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Network Working Group G. Malkin, Editor Request for Comments: 1983 Xylogics FYI: 18 August 1996 Obsoletes: 1392 Category: Informational

                      Internet Users' Glossary

Status of this Memo

 This memo provides information for the Internet community.  This memo
 does not specify an Internet standard of any kind.  Distribution of
 this memo is unlimited.


 There are many networking glossaries in existence.  This glossary
 concentrates on terms which are specific to the Internet.  Naturally,
 there are entries for some basic terms and acronyms because other
 entries refer to them.


 This document is the work of the User Glossary Working Group of the
 User Services Area of the Internet Engineering Task Force.  I would
 especially like to thank Ryan Moats/InterNIC for his careful review
 and many contributions to this document.

Table of Contents

 non-letter  . .  2      I . . . . . . . 26      R . . . . . . . 46
 A . . . . . . .  2      J . . . . . . . 33      S . . . . . . . 49
 B . . . . . . .  7      K . . . . . . . 33      T . . . . . . . 52
 C . . . . . . . 10      L . . . . . . . 33      U . . . . . . . 55
 D . . . . . . . 14      M . . . . . . . 35      V . . . . . . . 57
 E . . . . . . . 18      N . . . . . . . 39      W . . . . . . . 57
 F . . . . . . . 20      O . . . . . . . 42      X . . . . . . . 59
 G . . . . . . . 22      P . . . . . . . 43      Y . . . . . . . 60
 H . . . . . . . 23      Q . . . . . . . 46      Z . . . . . . . 60
 References  . . . . . . . . . . . . . . . . . . . . . . . . . . 61
 Security Considerations . . . . . . . . . . . . . . . . . . . . 62
 Editor's Address  . . . . . . . . . . . . . . . . . . . . . . . 62

Malkin Informational [Page 1] RFC 1983 Glossary August 1996


    A physical layer communications specification for 10Mbps, baseband
    data transmission over a coaxial cable (Thinnet) with a maximum
    cable segment length of 200 meters.
    A physical layer communications specification for 10Mbps, baseband
    data transmission over a coaxial cable (Thicknet) with a maximum
    cable segment length of 500 meters.
    A physical layer communications specification for 10Mbps, baseband
    data transmission over a fiber-optic cable.
    A physical layer communications specification for 10Mbps, baseband
    data transmission over a twisted-pair copper wire.
    The set of IEEE standards for the definition of LAN protocols.
    See also: IEEE.
    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]
 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.

Malkin Informational [Page 2] RFC 1983 Glossary August 1996

 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.
 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.
    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
    [Source: NNSC]
    See: Access Control List
    See: Administrative Domain
    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.
 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.

Malkin Informational [Page 3] RFC 1983 Glossary August 1996

 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.
 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.  See also: proxy ARP, Reverse Address Resolution
 Administrative Domain (AD)
    A collection of hosts and routers, and the interconnecting
    network(s), managed by a single administrative authority.
 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.  Now retired, 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]
    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]
    A name, usually short and easy to remember, that is translated
    into another name, usually long and difficult to remember.
 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

Malkin Informational [Page 4] RFC 1983 Glossary August 1996

    (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
    [Source: NNSC]
 American Standard Code for Information Interchange (ASCII)
    A standard character-to-number encoding widely used in the
    computer industry.  See also: EBCDIC.
 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.
    See: American National Standards Institute
    See: Application Program Interface
    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]
    A program that performs a function directly for a user.  FTP, mail
    and Telnet clients are examples of network applications.
 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]

Malkin Informational [Page 5] RFC 1983 Glossary August 1996

    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.
 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.
    See: Address Resolution Protocol
    See: Advanced Research Projects Agency
    See: Advanced Research Projects Agency Network
    See: Autonomous System
    See: American Standard Code for Information Interchange
    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,
    [Source: STD2]

Malkin Informational [Page 6] RFC 1983 Glossary August 1996

 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."
    See: Asynchronous Transfer Mode
    See: Acceptable Use Policy
    The verification of the identity of a person or process.
    [Source: MALAMUD]
 Autonomous System (AS)
    A collection of routers under a single administrative authority
    using a common Interior Gateway Protocol for routing packets.
    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.
    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.
 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.
    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]

