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Network Working Group                                  G. Malkin, EditorRequest for Comments: 1983                                      XylogicsFYI: 18                                                      August 1996Obsoletes:1392Category: InformationalInternet Users' GlossaryStatus 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.Abstract   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.Acknowledgements   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 . . . . . . .46A . . . . . . .  2      J . . . . . . . 33      S . . . . . . .49B . . . . . . .  7      K . . . . . . . 33      T . . . . . . .52C . . . . . . . 10      L . . . . . . . 33      U . . . . . . .55D . . . . . . . 14      M . . . . . . . 35      V . . . . . . .57E . . . . . . . 18      N . . . . . . . 39      W . . . . . . .57F . . . . . . . 20      O . . . . . . . 42      X . . . . . . .59G . . . . . . . 22      P . . . . . . . 43      Y . . . . . . .60H . . . . . . . 23      Q . . . . . . . 46      Z . . . . . . .60   References  . . . . . . . . . . . . . . . . . . . . . . . . . .61   Security Considerations . . . . . . . . . . . . . . . . . . . .62   Editor's Address  . . . . . . . . . . . . . . . . . . . . . . .62Malkin                       Informational                      [Page 1]

RFC 1983                        Glossary                     August 1996Glossary   10Base2      A physical layer communications specification for 10Mbps, baseband      data transmission over a coaxial cable (Thinnet) with a maximum      cable segment length of 200 meters.   10Base5      A physical layer communications specification for 10Mbps, baseband      data transmission over a coaxial cable (Thicknet) with a maximum      cable segment length of 500 meters.   10BaseF      A physical layer communications specification for 10Mbps, baseband      data transmission over a fiber-optic cable.   10BaseT      A physical layer communications specification for 10Mbps, baseband      data transmission over a twisted-pair copper wire.   802.x      The set of IEEE standards for the definition of LAN protocols.      See also: IEEE.   822      See:RFC 822   :-)      This odd symbol is one of the ways a person can portray "mood" in      the very flat medium of computers--by using "smiley faces".  This      is "metacommunication", and there are literally hundreds of such      symbols, from the obvious to the obscure.  This particular example      expresses "happiness".  Don't see it?  Tilt your head to the left      90 degrees.  Smiles are also used to denote sarcasm.      [Source: ZEN]   abstract syntax      A description of a data structure that is independent of machine-      oriented structures and encodings.      [Source:RFC1208]   Abstract Syntax Notation One (ASN.1)      The language used by the OSI protocols for describing abstract      syntax.  This language is also used to encode SNMP packets.  ASN.1      is defined in ISO documents 8824.2 and 8825.2.  See also: Basic      Encoding Rules.Malkin                       Informational                      [Page 2]

RFC 1983                        Glossary                     August 1996   Acceptable Use Policy (AUP)      Many transit networks have policies which restrict the use to      which the network may be put.  For example, some networks may only      be used for non-commercial purposes.  Some AUPs limit the type of      material which can be made available to the public (e.g.,      pornographic material).  Enforcement of AUPs varies with the      network.  See also: netiquette.   Access Control List (ACL)      Most network security systems operate by allowing selective use of      services.  An Access Control List is the usual means by which      access to, and denial of, services is controlled.  It is simply a      list of the services available, each with a list of the hosts      permitted to use the service.   ACK      See: Acknowledgment   acknowledgment (ACK)      A type of message sent to indicate that a block of data arrived at      its destination without error.  See also: Negative      Acknowledgement.      [Source: NNSC]   ACL      See: Access Control List   AD      See: Administrative Domain   address      There are four types of addresses in common use within the      Internet.  They are email address; IP, internet or Internet      address; hardware or MAC address; and URL.  See also: email      address, IP address, internet address, MAC address, Uniform      Resource Locator.   address mask      A bit mask used to identify which bits in an IP address correspond      to the network and subnet portions of the address.  This mask is      often referred to as the subnet mask because the network portion      of the address (i.e., the network mask) can be determined by the      encoding inherent in an IP address.  See also: Classless Inter-      domain Routing.Malkin                       Informational                      [Page 3]

