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10Base2

A physical layer communications specification for 10Mbps, baseband data transmission over a coaxial cable (Thinnet) with a maximum cable segment length of 200 meters. [Source: RFC1983]

10Base5

A physical layer communications specification for 10Mbps, baseband data transmission over a coaxial cable (Thicknet) with a maximum cable segment length of 500 meters. [Source: RFC1983]

10BaseF

A physical layer communications specification for 10Mbps, baseband data transmission over a fiber-optic cable. [Source: RFC1983]

10BaseT

A physical layer communications specification for 10Mbps, baseband data transmission over a twisted-pair copper wire. See also: Ethernet, twisted pair. [Source: RFC1983]

802.11

The set of IEEE Working Groups and subsequent standards for the definition of wireless LAN protocols. The Physical Layer (air interface) incorporates Spread Spectrum techniques to avoid detection, interception and interference between devices. The results so far are 802.11b, which has a data rate of 11Mbit/s and uses the 2.4GHz radio band, then 802.11a which has a data rate of 54Mbit/s and uses the 5GHz radio band, so it is not inherently interoperable with 802.11b. Subsequently 802.11g has a data rate of greater than 20MBit/s with the 2.4GHz range, so there is scope for interworking with 802.11b devices. Then 802.11h enhances the 802.11a standard to select frequencies and trim power output to avoid interference with HIPERLAN devices in Europe which use the same 5GHz band. The 2.4GHz and 5GHz radio bands are licence exempt so are attractive to general users.

There is a built-in security method, Wired Equivalent Privacy (WEP) within 802.11b standard, but there is an initial move to use 802.1x security mechanisms before 802.11i is fully developed to enhance security and authentication mechanisms (ongoing at March 2003). See also: 802.x, Bluetooth, HIPERLAN, IEEE, Spread Spectrum, Wired Equivalent Privacy, Wireless Local Area Network.

802.x

The set of IEEE Working Groups and subsequent standards for the definition of fixed and wireless LAN and MAN protocols. See also: 802.11, Bluetooth, IEEE, Wireless Local Area Network.

822

See: RFC 822

:-)

This odd symbol is one of the ways a person can portray "mood" in the very flat medium of computers--by using "smiley faces". This is "metacommunication", and there are literally hundreds of such symbols, from the obvious to the obscure. This particular example expresses "happiness". Don't see it? Tilt your head to the left 90 degrees. Smiles are also used to denote sarcasm. [Source: ZEN]

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A

Address record for a host of given name in Domain Name Service.

AbMAN

Aberdeen Metropolitan Area Network.

abstract syntax

A description of a data structure that is independent of machine- oriented structures and encodings. [Source: RFC1208]

Abstract Syntax Notation One (ASN.1)

The language used by the OSI protocols for describing abstract syntax. This language is also used to encode SNMP packets. ASN.1 is defined in ISO documents 8824.2 and 8825.2. See also: Basic Encoding Rules. [Source: RFC1392]

Acceptable Use Policy (AUP)

Many transit networks have policies which restrict the use to which the network may be put. For example, some networks may only be used for non-commercial purposes. Some AUPs limit the type of material which can be made available to the public (e.g., pornographic material). Enforcement of AUPs varies with the network. See also: netiquette. [Source: RFC1983]

Access Control List (ACL)

Most network security systems operate by allowing selective use of services. An Access Control List is the usual means by which access to, and denial of, services is controlled. It is simply a list of the services available, each with a list of the hosts permitted to use the service. [Source: RFC1392]

ACK

See: Acknowledgment

acknowledgment (ACK)

A type of message sent to indicate that a block of data arrived at its destination without error. See also: Negative Acknowledgement. [Source: NNSC]

ACL

See: Access Control List

ACSE

Association Control Service Element. The method used in OSI for establishing a call between two applications. Checks the identities and contexts of the application entities, and could apply an authentication security check. [Source: RFC1208]

AD

See: Administrative Domain

address

There are four types of addresses in common use within the Internet. They are email address; IP, internet or Internet address; hardware or MAC address; and URL. See also: email address, IP address, internet address, MAC address, Uniform Resource Locator. [Source: RFC1983]

address mask

A bit mask used to identify which bits in an IP address correspond to the network and subnet portions of the address. This mask is often referred to as the subnet mask because the network portion of the address (i.e., the network mask) can be determined by the encoding inherent in an IP address. See also: Classless Inter- domain Routing. [Source: RFC1983]

address resolution

Conversion of a network-layer address (e.g. IP address) into the corresponding physical address (e.g., MAC address). See also: IP address, MAC address. [Source: RFC1983]

Address Resolution Protocol (ARP)

Used to dynamically discover the low level physical network hardware address that corresponds to the high level IP address for a given host. ARP is limited to physical network systems that support broadcast packets that can be heard by all hosts on the network. It is defined in RFC 826. See also: proxy ARP, Reverse Address Resolution Protocol. [Source: RFC1983]

ADMD

Administration Management Domain. An X.400 Message Handling System public service carrier. Examples:- MCImail and ATTmail in the U.S., British Telecom Gold400mail in the U.K. The ADMDs in all countries worldwide together provide the X.400 backbone. See PRMD. [Source: RFC1208]

Administrative Domain (AD)

A collection of hosts and routers, and the interconnecting network(s), managed by a single administrative authority. [Source: RFC1392]

administrivia

Administrative tasks, most often related to the maintenance of mailing lists, digests, news gateways, etc.

Advanced Research Projects Agency (ARPA)

An agency of the U.S. Department of Defense responsible for the development of new technology for use by the military. ARPA (formerly known as DARPA, nee ARPA) was responsible for funding much of the development of the Internet we know today, including the Berkeley version of Unix and TCP/IP. [Source: NNSC]

Advanced Research Projects Agency Network (ARPANET)

A pioneering longhaul network funded by ARPA. It served as the basis for early networking research, as well as a central backbone during the development of the Internet. The ARPANET consisted of individual packet switching computers interconnected by leased lines. See also: Advanced Research Projects Agency. [Source: FYI4]

agent

In the client-server model, the part of the system that performs information preparation and exchange on behalf of a client or server application. [Source: RFC1208]

alias

A name, usually short and easy to remember, that is translated into another name, usually long and difficult to remember. [Source: RFC1392]

American National Standards Institute (ANSI)

This organization is responsible for approving U.S. standards in many areas, including computers and communications. Standards approved by this organization are often called ANSI standards (e.g., ANSI C is the version of the C language approved by ANSI). ANSI is a member of ISO. See also: International Organization for Standardization. [Source: NNSC]

American Standard Code for Information Interchange (ASCII)

A standard character-to-number encoding widely used in the computer industry. See also: EBCDIC. [Source: RFC1392]

anonymous FTP

Anonymous FTP allows a user to retrieve documents, files, programs, and other archived data from anywhere in the Internet without having to establish a userid and password. By using the special userid of "anonymous" the network user will bypass local security checks and will have access to publicly accessible files on the remote system. See also: archive site, File Transfer Protocol, World Wide Web. [Source: RFC1983]

ANSI

See: American National Standards Institute

AOW

Asia and Oceania Workshop. One of the three regional OSI Implementors Workshops, equivalent to OIW and EWOS.

API

See: Application Program Interface

Appletalk

A networking protocol developed by Apple Computer for communication between Apple Computer products and other computers. This protocol is independent of the network layer on which it is run. Current implementations exist for Localtalk, a 235Kb/s local area network; and Ethertalk, a 10Mb/s local area network. [Source: NNSC]

application

A program that performs a function directly for a user. FTP, mail and Telnet clients are examples of network applications. [Source: RFC1392]

application layer

The top layer of the network protocol stack. The application layer is concerned with the semantics of work (e.g., formatting electronic mail messages). How to represent that data and how to reach the foreign node are issues for lower layers of the network. [Source: MALAMUD]

Application Program Interface (API)

A set of calling conventions which define how a service is invoked through a software package. [Source: RFC1208]

archie

A system to automatically gather, index and serve information on the Internet. The initial implementation of archie provided an indexed directory of filenames from all anonymous FTP archives on the Internet. Later versions provide other collections of information. See also: archive site, Gopher, Prospero, Wide Area Information Servers. [Source: RFC1392]

archive site

A machine that provides access to a collection of files across the Internet. For example, an anonymous FTP archive site provides access to arcived material via the FTP protocol. WWW servers can also serve as archive sites. See also: anonymous FTP, archie, Gopher, Prospero, Wide Area Information Servers, World Wide Web. [Source: RFC1392]

ARP

See: Address Resolution Protocol

ARPA

See: Defense Advanced Research Projects Agency

ARPANET

See: Advanced Research Projects Agency Network

AS

See: Autonomous System

ASCII

See: American Standard Code for Information Interchange

ASN.1

See: Abstract Syntax Notation One

assigned numbers

The RFC [STD2] which documents the currently assigned values from several series of numbers used in network protocol implementations. This RFC is updated periodically and, in any case, current information can be obtained from the Internet Assigned Numbers Authority (IANA). If you are developing a protocol or application that will require the use of a link, socket, port, protocol, etc., please contact the IANA to receive a number assignment. See also: Internet Assigned Numbers Authority, STD. [Source: STD2]

asynchronous

Transmission by individual bytes, not related to specific timing on the transmitting end.

Asynchronous Transfer Mode (ATM)

A standard which defines high-load, high-speed (1.544Mbps through 1.2Gbps), fixed-size packet (cell) switching with dynamic bandwidth allocation. ATM is also known as "fast packet." [Source: RFC1983]

ATM

See: Asynchronous Transfer Mode

AUP

See: Acceptable Use Policy

attribute

The form of information items provided by the X.500 Directory Service. The directory information base consists of entries, each containing one or more attributes. Each attribute consists of a type identifier together with one or more values. Each directory Read operation can retrieve some or all attributes from a designated entry. [Source: RFC1208]

AUSCERT

Australian Computer Emergency Response Team.

authentication

The verification of the identity of a person or process. [Source: MALAMUD]

auto-magic

Something which happens pseudo-automatically, and is usually too complex to go into any further than to say it happens ``auto-magically.''

Autonomous System (AS)

Internet (TCP/IP) terminology for a collection of routers under a single administrative authority using a common Interior Gateway Protocol (IGP) for routing packets. See subnetwork. [Source: RFC1392]

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backbone

The top level in a hierarchical network. Stub and transit networks which connect to the same backbone are guaranteed to be interconnected. See also: stub network, transit network. [Source: RFC1392]

bandwidth

Technically, the difference, in Hertz (Hz), between the highest and lowest frequencies of a transmission channel. However, as typically used, the amount of data that can be sent through a given communications circuit. [Source: RFC1392]

bang path

A series of machine names used to direct electronic mail from one user to another, typically by specifying an explicit UUCP path through which the mail is to be routed. See also: email address, mail path, UNIX-to-UNIX CoPy. [Source: RFC1392]

BAR

Backbone Access Router between a MAN and the JANET backbone.

baseband

A transmission medium through which digital signals are sent without complicated frequency shifting. In general, only one communication channel is available at any given time. Ethernet is an example of a baseband network. See also: broadband, Ethernet. [Source: NNSC]

Basic Encoding Rules (BER)

Standard rules for encoding data units described in ASN.1. Sometimes incorrectly lumped under the term ASN.1, which properly refers only to the abstract syntax description language, not the encoding technique. See also: Abstract Syntax Notation One. [Source: NNSC]

BBS

See: Bulletin Board System

BCNU

Be Seein' You [Source: RFC1392]

BCP

The newest subseries of RFCs which are written to describe Best Current Practices in the Internet. Rather than specifying a protocol, these documents specify the best ways to use the protocols and the best ways to configure options to ensure interoperability between various vendors' products. BCPs carry the endorsement of the IESG. See also: Request For Comments, Internet Engineering Steering Group. [Source: RFC1983]

BDP

Netscape's Browser Distribution Program.

BECTa

British Educational Communications and Technology Agency.

BER

See: Basic Encoding Rules

Berkeley Internet Name Domain (BIND)

Implementation of a DNS server developed and distributed by the University of California at Berkeley. Many Internet hosts run BIND, and it is the ancestor of many commercial BIND implementations. See also: Domain Name System. [Source: RFC1983]

Berkeley Software Distribution (BSD)

Implementation of the UNIX operating system and its utilities developed and distributed by the University of California at Berkeley. "BSD" is usually preceded by the version number of the distribution, e.g., "4.3 BSD" is version 4.3 of the Berkeley UNIX distribution. Many Internet hosts run BSD software, and it is the ancestor of many commercial UNIX implementations. [Source: NNSC]

BGP

See: Border Gateway Protocol

big-endian

A format for storage or transmission of binary data in which the most significant bit (or byte) comes first. The term comes from "Gulliver's Travels" by Jonathan Swift. The Lilliputians, being very small, had correspondingly small political problems. The Big-Endian and Little-Endian parties debated over whether soft- boiled eggs should be opened at the big end or the little end. See also: little-endian. [Source: RFC1208]

binary

11001001

BIND

See: Berkeley Internet Name Domain

Birds Of a Feather (BOF)

A Birds Of a Feather (flocking together) is an informal discussion group. It is formed, often ad hoc, to consider a specific issue and, therefore, has a narrow focus. See also: Working Group. [Source: RFC1392]

Bitnet

Because It's Time NETwork. An academic computer network that provided interactive electronic mail and file transfer services, using a store-and-forward protocol, based on IBM Network Job Entry protocols. Bitnet-II encapsulated the Bitnet protocol within IP packets and depended on the Internet to route them. [Source: RFC1208]

Blue Book

the document describing a File Transfer Protocol used in the UK academic and research community which was implemented on a wide range of computers and which allowed file transfers between dissimilar computers. Also known as Network Independent File Transfer Protocol (NIFTP). Now mostly superseded by Internet protocols (see FTP).

Bluetooth

An IEEE standard 802.15.1 for short range (up to 10m) wireless links between mobile computers, phones and other portable peripheral devices. This uses the 2.4GHz band with a data rate of 1Mbit/s. Work was in progress in March 2002 on a High Rate (20Mbit/s or greater) version 802.15.3 in the same 2.4GHz band. Also known as Personal Area Network. See also: Wireless Local Area Network.

BNC

Bayonet Nut Connector. A connector used on coaxial cables such as 10Base2 Ethernet.

BOC

Bell Operating Company. More commonly referred to as RBOC for Regional Bell Operating Company. The local telephone company in each of the seven U.S. regions. [Source: RFC1208]

BOF

See: Birds Of a Feather

BOOTP

The Bootstrap Protocol, described in RFC 951 and RFC 1084, is used for booting diskless nodes. Updated in RFC 1395 and RFC 1497 and superseded by DHCP. See also: Reverse Address Resolution Protocol, Dynamic Host Configuration Protocol. [Source: RFC1392]

Border Gateway Protocol (BGP)

The Border Gateway Protocol is an exterior gateway protocol defined in RFC 1267 and RFC 1268. It's design is based on experience gained with EGP, as defined in STD 18, RFC 904, and EGP usage in the NSFNET Backbone, as described in RFC 1092 and RFC 1093. See also: Exterior Gateway Protocol. [Source: RFC1392]

bounce

The return of a piece of mail because of an error in its delivery. [Source: ZEN]

bridge

A device which forwards traffic between network segments based on datalink layer information. These segments would have a common network layer address. See also: gateway, router. [Source: RFC1392]

broadband

A transmission medium capable of supporting a wide range of frequencies. It can carry multiple signals by dividing the total capacity of the medium into multiple, independent bandwidth channels, where each channel operates only on a specific range of frequencies. See also: baseband. [Source: RFC1392]

broadcast

A special type of multicast packet which all nodes on the network are always willing to receive. See also: multicast, unicast. [Source: RFC1392]

broadcast storm

An incorrect packet broadcast onto a network that causes multiple hosts to respond all at once, typically with equally incorrect packets which causes the storm to grow exponentially in severity. [Source: RFC1392] See also: Ethernet meltdown.

brouter

A device which bridges some packets (i.e., forwards based on datalink layer information) and routes other packets (i.e., forwards based on network layer information). The bridge/route decision is based on configuration information. See also: bridge, router. [Source: RFC1392]

BSD

See: Berkeley Software Distribution

BTW

An abbreviation for ``By The Way''.