Malkin Informational [Page 7] RFC 1983 Glossary August 1996

 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]
    See: Bulletin Board System
    Be Seein' You
    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.
    See: Basic Encoding Rules
 Berkeley Internet Name Daemon (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.
 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]
    See: Border Gateway Protocol
    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

Malkin Informational [Page 8] RFC 1983 Glossary August 1996

    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]
    See: Berkeley Internet Name Daemon
 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.
    An academic computer network that provides interactive electronic
    mail and file transfer services, using a store-and-forward
    protocol, based on IBM Network Job Entry protocols.  Bitnet-II
    encapsulates the Bitnet protocol within IP packets and depends on
    the Internet to route them.
    See: Birds Of a Feather
    The Bootstrap Protocol, described in RFC 1542, is used for booting
    diskless nodes.  See also: Dynamic Host Configuration Protocol,
    Reverse Address Resolution Protocol.
 Border Gateway Protocol (BGP)
    The Border Gateway Protocol is an exterior gateway protocol
    defined in RFC 1771.  It's design is based on experience gained
    with EGP, as defined in RFC 904, and EGP usage in the NSFNET
    Backbone, as described in RFCs 1092 and 1093.  See also: Exterior
    Gateway Protocol.
    The return of a piece of mail because of an error in its delivery.
    [Source: ZEN]
    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.

Malkin Informational [Page 9] RFC 1983 Glossary August 1996

    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.
    A special type of multicast packet which all nodes on the network
    are always willing to receive.  See also: multicast, unicast.
 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.
    See also: Ethernet meltdown.
    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,
    See: Berkeley Software Distribution
    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]
 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.

Malkin Informational [Page 10] RFC 1983 Glossary August 1996

    See: Coordinating Committee for Intercontinental Research Networks
    See: Comite Consultatif International de Telegraphique et
    See: Computer Emergency Response Team
    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.  See
    also: Cyclic Redundancy Check.
    [Source: NNSC]
    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 a circuit switched network.
    See also: connection-oriented, connectionless, packet switching.
 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.
    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]

Malkin Informational [Page 11] RFC 1983 Glossary August 1996

 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.
    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.
 Comite Consultatif International de Telegraphique et Telephonique (
    This organization is now part of the International
    Telecommunications Union 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-TSS.  See also:
    International Telecommunications Union - Telecommunications
    Standards Sector.
 Computer Emergency Response Team (CERT)
    The CERT was formed by ARPA 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 "",
    where security-related documents and tools are archived.  The CERT
    may be reached by email at "" and by telephone at
    +1-412-268-7090 (24-hour hotline).  See also: Advanced Research
    Projects Agency, worm.
    Congestion occurs when the offered load exceeds the capacity of a
    data communication path.

Malkin Informational [Page 12] RFC 1983 Glossary August 1996

    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.
    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.
 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]
    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.
    See: cyclic redundancy check

Malkin Informational [Page 13] RFC 1983 Glossary August 1996

    See: Corporation for Research and Educational Networking
    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
    See: Campus Wide Information system
    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.  See also: checksum.
    [Source: MALAMUD]
    A non-profit company founded in July 1993 to help the European
    research community enhance their networking facilities.  It
    focuses on the establishment of a high-speed computer network
    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.
 Data Encryption Standard (DES)
    A popular, standard encryption scheme.  See also: encryption,
    Pretty Good Privacy, RSA.
    A self-contained, independent entity of data carrying sufficient
    information to be routed from the source to the destination

Malkin Informational [Page 14] RFC 1983 Glossary August 1996

    computer without reliance on earlier exchanges between this source
    and destination computer and the transporting network.  See also:
    frame, packet.
    [Source: J. Postel]
    See: Defense Information Systems Agency
    Data Circuit-terminating Equipment
    See: Distributed Computing Environment
    See: Defense Data Network
    See: Defense Data Network Network Information Center
    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.
 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 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.
 Defense Data Network Network Information Center (DDN NIC)
    Previously called "The NIC", the DDN NIC's primary responsibility
    was the assignment of Internet network addresses and Autonomous
    System numbers, the administration of the root domain, and
    providing information and support services to the Internet for the
    DDN.  Since the creation of the InterNIC, the DDN NIC performs
    these functions only for the DDN.  See also: Autonomous System,
    network address, Internet Registry, InterNIC, Network Information
    Center, Request For Comments.