RFC 1983                        Glossary                     August 1996   address resolution      Conversion of a network-layer address (e.g. IP address) into the      corresponding physical address (e.g., MAC address).  See also: IP      address, MAC address.   Address Resolution Protocol (ARP)      Used to dynamically discover the low level physical network      hardware address that corresponds to the high level IP address for      a given host.  ARP is limited to physical network systems that      support broadcast packets that can be heard by all hosts on the      network.  See also: proxy ARP, Reverse Address Resolution      Protocol.   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]   agent      In the client-server model, the part of the system that performs      information preparation and exchange on behalf of a client or      server application.      [Source:RFC1208]   alias      A name, usually short and easy to remember, that is translated      into another name, usually long and difficult to remember.   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 standardsMalkin                       Informational                      [Page 4]

RFC 1983                        Glossary                     August 1996      (e.g., ANSI C is the version of the C language approved by ANSI).      ANSI is a member of ISO.  See also: International Organization for      Standardization.      [Source: NNSC]   American Standard Code for Information Interchange (ASCII)      A standard character-to-number encoding widely used in the      computer industry.  See also: EBCDIC.   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.   ANSI      See: American National Standards Institute   API      See: Application Program Interface   Appletalk      A networking protocol developed by Apple Computer for      communication between Apple Computer products and other computers.      This protocol is independent of the network layer on which it is      run.  Current implementations exist for Localtalk, a 235Kb/s local      area network; and Ethertalk, a 10Mb/s local area network.      [Source: NNSC]   application      A program that performs a function directly for a user.  FTP, mail      and Telnet clients are examples of network applications.   application layer      The top layer of the network protocol stack.  The application      layer is concerned with the semantics of work (e.g. formatting      electronic mail messages).  How to represent that data and how to      reach the foreign node are issues for lower layers of the network.      [Source: MALAMUD]   Application Program Interface (API)      A set of calling conventions which define how a service is invoked      through a software package.      [Source:RFC1208]Malkin                       Informational                      [Page 5]

RFC 1983                        Glossary                     August 1996   archie      A system to automatically gather, index and serve information on      the Internet.  The initial implementation of archie provided an      indexed directory of filenames from all anonymous FTP archives on      the Internet.  Later versions provide other collections of      information.  See also: archive site, Gopher, Prospero, Wide Area      Information Servers.   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.   ARP      See: Address Resolution Protocol   ARPA      See: Advanced Research Projects Agency   ARPANET      See: Advanced Research Projects Agency Network   AS      See: Autonomous System   ASCII      See: American Standard Code for Information Interchange   ASN.1      See: Abstract Syntax Notation One   assigned numbers      The RFC [STD2] which documents the currently assigned values from      several series of numbers used in network protocol      implementations.  This RFC is updated periodically and, in any      case, current information can be obtained from the Internet      Assigned Numbers Authority (IANA).  If you are developing a      protocol or application that will require the use of a link,      socket, port, protocol, etc., please contact the IANA to receive a      number assignment.  See also: Internet Assigned Numbers Authority,      STD.      [Source: STD2]Malkin                       Informational                      [Page 6]

RFC 1983                        Glossary                     August 1996   Asynchronous Transfer Mode (ATM)      A standard which defines high-load, high-speed (1.544Mbps through      1.2Gbps), fixed-size packet (cell) switching with dynamic      bandwidth allocation.  ATM is also known as "fast packet."   ATM      See: Asynchronous Transfer Mode   AUP      See: Acceptable Use Policy   authentication      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.   backbone      The top level in a hierarchical network.  Stub and transit      networks which connect to the same backbone are guaranteed to be      interconnected.  See also: stub network, transit network.   bandwidth      Technically, the difference, in Hertz (Hz), between the highest      and lowest frequencies of a transmission channel.  However, as      typically used, the amount of data that can be sent through a      given communications circuit.   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.   baseband      A transmission medium through which digital signals are sent      without complicated frequency shifting.  In general, only one      communication channel is available at any given time.  Ethernet is      an example of a baseband network.  See also: broadband, Ethernet.      [Source: NNSC]Malkin                       Informational                      [Page 7]