Bulletin Board System (BBS)

A computer, and associated software, which typically provides electronic messaging services, archives of files, and any other services or activities of interest to the bulletin board system's operator. Although BBS's have traditionally been the domain of hobbyists, an increasing number of BBS's are connected directly to the Internet, and many BBS's are currently operated by government, educational, and research institutions. See also: Electronic Mail, Internet, Usenet. [Source: NWNET]

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C&NL MAN

Cumbra and North Lancashire Metropolitan Area Network.

Campus Wide Information System (CWIS)

A CWIS makes information and services publicly available on campus via kiosks, and makes interactive computing available via kiosks, interactive computing systems and campus networks. Services routinely include directory information, calendars, bulletin boards, databases. [Source: RFC1392]

catenet

A network in which hosts are connected to networks with varying characteristics, and the networks are interconnected by gateways (routers). The Internet is an example of a catenet. See IONL. [Source: RFC1208]

CCIRN

See: Coordinating Committee for Intercontinental Research Networks

CCITT

See: Comite Consultatif International de Telegraphique et Telephonique

CCR

Commitment, Concurrency, and Recovery. An OSI application service element used to create atomic operations across distributed systems. Used primarily to implement two-phase commit for transactions and nonstop operations. [Source: RFC1208]

CERNET

China Education and Research Network.

CERT

See: Computer Emergency Response Team

CFV (Call For Votes)

Initiates the voting period for a Usenet newsgroup. At least one (occasionally two or more) email address is customarily included as a repository for the votes.

checksum

A computed value which is dependent upon the contents of a packet. This value is sent along with the packet when it is transmitted. The receiving system computes a new checksum based upon the received data and compares this value with the one sent with the packet. If the two values are the same, the receiver has a high degree of confidence that the data was received correctly. [Source: NNSC]

CHEST

Combined Higher Education Software Team negociates agreements with suppliers, especially for site licences, for the education community, thus making it the educational shop window for purchases of software, data, information, traning materials and other IT related products.

CIDR

See: Classless Inter-domain Routing

circuit switching

A communications paradigm in which a dedicated communication path is established between two hosts, and on which all packets travel. The telephone system is an example of circuit switched network. See also: connection-oriented, connectionless, packet switching. [Source: RFC1392]

ClariNews

The fee-based Usenet newsfeed available from ClariNet Communications.

Classless Inter-domain Routing (CIDR)

A proposal, set forth in RFC 1519, to allocate IP addresses so as to allow the addresses to be aggregated when advertised as routes. It is based on the elimination of intrinsic IP network addresses; that is, the determination of the network address based on the first few bits of the IP address. See also: IP address, network address, supernet. [Source: RFC1983]

ClydeNet

River Clyde area's Metropolitan Area Network.

client

A computer system or process that requests a service of another computer system or process. A workstation requesting the contents of a file from a file server is a client of the file server. See also: client-server model, server. [Source: NNSC]

client-server model

A common way to describe the paradigm of many network protocols. Examples include the name-server/name-resolver relationship in DNS and the file-server/file-client relationship in NFS. See also: client, server, Domain Name System, Network File System. [Source: RFC1392]

CLNP

Connectionless Network Protocol. The OSI protocol for providing the OSI Connectionless Network Service (datagram service). CLNP is the OSI equivalent to Internet IP, and is sometimes called ISO IP. [Source: RFC1208]

CLTP

Connectionless Transport Protocol. Provides for end-to-end Transport data addressing (via Transport selector) and error control (via checksum), but cannot guarantee delivery or provide flow control. The OSI equivalent of UDP. [Source: RFC1208]

CMIP

Common Management Information Protocol. The OSI network management protocol. [Source: RFC1208]

CMOT

CMIP Over TCP. An effort to use the OSI network management protocol to manage TCP/IP networks. [Source: RFC1208]

CNAME

Canonical Name (alternative name for a host) in Domain Name Service.

CNI

See: Coalition for Networked Information

Coalition for Networked Information (CNI)

A consortium formed by American Research Libraries, CAUSE, and EDUCOM (no, they are not acronyms) to promote the creation of, and access to, information resources in networked environments in order to enrich scholarship and enhance intellectual productivity. [Source: RFC1392]

Coloured Books

set of standard protocols and recommendations for the different aspects of networking software developed and used by the UK academic and research community. Now superseded by Internet protocols. See also protocol.

Comite Consultatif International de Telegraphique et Telephonique

(CCITT) This organization is part of the United National International Telecommunications Union (ITU) and is responsible for making technical recommendations about telephone and data communications systems. Every four years CCITT holds plenary sessions where they adopt new standards; the most recent was in 1992. Recently, the ITU reorganized and CCITT was renamed the ITU-T. See also: International Telecommunications Union - Telecommunications. [Source: RFC1983]

Computer Emergency Response Team (CERT)

The CERT was formed by DARPA in November 1988 in response to the needs exhibited during the Internet worm incident. The CERT charter is to work with the Internet community to facilitate its response to computer security events involving Internet hosts, to take proactive steps to raise the community's awareness of computer security issues, and to conduct research targeted at improving the security of existing systems. CERT products and services include 24-hour technical assistance for responding to computer security incidents, product vulnerability assistance, technical documents, and tutorials. In addition, the team maintains a number of mailing lists (including one for CERT Advisories), and provides an anonymous FTP server, at "cert.org", where security-related documents and tools are archived. The CERT may be reached by email at "cert@cert.org" and by telephone at +1-412-268-7090 (24-hour hotline). See also: Advanced Research Projects Agency, worm. [Source: RFC1392]

congestion

Congestion occurs when the offered load exceeds the capacity of a data communication path. [Source: RFC1392]

connection-oriented

The data communication method in which communication proceeds through three well-defined phases: connection establishment, data transfer, connection release. TCP is a connection-oriented protocol. See also: circuit switching, connectionless, packet switching, Transmission Control Protocol. [Source: RFC1392]

connectionless

The data communication method in which communication occurs between hosts with no previous setup. Packets between two hosts may take different routes, as each is independent of the other. UDP is a connectionless protocol. See also: circuit switching, connection-oriented, packet switching, User Datagram Protocol. [Source: RFC1392]

Coordinating Committee for Intercontinental Research Networks (CCIRN)

A committee that includes the United States FNC and its counterparts in North America and Europe. Co-chaired by the executive directors of the FNC and the European Association of Research Networks (RARE), the CCIRN provides a forum for cooperative planning among the principal North American and European research networking bodies. See also: Federal Networking Council, RARE. [Source: MALAMUD]

core gateway

Historically, one of a set of gateways (routers) operated by the Internet Network Operations Center at Bolt, Beranek and Newman (BBN). The core gateway system formed a central part of Internet routing in that all groups must advertise paths to their networks from a core gateway. [Source: MALAMUD]

Corporation for Research and Educational Networking (CREN)

This organization was formed in October 1989, when Bitnet and CSNET (Computer + Science NETwork) were combined under one administrative authority. CSNET is no longer operational, but CREN still runs Bitnet. See also: Bitnet. [Source: NNSC]

COS

Corporation for Open Systems. A vendor and user group for conformance testing, certification, and promotion of OSI products. [Source: RFC1208]

COSINE

Cooperation for Open Systems Interconnection Networking in Europe. A program sponsored by the European Commission, aimed at using OSI to tie together European research networks. [Source: RFC1208]

C-Pop

Core Point of Presence on JANET backbone.

cracker

A cracker is an individual who attempts to access computer systems without authorization. These individuals are often malicious, as opposed to hackers, and have many means at their disposal for breaking into a system. See also: hacker, Computer Emergency Response Team, Trojan Horse, virus, worm. [Source: RFC1392]

CRC

See: cyclic redundancy check

CREN

See: Corporation for Research and Educational Networking

CSMA/CD

Carrier Sense Multiple Access with Collision Detection. The access method used by local area networking technologies such as Ethernet. [Source: RFC1208]

CSNET

Computer+Science Network. Formerly a large computer network, mostly in the U.S. but with international connections. CSNET sites included universities, research labs, and some commercial companies. Now merged with BITNET to form CREN. See Corporation for Research and Educational Networking. [Source: RFC1208]

CU-SeeMe

Pronnounced "See you, See me," CU-SeeMe is a publicly available videoconferencing program developed at Cornell University. It allows anyone with audio/video capabilites and an Internet connection to videoconference with anyone else with the same capabilities. It also allows multiple people to tie into the same videoconference. [Source: RFC1983]

CWIS

See: Campus Wide Information system

Cyberspace

A term coined by William Gibson in his fantasy novel Neuromancer to describe the "world" of computers, and the society that gathers around them. [Source: ZEN]

Cyclic Redundancy Check (CRC)

A number derived from a set of data that will be transmitted. By recalculating the CRC at the remote end and comparing it to the value originally transmitted, the receiving node can detect some types of transmission errors. [Source: MALAMUD]

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DARPA

Defense Advanced Research Projects Agency. See: Advanced Research Projects Agency

Data Encryption Key (DEK)

Used for the encryption of message text and for the computation of message integrity checks (signatures). See also: encryption. [Source: RFC1392]

Data Encryption Standard (DES)

A popular, standard encryption scheme. See also: encryption, Pretty Good Privacy, RSA. [Source: RFC1983]

datagram

A self-contained, independent entity of data carrying sufficient information to be routed from the source to the destination computer without reliance on earlier exchanges between this source and destination computer and the transporting network. See also: frame, packet. [Source: J. Postel]

Data Link Layer

The OSI layer that is responsible for data transfer across a single physical connection, or series of bridged connections, between two Network entities. [Source: RFC1208]

DCA

See: Defense Information Systems Agency

DCE (1)

Data Circuit-terminating Equipment

DCE (2)

See: Distributed Computing Environment

DDN

See: Defense Data Network

DDN NIC

See: Defense Data Network Network Information Center

DECnet

A proprietary network protocol designed by Digital Equipment Corporation. The functionality of each Phase of the implementation, such as Phase IV and Phase V, is different. [Source: RFC1392]

default route

A routing table entry which is used to direct packets addressed to networks not explicitly listed in the routing table. [Source: MALAMUD]

Defense Advanced Research Projects Agency (DARPA)

See: Advanced Research Projects Agency.

Defense Data Network (DDN)

A global communications network serving the US Department of Defense composed of MILNET, other portions of the Internet, and classified networks which are not part of the Internet. The DDN is used to connect military installations and is managed by the Defense Information Systems Agency. See also: Defense Information Systems Agency. [Source: RFC1392]

Defense Data Network Network Information Center (DDN NIC)

Often called "The NIC", the DDN NIC's primary responsibility is the assignment of Internet network addresses and Autonomous System numbers, the administration of the root domain, and providing information and support services to the DDN. It is also a primary repository for RFCs. See also: Autonomous System, network address, Internet Registry, Network Information Center, Request For Comments. [Source: RFC1392]

Defense Information Systems Agency (DISA)

Formerly called the Defense Communications Agency (DCA), this is the government agency responsible for managing the DDN portion of the Internet, including the MILNET. Currently, DISA administers the DDN, and supports the user assistance services of the DDN NIC. See also: Defense Data Network. [Source: RFC1392]

DEK

See: Data Encryption Key

DES

See: Data Encryption Standard

DHCP

See: Dynamic Host Configuration Protocol

dialup

A temporary, as opposed to dedicated, connection between machines established over a standard phone line. [Source: RFC1392]

Directory Access Protocol

X.500 protocol used for communication between a Directory User Agent and a Directory System Agent. [Source: MALAMUD]

Directory System Agent (DSA)

The software that provides the X.500 Directory Service for a portion of the directory information base. Generally, each DSA is responsible for the directory information for a single organization or organizational unit. [Source: RFC1208]

Directory User Agent (DUA)

The software that accesses the X.500 Directory Service on behalf of the directory user. The directory user may be a person or another software element. [Source: RFC1208]

DISA

See: Defense Information Systems Agency

disassembling

Converting a binary program into human-readable machine language code. See also PAD.

Distributed Computing Environment (DCE)

An architecture of standard programming interfaces, conventions, and server functionalities (e.g., naming, distributed file system, remote procedure call) for distributing applications transparently across networks of heterogeneous computers. Promoted and controlled by the Open Software Foundation (OSF), a consortium led by Digital, IBM and Hewlett Packard. [Source: RFC1208]

distributed database

A collection of several different data repositories that looks like a single database to the user. A prime example in the Internet is the Domain Name System. [Source: RFC1392]

DIX Ethernet

See: Ethernet

DNS

See: Domain Name System

Document Type Definition

Definition of a language built on eXtensible Markup Language (XML) or Standardised General Markup Language (SGML).

domain

"Domain" is a heavily overused term in the Internet. It can be used in the Administrative Domain context, or the Domain Name context. See also: Administrative Domain, Domain Name System. [Source: RFC1392]

Domain Name System (DNS)

The DNS is a general purpose distributed, replicated, data query service. The principal use is the lookup of host IP addresses based on host names. The style of host names now used in the Internet is called "domain name", because they are the style of names used to look up anything in the DNS. Some important domains are: .COM (commercial), .EDU (educational), .NET (network operations), .GOV (U.S. government), and .MIL (U.S. military). Most countries also have a domain. The country domain names are based on ISO 3166. For example, .US (United States), .UK (United Kingdom), .AU (Australia). It is defined in STD 13, RFC 1034 and RFC 1035. See also: Fully Qualified Domain Name, Mail Exchange Record. [Source: RFC1983]

dot address (dotted decimal notation)

Dot address refers to the common notation for IP addresses of the form A.B.C.D; where each letter represents, in decimal, one byte of a four byte IP address. See also: IP address. [Source: FYI4]

DPA

Data Protection Act.

DS1

A framing specification for T-1 synchronous lines. See also: T1 [Source: RFC1392]

DS3

A framing specification for T-3 synchronous lines. See also: T3 [Source: RFC1392]

DSA

See: Directory System Agent

DSU

Data Service Unit, a physical cable interface on a network link.

DTD

See: Document Type Definition

DTE

Data Terminal Equipment

DUA

See: Directory User Agent

dynamic adaptive routing

Automatic rerouting of traffic based on a sensing and analysis of current actual network conditions. NOTE: this does not include cases of routing decisions taken on predefined information. [Source: J. Postel]

DUL

Dial-up User List, which has entries for ranges of IP addresses used by Internet Service Providers for modem users.

DWDM

Dense Wave Division Multiplexing, a technique for passing multiple data streams along an optical fibre cable using different wavelengths as carriers.

Dynamic Host Configuration Protocol (DHCP)

A framework for passing configuration information to hosts on a TCP/IP network, using an options field; a development from the BOOTP Bootstrap Protocol. Described in RFC 1533 and RFC 1534 and updated in RFC 2132. See also: BOOTP.

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E1

The basic building block for European multi-megabit data rates, with a bandwidth of 2.048Mbps. See also: T1. [Source: RFC1983]

E3

A European standard for transmitting data at 57.344Mbps. See also: T3. [Source: RFC1983]

EARN

European Academic and Research Network. See: Trans-European Research and Education Networking Association. [Source: RFC1983]

EaStMAN

Edinburgh and Stirling Metropolitan Area Network.

EastNet

East of England Regional Network.

EBCDIC

See: Extended Binary Coded Decimal Interchange Code

Ebone

A pan-European backbone service. [Source: RFC1392]

EFF

See: Electronic Frontier Foundation

EFLA

See: Extended Four Letter Acronym

EGP

See: Exterior Gateway Protocol

Electronic Frontier Foundation (EFF)

A foundation established to address social and legal issues arising from the impact on society of the increasingly pervasive use of computers as a means of communication and information distribution. [Source: RFC1392]

Electronic Mail (email)

A system whereby a computer user can exchange messages with other computer users (or groups of users) via a communications network. Electronic mail is one of the most popular uses of the Internet. [Source: NNSC]

email

See: Electronic mail

email address

The domain-based or UUCP address that is used to send electronic mail to a specified destination. For example an editor's address is "gmalkin@xylogics.com". See also: bang path, mail path, UNIX- to-UNIX CoPy. [Source: ZEN]

EMMAN

East Midlands Metropolitan Area Network.

encapsulation

The technique used by layered protocols in which a layer adds header information to the protocol data unit (PDU) from the layer above. As an example, in Internet terminology, a packet would contain a header from the physical layer, followed by a header from the datalink layer (e.g. Ethernet), followed by a header from the network layer (IP), followed by a header from the transport layer (TCP), followed by the application protocol data. [Source: RFC1208]

encryption

Encryption is the manipulation of a packet's data in order to prevent any but the intended recipient from reading that data. There are many types of data encryption, and they are the basis of network security. See also: Data Encryption Standard. [Source: RFC1392]

end system

An OSI system which contains application processes capable of communicating through all seven layers of OSI protocols. Equivalent to Internet host. [Source: RFC1208]

entity

OSI terminology for a layer protocol machine. An entity within a layer performs the functions of the layer within a single computer system, accessing the layer entity below and providing services to the layer entity above at local service access points. [Source: RFC1208]

error checking

The examination of received data for transmission errors. See also: checksum, Cyclic Redundancy Check. [Source: RFC1983]

ES-IS

End system to Intermediate system protocol. The OSI protocol by which end systems announce themselves to intermediate systems. [Source: RFC1208]

ESMTP

Extended Simple Mail Transfer Protocol. See Simple Mail Transfer Protocol.