Malkin Informational [Page 15] RFC 1983 Glossary August 1996

 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.
    See: Data Encryption Key
    See: Data Encryption Standard
    A temporary, as opposed to dedicated, connection between machines
    established over a phone line (analog or ISDN).  See also:
    Integrated Services Digital Network.
 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]
    See: Defense Information Systems Agency
 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]

Malkin Informational [Page 16] RFC 1983 Glossary August 1996

 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.
 DIX Ethernet
    See: Ethernet
    See: Domain Name System
    "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.
 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).  See also: Fully Qualified Domain Name,
    Mail Exchange Record.
 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]
    See: Directory System Agent
    Data Terminal Equipment
    See: Directory User Agent

Malkin Informational [Page 17] RFC 1983 Glossary August 1996

 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]
    The basic building block for European multi-megabit data rates,
    with a bandwidth of 2.048Mbps.  See also: T1.
    A European standard for transmitting data at 57.344Mbps.  See
    also: T3.
    European Academic and Research Network.  See: Trans-European
    Research and Education Networking Association.
    See: Extended Binary Coded Decimal Interchange Code
    A pan-European backbone service.
    See: Electronic Frontier Foundation
    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
 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]
    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

Malkin Informational [Page 18] RFC 1983 Glossary August 1996

    is "".  See also: bang path, mail path, UNIX-
    to-UNIX CoPy.
    [Source: ZEN]
    The technique used by layered protocols in which a layer adds
    header information to the protocol data unit (PDU) from the layer
    above.  For 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 (e.g. TCP), followed by the application protocol
    [Source: RFC1208]
    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.
 error checking
    The examination of received data for transmission errors.  See
    also: checksum, Cyclic Redundancy Check.
    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
 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]
 Extended Binary Coded Decimal Interchange Code (EBCDIC)
    A standard character-to-number encoding used primarily by IBM
    computer systems.  See also: ASCII.
 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 RFC 904.  See also:

Malkin Informational [Page 19] RFC 1983 Glossary August 1996

    Autonomous System, Border Gateway Protocol, Interior Gateway
 eXternal Data Representation (XDR)
    A standard for machine independent data structures developed by
    Sun Microsystems and defined in RFCs 1014 and 1832.  It is similar
    to ASN.1.  See also: Abstract Syntax Notation One.
    [Source: RFC1208]
    A non-profit corporation, established in 1987, whose mission is to
    advance the use of computer networks to improve research and
    Frequently Asked Question
    See: Fiber Distributed Data Interface
 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,
    ARPA, NSF, NASA, and HHS.  See also: Advanced Research Projects
    Agency, National Science Foundation.
 Fiber Distributed Data Interface (FDDI)
    A high-speed (100Mb/s) LAN standard.  The underlying medium is
    fiber 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.

Malkin Informational [Page 20] RFC 1983 Glossary August 1996

 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.  See also: anonymous FTP.
    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.
    See: Federal Information Exchange
    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, Usenet.
    See: Four Letter Extended Acronym
    See: Federal Networking Council
 Four Letter Extended Acronym (FLEA)
    A recognition of the fact that there are far too many TLAs.  See
    also: Three Letter Acronym.
    See: Fully Qualified Domain Name
    A piece of a packet.  When a router is forwarding an IP packet to
    a network that has a maximum transmission unit 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.

Malkin Informational [Page 21] RFC 1983 Glossary August 1996

    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.
    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.
    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]
    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
    "" is an FQDN.  See also: hostname, Domain Name
    For Your Information
    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
    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 "".
    Pronounced "gate-dee".  See also: Exterior Gateway Protocol, Open
    Shortest-Path First, Routing Information Protocol, routed.

Malkin Informational [Page 22] RFC 1983 Glossary August 1996

    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.
    A distributed information service, developed at the University of
    Minnesota, that makes hierarchical collections of information
    available 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.
    See: Government OSI Profile
 Government OSI Profile (GOSIP)
    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.
    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.
    The portion of a packet, preceding the actual data, containing
    source and destination information. It may also error checking and
    other fields.  A header is also the part of an electronic mail
    message which precedes the body of a message and contains, among
    other things, the message originator, date and time.  See also:
    Electronic Mail, packet, error checking.
 heterogeneous network
    A network running multiple network layer protocols.  See also:
    DECnet, IP, IPX, XNS, homogeneous network.