RFC 1983                        Glossary                     August 1996   Basic Encoding Rules (BER)      Standard rules for encoding data units described in ASN.1.      Sometimes incorrectly lumped under the term ASN.1, which properly      refers only to the abstract syntax description language, not the      encoding technique.  See also: Abstract Syntax Notation One.      [Source: NNSC]   BBS      See: Bulletin Board System   BCNU      Be Seein' You   BCP      The newest subseries of RFCs which are written to describe Best      Current Practices in the Internet.  Rather than specifying a      protocol, these documents specify the best ways to use the      protocols and the best ways to configure options to ensure      interoperability between various vendors' products.  BCPs carry      the endorsement of the IESG.  See also: Request For Comments,      Internet Engineering Steering Group.   BER      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]   BGP      See: Border Gateway Protocol   big-endian      A format for storage or transmission of binary data in which the      most significant bit (or byte) comes first.  The term comes from      "Gulliver's Travels" by Jonathan Swift.  The Lilliputians, being      very small, had correspondingly small political problems.  TheMalkin                       Informational                      [Page 8]

RFC 1983                        Glossary                     August 1996      Big-Endian and Little-Endian parties debated over whether soft-      boiled eggs should be opened at the big end or the little end.      See also: little-endian.      [Source:RFC1208]   binary      11001001   BIND      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.   Bitnet      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.   BOF      See: Birds Of a Feather   BOOTP      The Bootstrap Protocol, described inRFC 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 inRFC 1771.  It's design is based on experience gained      with EGP, as defined inRFC 904, and EGP usage in the NSFNET      Backbone, as described in RFCs 1092 and 1093.  See also: Exterior      Gateway Protocol.   bounce      The return of a piece of mail because of an error in its delivery.      [Source: ZEN]   bridge      A device which forwards traffic between network segments based on      datalink layer information.  These segments would have a common      network layer address.  See also: gateway, router.Malkin                       Informational                      [Page 9]

RFC 1983                        Glossary                     August 1996   broadband      A transmission medium capable of supporting a wide range of      frequencies.  It can carry multiple signals by dividing the total      capacity of the medium into multiple, independent bandwidth      channels, where each channel operates only on a specific range of      frequencies.  See also: baseband.   broadcast      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.   brouter      A device which bridges some packets (i.e. forwards based on      datalink layer information) and routes other packets (i.e.      forwards based on network layer information).  The bridge/route      decision is based on configuration information.  See also: bridge,      router.   BSD      See: Berkeley Software Distribution   BTW      By The Way   Bulletin Board System (BBS)      A computer, and associated software, which typically provides      electronic messaging services, archives of files, and any other      services or activities of interest to the bulletin board system's      operator.  Although BBS's have traditionally been the domain of      hobbyists, an increasing number of BBS's are connected directly to      the Internet, and many BBS's are currently operated by government,      educational, and research institutions.  See also: Electronic      Mail, Internet, Usenet.      [Source: NWNET]   Campus Wide Information System (CWIS)      A CWIS makes information and services publicly available on campus      via kiosks, and makes interactive computing available via kiosks,      interactive computing systems and campus networks. Services      routinely include directory information, calendars, bulletin      boards, databases.Malkin                       Informational                     [Page 10]

RFC 1983                        Glossary                     August 1996   CCIRN      See: Coordinating Committee for Intercontinental Research Networks   CCITT      See: Comite Consultatif International de Telegraphique et      Telephonique   CERT      See: Computer Emergency Response Team   checksum      A computed value which is dependent upon the contents of a packet.      This value is sent along with the packet when it is transmitted.      The receiving system computes a new checksum based upon the      received data and compares this value with the one sent with the      packet.  If the two values are the same, the receiver has a high      degree of confidence that the data was received correctly.  See      also: Cyclic Redundancy Check.      [Source: NNSC]   CIDR      See: Classless Inter-domain Routing   circuit switching      A communications paradigm in which a dedicated communication path      is established between two hosts, and on which all packets travel.      The telephone system is an example of a circuit switched network.      See also: connection-oriented, connectionless, packet switching.   Classless Inter-domain Routing (CIDR)      A proposal, set forth inRFC 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.   client      A computer system or process that requests a service of another      computer system or process.  A workstation requesting the contents      of a file from a file server is a client of the file server.  See      also: client-server model, server.      [Source: NNSC]Malkin                       Informational                     [Page 11]