Ethernet

A 10-Mb/s standard for LANs, initially developed by Xerox, and later refined by Digital, Intel and Xerox (DIX). All hosts are connected to a coaxial cable where they contend for network access using a Carrier Sense Multiple Access with Collision Detection (CSMA/CD) paradigm. See also: 802.x, Local Area Network, token ring. [Source: RFC1392]

Ethernet meltdown

An event that causes saturation, or near saturation, on an Ethernet. It usually results from illegal or misrouted packets and typically lasts only a short time. See also: broadcast storm. [Source: COMER]

ETSI

See: European Telecommunications Standards Institute

EUNet

European UNIX Network, an Internet Service Provider. [Source: RFC1208]

European Telecommunications Standards Institute

A pan-European organisation of administrations, network operators, manufacturers, service providers, research bodies and users. ETSI develops standards and tecnical documentation in telecommunications, broadcasting and information technology.

EUUG

European UNIX Users Group. [Source: RFC1208]

European Academic and Research Network (EARN)

European Academic and Research Network. See: Trans-European Research and Education Networking Association. [Source: RFC1983]

EWOS

European Workshop for Open Systems. The OSI Implementors Workshop for Europe. See OIW. [Source: RFC1208]

Extended Binary Coded Decimal Interchange Code (EBCDIC)

A standard character-to-number encoding used primarily by IBM computer systems. See also: ASCII. [Source: RFC1392]

Extendable Markup Language (XML)

A subset of Standardised General Markup Language, for development of markup applications using Document Type Definitions (DTDs) in areas such as database searches and information interchange, in electronic business transactions and eleswhere.

Extended Four Letter Acronym (EFLA)

A recognition of the fact that there are far too many TLAs. See also: Three Letter Acronym. [Source: K. Morgan]

Exterior Gateway Protocol (EGP)

A protocol which distributes routing information to the routers which connect autonomous systems. The term "gateway" is historical, as "router" is currently the preferred term. There is also a routing protocol called EGP defined in STD 18, RFC 904. See also: Autonomous System, Border Gateway Protocol, Interior Gateway Protocol. [Source: RFC1392]

eXternal Data Representation (XDR)

A standard for machine independent data structures developed by Sun Microsystems and defined in RFC 1014. It is similar to ASN.1. See also: Abstract Syntax Notation One. [Source: RFC1208]

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FARNET

A non-profit corporation, established in 1987, whose mission is to advance the use of computer networks to improve research and education. [Source: RFC1392]

FAQ

Frequently Asked Question [Source: RFC1392]

FaTMAN

Fife and Tayside Metropolitan Area Network.

Fawn Book

the document produced for the JNT defining the Simple Screen Management Protocol (SSMP).

FDDI

See: Fibre Distributed Data Interface

FEDA

Formerly Further Education Development Agency, now called Learning and Skills Development Agency (LSDA).

FEFC

Formerly Further Education Funding Council, now called Learning and Skills Council (LSC).

Federal Information Exchange (FIX)

One of the connection points between the American governmental internets and the Internet. [Source: SURA]

Federal Networking Council (FNC)

The coordinating group of representatives from those federal agencies involved in the development and use of federal networking, especially those networks using TCP/IP and the Internet. Current members include representatives from DOD, DOE, DARPA, NSF, NASA, and HHS. See also: Defense Advanced Research Projects Agency, National Science Foundation. [Source: RFC1392]

Fibre Distributed Data Interface (FDDI)

A high-speed (100Mb/s) LAN standard. The underlying medium is fibre optics, and the topology is a dual-attached, counter- rotating token ring. See also: Local Area Network, token ring. [Source: RFC1208]

file transfer

The copying of a file from one computer to another over a computer network. See also: File Transfer Protocol, Kermit, Gopher, World Wide Web. [Source: RFC1983]

File Transfer Protocol (FTP)

A protocol which allows a user on one host to access, and transfer files to and from, another host over a network. Also, FTP is usually the name of the program the user invokes to execute the protocol. The IP version is defined in STD 9, RFC 959. See also: anonymous FTP, FTAM. [Source: RFC1392]

Compare the Unix "Anonymous FTP" (see above) with the UK JNT Network Independent File Transfer Protocol or NIFTP (now almost extinct), also known as "Blue Book" (see above). The Unix commands are "ftp" and "hhcp" respectively.

finger

A protocol, defined in RFC 1288, that allows information about a system or user on a system to be retrived. Finger also refers to the commonly used program which retrieves this information. Information about all logged in users, as well is information about specific users may be retrieved from local or remote systems. Some sites consider finger to be a security risk and have either disabled it, or replaced it with a simple message. [Source: RFC1983]

FIPS

Federal Information Processing Standard.

FIX

See: Federal Information Exchange

flame

A strong opinion and/or criticism of something, usually as a frank inflammatory statement, in an electronic mail message. It is common to precede a flame with an indication of pending fire (i.e., FLAME ON!). Flame Wars occur when people start flaming other people for flaming when they shouldn't have. See also: Electronic Mail. [Source: RFC1392]

FLEA

See: Four Letter Extended Acronym

FNC

See: Federal Networking Council

For Your Information (FYI)

A subseries of RFCs that are not technical standards or descriptions of protocols. FYIs convey general information about topics related to TCP/IP or the Internet. See also: Request For Comments, STD. [Source: RFC1392]

FQDN

See: Fully Qualified Domain Name

fragment

A piece of a packet. When a router is forwarding an IP packet to a network that has a maximum packet size smaller than the packet size, it is forced to break up that packet into multiple fragments. These fragments will be reassembled by the IP layer at the destination host. See also: Maximum Transmission Unit. [Source: RFC1392]

fragmentation

The IP process in which a packet is broken into smaller pieces to fit the requirements of a physical network over which the packet must pass. See also: reassembly. [Source: RFC1392]

frame

A frame is a datalink layer "packet" which contains the header and trailer information required by the physical medium. That is, network layer packets are encapsulated to become frames. See also: datagram, encapsulation, packet. [Source: RFC1392]

freenet

Community-based bulletin board system with email, information services, interactive communications, and conferencing. Freenets are funded and operated by individuals and volunteers -- in one sense, like public television. They are part of the National Public Telecomputing Network (NPTN), an organization based in Cleveland, Ohio, devoted to making computer telecommunication and networking services as freely available as public libraries. [Source: LAQUEY]

FTAM

File Transfer, Access, and Management. The OSI remote file service and protocol. [Source: RFC1208]

FTP

See: File Transfer Protocol

Fully Qualified Domain Name (FQDN)

The FQDN is the full name of a system, rather than just its hostname. For example, "venera" is a hostname and "venera.isi.edu" is an FQDN. See also: hostname, Domain Name System. [Source: RFC1392]

FYI

See: For Your Information

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G.703

ITU-T standard for physical and logical traits of transmissions over digital circuits, including US 1.544Mbit/s and European 2.048Mbit/s (typically used to refer to the latter).

gated

Gatedaemon. A program which supports multiple routing protocols and protocol families. It may be used for routing, and makes an effective platform for routing protocol research. The software is freely available by anonymous FTP from "gated.cornell.edu". Pronounced "gate-dee". See also: Exterior Gateway Protocol, Open Shortest Path First..., Routing Information Protocol, routed. Source: RFC1983]

gateway

The term "router" is now used in place of the original definition of "gateway". Currently, a gateway is a communications device/program which passes data between networks having similar functions but dissimilar implementations. This should not be confused with a protocol converter. By this definition, a router is a layer 3 (network layer) gateway, and a mail gateway is a layer 7 (application layer) gateway. See also: mail gateway, router, protocol converter. [Source: RFC1392]

Gbit/s

Gigabits (thousand million - or strictly 2 to the power 30 - bits) per second.

GÉANT

A development from the former TEN-155 pan-European research network, creating a core network and access links to countries at Gigabit speeds.

General Packet Radio Service (GPRS)

An ETSI standard for packet-based wireless data communications at speeds up to a theoretical 171 kilobits per second, for continuous connection to the Internet, for portable computers and mobile phones. Addition of Virtual Private Network facilities will allow a degree of security for mobile access to important data. GPRS is based on the Global System for Mobile infrastructure, using up to 8 time slots (provided for 8 voice calls on a given frequency) only when there is information to transmit, rather than completely reserved as in a voice circuit. GPRS is being developed into Enhanced Data GSM Environment (EDGE), using a new modulation scheme for higher data rates up to 384 kilobits per second, as a step on the way to Universal Mobile Telecommunications Service (UMTS). See also: Virtual Private Network.

Global System for Mobile communications

An ETSI standard for second generation digital cellular wireless voice and data communications using time division multiple access transmission methods. Formerly known as Groupe Spécial Mobile, which was the study group of the Conference of European Posts and Telegraphs (CEPT) set up to develop a pan-European system for terrestrial mobiles.

Gopher

A distributed information service developed at the University of Minnesota, that makes available hierarchical collections of information across the Internet. Gopher uses a simple protocol, defined in RFC 1436, that allows a single Gopher client to access information from any accessible Gopher server, providing the user with a single "Gopher space" of information. Public domain versions of the client and server are available. See also: archie, archive site, Prospero, Wide Area Information Servers. [Source: RFC1392]

GOSIP

See: Government OSI Profile

Government OSI Profile

A subset of OSI standards specific to U.S. Government procurements, designed to maximize interoperability in areas where plain OSI standards are ambiguous or allow excessive options. [Source: BIG-LAN]

GPRS

See: General Packet Radio Service

Green Book

the document listing recommendations on the use of Triple-X and the definition of the TS29 protocol, formerly used in UK Universities.

Grey Book

the document describing the JNT Interim Mail Protocol used in the UK for mail transfers. Mostly superseded by Internet mail protocols such as SMTP (q.v.).

gross

A dozen dozen (144).

GSM

See: Global System for Mobile communications

GUI

Graphical User Interface, typically consisting of windows, menus and pointer (e.g. mouse) hence WIMP.

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hacker

A person who delights in having an intimate understanding of the internal workings of a system, computers and computer networks in particular. The term is often misused in a pejorative context, where "cracker" would be the correct term. See also: cracker. [Source: RFC1392]

HDLC

High level Data Link Control, ISO standard for carrying data over a link with error and flow control.

header

The portion of a packet, preceding the actual data, containing source and destination addresses, and error checking and other fields. A header is also the part of an electronic mail message that precedes the body of a message and contains, among other things, the message originator, date and time. See also: Electronic Mail, packet, error checking. [Source: RFC1392]

heterogeneous network

A network running multiple network layer protocols. See also: DECnet, IP, IPX, XNS, homogeneous network. [Source: RFC1983]

hierarchical routing

The complex problem of routing on large networks can be simplified by reducing the size of the networks. This is accomplished by breaking a network into a hierarchy of networks, where each level is responsible for its own routing. The Internet has, basically, three levels: the backbones, the mid-levels, and the stub networks. The backbones know how to route between the mid-levels, the mid-levels know how to route between the sites, and each site (being an autonomous system) knows how to route internally. See also: Autonomous System, Exterior Gateway Protocol, Interior Gateway Protocol, stub network, transit network. [Source: RFC1392]

High Performance Computing and Communications (HPCC)

High performance computing encompasses advanced computing, communications, and information technologies, including scientific workstations, supercomputer systems, high speed networks, special purpose and experimental systems, the new generation of large scale parallel systems, and application and systems software with all components well integrated and linked over a high speed network. [Source: HPCC]

High Performance Parallel Interface (HIPPI)

An emerging ANSI standard which extends the computer bus over fairly short distances at speeds of 800 and 1600 Mb/s. HIPPI is often used in a computer room to connect a supercomputer to routers, frame buffers, mass-storage peripherals, and other computers. See also: American National Standards Institute [Source: MALAMUD]

HIPERLAN

High Performance radio Local Area Network, an ESTI standard EN 300 652 for high speed data communications at 20Mbit/s in the 5GHz range, either between portable devices or as an extension of a wired network infrastructure. There is a development to produce HIPERLAN2, which can be used for 3G mobile phone core networks as well as 54Mbit/s data networks in the 5GHz radio range. See also 802.11, Wireless Local Area Network.

HIPPI

See: High Performance Parallel Interface

homogeneous network

A network running a single network layer protocol. See also: DECnet, IP, IPX, XNS, heterogeneous network. [Source: RFC1983]

hop

A term used in routing. A path to a destination on a network is a series of hops, through routers, away from the origin. [Source: RFC1392]

host

A computer that allows users to communicate with other host computers on a network. Individual users communicate by using application programs, such as electronic mail, Telnet and FTP. [Source: NNSC]

host address

See: internet address

hostname

The name given to a machine. See also: Fully Qualified Domain Name. [Source: ZEN]

host number

See: host address

HPCC

See: High Performance Computing and Communications

HTML

See: Hypertext Markup Language

HTTP

See: Hypertext Transfer Protocol

hub

A device connected to several other devices. In ARCnet, a hub is used to connect several computers together. In a message handling service, a hub is used for the transfer of messages across the network. [Source: MALAMUD]

hyperlink

A pointer within a hypertext document which points (links) to another document, which may or may not also be a hypertext document. See also: hypertext. [Source: RFC1983]

hypertext

A document, written in HTML, which contains hyperlinks to other documents, which may or may not also be hypertext documents. Hypertext documents are usually retrieved using WWW. See also: hyperlink, Hypertext Markup Language, World Wide Web. [Source: RFC1983]

Hypertext Markup Language (HTML)

The language used to create hypertext documents. It is a subset of SGML and includes the mechanisms to establish hyperlinks to other documents. See also: hypertext, hyperlink, Standardized General Markup Language. [Source: RFC1983]

Hypertext Markup Protocol (HTTP)

The protocol used by WWW to transfer HTML files. A formal standard is still under development in the IETF. See also: hyperlink, hypertext, Hypertext Markup Language, World Wide Web. [Source: RFC1983]

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I-D

See: Internet-Draft

IAB

See: Internet Architecture Board

IANA

See: Internet Assigned Numbers Authority

ICANN

See: Internet Corporation for Assigned Numbers and Names

ICMP

See: Internet Control Message Protocol

ICT

Information and Communications Technologies (or variations thereof, sometimes CIT).

IEAK

Internet Explorer Administration Kit (Microsoft).

IEEE

Institute of Electrical and Electronics Engineers

IEEE 802

See: 802.x

IEN

See: Internet Experiment Note

IESG

See: Internet Engineering Steering Group

IETF

See: Internet Engineering Task Force

IINREN

See: Interagency Interim National Research and Education Network

IIS

Internet Information Service (Microsoft).

IGP

See: Interior Gateway Protocol

IGRP

Internet Gateway Routing Protocol. A proprietary IGP used by cisco System's routers. [Source: RFC1208]

IMAP

See: Internet Message Access Protocol

IMHO

"In My Humble Opinion"; usually accompanies a statement that may bring about personal offense or strong disagreement. Rarely used in Yorkshire, where opinions are anything but humble, especially about cricket or rugby.