Malkin Informational [Page 23] RFC 1983 Glossary August 1996

 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.
 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
    [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]
    See: High Performance Parallel Interface
    See: Hypertext Markup Language
 homogeneous network
    A network running a single network layer protocol.  See also:
    DECnet, IP, IPX, XNS, heterogeneous network.
    A term used in routing.  A path to a destination on a network is a
    series of hops, through routers, away from the origin.

Malkin Informational [Page 24] RFC 1983 Glossary August 1996

    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
    The name given to a machine.  See also: Fully Qualified Domain
    [Source: ZEN]
 host number
    See: host address
    See: High Performance Computing and Communications
    See: Hypertext Transfer Protocol
    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
    [Source: MALAMUD]
    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.
    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.
 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.

Malkin Informational [Page 25] RFC 1983 Glossary August 1996

 Hypertext Transfer 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.
    See: Internet-Draft
    See: Internet Architecture Board
    See: Internet Assigned Numbers Authority
    See: Internet Control Message Protocol
    Institute of Electrical and Electronics Engineers
 IEEE 802
    See: 802.x
    See: Internet Experiment Note
    See: Internet Engineering Planning Group
    See: Internet Engineering Steering Group
    See: Internet Engineering Task Force
    See: Interagency Interim National Research and Education Network
    See: Interior Gateway Protocol
    In My Humble Opinion
    See: Internet Monthly Report

Malkin Informational [Page 26] RFC 1983 Glossary August 1996

 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.
 Intermediate System (IS)
    An OSI system which performs network layer forwarding.  It is
    analogous to an IP router.  See also: Open Systems
    Interconnection, router.
 Intermediate System-Intermediate System (IS-IS)
    The OSI IGP.  See also: Open Systems Interconnection, Interior
    Gateway Protocol.
 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.

Malkin Informational [Page 27] RFC 1983 Glossary August 1996

 International Telecommunications Union -
         Telecommunications Standards Sector (ITU-TSS)
    The new name for CCITT since the ITU reorganization. The function
    is the same; only the name has been changed
    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.
    (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.
 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.
 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
 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 "".  See also:
    assigned numbers, STD.

Malkin Informational [Page 28] RFC 1983 Glossary August 1996

 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.
    [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.
 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.
 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.
 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.
 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

Malkin Informational [Page 29] RFC 1983 Glossary August 1996

 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
 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 through 1886.  The name IPng (IP next
    generation) is a nod to STNG (Star Trek Next Generation).
 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.
 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.

Malkin Informational [Page 30] RFC 1983 Glossary August 1996

 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.
    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
    The ability of software and hardware on multiple machines from
    multiple vendors to communicate meaningfully.
 IP (IPv4)
    See: Internet Protocol
 IPng (IPv6)
    See: Internet Protocol Version 6
 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.

Malkin Informational [Page 31] RFC 1983 Glossary August 1996

 IP datagram
    See: datagram
    See: Internetwork Packet eXchange
    See: Internet Registry
    See: Internet Relay Chat
    See: Internet Research Steering Group
    See: Internet Research Task Force
    See: Intermediate System
    See: Intermediate System-Intermediate System
    See: Integrated Services Digital Network
    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.
    See: Internet Society
    See: ISO Development Environment
    See: International Telecommunications Union -
         Telecommunications Standards Sector
    See: International Telecommunications Union

Malkin Informational [Page 32] RFC 1983 Glossary August 1996

    Joyce K. Reynolds
    A popular implementation of TCP/IP and associated protocols for
    amateur packet radio systems.  See also: TCP/IP Protocol Suite.
    [Source: RFC1208]
    Kerberos is the security system of MIT's Project Athena.  It is
    based on symmetric key cryptography.  See also: encryption.
    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]
    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.
 Knowbot Information Services
    An experimental directory service.  See also: white pages, whois,
    See: Local Area Network
    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,

Malkin Informational [Page 33] RFC 1983 Glossary August 1996

    TCP/IP Protocol Suite.
    See: Lightweight Directory Access Protocol
 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.
    A pointer which may be used to retreive the file or data to which
    the pointer points.
 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.
    A format for storage or transmission of binary data in which the
    least significant byte (bit) comes first.  See also: big-endian.
    [Source: RFC1208]
    See: Logical Link Control
 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, Fiber Distributed Data Interface, token ring,
    Metropolitan Area Network, Wide 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.
    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