RFC 1983                        Glossary                     August 1996   client-server model      A common way to describe the paradigm of many network protocols.      Examples include the name-server/name-resolver relationship in DNS      and the file-server/file-client relationship in NFS.  See also:      client, server, Domain Name System, Network File System.   CNI      See: Coalition for Networked Information   Coalition for Networked Information (CNI)      A consortium formed by American Research Libraries, CAUSE, and      EDUCOM (no, they are not acronyms) to promote the creation of, and      access to, information resources in networked environments in      order to enrich scholarship and enhance intellectual productivity.   Comite Consultatif International de Telegraphique et Telephonique (      CCITT)      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 "cert.org",      where security-related documents and tools are archived.  The CERT      may be reached by email at "cert@cert.org" and by telephone at      +1-412-268-7090 (24-hour hotline).  See also: Advanced Research      Projects Agency, worm.   congestion      Congestion occurs when the offered load exceeds the capacity of a      data communication path.Malkin                       Informational                     [Page 12]

RFC 1983                        Glossary                     August 1996   connection-oriented      The data communication method in which communication proceeds      through three well-defined phases: connection establishment, data      transfer, connection release.  TCP is a connection-oriented      protocol.  See also: circuit switching, connectionless, packet      switching, Transmission Control Protocol.   connectionless      The data communication method in which communication occurs      between hosts with no previous setup.  Packets between two hosts      may take different routes, as each is independent of the other.      UDP is a connectionless protocol.  See also: circuit switching,      connection-oriented, packet switching, User Datagram Protocol.   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]   cracker      A cracker is an individual who attempts to access computer systems      without authorization.  These individuals are often malicious, as      opposed to hackers, and have many means at their disposal for      breaking into a system.  See also: hacker, Computer Emergency      Response Team, Trojan Horse, virus, worm.   CRC      See: cyclic redundancy checkMalkin                       Informational                     [Page 13]

RFC 1983                        Glossary                     August 1996   CREN      See: Corporation for Research and Educational Networking   CU-SeeMe      Pronnounced "See you, See me," CU-SeeMe is a publicly available      videoconferencing program developed at Cornell University.  It      allows anyone with audio/video capabilites and an Internet      connection to videoconference with anyone else with the same      capabilities.  It also allows multiple people to tie into the same      videoconference.   CWIS      See: Campus Wide Information system   Cyberspace      A term coined by William Gibson in his fantasy novel Neuromancer      to describe the "world" of computers, and the society that gathers      around them.      [Source: ZEN]   Cyclic Redundancy Check (CRC)      A number derived from a set of data that will be transmitted.  By      recalculating the CRC at the remote end and comparing it to the      value originally transmitted, the receiving node can detect some      types of transmission errors.  See also: checksum.      [Source: MALAMUD]   DANTE      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      infrastructure.   DARPA      Defense Advanced Research Projects Agency      See: Advanced Research Projects Agency   Data Encryption Key (DEK)      Used for the encryption of message text and for the computation of      message integrity checks (signatures).  See also: encryption.   Data Encryption Standard (DES)      A popular, standard encryption scheme.  See also: encryption,      Pretty Good Privacy, RSA.   datagram      A self-contained, independent entity of data carrying sufficient      information to be routed from the source to the destinationMalkin                       Informational                     [Page 14]

RFC 1983                        Glossary                     August 1996      computer without reliance on earlier exchanges between this source      and destination computer and the transporting network.  See also:      frame, packet.      [Source: J. Postel]   DCA      See: Defense Information Systems Agency   DCE      Data Circuit-terminating Equipment   DCE      See: Distributed Computing Environment   DDN      See: Defense Data Network   DDN NIC      See: Defense Data Network Network Information Center   DECnet      A proprietary network protocol designed by Digital Equipment      Corporation.  The functionality of each Phase of the      implementation, such as Phase IV and Phase V, is different.   default route      A routing table entry which is used to direct packets addressed to      networks not explicitly listed in the routing table.      [Source: MALAMUD]   Defense Data Network (DDN)      A global communications network serving the US Department of      Defense composed of MILNET, other portions of the Internet, and      classified networks which are not part of the Internet.  The DDN      is used to connect military installations and is managed by the      Defense Information Systems Agency.  See also: Defense Information      Systems Agency.   Defense Data Network Network Information Center (DDN NIC)      Previously called "The NIC", the DDN NIC's primary responsibility      was the assignment of Internet network addresses and Autonomous      System numbers, the administration of the root domain, and      providing information and support services to the Internet for the      DDN.  Since the creation of the InterNIC, the DDN NIC performs      these functions only for the DDN.  See also: Autonomous System,      network address, Internet Registry, InterNIC, Network Information      Center, Request For Comments.Malkin                       Informational                     [Page 15]

