimal sequencing or error detection support. AAL5 supports connection-oriented, VBR services. AAL5 is used predominantly for the transfer of classic IP over ATM and LANE traffic. AAL5 uses SEAL and is the least complex of the current AAL recommendations. AAL5 has no per-cell length or per-cell CRC fields, and offers low bandwidth overhead and simpler processing requirements in exchange for reduced bandwidth capacity and error-recovery capability.
Standard Organization: ATM Forum and ITU-T
Reference Document: ITU-T I.366.2

AARP: AppleTalk Address Resolution Protocol
AppleTalk Address Resolution Protocol (AARP), similar to the Address Resolution Protocol (ARP), maps AppleTalk nodes addresses at the network layer to the physical layer (usually MAC) addresses. The AARP table allows for management of the Address Mapping Table on the managed device.
Standard Organization: Apple

ACSE: Association Control Service Element
Association Control Service Element (ACSE), an application layer protocol in the OSI model defined by ISO, is designed to establish and release an application-association between two AEIs and to determine the application context of that association. The ACSE supports two modes of communication: connection-oriented and connectionless. For the connection-oriented mode, the application association is established and released by the reference of ACSE connection-oriented services. For the connectionless mode, the application association exists during the invocation of the single ACSE connectionless mode service, A UNIT-DATA.
Standard Organization: ISO / ITU-T
Reference Document: ISO 8650 / X.227

ADCCP: Advanced Data Communications Control Protocol
Advanced Data Communications Control Protocol(ADCCP) is a bit-oriented data link control protocol that places data on a network and ensures proper delivery to a destination. ADCCP is based on the IBM's SDLC (Synchronous Data Link Control) protocol. The HDLC (High Level Data Link Control) by ISO and the LAPB(Link Access Protocol-Balanced) by ITU/CCITT are based on the ADCCP.
Standard Organization: ANSI
Reference Document: ANSI X3.66

ADSL Lite
ADSL Lite, also known as universal ADSL, splitterless ADSL or G.lite, is one of the Digital Subscriber Line technologies that allows broadband data access over normal phone lines (twisted pair cables, also called POTS). ADSL Lite offers a maximum of 1.5 Mbit/s downstream and 512 kbit/s upstream and does not require the use of phone line splitters.
Standard Organization: ANSI/ITU-T

ADSL: Asynchronous Digital Subscriber Line
Asynchronous Digital Subscriber Line (ADSL) is one of the Digital Subscriber Line technologies that allows broadband data access over normal phone lines (twisted pair cables, also called POTS). ADSL allows higher speed for data downstream than upstream and this is why the word "Asynchronous" is there. For conventional ADSL, downstream rates start at 256 kbit/s and typically reach 8 Mbit/s within 1.5 km (5000 ft) of the DSLAM equipped central office or remote terminal. Upstream rates start at 64 kbit/s and typically reach 256 kbit/s but can go as high as 1024 kbit/s. The name ADSL Lite is sometimes used for the slower versions.
Standard Organization: ANSI/ITU-T

ADSP: AppleTalk Data Stream Protocol
AppleTalk Data Stream Protocol (ADSP) is a session-level protocol that provides symmetric, connection-oriented, full-duplex communication between two sockets on the AppleTalk network. In addition, it handles flow-control and reliability and provides a data channel for the hosts, which is a simple transport method for data accross a network. ADSP is a connection-oriented protocol that guarantees in-sequence data delivery with flow control.
Standard Organization: Apple

AEP: AppleTalk Echo Protocol
AppleTalk Echo Protocol (AEP) is a transport layer protocol in the AppleTalk protocol suite designed to test the reachability of network nodes. AEP generates packets to be sent to the network node and is identified in the Type field of a packet as an AEP packet. The packet is first passed to the source DDP. After it is identified as an AEP packet, it is forwarded to the node where the packet is examined by the DDP at the destination. After the packet is identified as an AEP packet, the packet is then copied and a field in the packet is altered to create an AEP reply packet, and is then returned to the source node.
Standard Organization: Apple