Malkin Informational [Page 34] RFC 1983 Glossary August 1996

    also: Electronic Mail, mailing list, Usenet.
    [Source: LAQUEY]
    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]
    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
    [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
    [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]

Malkin Informational [Page 35] RFC 1983 Glossary August 1996

 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
 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,
    [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. for the IETF mailing list) or
    majordomo server.  See also: Electronic Mail, mail exploder, email
    address, moderator, 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.
    See: Metropolitan Area Network

Malkin Informational [Page 36] RFC 1983 Glossary August 1996

 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.
    [Source: BIG-LAN]
    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]
 Maximum Transmission Unit (MTU)
    The largest frame length which may be sent on a physical medium.
    See also: frame, fragment, fragmentation.
    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.
 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.
 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.
 message switching
    See: packet switching

Malkin Informational [Page 37] RFC 1983 Glossary August 1996

 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 fiber 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]
    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.
 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.
    See: Multipurpose Internet Mail Extensions
    See: Microcom Networking Protocol
    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.
    Multicast Open Shortest-Path First. See: Open Shortest-Path First.
    See: Maximum Transmission Unit
    See: Multi-User Dungeon
    A packet with a special destination address which multiple nodes
    on the network may be willing to receive.  See also: broadcast,

Malkin Informational [Page 38] RFC 1983 Glossary August 1996

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

Malkin Informational [Page 39] RFC 1983 Glossary August 1996

 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 was a highspeed,
    hierarchical "network of networks."  At the highest level, it had
    a backbone network of nodes, interconnected with T3 (45Mbps)
    facilities which spaned 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.
 Negative Acknowledgment (NAK)
    Response to the receipt of either a corrupted or unnexpected
    packet of information.  See also: Acknowledgement.
    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]
    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.
    See: Usenet
    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.
 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

Malkin Informational [Page 40] RFC 1983 Glossary August 1996

    globally unique.  See also: Internet, IP address, subnet address,
    host address, Internet Registry.
 Network File System (NFS)
    A protocol developed by Sun Microsystems, and defined in RFC 1094
    (RFC 1813 defines Version 3), 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.
 Network Information Services (NIS)
    A set of services, generally provided by a NIC, to assist users in
    using the network.  See also: Network Information Center.
 Network News Transfer Protocol (NNTP)
    A protocol, defined in RFC 977, for the distribution, inquiry,
    retrieval, and posting of news articles.  See also: Usenet.
 network mask
    See: address mask
 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.  See also: Internet.
    [Source: NNSC]
    See: Network File System
    See: Network Information Center

Malkin Informational [Page 41] RFC 1983 Glossary August 1996

    This is the domain name of the DDN NIC.  See also: Defense Data
    Network, Domain Name System, Network Information Center.
    See: Network Information Services
    See: National Institute of Standards and Technology
    See: Network News Transfer Protocol
    See: Network Operations Center
 Nodal Switching System (NSS)
    Main routing nodes in the NSFnet backbone.  See also: backbone,
    National Science Foundation.
    [Source: MALAMUD]
    An addressable device attached to a computer network.  See also:
    host, router.
    See: National Research and Education Network
    See: National Science Foundation
    See: Nodal Switching System
    See: Network Time Protocol
    See: Online Computer Library Catalog
    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.
 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

Malkin Informational [Page 42] RFC 1983 Glossary August 1996

    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 RFCs 1583 and 1793.  The
    multicast version, MOSPF, is defined in RFC 1584.  See also:
    Interior Gateway Protocol, Routing Information Protocol.
 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.
    See: Open Systems Interconnection
 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
    [Source: NNSC]
    See: Open Shortest-Path First
    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.
 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]

Malkin Informational [Page 43] RFC 1983 Glossary August 1996

 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,
    [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.
    Public Domain
    See: Protocol Data Unit
    See: Privacy Enhanced Mail
    See: Pretty Good Privacy
    See: Packet INternet Groper
 Point Of Presence (POP)
    A site where there exists a collection of telecommunications
    equipment, usually digital leased lines and multi-protocol
 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]
    See: Post Office Protocol and Point Of Presence
    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.