RFC 1983                        Glossary                     August 1996   Defense Information Systems Agency (DISA)      Formerly called the Defense Communications Agency (DCA), this is      the government agency responsible for managing the DDN portion of      the Internet, including the MILNET.  Currently, DISA administers      the DDN, and supports the user assistance services of the DDN NIC.      See also: Defense Data Network.   DEK      See: Data Encryption Key   DES      See: Data Encryption Standard   dialup      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]   DISA      See: Defense Information Systems Agency   Distributed Computing Environment (DCE)      An architecture of standard programming interfaces, conventions,      and server functionalities (e.g., naming, distributed file system,      remote procedure call) for distributing applications transparently      across networks of heterogeneous computers.  Promoted and      controlled by the Open Software Foundation (OSF), a consortium led      by Digital, IBM and Hewlett Packard.      [Source:RFC1208]Malkin                       Informational                     [Page 16]

RFC 1983                        Glossary                     August 1996   distributed database      A collection of several different data repositories that looks      like a single database to the user.  A prime example in the      Internet is the Domain Name System.   DIX Ethernet      See: Ethernet   DNS      See: Domain Name System   domain      "Domain" is a heavily overused term in the Internet.  It can be      used in the Administrative Domain context, or the Domain Name      context.  See also: Administrative Domain, Domain Name System.   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]   DSA      See: Directory System Agent   DTE      Data Terminal Equipment   DUA      See: Directory User AgentMalkin                       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]   E1      The basic building block for European multi-megabit data rates,      with a bandwidth of 2.048Mbps.  See also: T1.   E3      A European standard for transmitting data at 57.344Mbps.  See      also: T3.   EARN      European Academic and Research Network.  See: Trans-European      Research and Education Networking Association.   EBCDIC      See: Extended Binary Coded Decimal Interchange Code   Ebone      A pan-European backbone service.   EFF      See: Electronic Frontier Foundation   EGP      See: Exterior Gateway Protocol   Electronic Frontier Foundation (EFF)      A foundation established to address social and legal issues      arising from the impact on society of the increasingly pervasive      use of computers as a means of communication and information      distribution.   Electronic Mail (email)      A system whereby a computer user can exchange messages with other      computer users (or groups of users) via a communications network.      Electronic mail is one of the most popular uses of the Internet.      [Source: NNSC]   email      See: Electronic mail   email address      The domain-based or UUCP address that is used to send electronic      mail to a specified destination.  For example an editor's addressMalkin                       Informational                     [Page 18]

RFC 1983                        Glossary                     August 1996      is "gmalkin@xylogics.com".  See also: bang path, mail path, UNIX-      to-UNIX CoPy.      [Source: ZEN]   encapsulation      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      data.      [Source:RFC1208]   encryption      Encryption is the manipulation of a packet's data in order to      prevent any but the intended recipient from reading that data.      There are many types of data encryption, and they are the basis of      network security.  See also: Data Encryption Standard.   error checking      The examination of received data for transmission errors.  See      also: checksum, Cyclic Redundancy Check.   Ethernet      A 10-Mb/s standard for LANs, initially developed by Xerox, and      later refined by Digital, Intel and Xerox (DIX).  All hosts are      connected to a coaxial cable where they contend for network access      using a Carrier Sense Multiple Access with Collision Detection      (CSMA/CD) paradigm.  See also: 802.x, Local Area Network, token      ring.   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 inRFC 904.  See also:Malkin                       Informational                     [Page 19]