AES: Advanced Encryption Standard
The Advanced Encryption Standard (AES), also known as Rijndael, is a block cipher adopted as an encryption standard developed by NIST. AES is intended to specify an unclassified, publicly-disclosed, symmetric encryption algorithm. AES has a fixed block size of 128 bits and a key size of 128, 192 or 256 bits.
Standard Organization: NIST
Reference Document: Federal Information Processing Standards Publication 197

AES-CMAC
AES-CMAC, abbreviation of Advanced Encryption Standard-Cipher-based Message Authentication Code, is an authentication algorithm based on CMAC with the 128-bit Advanced Encryption Standard (AES). AES-CMAC achieves a security goal similar to that of HMAC. Since AES-CMAC is based on a symmetric key block cipher, AES, and HMAC is based on a hash function, such as SHA-1, AES-CMAC is appropriate for information systems in which AES is more readily available than a hash function.
Standard Organization: IETF
Reference Document: RFC 4493

AES-CMAC-PRF-128
AES-CMAC-PRF-128, abbreviation of Advanced Encryption Standard-Cipher-based Message Authentication Code-Pseudo-Random Function-128, is an authentication algorithm based on AES-CMAC. AES-CMAC-PRF-128 is identical to AES-CMAC except that the 128-bit key length restriction is removed.
Standard Organization: IETF
Reference Document: RFC 4615

AFP: Apple Filling Protocol
Apple Filing Protocol (AFP), formerly AppleTalk Filing Protocol, is the protocol for communicating with AppleShare file servers. Built on top of ASP, it provided services for authenticating users (extensible to different authentication methods including two-way random-number exchange) and for performing operations specific to the Macintosh HFS filesystem.
Standard Organization: Apple

AFP: AppleTalk Filing Protocol
AppleTalk Filing Protocol (AFP), renamed to Apple Filing Protocol now, is the protocol for communicating with AppleShare file servers. Built on top of ASP, it provided services for authenticating users (extensible to different authentication methods including two-way random-number exchange) and for performing operations specific to the Macintosh HFS filesystem.
Standard Organization: Apple

AH: Authentication Header
Authentication Header, a protocol in the IPsec (Internet Security) suite, is used to provide connectionless integrity and data origin authentication for IP datagrams, and to provide protection against replays. This protection service against replay is an optional service to be selected by the receiver when a Security Association is established. AH provides authentication for as much of the IP header as possible, as well as for upper level protocol data. However, some IP header fields may change in transit and the value of these fields, when the packet arrives at the receiver, may not be predictable by the sender. The values of such fields cannot be protected by AH. Thus the protection provided to the IP header by AH is only partial in some cases.
Standard Organization: IETF
Reference Document: RFC 2402

Airline protocol
Airline protocol refers to the airline reservation system data and the protocols, such as P1024B (ALC), P1024C (UTS), and MATIP, that transport the data between the mainframe and the Agent Set Control Unit (ASCU).

AKE: Augmented Key Exchange
Augmented Key Exchange(AKE) is a key exchange protocol for public key cryptography systems.
Standard Organization: IETF

ALC: Airline Control Protocol
Airline Control Protocol (ALC) is a data link layer polled protocol that runs in full-duplex mode over synchronous serial (V.24) lines and uses the binary-coded decimal (BCD) character set.

ANDNA: Abnormal Netsukuku Domain Name Anarchy
Abnormal Netsukuku Domain Name Anarchy (ANDNA), similar to the Domain Name System (DNS), is the distributed, non-hierarchical and decentralised system of hostname management in Netsukuku. The ANDNA database is scattered inside all the Netsukuku and works in the following way: in order to resolve a hostname, we just have to calculate its hash. The hash is nothing more than a number (IP), and the node related to that IP is called andna_hash_node. The hash_node will keep a small database, which associates all the hostnames related to it with the IP of the node, which has registered the same hostnames.