IMR

See: Internet Monthly Report

INTAP

Interoperability Technology Association for Information Processing. The technical organization which has the official charter to develop Japanese OSI profiles and conformance tests. [Source: RFC1208]

Integrated Services Digital Network (ISDN)

An emerging technology which is beginning to be offered by the telephone carriers of the world. ISDN combines voice and digital network services in a single medium, making it possible to offer customers digital data services as well as voice connections through a single "wire". The standards that define ISDN are specified by CCITT. See also: CCITT. [Source: RFC1208]

Interagency Interim National Research and Education Network (IINREN)

An evolving operating network system. Near term (1992-1996) research and development activities will provide for the smooth evolution of this networking infrastructure into the future gigabit NREN. [Source: HPCC]

Interior Gateway Protocol (IGP)

A protocol which distributes routing information to the routers within an autonomous system. The term "gateway" is historical, as "router" is currently the preferred term. See also: Autonomous System, Exterior Gateway Protocol, Open Shortest Path First..., Routing Information Protocol. [Source: RFC1392]

Intermediate System (IS)

An OSI system which performs network layer forwarding, i.e. not an end system. It is analogous to an IP router. See also: Open Systems Interconnection, router. [Source: RFC1392]

Intermediate System-Intermediate System (IS-IS)

The OSI IGP. See also: Open Systems Interconnection, Interior Gateway Protocol. [Source: RFC1392]

International Organization for Standardization (ISO)

A voluntary, nontreaty organization founded in 1946 which is responsible for creating international standards in many areas, including computers and communications. Its members are the national standards organizations of the 89 member countries, including ANSI for the U.S. See also: American National Standards Institute, Open Systems Interconnection. [Source: TAN]

International Telecommunications Union (ITU)

An agency of the United Nations which coordinates the various national telecommunications standards so that people in one country can communicate with people in another country. [Source: RFC1983]

International Telecommunications Union - Telecommunications (ITU-T)

The new name for CCITT since the ITU reorganization. The function is the same; only the name has been changed. [Source: RFC1983]

internet

While an internet is a network, the term "internet" is usually used to refer to a collection of networks interconnected with routers. See also: network. [Source: RFC1392]

Internet

(note the capital "I") The Internet is the largest internet in the world. Is a three level hierarchy composed of backbone networks (e.g., Ultranet), mid-level networks (e.g., NEARnet) and stub networks. The Internet is a multiprotocol internet. See also: backbone, mid-level network, stub network, transit network, Internet Protocol. [Source: RFC1983]

internet address

A IP address that uniquely identifies a node on an internet. An Internet address (capital "I"), uniquely identifies a node on the Internet. See also: internet, Internet, IP address. [Source: RFC1392]

Internet Architecture Board (IAB)

The IAB has been many things over the years. Originally the Internet Activities Board, it was responsible for the development of the protocols which make up the Internet. It later changed its name and charter to become the group most responsible for the architecture of the Internet, leaving the protocol details to the IESG. In June of 1992, it was chartered as a component of the Internet Society; this is the charter it holds today. The IAB is responsible for approving nominations to the IESG, architectural oversight for Internet Standard Protocols, IETF standards process oversight and appeals, IANA and RFC activities, and liaison to peer standards groups (e.g., ISO). See also: Internet Engineering Task Force, Internet Research Task Force, Internet Engineering Steering Group, Internet Assigned Numbers Authority, Request for Comments. [Source: RFC1983]

Internet Assigned Numbers Authority (IANA)

The central registry for various Internet protocol parameters, such as port, protocol and enterprise numbers, and options, codes and types. The currently assigned values are listed in the "Assigned Numbers" document [STD2]. To request a number assignment, contact the IANA at "iana@isi.edu". Now superseded by ICANN. See also: assigned numbers, STD. [Source: RFC1983]

Internet Corporation for Assigned Numbers and Names (ICANN)

Successor to Internet Assigned Numbers Authority for Internet management functions performed under contract to US Government.

Internet Control Message Protocol (ICMP)

ICMP is an extension to the Internet Protocol. It allows for the generation of error messages, test packets and informational messages related to IP. It is defined in STD 5, RFC 792. [Source: FYI4]

Internet-Draft (I-D)

Internet-Drafts are working documents of the IETF, its Areas, and its Working Groups. As the name implies, Internet-Drafts are draft documents. They are valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. Very often, I-Ds are precursors to RFCs. See also: Internet Engineering Task Force, Request For Comments. [Source: RFC1392]

Internet Engineering Planning Group (IEPG)

A group, primarily composed of Internet service operators, whose goal is to promote a globally coordinated Internet operating environment. Membership is open to all. [Source: RFC1983]

Internet Engineering Steering Group (IESG)

The IESG is composed of the IETF Area Directors and the IETF Chair. It provides the first technical review of Internet standards and is responsible for day-to-day "management" of the IETF. See also: Internet Engineering Task Force. [Source: RFC1392]

Internet Engineering Task Force (IETF)

The IETF is a large, open community of network designers, operators, vendors, and researchers whose purpose is to coordinate the operation, management and evolution of the Internet, and to resolve short-range and mid-range protocol and architectural issues. It is a major source of proposals for protocol standards which are submitted to the IAB for final approval. The IETF meets three times a year and extensive minutes are included in the IETF Proceedings. See also: Internet, Internet Architecture Board. [Source: FYI4]

Internet Experiment Note (IEN)

A series of reports pertinent to the Internet. IENs were published in parallel to RFCs and were intended to be "working documents." They have been replaced by Internet-Drafts and are currently of historic value only. See also: Internet-Draft, Request For Comments. [Source: RFC1392]

Internet Message Access Protocol (IMAP)

A protocol defined by RFC2060 and others, allowing a client to read and manipulate electronic mail messages and message folders (mailboxes) on a server.

Internet Monthly Report (IMR)

Published monthly, the purpose of the Internet Monthly Reports is to communicate to the Internet Research Group the accomplishments, milestones reached, or problems discovered by the participating organizations. [Source: RFC1392]

internet number

See: internet address

Internet Protocol (IP, IPv4)

The Internet Protocol (version 4), defined in RFC 791, is the network layer for the TCP/IP Protocol Suite. It is a connectionless, best-effort packet switching protocol. See also: packet switching, TCP/IP Protocol Suite, Internet Protocol Version 6. [Source: RFC1983]

Internet Protocol security (IPsec)

A packet layer security standard consisting of Authentication Header (AH) and Encapsulating Security Payload (ESP) elements, defined in RFC 2402 and RFC 2406 respectively. Useful for Virtual Private Networks.

Internet Protocol Version 6 (IPng, IPv6)

IPv6 (version 5 is a stream protocol used for special applications) is a new version of the Internet Protocol which is designed to be an evolutionary step from its predecessor, version 4. There are many RFCs defining various portions of the protocol, its auxiliary protocols, and the transition plan from IPv4. The core RFCs are 1883, 1884, 1885 and 1886; also updated at RFC2460. The name IPng (IP next generation) is a nod to STNG (Star Trek Next Generation). [Source: RFC1392]

Internet Registry (IR)

The IANA has the discretionary authority to delegate portions of its responsibility and, with respect to network address and Autonomous System identifiers, has lodged this responsibility with an IR. The IR function is performed by the DDN NIC. See also: Autonomous System, network address, Defense Data Network..., Internet Assigned Numbers Authority. [Source: RFC1392]

Internet Relay Chat (IRC)

A world-wide "party line" protocol that allows one to converse with others in real time. IRC is structured as a network of servers, each of which accepts connections from client programs, one per user. See also: talk. [Source: HACKER]

Internet Research Steering Group (IRSG)

The "governing body" of the IRTF. See also: Internet Research Task Force. [Source: MALAMUD]

Internet Research Task Force (IRTF)

The IRTF is chartered by the IAB to consider long-term Internet issues from a theoretical point of view. It has Research Groups, similar to IETF Working Groups, which are each tasked to discuss different research topics. Multi-cast audio/video conferencing and privacy enhanced mail are samples of IRTF output. See also: Internet Architecture Board, Internet Engineering Task Force, Privacy Enhanced Mail. [Source: RFC1392]

Internet Society (ISOC)

The Internet Society is a non-profit, professional membership organization which facilitates and supports the technical evolution of the Internet, stimulates interest in and educates the scientific and academic communities, industry and the public about the technology, uses and applications of the Internet, and promotes the development of new applications for the system. The Society provides a forum for discussion and collaboration in the operation and use of the global Internet infrastructure. The Internet Society publishes a quarterly newsletter, the Internet Society News, and holds an annual conference, INET. The development of Internet technical standards takes place under the auspices of the Internet Society with substantial support from the Corporation for National Research Initiatives under a cooperative agreement with the US Federal Government. [Source: V. Cerf]

Internetwork Packet eXchange (IPX)

Novell's protocol used by Netware. A router with IPX routing can interconnect LANs so that Novell Netware clients and servers can communicate. See also: Local Area Network. [Source: RFC1392]

InterNIC

A five year project, partially supported by the National Science Foundation, to provide network information services to the networking community. The InterNIC began operations in April of 1993 and is now a collaborative project of two organizations: AT&T, which provides Directory and Database Services from South Plainsfield, NJ; and Network Solutions, Inc., which provides Registration Services from their headquarters in Herndon, VA. Services are provided via the Internet, and by telephone, FAX, and hardcopy. [Source: RFC1983]

interoperability

The ability of software and hardware on multiple machines from multiple vendors to communicate meaningfully. [Source: RFC1392]

IONL

Internal Organization of the Network Layer. The OSI standard for the detailed architecture of the Network Layer. Basically, it partitions the Network layer into subnetworks interconnected by convergence protocols (equivalent to internetworking protocols), creating what Internet calls a catenet or internet. [Source: RFC1208]

IP (IPv4)

See: Internet Protocol

IP address

The 32-bit address defined by the Internet Protocol in RFC 791. It is usually represented in dotted decimal notation. See also: dot address, internet address, Internet Protocol, network address, subnet address, host address. [Source: RFC1392]

IP datagram

See: datagram

IPng (IPv6)

See: Internet Protocol Version 6

IPsec

See: Internet Protocol security

IPX

See: Internetwork Packet eXchange

IR

See: Internet Registry

IRC

See: Internet Relay Chat

IRSG

See: Internet Research Steering Group

IRTF

See: Internet Research Task Force

IS

See: Intermediate System

IS-IS

See: Intermediate System-Intermediate System

ISDN

See: Integrated Services Digital Network

ISO

See: International Organization for Standardization

ISO Development Environment (ISODE)

Software that allows OSI services to use a TCP/IP network. Pronounced eye-so-dee-eee. See also: Open Systems Interconnection, TCP/IP Protocol Suite. [Source: RFC1392]

ISOC

See: Internet Society

ISODE

See: ISO Development Environment

ISP

Internet Service Provider, a purveyor of access to the Internet.

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JANET

Formerly Joint Academic Network. The United Kingdom education and research network. See also SUPERJANET.

JANET-CERT

JANET Computer Emergency Response Team. See also: Computer Emergency Response Team.

JANET National User Group (JNUG)

The JANET National User Group (JNUG) represents the views and concerns of people who use the national academic network, JANET, to those who are responsible for its funding. The Group encompasses representatives from Regional User Groups and Affiliated Groups.

JANET User Group for Administration (JUGA)

The JANET User Group for Administration (JUGA) exists to promote the use of information technology, primarily via JANET by administrators in Higher Education. JUGA is a Affiliated Group of the JANET National User Group, through which the views of the users on JANET and UKERNA services are presented to the JISC Committee on Networking. See also: JANET National User Group.

JANET User Group for Libraries (JUGL)

The JANET User Group for Libraries (JUGL) supports Library and Information Professionals in the use and development of Electronic Networking for information provision. JUGL is a Affiliated Group of the JANET National User Group, through which the views of the users on JANET and UKERNA services are presented to the JISC Committee on Networking. See also: JANET National User Group.

JANET Yorkshire and Northumbria Regional User Group (JYNRUG)

The JANET Yorkshire and Northumbria Regional User Group represents the views of users of JANET within the ancient regions of Yorkshire and Northumbria, plus any modern additions. See also: JANET National User Group.

JCALT

JISC Committee for Awareness, Liaison and Training, promoting use and effectiveness of ICT in post-16 education.

JCCS

JISC Committee for Content and Services, to identify, procure and deliver content for all sectors of further and higher education, within a content management structure, for maximum uptake of resources.

JCLT

JISC Committee for Learning and Teaching, to facilitate coordination and effectiveness of Information Learning Technologies (ILT) in learning and teaching in UK colleges and universities.

JCIE

JISC Committee for Information Environment, build on existing strategies, to create a common information environment, with mechanisms for access and delivery of resources and finding quality information of relevance.

JCN

JISC Committee for Networking, which oversees JISC-funded networking and networked services, including JANET.

JCP

JANET Connection Point.

JCS

JANET Customer Service, at UKERNA.

JCSR

JISC Committee for Support of Research, to identify requirements of the research community which can be met from the JISC budget, and work with the Research Grid community e.g. on e-science programmes.

JCUR

JANET Connection and Upgrade Form, from UKERNA.

JIPS

The JANET Internet Protocol Service (JIPS) was the IP service on JANET, in its X.25 network days, using the technique of "IP tunnelling" - ie encapsulation of the X.25 packets into TCP/IP packets. The result was that UK institutions could connect to hosts on the world wide Internet with programs such as telnet, anonymous ftp, gopher and World Wide Web browsers, before JANET became a fully IP network.

JISC

Joint Information Systems Committee, consisting of representatives of UK Funding Councils and other stakeholders, for controlling budgets on networking and other information systems projects. There are six subcommittees as constituted in February 2002, JCALT, JCCS, JCLT, JCIE, JCN and JCSR.

JISC Assist

JISC Activities, Services and Special Initiatives Support Team, which is the awareness-raising unit for better understanding of the role of information systemsa and information technology in further and higher education institutions.

JISCMail

The National Academic Mailing List Service, based at the Rutherford Appleton Laboratory.

JISC Technology Applications Programme

iA programme of over 100 projects to develop and demonstrate applications of Information and Communication Technology, produce technology reviews and establish four clearing houses to promote use of ICT to support staff and students in HIgher Education.

JKREY

Joyce K. Reynolds

JNT

the former UK Joint Network Team; sponsored by the Computer Board and SERC to manage academic network developments. Now known as UKERNA.

JNUG

See: JANET National User Group

JOD

JANET Operations Desk, based in London.

JTAP

See: JISC Technology Allicationa Programme

JTMP

Job Transfer and Manipulation Protocol; a protocol designed to allow jobs to be sent from one computer to another to be executed, and to allow specifications of output handling. See also Red Book.

JUGA

See: JANET User Group for Administration

JUGL

See: JANET User Group for Libraries

JUNET

Japan UNIX Network. [Source: RFC1208]

JWCS

JANET Web Cache Service, also known as the National Cache.

JYNRUG

See: JANET Yorkshire and Northumbria Regional User Group

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KA9Q

A popular implementation of TCP/IP and associated protocols for amateur packet radio systems. See also: TCP/IP Protocol Suite. [Source: RFC1208]

kbit/s

Kilobits (thousand - or strictly 2 to the power 10 - bits) per second.

Kentish MAN

Metropolitan Area Network for Kent (there is no MAN of Kent).

Kerberos

Kerberos is the security system of MIT's Project Athena. It is based on symmetric key cryptography. See also: encryption. [Source: RFC1392]

Kermit

A popular file transfer protocol developed by Columbia University. Because Kermit runs in most operating environments, it provides an easy method of file transfer. Kermit is NOT the same as FTP. See also: File Transfer Protocol [Source: MALAMUD]

kernel

The level of an operating system or networking system that contains the system-level commands or all of the functions hidden from the user. In a Unix system, the kernel is a program that contains the device drivers, the memory management routines, the scheduler, and system calls. This program is always running while the system is operating.

Knowbot

A "Knowledge Robot" is a program which seeks out information based on specified criteria. "Knowbot," as trademarked by CNRI, refers specifically to the search engine for Knowbot Information Services. See also: Corporation for National Research Initiatives, X.500, white pages, whois, netfind. [Source: RFC1983]

Knowbot Information Services

An experimental directory service. See also: white pages, WHOIS, X.500. [Source: RFC1983]

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LAN

See: Local Area Network

layer

Communication networks for computers may be organized as a set of more or less independent protocols, each in a different layer (also called level). The lowest layer governs direct host-to-host communication between the hardware at different hosts; the highest consists of user applications. Each layer builds on the layer beneath it. For each layer, programs at different hosts use protocols appropriate to the layer to communicate with each other. TCP/IP has five layers of protocols; OSI has seven. The advantages of different layers of protocols is that the methods of passing information from one layer to another are specified clearly as part of the protocol suite, and changes within a protocol layer are prevented from affecting the other layers. This greatly simplifies the task of designing and maintaining communication programs. See also: Open Systems Interconnection, TCP/IP Protocol Suite. [Source: RFC1392]

LDAP

See: Lightweight Directory Access Protocol.

learndirect

The learning services for Ufi are delivered through learndirect, which provides information and advice on high quality courses.

LeNSE

Learning Network for the South East.