RFC 1983                        Glossary                     August 1996      Autonomous System, Border Gateway Protocol, Interior Gateway      Protocol.   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]   FARNET      A non-profit corporation, established in 1987, whose mission is to      advance the use of computer networks to improve research and      education.   FAQ      Frequently Asked Question   FDDI      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.   finger      A protocol, defined inRFC 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.   FIX      See: Federal Information Exchange   flame      A strong opinion and/or criticism of something, usually as a frank      inflammatory statement, in an electronic mail message.  It is      common to precede a flame with an indication of pending fire (i.e.      FLAME ON!).  Flame Wars occur when people start flaming other      people for flaming when they shouldn't have.  See also: Electronic      Mail, Usenet.   FLEA      See: Four Letter Extended Acronym   FNC      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.   FQDN      See: Fully Qualified Domain Name   fragment      A piece of a packet.  When a router is forwarding an IP packet to      a network that has a maximum 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   fragmentation      The IP process in which a packet is broken into smaller pieces to      fit the requirements of a physical network over which the packet      must pass.  See also: reassembly.   frame      A frame is a datalink layer "packet" which contains the header and      trailer information required by the physical medium.  That is,      network layer packets are encapsulated to become frames.  See      also: datagram, encapsulation, packet.   freenet      Community-based bulletin board system with email, information      services, interactive communications, and conferencing.  Freenets      are funded and operated by individuals and volunteers -- in one      sense, like public television.  They are part of the National      Public Telecomputing Network (NPTN), an organization based in      Cleveland, Ohio, devoted to making computer telecommunication and      networking services as freely available as public libraries.      [Source: LAQUEY]   FTP      See: File Transfer Protocol   Fully Qualified Domain Name (FQDN)      The FQDN is the full name of a system, rather than just its      hostname.  For example, "venera" is a hostname and      "venera.isi.edu" is an FQDN.  See also: hostname, Domain Name      System.   FYI      For Your Information   FYI      A subseries of RFCs that are not technical standards or      descriptions of protocols.  FYIs convey general information about      topics related to TCP/IP or the Internet.  See also: Request For      Comments.   gated      Gatedaemon.  A program which supports multiple routing protocols      and protocol families.  It may be used for routing, and makes an      effective platform for routing protocol research.  The software is      freely available by anonymous FTP from "gated.cornell.edu".      Pronounced "gate-dee".  See also: Exterior Gateway Protocol, Open      Shortest-Path First, Routing Information Protocol, routed.Malkin                       Informational                     [Page 22]

RFC 1983                        Glossary                     August 1996   gateway      The term "router" is now used in place of the original definition      of "gateway".  Currently, a gateway is a communications      device/program which passes data between networks having similar      functions but dissimilar implementations.  This should not be      confused with a protocol converter.  By this definition, a router      is a layer 3 (network layer) gateway, and a mail gateway is a      layer 7 (application layer) gateway.  See also: mail gateway,      router, protocol converter.   Gopher      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 inRFC 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.   GOSIP      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.   hacker      A person who delights in having an intimate understanding of the      internal workings of a system, computers and computer networks in      particular.  The term is often misused in a pejorative context,      where "cracker" would be the correct term.  See also: cracker.   header      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      network.      [Source: HPCC]   High Performance Parallel Interface (HIPPI)      An emerging ANSI standard which extends the computer bus over      fairly short distances at speeds of 800 and 1600 Mb/s.  HIPPI is      often used in a computer room to connect a supercomputer to      routers, frame buffers, mass-storage peripherals, and other      computers.  See also: American National Standards Institute      [Source: MALAMUD]   HIPPI      See: High Performance Parallel Interface   HTML      See: Hypertext Markup Language   homogeneous network      A network running a single network layer protocol.  See also:      DECnet, IP, IPX, XNS, heterogeneous network.   hop      A term used in routing.  A path to a destination on a network is a      series of hops, through routers, away from the origin.Malkin                       Informational                     [Page 24]

RFC 1983                        Glossary                     August 1996   host      A computer that allows users to communicate with other host      computers on a network.  Individual users communicate by using      application programs, such as electronic mail, Telnet and FTP.      [Source: NNSC]   host address      See: internet address   hostname      The name given to a machine.  See also: Fully Qualified Domain      Name.      [Source: ZEN]   host number      See: host address   HPCC      See: High Performance Computing and Communications   HTTP      See: Hypertext Transfer Protocol   hub      A device connected to several other devices.  In ARCnet, a hub is      used to connect several computers together.  In a message handling      service, a hub is used for the transfer of messages across the      network.      [Source: MALAMUD]   hyperlink      A pointer within a hypertext document which points (links) to      another document, which may or may not also be a hypertext      document.  See also: hypertext.   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.   I-D      See: Internet-Draft   IAB      See: Internet Architecture Board   IANA      See: Internet Assigned Numbers Authority   ICMP      See: Internet Control Message Protocol   IEEE      Institute of Electrical and Electronics Engineers   IEEE 802      See: 802.x   IEN      See: Internet Experiment Note   IEPG      See: Internet Engineering Planning Group   IESG      See: Internet Engineering Steering Group   IETF      See: Internet Engineering Task Force   IINREN      See: Interagency Interim National Research and Education Network   IGP      See: Interior Gateway Protocol   IMHO      In My Humble Opinion   IMR      See: Internet Monthly ReportMalkin                       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   internet      While an internet is a network, the term "internet" is usually      used to refer to a collection of networks interconnected with      routers.  See also: network.   Internet      (note the capital "I") The Internet is the largest internet in the      world.  Is a three level hierarchy composed of backbone networks      (e.g. Ultranet), mid-level networks (e.g., NEARnet) and stub      networks.  The Internet is a multiprotocol internet.  See also:      backbone, mid-level network, stub network, transit network,      Internet Protocol.   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      Comments.   Internet Assigned Numbers Authority (IANA)      The central registry for various Internet protocol parameters,      such as port, protocol and enterprise numbers, and options, codes      and types.  The currently assigned values are listed in the      "Assigned Numbers" document [STD2].  To request a number      assignment, contact the IANA at "iana@isi.edu".  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      organizations.Malkin                       Informational                     [Page 29]

