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List of netowrking, wireless, broadband, satellite, telephony, general computing and other technical terms used throughout the site.
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Term Description
A-MPDU A-MPDU (Aggregate MAC Protocol Data Unit) and A-MSDU (Aggregate MAC Service Data Unit) are types of packet aggregation part of the 802.11n (and 802.11ac) wireless networking standards. Packet aggregation increases throughput at a potential performance penalty of increased data retransmissions.

A-MPDU aggregates packets into frames of up to 64 kilobytes. It is an alternative to A-MSDU that has more overhead, however it also causes fewer retransmissions. Because of this, A-MPDU often performs better and is preferred to A-MSDU.
A-MSDU A-MSDU (Aggregate MAC Service Data Unit) and A-MPDU (Aggregate MAC Protocol Data Unit) are types of packet aggregation part of the 802.11n (and 802.11ac) wireless networking standards. Packet aggregation increases throughput by lowering header overhead, at a potential performance penalty of increased data retransmission.

A-MSDU aggregates packets into frames of up to 7935 bytes with a single MAC header and CRC. Because of that, it reduces header overhead, however it also has a potential performance penalty of increased data retransmissions. A-MPDU has higher header overhead, and causes fewer retransmissions than A-MSDU.
access point A wireless access point (AP) in computer networking is a hardware device that allows wireless clients to connect to a wired network using Wi-Fi. The AP usually connects to a NAT router via a wired network, however, it can also be integrated as part of a wireless router as well.

What differentiates an access point from wireless repeaters/extenders is that it is connected via wired network to its gateway and possibly the internet.
ad-hoc ad-hoc mode (a.k.a peer-to-peer mode, or Independent Basic Service Set - IBSS) in wireless networking refers to a framework in which devices or stations communicate directly with each other, without the use of an access point. Ad-hoc mode is useful for establishing a network where access points do not exist.
ADSL ADSL (asymmetric DSL) is a type of Digital Subscriber line (DSL) that provides greater downstream(download from provider to consumer) bandwidth at the expense of lesser upstream (upload) speed.
AES AES (Advanced Encryption Standard, a.k.a. Rijndael) is a symetric block cypher developed by belgian cryptographers Joan Daemen and Vincent Rijmen, that won the NIST's contest for a replacement of DES (Data Encryption Standard).

AES currently supports 128, 192 and 256-bit keys and encryption blocks, and can be extended in 32-bit multiples.

AES is used in securing wireless networks, and it is considered to be among the most secure of all commonly installed wireless encryption standards.
AIMD AIMD (Additive Increase / Multiplicative Decrease) is the congestion control protocol used in TCP. It involves increase-by-one and decrease-to-half (per window of packets acknowledged) strategy for congestion window adjustment.
ARP ARP (Address Resolution Protocol) is a protocol for mapping IP adresses to MAC (Media Access Control) physical machine adresses.

ARP uses an ARP cache table to maintain a correlation and convert between each MAC address and its corresponding IP address in both directions.

ARP is used in all Ethernet/IP networks to resolve IP addresses to physical device addresses. It is not routable.

See also: RFC 826
ARPANET ARPAnet was a large WAN established in 1969, essentially the precursor to the Internet. ARPAnet was created by the US Defence Advanced Research Project Agency (ARPA) to test new networking technologies. It originally linked UCLA and Stanford, followed by the University of Utah.
ASCII ASCII (American National Standard Code for Information Interchange) is the most common format for computer text files. In general, ASCII is the standard code for information interchange among dissimilar computers and computer programs, using a coded character set consisting of 7-bit coded characters (8 bits including parity check).
ASIC ASIC (application-specific integrated circuit) is a microchip designed for a special application, such as such as a particular kind of transmission protocol or a hand-held computer. The term can be contrasted with general integrated circuits, such as the microprocessor and the random access memory chips in PCs.
ASN ASN (Autonomous System Number) is a special number assigned by IANA to identify individual networks or relatively large network segments. ASNs are primarily used with Border Gateway Protocol (BGP) routing.

BGP routing information is largely based on ASN hops, and manually configured static preferences.

Note: AS numbers are assigned in blocks by IANA to Regional Internet Registries (RIRs). The appropriate RIR then assigns AS numbers to entities within its designated area from the block assigned by IANA.
ATA ATA (Analog Terminal Adapter) is a device that connects an analog telephone to a VoIP network.

ATAs, usually have an Ethernet (RJ-48) jack, and an RJ-11 phone jack, and use either the SIP or IAX industry standard protocols. ATAs are also refered to as VoIP Gateways, TA (Terminal Adapter),or FXS Adapters. Some ATAs are locked to a particular VoIP provider.
ATM ATM (Asynchronous Transfer Mode) is a high-speed network protocol designed to support both voice and data communication. ATM is composed of 53 byte cells having 48 byte payloads, does not involve routing and is especially good for real time voice and video. DSL implementations often use ATM as the underlying data-transport protocol beneath TCP/IP.
ATU ATU (ADSL Transceiver/Termination Unit) is a device that provides ADSL modulation of the telephone line, os simply an ADSL modem. The device at the server side is called ATU-C (Central office), the client's device is called ATU-R (Remote).

ATU-C/R are in essence the ADSL modems that sit on both sides of the telco copper loop.
AWG AWG (American Wire Gauge) is a measure of the thickness of wiring - the lower the AWG number, the thicker the wire. Generally, thicker wire can carry electrical current longer distances and is less susceptible to interference.
Term Description
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