Lightweight Directory Access Protocol

This protocol provides access for management and browser applications that provide read/write interactive access to the X.500 Directory. See also: X.500. [Source: RFC1983]

link

A pointer which may be used to retreive the file or data to which the pointer points. [Source: RFC1983]

LINX

London InterNet eXchange, an interconnection point for Internet Service providers in the UK (and elsewhere).

list server

An automated mailing list distribution system. List servers handle the administrivia of mailing list maintenance, such as the adding and deleting of list members. See also: mailing list. [Source: RFC1983]

listserv

An automated mailing list distribution system originally designed for the Bitnet/EARN network. See also: mailing list. [Source: RFC1392]

little-endian

A format for storage or transmission of binary data in which the least significant byte (bit) comes first. See also: big-endian. [Source: RFC1208]

LJUG

See: London JANET User Group

LLC

See: Logical Link Control

LMN

London Metropolitan Network.

Local Area Network (LAN)

A data network intended to serve an area of only a few square kilometers or less. Because the network is known to cover only a small area, optimizations can be made in the network signal protocols that permit data rates up to 100Mb/s. See also: Ethernet, Fibre Distributed Data Interface, token ring, Metropolitan Area Network, Wide Area Network, Wireless Local Area Network. [Source: NNSC]

Logical Link Control (LLC)

The upper portion of the datalink layer, as defined in IEEE 802.2. The LLC sublayer presents a uniform interface to the user of the datalink service, usually the network layer. Beneath the LLC sublayer is the MAC sublayer. See also: 802.x, layer, Media Access Control. [Source: RFC1392]

London JANET User Group (LJUG)

The London JANET User Group presents the views of the users on JANET and UKERNA services to the JISC Committee on Networking through the JANET National User Group. See also: JANET National User Group.

LSC

Learning and Skills Council, successor to FEFC.

LSDA

Learning and Skills Development Agency, successor to FEDA.

Lurking

No active participation on the part of a subscriber to an mailing list or USENET newsgroup. A person who is lurking is just listening to the discussion. Lurking is encouraged for beginners who need to get up to speed on the history of the group. See also: Electronic Mail, mailing list, Usenet. [Source: LAQUEY]

Lycos

Lycos, Inc. is a new venture formed in late June 1995, to develop and market the Lycos technology originally developed under the direction of Dr. Michael ("Fuzzy") Mauldin at Carnegie Mellon University. The part of Lycos you see when you do a search is the search engine. "Lycos" comes from Lycosidae, a cosmopolitan family of relatively large active ground spiders (Wolf Spiders) that catch their prey by pursuit, rather than in a web. [Source: Lycos's FAQ]

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MAC

See: Media Access Control

MAC address

The hardware address of a device connected to a shared media. See also: Media Access Control, Ethernet, token ring. [Source: MALAMUD]

mail bridge

A mail gateway that forwards electronic mail between two or more networks while ensuring that the messages it forwards meet certain administrative criteria. A mail bridge is simply a specialized form of mail gateway that enforces an administrative policy with regard to what mail it forwards. See also: Electronic Mail, mail gateway. [Source: NNSC]

Mail Exchange Record (MX Record)

A DNS resource record type indicating which host can handle mail for a particular domain. See also: Domain Name System, Electronic Mail. [Source: MALAMUD]

mail exploder

Part of an electronic mail delivery system which allows a message to be delivered to a list of addresses. Mail exploders are used to implement mailing lists. Users send messages to a single address and the mail exploder takes care of delivery to the individual mailboxes in the list. See also: Electronic Mail, email address, mailing list. [Source: RFC1208]

mail gateway

A machine that connects two or more electronic mail systems (including dissimilar mail systems) and transfers messages between them. Sometimes the mapping and translation can be quite complex, and it generally requires a store-and-forward scheme whereby the message is received from one system completely before it is transmitted to the next system, after suitable translations. See also: Electronic Mail. [Source: RFC1208]

mail path

A series of machine names used to direct electronic mail from one user to another. This system of email addressing has been used primarily in UUCP networks which are trying to eliminate its use altogether. See also: bang path, email address, UNIX-to-UNIX CoPy. [Source: RFC1392]

mail server

A software program that distributes files or information in response to requests sent via email. Internet examples include Almanac and netlib. Mail servers have also been used in Bitnet to provide FTP-like services. See also: Bitnet, Electronic Mail, FTP. [Source: NWNET]

mailing list

A list of email addresses, used by a mail exploder, to forward messages to groups of people. Generally, a mailing list is used to discuss certain set of topics, and different mailing lists discuss different topics. A mailing list may be moderated. This means that messages sent to the list are actually sent to a moderator who determines whether or not to send the messages on to everyone else. Requests to subscribe to, or leave, a mailing list should ALWAYS be sent to the list's "-request" address (e.g., ietf-request@cnri.reston.va.us for the IETF mailing list) or majordomo server. See also: Electronic Mail, mail exploder, email address, moderator, majordomo. [Source: RFC1983]

majordomo

A program which handles mailing list maintenance (affectionately known as administrivia) such as adding and removing addresses from mailing lists. See also: email address, mailing list. [Source: RFC1983]

MAN

See: Metropolitan Area Network

Management Information Base (MIB)

The set of parameters an SNMP management station can query or set in the SNMP agent of a network device (e.g., router). Standard, minimal MIBs have been defined, and vendors often have Private enterprise MIBs. In theory, any SNMP manager can talk to any SNMP agent with a properly defined MIB. See also: client-server model, Simple Network Management Protocol, SMI. [Source: BIG-LAN]

MAPS

Mail Abuse Prevention System.

Martian

A humorous term applied to packets that turn up unexpectedly on the wrong network because of bogus routing entries. Also used as a name for a packet which has an altogether bogus (non-registered or ill-formed) internet address. [Source: RFC1208]

MAU (1)

Multistation Access Unit, for connection and control of Token Ring network stations in a star arrangement. Also known as MSAU.

MAU (2)

Monitoring and Advisory Unit, a JISC-sponsored service to manage contracts between JISC and several JISC-funded services.

Maximum Transmission Unit (MTU)

The largest frame length which may be sent on a physical medium. See also: frame, fragmentation, frame. [Source: RFC1392]

Mbit/s

Megabits (million - or strictly 2 to the power 20 - bits) per second.

mbone

The Multicast Backbone is based on IP multicasting using class-D addresses. The mbone concept was adopted at the March 1992 IETF in San Diego, during which it was used to audiocast to 40 people throughout the world. At the following meeting, in Cambridge, the name mbone was adopted. Since then the audiocast has become full two-way audio/video conferencing using two video channels, four audio channels, and involving hundreds of remote users. See also: multicast, Internet Engineering Task Force. [Source: RFC1983]

MD-2, MD-4, MD-5

See: Message Digest.

Media Access Control (MAC)

The lower portion of the datalink layer. The MAC differs for various physical media. See also: MAC Address, Ethernet, Logical Link Control, token ring. [Source: RFC1392]

medium

The material used to support the transmission of data. This can be copper wire, coaxial cable, optical fibre, or electromagnetic wave (as in microwave).

Message Digest (MD-2, MD-4, MD-5)

Message digests are algorithmic operations, generally performed on text, which produce a unique signature for that text. MD-2, described in RFC 1319; MD-4, described in RFC 1320; and MD-5, described in RFC 1321 all produce a 128-bit signature. They differ in their operating speed and resistance to crypto-analytic attack. Generally, one must be traded off for the other. [Source: RFC1983]

message switching

See: packet switching

Metropolitan Area Network (MAN)

A data network intended to serve an area approximating that of a large city. Such networks are being implemented by innovative techniques, such as running fibre cables through subway tunnels. A popular example of a MAN is SMDS. See also: Local Area Network, Switched Multimegabit Data Service, Wide Area Network. [Source: NNSC]

MHS

Message Handling System. The system of message user agents, message transfer agents, message stores, and access units which together provide OSI electronic mail. MHS is specified in the CCITT X.400 series of Recommendations. [Source: RFC1208]

MIB

See: Management Information Base

Microcom Networking Protocol (MNP)

A series of protocols built into most modems which error-check or compress data being transmitted over a phone line. [Source: RFC1983]

MidJUG

See: Midlands JANET User Group

Midlands JANET User Group (MidJUG)

The Midlands JANET User Group presents the views of the users on JANET and UKERNA services to the JISC Committee on Networking through the JANET National User Group. See also: JANET National User Group.

mid-level network

Mid-level networks (a.k.a. regionals) make up the second level of the Internet hierarchy. They are the transit networks which connect the stub networks to the backbone networks. See also: backbone, Internet, stub network, transit network. [Source: RFC1392]

MidMAN

Midlands Metropolitan Area Network.

MILNET

MILitary NETwork. Originally part of the ARPANET, MILNET was partitioned in 1984 to make it possible for military installations to have reliable network service, while the ARPANET continued to be used for research. See DDN. [Source: RFC1208]

MIME

See: Multipurpose Internet Mail Extensions

MMC

Microsoft Management Console.

MNP

See: Microcom Networking Protocol.

moderator

A person, or small group of people, who manage moderated mailing lists and newsgroups. Moderators are responsible for determining which email submissions are passed on to list. See also: Electronic Mail, mailing list, Usenet. [Source: RFC1392]

MOSPF

Multicast Open Shortest-Path First. See: Open Shortest-Path First. [Source: RFC1983]

MSC

Monitoring SubCommittee, a subcommittee of JCN to monitor the performance of JANET, now superseded by SPAG.

MTA

Message Transfer Agent. An OSI application process used to store and forward messages in the X.400 Message Handling System. Equivalent to Internet mail agent. [Source: RFC1208]

MTU

See: Maximum Transmission Unit

MUD

See: Multi-User Dungeon

multicast

A packet with a special destination address which multiple nodes on the network may be willing to receive. See also: broadcast, unicast. [Source: RFC1208]

multihomed host

A host which has more than one connection to a network. The host may send and receive data over any of the links but will not route traffic for other nodes. See also: host, router. [Source: MALAMUD]

multiplex

The division of a single transmission medium into multiple logical channels supporting many simultaneous sessions. For example, one network may have simultaneous FTP, telnet, rlogin, and SMTP connections, all going at the same time.

Multipurpose Internet Mail Extensions (MIME)

An extension to Internet email which provides the ability to transfer non-textual data, such as graphics, audio and fax. It is defined in RFC 1341. See also: Electronic Mail. [Source: RFC1392]

Multi-User Dungeon (MUD)

Adventure, role playing games, or simulations played on the Internet. Devotees call them "text-based virtual reality adventures". The games can feature fantasy combat, booby traps and magic. Players interact in real time and can change the "world" in the game as they play it. Most MUDs are based on the Telnet protocol. See also: Telnet. [Source: LAQUEY]

MX Record

See: Mail Exchange Record

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NAK

See: Negative Acknowledgment

NAT

See: Network Address Translation.

name resolution

The process of mapping a name into its corresponding address. See also: Domain Name System. [Source: RFC1208]

Name Registration Scheme

All sites connected to JANET via X25 were expected to register with the national 'Name Registration Scheme' (NRS). The NRS maintained a database which recorded, for each service on each site (such as X29 or Coloured Book mail), a 'standard' name and an 'abbreviated name' for that service, together with its numeric JANET address. The full form of identification using an NRS name was: UK.AC.. . With the replacement of X25 by IP services, the NRS did not last usefully beyond mid-1997.

name resolution

The process of mapping a name into the corresponding address. See also: DNS. [Source: RFC1208]

Name Server

software which matches mnemonic names to raw addresses. This might be a Campus Name Server for local PCs (using a JNT protocol called Name Lookup Protocol or NLP), or a Domain Name Server for local hosts on an Internet site - such as the Bradford campus network.

Name Server record

A DNS resource record type indicating which host can provide the Domain Name Service facilities for a particular domain. See also: Domain Name System.

namespace

A commonly distributed set of names in which all names are unique. [Source: MALAMUD]

National Institute of Standards and Technology (NIST)

United States governmental body that provides assistance in developing standards. Formerly the National Bureau of Standards. [Source: MALAMUD]

National Research and Education Network (NREN)

The NREN is the realization of an interconnected gigabit computer network devoted to Hign Performance Computing and Communications. See also: HPPC, IINREN. [Source: HPCC]

National Science Foundation (NSF)

A U.S. government agency whose purpose is to promote the advancement of science. NSF funds science researchers, scientific projects, and infrastructure to improve the quality of scientific research. The NSFNET, funded by NSF, was once an essential part of academic and research communications. It wass a highspeed "network of networks" which is hierarchical in nature. At the highest level, it had a backbone network of nodes, interconnected with T3 (45Mbps) facilities which spanned the continental United States. Attached to that were mid-level networks and attached to the mid-levels were campus and local networks. See also: backbone network, mid- level network. [Source: RFC1983]

Negative Acknowledgment (NAK)

Response to receipt of a corrupted packet of information. See also: Acknowledgement. [Source: RFC1392]

NetBIOS

Network Basic Input Output System. The standard interface to networks on IBM PC and compatible systems before the rise of TCP/IP.

net.citizen

An inhabitant of Cyberspace. One usually tries to be a good net.citizen, lest one be flamed.

netfind

A research prototype to provide a simple Internet "white pages" user directory. Developed at the University of Colorado, Boulder, it tries to locate telephone and email information given a person's name and a rough description of where the person works. See also: Knowbot, whois, white pages, X.500. [Source: Ryan Moats]

netiquette

A pun on "etiquette" referring to proper behavior on a network. RFC 1855 (FYI 28) contains a netiquette guide produced by the User Services area of the IETF. See also: Acceptable Use Policy, Internet Engineering Task Force. [Source: RFC1983]

Netnews

See: Usenet

network

A computer network is a data communications system which interconnects computer systems at various different sites. A network may be composed of any combination of LANs, MANs or WANs. See also: Local Area Network, Metropolitan Area Network, Wide Area Network, internet. [Source: RFC1392]

network address

The network portion of an IP address. For a class A network, the network address is the first byte of the IP address. For a class B network, the network address is the first two bytes of the IP address. For a class C network, the network address is the first three bytes of the IP address. In each case, the remainder is the host address. In the Internet, assigned network addresses are globally unique. See also: Internet, IP address, subnet address, host address, Internet Registry, OSI Network Address. [Source: RFC1392]

Network Address Translation (NAT)

A method of converting between a range of IP addresses on the public side of a routing device, and a (typically smaller) range of IP addresses on the private side. Often used as to conserve IP addresses, since the private side can use "unrouteable" ranges of IP numbers, which can be safely re-used in many such locations. Also used to conceal identities of private hosts when implemented as part of a firewall. See also: Unroutable Address, IP Address.

Network File System (NFS)

A protocol developed by Sun Microsystems, and defined in RFC 1094, which allows a computer system to access files over a network as if they were on its local disks. This protocol has been incorporated in products by more than two hundred companies, and is now a de facto Internet standard. [Source: NNSC]

Network Information Center (NIC)

A NIC provides information, assistance and services to network users. See also: Network Operations Center. [Source: RFC1392]

Network Information Services (NIS)

A set of services, generally provided by a NIC, to assist users in using the network. Also a service used by UNIX administrators to manage databases distributed across a network (a product of Sun Microsystems(R) - formerly known as Yellow Pages). See also: Network Information Center. [Source: RFC1392]

Network Layer

The OSI layer that is responsible for routing, switching, and subnetwork access across the entire OSI environment. [Source: RFC1208]

network mask

See: address mask

Network News Transfer Protocol (NNTP)

A protocol, defined in RFC 977, for the distribution, inquiry, retrieval, and posting of news articles. See also: Usenet. [Source: RFC1392]

network number

See: network address

Network Operations Center (NOC)

A location from which the operation of a network or internet is monitored. Additionally, this center usually serves as a clearinghouse for connectivity problems and efforts to resolve those problems. See also: Network Information Center. [Source: NNSC]

Network Time Protocol (NTP)

A protocol that assures accurate local timekeeping with reference to radio and atomic clocks located on the Internet. This protocol is capable of synchronizing distributed clocks within milliseconds over long time periods. It is defined in STD 12, RFC 1119 (POSTSCRIPT format) and updated in RFC 1305. See also: Internet. [Source: NNSC]

NFS

See: Network File System

NGfL

National Grid for Learning.

NIC (1)

See: Network Information Center

NIC (2)

Network Interface Card.

NIC.DDN.MIL

This is the domain name of the DDN NIC. See also: Defense Data Network..., Domain Name System, Network Information Center. [Source: RFC1983]

NIFTP

Network Independent File Transfer Protocol. See Blue Book and FTP.

NILTA

National Information and Learning Technology Association. An Affiliated Group of the JANET National User Group.