RFC 1983                        Glossary                     August 1996   internet number      See: internet address   Internet Protocol (IP, IPv4)      The Internet Protocol (version 4), defined inRFC 791, is the      network layer for the TCP/IP Protocol Suite.  It is a      connectionless, best-effort packet switching protocol.  See also:      packet switching, TCP/IP Protocol Suite, Internet Protocol Version      6.   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.   InterNIC      A five year project, partially supported by the National Science      Foundation, to provide network information services to the      networking community.  The InterNIC began operations in April of      1993 and is now a collaborative project of two organizations:      AT&T, which provides Directory and Database Services from South      Plainsfield, NJ; and Network Solutions, Inc., which provides      Registration Services from their headquarters in Herndon, VA.      Services are provided via the Internet, and by telephone, FAX, and      hardcopy.   interoperability      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 inRFC 791.      It is usually represented in dotted decimal notation.  See also:      dot address, internet address, Internet Protocol, network address,      subnet address, host address.Malkin                       Informational                     [Page 31]

RFC 1983                        Glossary                     August 1996   IP datagram      See: datagram   IPX      See: Internetwork Packet eXchange   IR      See: Internet Registry   IRC      See: Internet Relay Chat   IRSG      See: Internet Research Steering Group   IRTF      See: Internet Research Task Force   IS      See: Intermediate System   IS-IS      See: Intermediate System-Intermediate System   ISDN      See: Integrated Services Digital Network   ISO      See: International Organization for Standardization   ISO Development Environment (ISODE)      Software that allows OSI services to use a TCP/IP network.      Pronounced eye-so-dee-eee.  See also: Open Systems      Interconnection, TCP/IP Protocol Suite.   ISOC      See: Internet Society   ISODE      See: ISO Development Environment   ITU      See: International Telecommunications Union -           Telecommunications Standards Sector   ITU-TSS      See: International Telecommunications UnionMalkin                       Informational                     [Page 32]

RFC 1983                        Glossary                     August 1996   JKREY      Joyce K. Reynolds   KA9Q      A popular implementation of TCP/IP and associated protocols for      amateur packet radio systems.  See also: TCP/IP Protocol Suite.      [Source:RFC1208]   Kerberos      Kerberos is the security system of MIT's Project Athena.  It is      based on symmetric key cryptography.  See also: encryption.   Kermit      A popular file transfer protocol developed by Columbia University.      Because Kermit runs in most operating environments, it provides an      easy method of file transfer.  Kermit is NOT the same as FTP.  See      also: File Transfer Protocol      [Source: MALAMUD]   Knowbot      A "Knowledge Robot" is a program which seeks out information based      on specified criteria.  "Knowbot," as trademarked by CNRI, refers      specifically to the search engine for Knowbot Information      Services.  See also: Corporation for National Research      Initiatives, X.500, white pages, whois, netfind.   Knowbot Information Services      An experimental directory service.  See also: white pages, whois,      X.500.   LAN      See: Local Area Network   layer      Communication networks for computers may be organized as a set of      more or less independent protocols, each in a different layer      (also called level).  The lowest layer governs direct host-to-host      communication between the hardware at different hosts; the highest      consists of user applications.  Each layer builds on the layer      beneath it.  For each layer, programs at different hosts use      protocols appropriate to the layer to communicate with each other.      TCP/IP has five layers of protocols; OSI has seven.  The      advantages of different layers of protocols is that the methods of      passing information from one layer to another are specified      clearly as part of the protocol suite, and changes within a      protocol layer are prevented from affecting the other layers.      This greatly simplifies the task of designing and maintaining      communication programs.  See also: Open Systems Interconnection,Malkin                       Informational                     [Page 33]