Malkin Informational [Page 44] RFC 1983 Glossary August 1996

 Post Office Protocol (POP)
    A protocol designed to allow single user hosts to read electronic
    mail from a server.  Version 3, the most recent and most widely
    used, is defined in RFC 1725.  See also: Electronic Mail.
 Postal Telegraph and Telephone (PTT)
    Outside the USA, PTT refers to a telephone service provider, which
    is usually a monopoly, in a particular country.
    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]
    See: Point-to-Point Protocol
 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.
 Privacy Enhanced Mail (PEM)
    Internet email which provides confidentiality, authentication and
    message integrity using various encryption methods.  See also:
    Electronic Mail, encryption.
    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.
    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]

Malkin Informational [Page 45] RFC 1983 Glossary August 1996

 protocol converter
    A device/program which translates between different protocols
    which serve similar functions (e.g. TCP and TP4).
 Protocol Data Unit (PDU)
    "PDU" is internationalstandardscomitteespeak for packet.  See
    also: packet.
 protocol stack
    A layered set of protocols which work together to provide a set of
    network functions.  See also: layer, protocol.
 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]
    See: Packet Switch Node.
    See: Postal, Telegraph and Telephone
    A backup of packets awaiting processing.
    Reseaux Associes pour la Recherche Europeenne.  See: Trans-
    European Research and Education Networking Association.
    See: Reverse Address Resolution Protocol
    Regional Bell Operating Company
 Read The F*cking Manual (RTFM)
    This acronym is often used when someone asks a simple or common
 Read The Source Code (RTSC)
    This acronym is often used when a software developer asks a
    question about undocumented code.

Malkin Informational [Page 46] RFC 1983 Glossary August 1996

    The IP process in which a previously fragmented packet is
    reassembled before being passed to the transport layer.  See also:
    See: recursive
    See: mid-level network
 remote login
    Operating on a remote computer, using a protocol over a computer
    network, as though locally attached.  See also: Telnet.
 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]
    A device which propagates electrical signals from one cable to
    another.  See also: bridge, gateway, router.
 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,
    FYI, STD.
 Reseaux IP Europeens (RIPE)
    A collaboration between European networks which use the TCP/IP
    protocol suite.
 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:

Malkin Informational [Page 47] RFC 1983 Glossary August 1996

    Address Resolution Protocol, BOOTP, internet address, MAC address.
    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.  822 format was
    previously known as 733 format.  See also: Electronic Mail.
    [Source: COMER]
    See: Routing Information Protocol
    See: Reseaux IP Europeenne
 Round-Trip Time (RTT)
    A measure of the current delay on a network.
    [Source: MALAMUD]
    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.
    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,
    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.
    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.
 routing domain
    A set of routers exchanging routing information within an
    administrative domain.  See also: Administrative Domain, router.

Malkin Informational [Page 48] RFC 1983 Glossary August 1996

 Routing Information Protocol (RIP)
    A distance vector, as opposed to link state, routing protocol.  It
    is an Internet standard IGP defined in RFC 1058.  See also:
    Interior Gateway Protocol, Open Shortest-Path First.
    See: Remote Procedure Call
    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.
    See: Read The F*cking Manual
    See: Read The Source Code
    See: Round-Trip Time
    See: Synchronous Digital Hierarchy
 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, but is not an Internet Standard.  It is being
    replaced by PPP.  See also: Point-to-Point Protocol.
    A provider of resources (e.g. file servers and name servers).  See
    also: client, Domain Name System, Network File System.
    See: Standardized Generalized Markup Language
    Special Interest Group
    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.

Malkin Informational [Page 49] RFC 1983 Glossary August 1996

 Simple Mail Transfer Protocol (SMTP)
    A protocol used to transfer electronic mail between computers.  It
    is specified in RFC 821, 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.
 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.
    See: Serial Line IP
    See: Switched Multimegabit Data Service
    See: Structure of Management Information
    See: Simple Mail Transfer Protocol
    See: Systems Network Architecture
 snail mail
    A pejorative term referring to the U.S. postal service.
    See: Simple Network Management Protocol
    See: Synchronous Optical NETwork
 Standardized Generalized Markup Language (SGML)
    An international standard for the definition of system-
    independent, device-independent methods of representing text in
    electronic form.  See also: Hypertext Markup Language.
    A subseries of RFCs that specify Internet standards.  The official
    list of Internet standards is in STD 1.  See also: Request For

Malkin Informational [Page 50] RFC 1983 Glossary August 1996

    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
    [Source: MALAMUD]
 Structure of Management Information (SMI)
    The rules used to define the objects that can be accessed via a
    network management protocol.  These rules are defined in RFC 1155
    (STD 17).  The acronym is pronounced "Ess Em Eye."  See also:
    Management Information Base.  .br [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.
    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.
 subnet mask
    See: address mask
 subnet number
    See: subnet address
    An aggregation of IP network addresses advertised as a single
    classless network address.  For example, given four Class C IP
    networks:,, and, each
    having the intrinsic network mask of; one can
    advertise the address with a subnet mask of  See also: IP address, network address, network
    mask, Classless Inter-domain Routing.