NIS

See: Network Information Services

NISS

National Information Services and Systems. A JISC service carrying professionally maintained online information services for and about the education sector.

NIST

See: National Institute of Standards and Technology

nln

National Learning Network.

NMS

Network Management Station. The system responsible for managing a (portion of a) network. The NMS talks to network management agents, which reside in the managed nodes, via a network management protocol. See agent. [Source: RFC1208]

NNTP

See: Network News Transfer Protocol

NNW

Network North West, a Metropolitan Area Network for Manchester and environs.

NOC

See: Network Operations Center

Nodal Switching System (NSS)

Main routing nodes in the NSFnet backbone. See also: backbone, National Science Foundation. [Source: MALAMUD]

node

An addressable device attached to a computer network. See also: host, router. [Source: RFC1392]

NorMAN

North East Metropolitan Area Network.

North West JANET Regional User Group (NWJRUG)

The North West JANET Regional User Group represents the views of users of JANET within the ancient regions of Staffordshire, Cheshire, Lancashire and Cumbria, plus any modern additions. See also: JANET National User Group.

NOSC

Network Operations and Service Centre.

NREN

See: National Research and Education Network

NRS

see Name Registration Scheme.

NS

See: Name Server record

NSAP

Network Service Access Point. The point at which the OSI Network Service is made available to a Transport entity. The NSAPs are identified by OSI Network Addresses. [Source: RFC1208]

NSF

See: National Science Foundation

NSS

See: Nodal Switching System

NT

New Technology, a version of Microsoft Windows operating system. The initials WNT bear the same relationship to VMS as IBM does to HAL. I'm sorry Dave...

NTP

Network Time Protocol, defined by RFC 958, and updated to version 3 in RFC 1305, provides the mechanisms to synchronise hosts and coordinate time distribution in a large diverse internet.

NTU

Network Termination Unit

NWJRUG

See: North West JANET Regional User Group

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OCLC

See: Online Computer Library Catalog

octet

An octet is 8 bits. This term is used in networking, rather than byte, because some systems have bytes that are not 8 bits long. [Source: RFC1392]

ODBC

Open DataBase Connectivity. An application programming interface to allow programs to use databases, using Structured Query Language as its database access language.

OIW

Workshop for Implementors of OSI. Frequently called NIST OIW or the NIST Workshop, this is the North American regional forum at which OSI implementation agreements are decided. It is equivalent to EWOS in Europe and AOW in the Pacific. [Source: RFC1208]

ONC(tm)

Open Network Computing. A distributed applications architecture promoted and controlled by a consortium led by Sun Microsystems. [Source: RFC1208]

Online Computer Library Catalog

OCLC is a nonprofit membership organization offering computer- based services to libraries, educational organizations, and their users. The OCLC library information network connects more than 10,000 libraries worldwide. Libraries use the OCLC System for cataloging, interlibrary loan, collection development, bibliographic verification, and reference searching. [Source: OCLC]

Open Shortest-Path First (OSPF)

A link state, as opposed to distance vector, routing protocol. It is an Internet standard IGP defined in RFC 1583 and RFC 1793. The multicast version, MOSPF, is defined in RFC 1584. See also: Interior Gateway Protocol, Routing Information Protocol. [Source: RFC1392]

Open Systems Interconnection (OSI)

A suite of protocols, designed by ISO committees, to be the international standard computer network architecture. See also: International Organization for Standardization. [Source: RFC1392]

OSI

See: Open Systems Interconnection

OSI Network Address

The address, consisting of up to 20 octets, used to locate an OSI Transport entity. The address is formatted into an Initial Domain Part which is standardized for each of several addressing domains, and a Domain Specific Part which is the responsibility of the addressing authority for that domain. [Source: RFC1208]

OSI Presentation Address

The address used to locate an OSI Application entity. It consists of an OSI Network Address and up to three selectors, one each for use by the Transport, Session, and Presentation entities. [Source: RFC1208]

OSI Reference Model

A seven-layer structure designed to describe computer network architectures and the way that data passes through them. This model was developed by the ISO in 1978 to clearly define the interfaces in multivendor networks, and to provide users of those networks with conceptual guidelines in the construction of such networks. See also: International Organization for Standardization. [Source: NNSC]

OSPF

See: Open Shortest-Path First

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packet

The unit of data sent across a network. "Packet" a generic term used to describe unit of data at all levels of the protocol stack, but it is most correctly used to describe application data units. See also: datagram, frame. [Source: RFC1392]

Packet InterNet Groper (PING)

A program used to test reachability of destinations by sending them an ICMP echo request and waiting for a reply. The term is used as a verb: "Ping host X to see if it is up!" See also: Internet Control Message Protocol. [Source: RFC1208]

Packet Switch Node (PSN)

A dedicated computer whose purpose is to accept, route and forward packets in a packet switched network. See also: packet switching, router. [Source: NNSC]

packet switching

A communications paradigm in which packets (messages) are individually routed between hosts, with no previously established communication path. See also: circuit switching, connection- oriented, connectionless. [Source: RFC1392]

PAD

Packet Assembler Disassembler; the hardware or software interface between a user's terminal and a packet-switching network. A PAD assembles the user's input characters into packets for network transmission, and disassembles packets of output characters into their component characters for output on the terminal. The PAD facility may run on a host computer or on a dedicated processor (such as the JNT-PAD).

Particle Physics Network Co-ordinating Group (PPNCG)

The Particle Physics Network Co-ordinating Group (PPNCG) is responsible for the networking interests of the UK particle physics community. Formally it is a sub-committee of the Particle Physics Committee (PPC) of the Particle Physics and Astronomy Research Council (PPARC). PPNCG is also a Affiliated Group of the JANET National User Group, through which the views of the users on JANET and UKERNA services are presented to the JISC Committee on Networking. See also: JANET National User Group.

PCI

Protocol Control Information. The protocol information added by an OSI entity to the service data unit passed down from the layer above, all together forming a Protocol Data Unit (PDU). [Source: RFC1208]

PD

Public Domain

PDU

See: Protocol Data Unit

PEM

See: Privacy Enhanced Mail

PGP

See: Pretty Good Privacy

PHP

PHP: Hypertext Processor. An HTML-embedded scripting language used to create dynamic web pages by running scripts on the web server and embedding the results in web pages. Available from www.php.net.

Physical Layer

The OSI layer that provides the means to activate and use physical connections for bit transmission. In plain terms, the Physical Layer provides the procedures for transferring a single bit across a Physical Media. [Source: RFC1208]

Physical Media

Any means in the physical world for transferring signals between OSI systems. Considered to be outside the OSI Model, and therefore sometimes referred to as "Layer 0." The physical connector to the media can be considered as defining the bottom interface of the Physical Layer, i.e., the bottom of the OSI Reference Model. [Source: RFC1208]

PING

See: Packet INternet Groper

Pink Book

the document describing the implementation of X25 protocol level 3 over a Connection Orientated Network Service based on lower layers of Ethernet protocol. This enables interconnectivity between e.g. Ethernet based PCs and X25 based hosts, and supports Coloured Book protocols for file transfer and terminal access, e.g. with the Rainbow package. Since it is based on ISO standards, Pink Book is not strictly a "Coloured Book" in the JANET usage.

Point Of Presence (POP)

A site where there exists a collection of telecommunications equipment, usually digital leased lines and multi-protocol routers. [Source: RFC1392]

Point-to-Point Protocol (PPP)

The Point-to-Point Protocol, defined in RFC 1661, provides a method for transmitting packets over serial point-to-point links. There are many other RFCs which define extensions to the basic protocol. See also: Serial Line IP. [Source: FYI4]

polling

Connecting to another system to check for things like mail or news.

POP

See: Post Office Protocol and Point Of Presence

port

A port is a transport layer demultiplexing value. Each application has a unique port number associated with it. See also: Transmission Control Protocol, User Datagram Protocol. [Source: RFC1392]

Portal

A web site integrating many facilities within one user interface. Only of value if the infrastructure for personal information databases, authentication and authorisation methods, group communication, business processes and timely content have already been engineered for harmonious web access. Driver software to address a multiplicity of browser devices, from PCs and personal digital assistants to mobile phones and interactive TV, should make content available in many environments.

POSI

Promoting Conference for OSI. The OSI "800-pound gorilla" in Japan. Consists of executives from the six major Japanese computer manufacturers and Nippon Telephone and Telegraph. They set policies and commit resources to promote OSI. [Source: RFC1208]

Post Office Protocol (POP)

A protocol designed to allow single user hosts to read mail from a server. Version 3, the most recent and most widely used, is defined in RFC 1725. See also: Electronic Mail. [Source: RFC1983]

Postal Telegraph and Telephone (PTT)

Outside the USA, PTT refers to a telephone service provider, which is usually a monopoly, in a particular country. [Source: RFC1392]

postmaster

The person responsible for taking care of electronic mail problems, answering queries about users, and other related work at a site. See also: Electronic Mail. [Source: ZEN]

PPNCG

See: Particle Physics Network Co-ordinating Group

PPP

See: Point-to-Point Protocol

Presentation Address

See OSI Presentation Address.

Presentation Layer

The OSI layer that determines how Application information is represented (i.e., encoded) while in transit between two end systems. [Source: RFC1208]

Pretty Good Privacy (PGP)

A program, developed by Phil Zimmerman, which cryptographically protects files and electronic mail from being read by others. It may also be used to digitally sign a document or message, thus authenticating the creator. See also: encryption, Data Encryption Standard, RSA. [Source: RFC1983]

Privacy Enhanced Mail (PEM)

Internet email which provides confidentiality, authentication and message integrity using various encryption methods. See also: Electronic Mail, encryption. [Source: RFC1392]

PRMD

Private Management Domain. An X.400 Message Handling System private organization mail system. Example:- NASAmail. See ADMD. [Source: RFC1208]

Prospero

A distributed filesystem which provides the user with the ability to create multiple views of a single collection of files distributed across the Internet. Prospero provides a file naming system, and file access is provided by existing access methods (e.g., anonymous FTP and NFS). The Prospero protocol is also used for communication between clients and servers in the archie system. See also: anonymous FTP, archie, archive site, Gopher, Network File System, Wide Area Information Servers. [Source: RFC1392]

protocol

A formal description of message formats and the rules two computers must follow to exchange those messages. Protocols can describe low-level details of machine-to-machine interfaces (e.g., the order in which bits and bytes are sent across a wire) or high-level exchanges between allocation programs (e.g., the way in which two programs transfer a file across the Internet). [Source: MALAMUD]

protocol converter

A device/program which translates between different protocols which serve similar functions (e.g., TCP and TP4). [Source: RFC1392]

Protocol Data Unit (PDU)

"PDU" is internationalstandardscomitteespeak for packet. See also: packet. [Source: RFC1392]

protocol stack

A layered set of protocols which work together to provide a set of network functions. See also: layer, protocol. [Source: RFC1392]

proxy

The mechanism whereby one system "fronts for" another system in responding to protocol requests. Proxy systems are used in network management to avoid having to implement full protocol stacks in simple devices, such as modems. [Source: RFC1208]

proxy ARP

The technique in which one machine, usually a router, answers ARP requests intended for another machine. By "faking" its identity, the router accepts responsibility for routing packets to the "real" destination. Proxy ARP allows a site to use a single IP address with two physical networks. Subnetting would normally be a better solution. See also: Address Resolution Protocol [Source: RFC1208]

PSN

See: Packet Switch Node.

PSS

the Packet SwitchStream of British Telecom. PSS includes a UK packet-switching network service as well as a set of PADs in various cities. Now part of Global Network Services.

PTT

See: Postal, Telegraph and Telephone

PTO

Public Telecommunications Operator. See also: Postal, Telegraph and Telephone.

PTR

Name record for a host of given address, for reverse lookup, in Domain Name Service.

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QoS

Quality of Service, a measure of the priority of packets in a shared network, principally in terms of latency in transmission. Of interest in real-time applications e.g. video.

queue

A backup of packets awaiting processing. [Source: RFC1392]

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RADIUS

Remote Authentication Dial In User Service is a protocol which allows an Authentication Server to authenticate, authorise and carry configuration information for one or more Network Access servers. These have links, typically for dialup access clients, that need authentication. This allows username and password information to be held in one place for many access lines. The current definition of RADIUS is in RFC 2865 and RFC 2866 for accounting (originally in RFC 2058 and RFC 2059 respectively) with several others for extensions, such as IP Version 6 at RFC 3162.

Rainbow

a package for the PC allowing file transfer and terminal access between Ethernet based PCs and Ethernet or X25 based hosts, via Coloured Book protocols, running over Pink Book protocol. Written by Edinburgh University. Of historical interest.

RARE

See: Reseaux Associes pour la Recherche Europeenne

RARP

See: Reverse Address Resolution Protocol

RBL

Real-time Blackhole List, a MAPS service for blocking electronic mail from rogue mail relays.

RBOC

Regional Bell Operating Company [Source: RFC1392]

RCP

See: Remote copy program

RDN

Regional Distribution Network, a sort of organisation for a Metropolitan Area Network. See also RPAN.

Read the Fine Manual (RTFM)

This acronym is often used when someone asks a simple or common question. Replace "Fine" with a more vulgar word if desired.

Read the Source Code (RTSC)

This acronym is often used when a software developer asks a question about undocumented code. [Source: RFC1983]

reassembly

The IP process in which a previously fragmented packet is reassembled before being passed to the transport layer. See also: fragmentation. [Source: RFC1392]

recursion

The facility of a programming language to be able to call functions from within themselves.

recursive

See: recursive [Source: RFC1392]

Red Book

Red Book Job Transfer and Manipulation Protocol; a JTMP used in the UK academic and research community. See also JTMP.

regional

See: mid-level network. [Source: RFC1392]

remote login

Operating on a remote computer, using a protocol over a computer network, as though locally attached. See also: Telnet. [Source: RFC1392]

Remote Procedure Call (RPC)

An easy and popular paradigm for implementing the client-server model of distributed computing. In general, a request is sent to a remote system to execute a designated procedure, using arguments supplied, and the result returned to the caller. There are many variations and subtleties in various implementations, resulting in a variety of different (incompatible) RPC protocols. [Source: RFC1208]

repeater

A device which propagates electrical signals from one cable to another. See also: bridge, gateway, router. [Source: RFC1392]

Request For Comments (RFC)

The document series, begun in 1969, which describes the Internet suite of protocols and related experiments. Not all (in fact very few) RFCs describe Internet standards, but all Internet standards are written up as RFCs. The RFC series of documents is unusual in that the proposed protocols are forwarded by the Internet research and development community, acting on their own behalf, as opposed to the formally reviewed and standardized protocols that are promoted by organizations such as CCITT and ANSI. See also: BCP, For Your Information, STD. [Source: RFC1392]

Reseaux Associes pour la Recherche Europeenne (RARE)

European association of research networks. [Source: RFC1208]

Reseaux IP Europeenne (RIPE)

A collaboration between European networks which use the TCP/IP protocol suite. [Source: RFC1392]

resolve

Translate an Internet name into its equivalent IP address or other DNS information.

Reverse Address Resolution Protocol (RARP)

A protocol, defined in RFC 903, which provides the reverse function of ARP. RARP maps a hardware (MAC) address to an internet address. It is used primarily by diskless nodes when they first initialize to find their internet address. See also: Address Resolution Protocol, BOOTP, internet address, MAC address. [Source: RFC1392]

RFC

See: Request For Comments

RFC 822

The Internet standard format for electronic mail message headers. Mail experts often refer to "822 messages". The name comes from "RFC 822", which contains the specification (STD 11, RFC 822). 822 format was previously known as 733 format. See also: Electronic Mail. [Source: COMER]

RFD (Request For Discussion)

Usually a two- to three-week period in which the particulars of newsgroup creation are battled out.

RIP

See: Routing Information Protocol

RIPA

Regulation of Investigatory Powers Act.