APON: ATM Passive Optical Network
ATM Passive Optical Network (APON), or ATM PON, is the initial PON specification defined by the FSAN (Full Service Access Network) group using ATM as their layer 2 signaling protocol. Use of the term APON led users to believe that only ATM services could be provided to end-users, so the FSAN decided to broaden the name to Broadband PON (BPON). BPON systems offer numerous broadband services including Ethernet access and video distribution.
Standard Organization: ITU-T

APPC: Advanced Program-to-Program Communications
Advanced Program-to-Program Communications (APPC), a protocol roughly in the OSI presentation and session layers, is a programming interface standard in the IBM SNA system that allows interconnected systems to communicate and share the processing of programs. Originally developed by IBM as a remote transaction processing tool between Logic Units (LUs), APPC is now used to provide distributed services within a heterogeneous computing environment. APPC establishes and tears down connections between communicating programs, and consists of two interfaces, a programming interface and a data-exchange interface. The former replies to requests from programs requiring communication; the latter establishes sessions between programs.
Standard Organization: IBM

AppleTalk
AppleTalk is a multi-layered protocol suite of Apple Computers, providing internetwork routing, transaction and data stream service, naming service and comprehensive file and print sharing among Apple systems using the LocalTalk interface built into the Apple hardware. AppleTalk ports to other network media such as Ethernet by the use of LocalTalk to Ethernet bridges or by Ethernet add-in boards for Apple machines. Many third-party applications exist for the AppleTalk protocols.
Standard Organization: Apple

APPN: Advanced Peer-to-Peer Networking
Advanced Peer-to-Peer Networking (APPN) is an enhancement to the original IBM SNA architecture. APPN, which includes a group of protocols, handles session establishment between peer nodes, dynamic transparent route calculation and traffic prioritization. Using APPN, a group of computers can be automatically configured by one of the computers acting as a network controller so that peer programs in various computers will be able to communicate with each other using specified network routing.
Standard Organization: IBM

ARP: Address Resolution Protocol
Address Resolution Protocol (ARP) performs mapping of an IP address to a physical machine address (MAC address for Ethernet) that is recognized in the local network. For example, in IP Version 4, an address is 32 bits long. In an Ethernet local area network, however, addresses for attached devices are 48 bits long.
Standard Organization: IETF
Reference Document: RFC 826

ASCII: American Standard Code for Information Interchange
American Standard Code for Information Interchange (ASCII) is 8-bit code for character representation (7 bits plus parity). ASCII codes represent text in computers, communications equipment, and other devices that work with text. Most modern character encodings have a historical basis in ASCII. It defines codes for 33 non-printing, mostly obsolete control characters that affect how text is processed, plus 95 printable characters as follows: !"#$%&'()*+,-./0123456789:;<=> @ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_ `abcdefghijklmnopqrstuvwxyz{|}~
Standard Organization: ANSI

ASE: Application Service Element
Application Service Element (ASE), defined by ISO, is a protocol in the presentation layer of the OSI seven layer model which provides an abstracted interface layer to service application protocol data units (APDU). Because applications and networks vary, ASEs are split into common application service element (CASE) and Specific-application service elements (SASEs).
Standard Organization: ISO

ASN.1: Abstract Syntax Notation One
Abstract Syntax Notation One (ASN.1), an ISO/ITU-T standard, describes data structures for representing, encoding, transmitting, and decoding data. It provides a set of formal rules for describing the structure of objects regardless of language implementation and physical representation of these data, whatever the application, whether complex or very simple.
Standard Organization: ISO
Reference Document: X.680

ASP: AppleTalk Session Protocol
AppleTalk Session Protocol (ASP), a protocol developed by Apple Computers, provides session establishment, maintenance, and teardown, as well as request sequencing. ASP is built on top of AppleTalk Transaction Protocol (ATP) which is the original reliable session-level protocol for AppleTalk.
Standard Organization: Apple

