ARMWARE RFC Archive <- FYI Index (1..100)

FYI 18

(also RFC 1983)

Obsoletes RFC 1392

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.

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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.

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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

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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]

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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]

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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]

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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

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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.

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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.

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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]

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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.

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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

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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

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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.

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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]

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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.

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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]

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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

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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

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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,

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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]

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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

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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

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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

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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]

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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.

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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]

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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.

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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:

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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.

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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.

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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

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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.

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   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.

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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]

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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

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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.

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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.

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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

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      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

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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

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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.

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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.

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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

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