RIPE

See: Reseaux IP Europeenne

RJE

Remote Job Entry.

rlogin

A service offered by Berkeley UNIX which allows users of one machine to log into other UNIX systems (for which they are authorized) and interact as if their terminals were connected directly. Similar to Telnet. [Source: RFC1208]

ROSE

Remote Operations Service Element. A lightweight RPC protocol, used in OSI Message Handling, Directory, and Network Management application protocols. [Source: RFC1208]

Round-Trip Time (RTT)

A measure of the current delay on a network. [Source: MALAMUD]

route

The path that network traffic takes from its source to its destination. Also, a possible path from a given host to another host or destination. [Source: RFC1392]

routed

Route Daemon. A program which runs under 4.2BSD/4.3BSD UNIX systems (and derived operating systems) to propagate routes among machines on a local area network, using the RIP protocol. Pronounced "route-dee". See also: Routing Information Protocol, gated. [Source: RFC1392]

router

A device which forwards traffic between networks. The forwarding decision is based on network layer information and routing tables, often constructed by routing protocols. See also: bridge, gateway, Exterior Gateway Protocol, Interior Gateway Protocol. [Source: RFC1392]

routing

The process of selecting the correct interface and next hop for a packet being forwarded. See also: hop, router, Exterior Gateway Protocol, Interior Gateway Protocol. [Source: RFC1392]

routing domain

A set of routers exchanging routing information within an administrative domain. See also: Administrative Domain, router. [Source: RFC1392]

Routing Information Protocol (RIP)

A distance vector, as opposed to link state, routing protocol. It is an Internet standard IGP defined in STD 34, RFC 1058 (updated by RFC 1388). See also: Interior Gateway Protocol, Open Shortest Path First.... [Source: RFC1392]

RPAN

Regional Partner Academic Network - a sort of organisation for a Metropolitan Area Network. See also RDN.

RPC

See: Remote Procedure Call

RSA

A public-key cryptographic system which may be used for encryption and authentication. It was invented in 1977 and named for its inventors: Ron Rivest, Adi Shamir, and Leonard Adleman. See also: encryption, Data Encryption Standard, Pretty Good Privacy. [Source: RFC1983]

RSC

Regional Support Centre, a JISC-sponsored service to further (and higher) education institutions.

RSS

Relay Spam Stopper, a method of rejecting electronic mail from rogue mail relays.

RTFM

See: Read the Fine Manual

RTSC

See: Read the Source Code

RTSE

Reliable Transfer Service Element. A lightweight OSI application service used above X.25 networks to handshake application PDUs across the Session Service and TP0. Not needed with TP4, and not recommended for use in the U.S. except when talking to X.400 ADMDs. [Source: RFC1208]

RTT

See: Round-Trip Time

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SAP

Service Access Point. The point at which the services of an OSI layer are made available to the next higher layer. The SAP is named according to the layer providing the services, e.g., Transport services are provided at a Transport SAP (TSAP) at the top of the Transport Layer. [Source: RFC1208]

Scottish and Northern Ireland JANET User Group (SNIJUG)

The Scottish and Northern Ireland JANET User Group (SNIJUG) presents the views of the users on JANET and UKERNA services to the JISC Committee on Networking through the JANET National User Group. See also: JANET National User Group.

SDH

See: Synchronous Digital Hierarchy

selector

The identifier used by an OSI entity to distinguish among multiple SAPs at which it provides services to the layer above. See port. [Source: RFC1208]

Serial Line IP (SLIP)

A protocol used to run IP over serial lines, such as telephone circuits or RS-232 cables, interconnecting two systems. SLIP is defined in RFC 1055. See also: Point-to-Point Protocol. [Source: RFC1392]

SERJUG

See: South East JANET Regional User Group

server

A provider of resources (e.g., file servers and name servers). See also: client, Domain Name System, Network File System. [Source: RFC1392]

Service Level Agreement

A contractual agreement between a service provider and a service user about the level of performance of the service, and indeed the provider. An example is the SLA between JISC and UKERNA for the JANET service.

Session Layer

The OSI layer that provides means for dialogue control between end systems. [Source: RFC1208]

SGMP

Simple Gateway Management Protocol. The predecessor to SNMP. See SNMP. [Source: RFC1208]

SGML

See: Standardized Generalized Markup Language

SIG

Special Interest Group [Source: RFC1392]

signal-to-noise ratio

When used in reference to Usenet activity, signal-to-noise ratio describes the relation between amount of actual information in a discussion, compared to their quantity. More often than not, there's substantial activity in a newsgroup, but a very small number of those articles actually contain anything useful.

signature

The three or four line message at the bottom of a piece of email or a Usenet article which identifies the sender. Large signatures (over five lines) are generally frowned upon. See also: Electronic Mail, Usenet. [Source: RFC1392]

Simple Mail Transfer Protocol (SMTP)

A protocol, defined in RFC 821, used to transfer electronic mail between computers, with extensions specified in many other RFCs. It is a server to server protocol, so other protocols are used to access the messages. See also: Electronic Mail, Post Office Protocol, RFC 822. [Source: RFC1392]

Simple Network Management Protocol (SNMP)

The Internet standard protocol developed to manage nodes on an IP network. The first version is defined in RFC 1157 (STD 15). SNMPv2 (version 2) is defined in too many RFCs to list. It is currently possible to manage wiring hubs, toasters, jukeboxes, etc. See also: Management Information Base. [Source: RFC1392]

Simple Object Access Protocol (SOAP)

A lightweight messaging framework designed for exchange of structured information in a distributed, decentralised environment, of which the provision of services over the World Wide Web is an example. SOAP is issued by the World Wide Web Consortium (W3C) XML Protocol Working Group.

SLA

See: Service Level Agreement

SLIP

See: Serial Line IP

SMDS

See: Switched Multimegabit Data Service

SMI

See: Structure of Management Information

SMTP

See: Simple Mail Transfer Protocol

SNA

See: Systems Network Architecture

snail mail

A pejorative term referring to the U.S. postal service.

SNIJUG

See: Scottish and Northern Ireland JANET User Group

SNMP

See: Simple Network Management Protocol

SOA

See: Start of Authority Record

SOA

See: Start of Authority Record

SONET

See: Synchronous Optical NETwork

South East JANET Regional User Group (SERJUG)

The South East JANET Regional User Group (SERJUG) presents the views of the users on JANET and UKERNA services to the JISC Committee on Networking through the JANET National User Group. See also: JANET National User Group.

South West JANET Regional User Group (SWJRUG)

The South West JANET Regional User Group (SWJRUG) presents the views of the users on JANET and UKERNA services to the JISC Committee on Networking through the JANET National User Group. See also: JANET National User Group.

SPAG (1)

Standards Promotion and Application Group. A group of European OSI manufacturers which chooses option subsets and publishes these in a "Guide to the Use of Standards" (GUS). [Source: RFC1208]

SPAG (2)

Service Performance Advisory group, formerly MSC, a subgroup of JISC, responsible for development and trend analysis of JANET.

spam

send an email message or news message to large numbers of email distribution lists or Usenet newsgroups, to the annoyance of most recipients, and contrary to Netiquette.

Spread Spectrum

Transmission of a signal using a carrier whose frequency spectrum varies over a wide range in a pseudo random manner. Detection and interception are difficult as transmissions appear similar to background noise. Reception is done by cross correlation of the wide band signal with a replica of the spectrum of the sender, synchronised between sender and receiver.

The two main methods are Frequency Hopping (FH or FHSS) and Direct Sequence (DS or DSSS). In FH the output frequencies hop around the desired range according to a pseudo random sequence of numbers fed into the frequency synthesiser. In DS a narrow band signal is spread into a wideband signal using a pseudo random chipping code sequence (a rather higher data rate bit sequence) which determines the spreading ratio. This is also known as Phase Shift Keying or phase modulation. For 802.11b Wireless Local Area Networks the modulation scheme is known as Complementary Code Keying (CCK) and for 802.11a it is known as Orthogonal Frequency Division Multiplexing (OFDM). The signal is despread at the receiver with the same code sequence, using the redundant information in the code sequence to aid error correction in case of interference. See also: 802.11, Wireless Local Area Network.

SQL

Structured Query Language. The international standard language for defining and accessing relational databases. [Source: RFC1208]

Squid

A Web proxy cache package.

SSH

Secure Shell, a package for eliciting secure (i.e. encrypted) interactive connections across a public network such as the Internet.

SSL

Secure Socket Layer protocol, a method for eliciting secure (i.e. encrypted) connections (e.g. to web services) across a public network such as the Internet. Now extended as Transport Layer Security (TLS).

STAN

JANET Spam-relay Tester And Notification system, for checking electronic mail servers for weaknesses which might promote spam.

Standardized Generalized Markup Language (SGML)

An international standard for the definition of system- independent, device-independent methods of representing text in electronic form. Different applications can be developed using Document Type Definitions (DTDs) e.g. HTML. See also: Hypertext Markup Language. [Source: RFC1983]

Start of Authority Record (SOA Record)

A DNS resource record type indicating which host is authorative for a particular domain. See also: Domain Name System.

STD

A subseries of RFCs that specify Internet standards. The official list of Internet standards is in STD 1. See also: For Your Information, Request For Comments. [Source: RFC1392]

stream-oriented

A type of transport service that allows its client to send data in a continuous stream. The transport service will guarantee that all data will be delivered to the other end in the same order as sent and without duplicates. See also: Transmission Control Protocol. [Source: MALAMUD]

Structure of Management Information (SMI)

The rules used to define the objects that can be accessed via a network management protocol. This protocol is defined in STD 16, RFC 1155. See also: Management Information Base. [Source: RFC1208]

stub network

A stub network only carries packets to and from local hosts. Even if it has paths to more than one other network, it does not carry traffic for other networks. See also: backbone, transit network. [Source: RFC1392]

subnet

A portion of a network, which may be a physically independent network segment, which shares a network address with other portions of the network and is distinguished by a subnet number. A subnet is to a network what a network is to an internet. See also: internet, network. [Source: FYI4]

subnet address

The subnet portion of an IP address. In a subnetted network, the host portion of an IP address is split into a subnet portion and a host portion using an address (subnet) mask. See also: address mask, IP address, network address, host address. [Source: RFC1392]

subnet mask

See: address mask

subnet number

See: subnet address

subnetwork

A collection of OSI end systems and intermediate systems under the control of a single administrative domain and utilizing a single network access protocol. Examples:- private X.25 networks, collection of bridged LANs. [Source: RFC1208]

SUfi

Scottish University for industry.

summarize

To encapsulate a number of responses into one coherent, usable message. Often done on controlled mailing lists or active newsgroups, to help reduce bandwidth.

SuperJANET

SuperJANET 4 is a very high performance backbone network based on optical fibre technology, offering up to 2.5 Gigabits/sec transmission rates in April 2001. This new network is needed to support advanced applications requiring a mixture of voice, data, image and video communications. The network is designed to use the most up-to-date communications technology - synchronous digital hierarchy (SDH) access - within the backbone between Core Points of Presence (C-PoPs) and to Backbone Access Routers (BARs) at the boundary of each regional MAN. A testbed network using DWDM is also in use.

SWERN

South West England Regional Network.

Switched Multimegabit Data Service (SMDS)

An emerging high-speed datagram-based public data network service developed by Bellcore and expected to be widely used by telephone companies as the basis for their data networks. See also: Metropolitan Area Network. [Source: RFC1208]

SWJRUG

See: South West JANET Regional User Group

synchronous

Data communications in which transmissions are sent at a fixed rate, with the sending and receiving devices synchronized.

Synchronous Digital Hierarchy (SDH)

The European standard for high-speed data communications over fiber-optic media. The transmission rates range from 155.52Mbps to 2.5Gbps. [Source: RFC1983]

Synchronous Optical NETwork (SONET)

SONET is an international standard for high-speed data communications over fiber-optic media. The transmission rates range from 51.84Mbps to 2.5Gbps. [Source: RFC1983]

Systems Network Architecture (SNA)

A proprietary networking architecture used by IBM and IBM- compatible mainframe computers. [Source: NNSC]

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T1

A term for a digital carrier facility used to transmit a DS-1 formatted digital signal at 1.544 megabits per second. [Source: RFC1392]

T3

A term for a digital carrier facility used to transmit a DS-3 formatted digital signal at 44.746 megabits per second. [Source: FYI4]

TAC

See: Terminal Access Controller (TAC)

TAU

Technical Advisory Unit, a JISC sponsored service, performs regular monitoring of JANET, JISCMail and the National Cache, and advises JISC on technical matters.

talk

A protocol which allows two people on remote computers to communicate in a real-time fashion. See also: Internet Relay Chat. [Source: RFC1392]

TCP

See: Transmission Control Protocol

TCP/IP Protocol Suite

Transmission Control Protocol over Internet Protocol. This is a common shorthand which refers to the suite of transport and application protocols which runs over IP. See also: IP, ICMP, TCP, UDP, FTP, Telnet, SMTP, SNMP. [Source: RFC1392]

TechDis

JISC funded Technology for Disabilities information service.

TELENET

A public packet switched network using the CCITT X.25 protocols. It should not be confused with Telnet. [Source: RFC1392]

Telnet

Telnet is the Internet standard protocol for remote terminal connection service. It is defined in STD 8, RFC 854 and extended with options by many other RFCs. [Source: RFC1392]

TEN-155

Trans European Network at 155Mbit/s, now replaced by GÉANT.

TERENA

See: Trans-European Research and Education Networking Association

Terminal Access Controller (TAC)

A device which was once used to connect terminals to the Internet, usually using dialup modem connections and the TACACS protocol. While the device is no longer in use, TACACS+ is a protocol in current use. [Source: RFC1983]

terminal emulator

A program that allows a computer to emulate a terminal. The workstation thus appears as a terminal to the remote host. [Source: MALAMUD]

terminal server

A device which connects many terminals to a LAN through one network connection. A terminal server can also connect many network users to its asynchronous ports for dial-out capabilities and printer access. See also: Local Area Network. [Source: RFC1392]

TeX

A free typesetting system by Donald Knuth.

Three Letter Acronym (TLA)

A tribute to the use of acronyms in the computer field. See also: Extended Four Letter Acronym. [Source: RFC1392]

three-way-handshake

The process whereby two protocol entities synchronize during connection establishment. [Source: RFC1208]

Time to Live (TTL)

A field in the IP header which indicates how long this packet should be allowed to survive before being discarded. It is primarily used as a hop count. See also: Internet Protocol. [Source: MALAMUD]

TLA

See: Three Letter Acronym

TN3270

A variant of the Telnet program that allows one to attach to IBM mainframes and use the mainframe as if you had a 3270 or similar terminal. [Source: BIG-LAN]

token ring

A token ring is a type of LAN with nodes wired into a ring. Each node constantly passes a control message (token) on to the next; whichever node has the token can send a message. Often, "Token Ring" is used to refer to the IEEE 802.5 token ring standard, which is the most common type of token ring. See also: 802.x, Local Area Network. [Source: RFC1392]

topology

A network topology shows the computers and the links between them. A network layer must stay abreast of the current network topology to be able to route packets to their final destination. [Source: MALAMUD]

TP0

OSI Transport Protocol Class 0 (Simple Class). This is the simplest OSI Transport Protocol, useful only on top of an X.25 network (or other network that does not lose or damage data). [Source: RFC1208]

TP4

OSI Transport Protocol Class 4 (Error Detection and Recovery Class). This is the most powerful OSI Transport Protocol, useful on top of any type of network. TP4 is the OSI equivalent to TCP. [Source: RFC1208]

traceroute

A program available on many systems which traces the path a packet takes to a destination. It is mostly used to debug routing problems between hosts. There is also a traceroute protocol defined in RFC 1393. [Source: RFC1983]

transceiver

Transmitter-receiver. The physical device that connects a host interface to a local area network, such as Ethernet. Ethernet transceivers contain electronics that apply signals to the cable and sense collisions. [Source: RFC1208]

transit network

A transit network passes traffic between networks in addition to carrying traffic for its own hosts. It must have paths to at least two other networks. See also: backbone, stub network. [Source: RFC1392]

Transmission Control Protocol (TCP)

An Internet Standard transport layer protocol defined in RFC 793. It is connection-oriented and stream-oriented, as opposed to UDP. See also: connection-oriented, stream-oriented, User Datagram Protocol. [Source: RFC1392]

Transport Layer

The OSI layer that is responsible for reliable end- to-end data transfer between end systems. [Source: RFC1208]

Transport Layer Security (TLS)

An IETF standard in RFC 2246 for eliciting secure (i.e. encrypted) connections (e.g. to web services) across a public network such as the Internet. Formerly known as Secure Sockets Layer (SSL).

Trojan Horse

A computer program which carries within itself a means to allow the creator of the program access to the system using it. See also: virus, worm. See RFC 1135. [Source: RFC1392]

TS29

a network independent version of X29. The dependency of X29 on X25 is removed. See also Green Book.

TSI

The MAPS Transport Security Initiative.