ATCP: AppleTalk Control Protocol
AppleTalk Control Protocol (ATCP) is the protocol that establishes and configures AppleTalk over PPP. ATCP is responsible for configuring, enabling, and disabling the AppleTalk protocol modules on both ends of the point-to-point (PPP) link. ATCP uses the same packet exchange mechanism as the Link Control Protocol (LCP). ATCP packets may not be exchanged until PPP has reached the Network-Layer Protocol phase. ATCP packets received before this phase is reached should be silently discarded.
Standard Organization: Apple

ATIP: AppleTalk Tunneling Through IP
AppleTalk Tunneling Through IP (ATIP) is a protocol that allows an AppleTalk WAN with two or more native AppleTalk networks to be connected through a tunnel built on a TCP/IP internet. This protocol is replaced by AppleTalk Update-based Routing Protocol (AURP).
Standard Organization: IETF

ATM layer
The ATM layer, the layer 2 in the ATM reference model, provides an interface between the ATM adaptation layer (AAL) and the physical layer. This layer is responsible for relaying cells from the AAL to the physical layer, such as SONET, for transmission, and from the physical layer to the AAL for use at the end systems.
Standard Organization: ATM Forum and ITU-T
Reference Document: ITU-T I.361

ATM UNI
The ATM User-to-Network Interface (UNI) signaling protocols within the Signalling ATM Adaptation Layer (SAAL) are responsible for ATM call and connection control, including call establishment, call clearing, status enquiry and point-to-multipoint control between ATM end users and a private ATM switch, or between a private ATM switch and the public carrier ATM network. ATM UNI signaling message uses the Q.931 message format, which is made up of a message header and a variable number of Information Elements.
Standard Organization: ATM Forum and ITU-T
Reference Document: ITU-T I.432

ATM: Asynchronous Transfer Mode
The Asynchronous Transfer Mode (ATM) comprises a protocol suite under the ATM reference model, which establishes a mechanism to carry all traffic on a stream of fixed 53-byte packets (cells). A fixed-size packet can ensure that the switching and multiplexing function is carried out quickly and easily. ATM is a connection-oriented technology; i.e. two systems on the network should inform all intermediate switches about their service requirements and traffic parameters in order to establish communication.
Standard Organization: ATM Forum and ITU-T

ATMARP: ATM Address Resolution Protocol
ATM Address Resolution Protocol (ATMARP) is a specialised variant of ARP used to resolve layer-three (IP) addresses to layer-two (ATM NSAP or E.164) addresses in the Classical IP (CLIP) over ATM network environment. The main difference to traditional ARP is that - because ATM lacks a broadcast facility - there is a single designated ATMARP server whose layer-two address has to be configured statically in each client.
Standard Organization: IETF / ITU-T

ATP: ALPS Tunneling Protocol
ALPS Tunneling Protocol is a protocol used to transport ALPS data across a TCP/IP network between an ALC/UTS router and an AX.25/EMTOX router. It consists of a set of messages (or primitives) to activate and deactivate ALPS ATP circuits and to pass data.
Standard Organization: ALPS

ATP: AppleTalk Transaction Protocol
AppleTalk Transaction Protocol (ATP), built on top of Datagram Delivery Protocol (DDP), is a transport-level protocol that provides a loss-free transaction service between sockets. The service allows exchanges between two socket clients in which one client requests the other to perform a particular task and to report the results. ATP binds the request and the response together to ensure the reliable exchange of request-response pairs.
Standard Organization: Apple

AURP: AppleTalk Update-Based Routing Protocol
The AppleTalk Update-Based Routing Protocol (AURP) is a transport layer protocol in the AppleTalk protocol suite that allows two or more AppleTalk internetworks to be interconnected through a TCP/IP network to form an AppleTalk WAN. AURP is a method of encapsulating AppleTalk traffic in the header of a foreign protocol, allowing the connection of two or more discontiguous AppleTalk internetworks. This connection is called an AURP tunnel. In addition to its encapsulation function, AURP maintains routing tables for the entire AppleTalk WAN by exchanging routing information between exterior routers.
Standard Organization: Apple