Malkin Informational [Page 51] RFC 1983 Glossary August 1996

 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]
 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.
 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.
 Systems Network Architecture (SNA)
    A proprietary networking architecture used by IBM and IBM-
    compatible mainframe computers.
    [Source: NNSC]
    A term for a digital carrier facility used to transmit a DS-1
    formatted digital signal at 1.544 megabits per second.
    A term for a digital carrier facility used to transmit a DS-3
    formatted digital signal at 44.746 megabits per second.
    [Source: FYI4]
    See: Terminal Access Controller (TAC)
    A protocol which allows two people on remote computers to
    communicate in a real-time fashion.  See also: Internet Relay
    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.

Malkin Informational [Page 52] RFC 1983 Glossary August 1996

    The original name for what is now SprintNet.  It should not be
    confused with the Telnet protocol or application program.
    Telnet is the Internet standard protocol for remote terminal
    connection service.  It is defined in RFC 854 and extended with
    options by many other RFCs.
    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.
 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.
 Three Letter Acronym (TLA)
    A tribute to the use of acronyms in the computer field.  See also:
    Extended Four Letter Acronym.
 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]
    See: Three Letter Acronym
    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
    [Source: BIG-LAN]

Malkin Informational [Page 53] RFC 1983 Glossary August 1996

 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.
    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]
    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.
 Trans-European Research and Education Networking Association (TERENA)
    TERENA was formed in October 1994 by the merger of RARE and EARN
    to promote and participate in the development of a high quality
    international information and telecommunications infrastructure
    for the benefit of research and education.  See also: Reseaux
    Associes pour la Recherche Europeenne, European Academic and
    Research Network.
    [Source: TERENA Statutes]
    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.
 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

Malkin Informational [Page 54] RFC 1983 Glossary August 1996

 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.
    Ta-Ta For Now
    See: Time to Live
    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.
 twisted pair
    A type of cable in which pairs of conductors are twisted together
    to produce certain electrical properties.
    See: User Datagram Protocol
    An address which only one host will recognize.  See also:
    broadcast, multicast.
 Uniform Resource Locators (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.
 Universal Time Coordinated (UTC)
    This is Greenwich Mean Time.
    [Source: MALAMUD]
    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.

Malkin Informational [Page 55] RFC 1983 Glossary August 1996

 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
    [Source: LAQUEY]
    See: Uniform Resource Locators
    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 RFC 768.
    It is a connectionless protocol which adds a level of reliability
    and multiplexing to IP.  See also: connectionless, Transmission
    Control Protocol.
    See: Universal Time Coordinated
    See: UNIX-to-UNIX CoPy
    A program which reverses the effect of uuencode.  See also:
    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.

Malkin Informational [Page 56] RFC 1983 Glossary August 1996

    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.
 virtual circuit
    A network service which provides connection-oriented service
    without necessarily doing circuit-switching.  See also:
    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.
    See: World Wide Web
    See: Wide Area Information Servers
    See: Wide area network
    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 "".
    [Source: WebCrawler's "WebCrawler Facts"]
    See: Working Group
 white pages
    The Internet supports several databases that contain basic
    information about users, such as e-mail 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, InterNIC.
    An Internet program which allows users to query a database of
    people and other Internet entities, such as domains, networks, and
    hosts.  The primary database is kept at the InterNIC.  The

Malkin Informational [Page 57] RFC 1983 Glossary August 1996

    information stored includes a person's company name, address,
    phone number and email address.  The latest version of the
    protocol, WHOIS++, is defined in RFCs 1834 and 1835.  See also:
    InterNIC, white pages, Knowbot, netfind, X.500.
 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,
 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.
 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.
 World Wide Web (WWW, 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
    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.
    With Respect To