TTFN

Ta-Ta For Now [Source: RFC1392]

TTL

See: Time to Live

tunnelling

Tunnelling refers to encapsulation of protocol A within protocol B, such that A treats B as though it were a datalink layer. Tunnelling is used to get data between administrative domains which use a protocol that is not supported by the internet connecting those domains. See also: Administrative Domain. [Source: RFC1392]

TVN

Thames Valley Network.

twisted pair

A type of cable in which pairs of conductors are twisted together to produce certain electrical properties. [Source: RFC1392]

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UA

User Agent. An OSI application process that represents a human user or organization in the X.400 Message Handling System. Creates, submits, and takes delivery of messages on the user's behalf. [Source: RFC1208]

UBE

Unsolicited Bulk Email.

UCE

Unsolicited Commercial Email.

UCISA

Universities and Colleges Information Systems Association, with several subgroups, including UCISA-NG, the Networking Group (which is an Affiliated Group of the JANET National User Group).

UDP

See: User Datagram Protocol

Ufi

University for industry, not strictly a University, nor for Industry.

UHI Network

University of Highlands and Islands Network.

UKERNA

the UK Education and Research Networking Association; funded by the Joint Information Systems Committee of the Higher Education Funding Councils and others to manage the academic network and its developments. Formerly the JNT.

ULCC

University of London Computer Centre, home of various networking facilities.

unicast

An address which only one host will recognize. See also: broadcast, multicast. [Source: RFC1983]

Uniform Resource Locator (URL)

A URL is a compact (most of the time) string representation for a resource available on the Internet. URLs are primarily used to retrieve information using WWW. The syntax and semantics for URLs are defined in RFC 1738. See also: World Wide Web. [Source: RFC1983]

Universal Time Coordinated (UTC)

This is Greenwich Mean Time. [Source: MALAMUD]

UNIX-to-UNIX CoPy (UUCP)

This was initially a program run under the UNIX operating system that allowed one UNIX system to send files to another UNIX system via dial-up phone lines. Today, the term is more commonly used to describe the large international network which uses the UUCP protocol to pass news and electronic mail. See also: Electronic Mail, Usenet. [Source: RFC1392]

Unrouteable Address

Certain ranges of IP addresses are designated in RFC 1918 as exclusively for internal use. These are 10.0.0.0 to 10.255.255.255, 172.16.0.0 to 172.16.255.255, and 192.168.0.0 to 192.168.255.255. A correctly configured router will not allow packets from any of these addresses through to the Internet. The only way that information can pass between hosts with any of these IP addresses and the outside world is to have a device (typically a firewall) that translates between these internal addresses and a specific collection of IP addresses that are assigned in the normal way. The internal IP addresses can be safely re-used in many such locations. See also: Network Address Translation, IP Address.

urban legend

A story, which may have started with a grain of truth, that has been embroidered and retold until it has passed into the realm of myth. It is an interesting phenonmenon that these stories get spread so far, so fast and so often. Urban legends never die, they just end up on the Internet! Some legends that periodically make their rounds include "The Infamous Modem Tax," "Craig Shergold/Brain Tumor/Get Well Cards," and "The $250 Cookie Recipe". [Source: LAQUEY]

URL

See: Uniform Resource Locator

Usenet

A collection of thousands of topically named newsgroups, the computers which run the protocols, and the people who read and submit Usenet news. Not all Internet hosts subscribe to Usenet and not all Usenet hosts are on the Internet. See also: Network News Transfer Protocol, UNIX-to-UNIX CoPy. [Source: NWNET]

User Datagram Protocol (UDP)

An Internet Standard transport layer protocol defined in STD 6, RFC 768. It is a connectionless protocol which adds a level of reliability and multiplexing to IP. See also: connectionless, Transmission Control Protocol. [Source: RFC1392]

UTC

See: Universal Time Coordinated

UUCP

See: UNIX-to-UNIX CoPy

uudecode

A program which reverses the effect of uuencode. See also: uuencode. [Source: RFC1983]

uuencode

A program which reversibly converts a binary file in ASCII. It is used to send binary files via email, which generally does not allow (or garbles) the transmission of binary information. The original binary can be restored with uudecode. The encoding process generally creates an ASCII file larger than the original binary, so compressing the binary before running uuencode is highly recommended. [Source: RFC1983]

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VBS

Visual Basic Scriplet (Microsoft).

Veronica

A Gopher utility which effectively searches Gopher servers based on a user's list of keywords. The name was chosen to be a "mate" to another utility named "Archie." It later became an acronym for Very Easy Rodent Oriented Netwide Index to Computer Archives. See also: archie, Gopher. [Source: RFC1983]

virtual circuit

A network service which provides connection-oriented service regardless of the underlying network structure. See also: connection-oriented. [Source: RFC1392]

Virtual Private Network (VPN)

A client across a public network such as the Internet may appear to be part of a private network by encapsulating the private packets inside public packets which are routed in the normal way to a device (typically a firewall) on the private network which unpacks them and sends them on the private network, a process known as tunnelling. The tunnel can exist at the data link layer using Point to Point Tunnelling Protocol (PPTP) or the IETF standard Layer 2 Tunneling Protocol (L2TP) from RFC 2661, or at the IP layer using IETF-defined IP Security (IPsec) protocol extensions from RFC 2402 and RFC 2406. There should also be some form of authentication and authorisation, and encryption of at least the authentication process (and preferably data transfers too) so IPsec is the most desireable method.

virus

A program which replicates itself on computer systems by incorporating itself into other programs which are shared among computer systems. See also: Trojan Horse, worm. [Source: RFC1392]

VPN

See: Virtual Private Network

VTAS

Video Technology Advisory Service, a UKERNA service.

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W3

See: World Wide Web

W3C

World Wide Web Consortium, a governing body for web standards.

WAIS

See: Wide Area Information Servers

WAE

See: Wireless Application Environment

WAN

See: Wide area network

WAP

See: Wireless Application Protocol

WDP

See: Wireless Datagram Protocol

WEP

See: Wired Equivalent Privacy

WLAN

See: Wireless Local Area Network

WML

See: Wireless Markup Language

WPA

See: Wi-Fi Protected Access

WSP

See: Wireless Session Protocol

WTA

See: Wireless Telephony Application

WTLS

See: Wireless Transport Layer Security protocol

WTP

See: Wireless Transaction Protocol

WebCrawler

A WWW search engine. The aim of the WebCrawler Project is to provide a high-quality, fast, and free Internet search service. The WebCrawler may be reached at "http://webcrawler.com/". [Source: WebCrawler's "WebCrawler Facts"]

WG

See: Working Group

White Book

a document produced for the JNT setting out the strategy to be adopted by the Academic Community in its transition from interim standards (Coloured Books) to ISO standards. Overtaken by history - an IP.

white pages

The Internet supports several databases that contain basic information about users, such as email addresses, telephone numbers, and postal addresses. These databases can be searched to get information about particular individuals. Because they serve a function akin to the telephone book, these databases are often referred to as "white pages. See also: Knowbot, netfind, whois, X.500. [Source: RFC1392]

Wi-Fi Protected Access (WPA)

A development of Wired Equivalent Privacy to overcome deficiencies in WEP as used in Wireless LANs, by incorporating elements of 802.11i security before the latter (to be known subsequently as WPA v2) is fully developed. Temporary Key Integrity Protocol (TKIP) is incorporated to allow different encryption keys for each packet transmitted, as are RADIUS support and facilities to stop rogue network points attracting authenticated users to steal their credentials. See also: RADIUS, Wired Equivalent Privacy.

Wireless Application Protocol (WAP)

A stack of protocols, akin to the OSI model or the TCP/IP stack, to implement the layers needed for communication with wireless devices, security, applications, etc, promoted as an open standard by the WAP Forumwww.wapforum.org.

Wireless Application Protocol Gateway

A WAP client may receive documents from an ordinary WWW server via a WAP gateway, a proxy which converts between WAP requests and HTTP requests (including CGI programs) and converts the output to WAP formats (e.g. WML or WMLScript) followed by compression to binary for sending to the client. WWW pages may also be coded directly in WML on the WWW server before receipt by the gateway.

Wireless Application Environment (WAE)

WAE is the programming environment for WAP. WAE is handled by a browser program in the device, and consists of Wireless Markup Language (WML), WMLScript and Wireless Telephony Application (WTA).

Wireless Datagram Protocol (WDP)

The transport layer of WAP, which transforms datagrams from upper layer protocols into the formats specific to datapaths, bearers and devices, e.g. GSM or SMS or GPRS. Thus upper layers have no need to program for the physical layer of communication such as air interface.

Wired Equivalent Privacy (WEP)

A security protocol within IEE standard 802.11b intended to give Wireless Local Area Networks the degree of privacy expected of fixed LANs. Encryption over air between the devices and fixed access points (rather than end to end) goes part way towards countering the eavesdropping risk of signals spilling out of buildings. However, the length of the key may be only 40 bits (up to 128 bits is allowed) even if WEP is turned on, and the encryption method produces some predictable sequences, so it is prone to statistical analysis to recover keys. Also the Service Set Identifier (SSID) is broadcast in clear in probes from the access point (unless turned off); this is used as a "password" for packets sent between members of specific LANs, so is useful for eavesdroppers to acquire, especially if obvious names are chosen e.g. 10Downing.

As an interim solution, the IEE 802.1x standard is available for port-level authentication and key management i.e. rapid changes and secure key delivery. This incorporates Extensible Authentication Protocol (EAP) from RFC 2284. This was first designed for wired (e.g. dialup) links, and is not itself a cipher standard, so the first version authenticates the MAC address rather than the user. The authentication is passed through from the fixed access point to an authentication server such as RADIUS or Kerberos. However, there are no checks that an access point is what it claims to be, so there is a way of masquerading or intercepting the authentication process.

Work on the 802.11i standard is ongoing at March 2003, but this addresses such issues as mutual and per-packet authentication, and could incorporate Advanced Encryption Standard (AES). An interim standard Wi-Fi Protected Access (WPA) contains some of the technologies to overcome WEP deficiencies.

It is imperative that further security measures are taken on top of WEP and its immediate successors, such as Virtual Private Network schemes, although Network Layer solutions such as IPsec are tricky when roaming devices use DHCP for dynamic IP addresses, and products orientated to wireless working are necessary. See also: 802.11, Kerberos, RADIUS, Wireless Local Area Network, Wireless Protected Access.

Wireless Local Area Network (WLAN)

A data network intended to serve an area of only a few hundres square metres or less, using radio communications between mobile computers and (typically) a fixed access point which provides onward connections to fixed networks such as the Internet. There are several competing technologies such as HIPERLAN in Europe and the 802.11 series in the USA. This is the next level up in distance from Personal Area Networks such as Bluetooth. See also: Bluetooth, 802.11, HIPERLAN.

Wireless Markup Language (WML)

The markup language for WAP, a tag-based language like HTML. Strictly, WML is a Document Type Definition (DTD) of eXtendable Markup Language, which implied a relationship with the DTD for (strictly defined) HTML.

Wireless Session Protocol (WSP)

The session layer of WAP, handling the interface between the application layer WAE and the transaction layer WTP. Sessions can be connection-orientated or connectionless, and can be suspended and resumed on demand.

Wireless Telephony Application (WTA)

The telephony interface for WAP, part of Wireless Application Environment (WAE). WTA can control telephony functions of the device from WML or WMLScript, or from requests from the network.

Wireless Transport Layer Security protocol (WTLS)

WTLS handles security for WAP, i.e. encryption, decryption, user authentication and data integrity checking of datagrams from upper layer protocols before passing to the transport layer WDP. It is based on the fixed network Transport Layer Security (TLS) protocol, formerly Secure Sockets Layer.

Wireless Transaction Protocol (WTP)

WTP is the transaction layer of WAP, which takes data packets from the session layer WSP and chops them into lower layer datagrams to pass to the security layer WTLS, or reassembles them at the far end. WTP also tracks sequences of sent and received packets, handling retransmissions or acknowledgements as required.

whois

An Internet program which allows users to query a database of people and other Internet entities, such as domains, networks, and hosts, kept at the DDN NIC. The information for people shows a person's company name, address, phone number and email address. See also: Defense Data Network Network ..., white pages, Knowbot, X.500. [Source: FYI4]

Wide Area Information Servers (WAIS)

A distributed information service which offers simple natural language input, indexed searching for fast retrieval, and a "relevance feedback" mechanism which allows the results of initial searches to influence future searches. Public domain implementations are available. See also: archie, Gopher, Prospero. [Source: RFC1392]

Wide Area Network (WAN)

A network, usually constructed with serial lines, which covers a large geographic area. See also: Local Area Network, Metropolitan Area Network. [Source: RFC1392]

WML

See: Wireless Markup Language

WMLScript

A scripting language for WML, akin to Javascript or ECMAScript for HTML, which can control functions in the browser or the phone, using scripts downloaded from the server.

Working Group (WG)

A working group, within the IETF, is a group of people who work under a charter to achieve a certain goal. That goal may be the creation of an Informational document, the creation of a protocol specification, or the resolution of problems in the Internet. Most working groups have a finite lifetime. That is, once a working group has achieved its goal, it disbands. There is no official membership for a working group. Unofficially, a working group member is somebody who is on that working group's mailing list; however, anyone may attend a working group meeting. See also: Internet Engineering Task Force, Birds Of a Feather. [Source: RFC1983]

World Wide Web (WWW or W3)

A hypertext-based, distributed information system created by researchers at CERN in Switzerland. Users may create, edit or browse hypertext documents. The clients and servers are freely available. [Source: RFC1392]

workstation

A networked personal computing device with more power than a standard IBM PC or Macintosh. Typically, a workstation has an operating system such as unix that is capable of running several tasks at the same time. It has several megabytes of memory and a large, high-resolution display. Examples are Sun Sparcstations and Digital Alpha stations.

worm

A computer program which replicates itself and is self- propagating. Worms, as opposed to viruses, are meant to spawn in network environments. Network worms were first defined by Shoch & Hupp of Xerox in ACM Communications (March 1982). The Internet worm of November 1988 is perhaps the most famous; it successfully propagated itself on over 6,000 systems across the Internet. See also: Trojan Horse, virus. [Source: RFC1392]

WRT

With Respect To [Source: RFC1392]

WWW

See: World Wide Web

WYSIWYG

What You See is What You Get [Source: RFC1392]

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X

X is the name for TCP/IP based network-oriented window systems. Network window systems allow a program to use a display on a different computer. The most widely-implemented window system is X11 - a component of MIT's Project Athena. [Source: RFC1392]

X.21

An interface for synchronous operation on public data networks, a successor for V.24 and V.25 definitions, from ITU-T. Data rates can be up to 2Mbits/s.

X.25

A data communications interface specification developed to describe how data passes into and out of public data communications networks. The CCITT and ISO approved protocol suite defines protocol layers 1 through 3. [Source: RFC1392]

X.29

a protocol defining the control packet format between the PAD and remote host regarding the virtual terminal parameters (the X3 parameters) and changes in their values. X29 uses packets defined by X25.

X.400

The CCITT and ISO standard for electronic mail. It is widely used in Europe and Canada. See also: MHS. [Source: RFC1392]

X.500

The CCITT and ISO standard for electronic directory services. See also: DSA, white pages, Knowbot, WHOIS. [Source: RFC1392]

XDR

See: eXternal Data Representation

XDSL

A Digital Subscriber Line similar to ISDN.

Xerox Network System (XNS)

A network developed by Xerox corporation. Implementations exist for both 4.3BSD derived systems, as well as the Xerox Star computers. [Source: RFC1392]

XHTML

Extensible Hypertext Markup Language.

XML

See: Extendable Markup Language.

XNS

See: Xerox Network System

X/Open

A group of computer manufacturers that promotes the development of portable applications based on UNIX. They publish a document called the X/Open Portability Guide.

X Recommendations

The CCITT documents that describe data communication network standards. Well-known ones include:- X.25 Packet Switching standard, X.400 Message Handling System, and X.500 Directory Services.

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Yahoo!

Yahoo! is a hierarchical subject-oriented guide for the World Wide Web and Internet. Yahoo! lists sites and categorizes them into appropriate subject categories. Yahoo! may be reached at "http://www.yahoo.com/". [Source: Yahoo's "What is Yahoo?"]

Yellow Book or YBTS

Yellow Book Transport Service; a transport service protocol now rarely used by the UK academic and research community.

Yellow Pages (YP)

See: Network Information Services

YHMAN

Yorkshire and Humberside Metropolitan Area Network.

YP

See: Network Information Services

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zone

A logical group of network devices (AppleTalk). [Source: RFC1392]

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