Malkin Informational [Page 58] RFC 1983 Glossary August 1996

    See: World Wide Web
    What You See is What You Get
    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.
    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.
    The CCITT and ISO standard for electronic mail.  It is widely used
    in Europe and Canada.
    The CCITT and ISO standard for electronic directory services.  See
    also: white pages, Knowbot, whois.
    See: eXternal Data Representation
 Xerox Network System (XNS)
    A protocol suite developed by Xerox Corporation to run on LAN and
    WAN networks, where the LANs are typically Ethernet.
    Implementations exist for both Xerox's workstations and 4.3BSD,
    and 4.3BSD-derived, systems.  XNS denotes not only the protocol
    stack, but also an architecture of standard programming
    interfaces, conventions, and service functions for authentication,
    directory, filing, email, and remote procedure call.  XNS is also
    the name of Xerox's implementation.  See also: Ethernet, Berkeley
    Software Distribution, Local Area Network, Wide Area Network.
    [Source: Jeff Hodges]
    See: Xerox Network System

Malkin Informational [Page 59] RFC 1983 Glossary August 1996

    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
    [Source: Yahoo's "What is Yahoo?"]
 Yellow Pages (YP)
    A historic (i.e., no longer in use) service used by UNIX
    administrators to manage databases distributed across a network.
    See: Yellow Pages
    A logical group of network devices.

Malkin Informational [Page 60] RFC 1983 Glossary August 1996


 BIG-LAN "BIG-LAN Frequently Asked Questions Memo", BIG-LAN DIGEST
         V4:I8, February 14, 1992.
 COMER   Comer, Douglas, "Internetworking with TCP/IP: Principles,
         Protocols and Architecture", Prentice Hall, Englewood Cliffs,
         NJ, 1991.
 FYI4    Malkin, G., A. Marine, "FYI on Questions and Answers: Answers
         to Commonly asked "New Internet User" Questions", RFC 1325
         (FYI 4), Xylogics, SRI, May 1992.
 HACKER  "THIS IS THE JARGON FILE", Version 2.9.8, January 1992.
 HPCC    "Grand Challenges 1993: High Performance Computing and
         Communications", Committee on Physical, Mathmatical and
         Engineering Sciences of the Federal Coordinating Council for
         Science, Engineering and Technology.
 MALAMUD Malamud, Carl, "Analyzing Sun Networks", Van Nostrand
         Reinhold, New York, NY, 1992.
 NNSC    "NNSC's Hypercard Tour of the Internet".
 LAQUEY  LaQuey, Tracy, with Jeanne C. Ryer, "The Internet Companion:
         A Beginner's Guide to Global Networking", Addison-Wesley,
         Reading, MA, 1992.
 NWNET   Kochmer, Jonathan, and NorthWestNet, "The Internet Passport:
         NorthWestNets Guide to Our World Online", NorthWestNet,
         Bellevue, WA, 1992.
 RFC1208 Jacobsen, O., D. Lynch, "A Glossary of Networking Terms", RFC
         1208, Interop, Inc., March 1991.
         (STD 1), March 1996.
 STD2    Reynolds, J., J. Postel, "ASSIGNED NUMBERS", RFC 1700 (STD
         2), ISI, October 1994.
 TAN     Tanenbaum, Andrew S., "Computer Networks; 2nd ed.", Prentice
         Hall, Englewood Cliffs, NJ, 1989.
 ZEN     Kehoe, Brendan P., "Zen and the Art of the Internet",
         February 1992.

Malkin Informational [Page 61] RFC 1983 Glossary August 1996

Security Considerations

 While security is not explicitly discussed in this document, some of
 the glossary's entries are security related.  See the entries for
 Access Control List (ACL), authentication, Computer Emergency
 Response Team (CERT), cracker, Data Encryption Key (DEK), Data
 Encryption Standard (DES), encryption, Kerberos, Message Digest (MD-
 2, MD-4, MD-5), Pretty Good Privacy (PGP), Privacy Enhanced Mail
 (PEM), RSA, Trojan Horse, virus, and worm.

Editor's Address

 Gary Scott Malkin
 Xylogics/Bay Networks
 53 Third Avenue
 Burlington, MA 01803
 Phone:  (617) 238-6237
 EMail:  gmalkin@Xylogics.COM

Malkin Informational [Page 62]

/data/webs/external/dokuwiki/data/pages/rfc/fyi/fyi18.txt · Last modified: 1996/08/14 15:42 (external edit)