RFC 1983                        Glossary                     August 1996      TCP/IP Protocol Suite.   LDAP      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.   link      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.   little-endian      A format for storage or transmission of binary data in which the      least significant byte (bit) comes first.  See also: big-endian.      [Source:RFC1208]   LLC      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.   Lurking      No active participation on the part of a subscriber to an mailing      list or USENET newsgroup.  A person who is lurking is just      listening to the discussion.  Lurking is encouraged for beginners      who need to get up to speed on the history of the group.  SeeMalkin                       Informational                     [Page 34]

RFC 1983                        Glossary                     August 1996      also: Electronic Mail, mailing list, Usenet.      [Source: LAQUEY]   Lycos      Lycos, Inc. is a new venture formed in late June 1995, to develop      and market the Lycos technology originally developed under the      direction of Dr. Michael ("Fuzzy") Mauldin at Carnegie Mellon      University.  The part of Lycos you see when you do a search is the      search engine.  "Lycos" comes from Lycosidae, a cosmopolitan      family of relatively large active ground spiders (Wolf Spiders)      that catch their prey by pursuit, rather than in a web.      [Source: Lycos's FAQ]   MAC      See: Media Access Control   MAC address      The hardware address of a device connected to a shared media.  See      also: Media Access Control, Ethernet, token ring.      [Source: MALAMUD]   mail bridge      A mail gateway that forwards electronic mail between two or more      networks while ensuring that the messages it forwards meet certain      administrative criteria.  A mail bridge is simply a specialized      form of mail gateway that enforces an administrative policy with      regard to what mail it forwards.  See also: Electronic Mail, mail      gateway.      [Source: NNSC]   Mail Exchange Record (MX Record)      A DNS resource record type indicating which host can handle mail      for a particular domain.  See also: Domain Name System, Electronic      Mail.      [Source: MALAMUD]   mail exploder      Part of an electronic mail delivery system which allows a message      to be delivered to a list of addresses.  Mail exploders are used      to implement mailing lists.  Users send messages to a single      address and the mail exploder takes care of delivery to the      individual mailboxes in the list.  See also: Electronic Mail,      email address, mailing list.      [Source:RFC1208]Malkin                       Informational                     [Page 35]

RFC 1983                        Glossary                     August 1996   mail gateway      A machine that connects two or more electronic mail systems      (including dissimilar mail systems) and transfers messages between      them.  Sometimes the mapping and translation can be quite complex,      and it generally requires a store-and-forward scheme whereby the      message is received from one system completely before it is      transmitted to the next system, after suitable translations.  See      also: Electronic Mail.      [Source:RFC1208]   mail path      A series of machine names used to direct electronic mail from one      user to another.  This system of email addressing has been used      primarily in UUCP networks which are trying to eliminate its use      altogether.  See also: bang path, email address, UNIX-to-UNIX      CoPy.   mail server      A software program that distributes files or information in      response to requests sent via email.  Internet examples include      Almanac and netlib.  Mail servers have also been used in Bitnet to      provide FTP-like services.  See also: Bitnet, Electronic Mail,      FTP.      [Source: NWNET]   mailing list      A list of email addresses, used by a mail exploder, to forward      messages to groups of people.  Generally, a mailing list is used      to discuss certain set of topics, and different mailing lists      discuss different topics.  A mailing list may be moderated.  This      means that messages sent to the list are actually sent to a      moderator who determines whether or not to send the messages on to      everyone else.  Requests to subscribe to, or leave, a mailing list      should ALWAYS be sent to the list's "-request" address (e.g.      ietf-request@cnri.reston.va.us for the IETF mailing list) or      majordomo server.  See also: Electronic Mail, mail exploder, email      address, moderator, majordomo.   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.   MAN      See: Metropolitan Area NetworkMalkin                       Informational                     [Page 36]

RFC 1983                        Glossary                     August 1996   Management Information Base (MIB)      The set of parameters an SNMP management station can query or set      in the SNMP agent of a network device (e.g. router).  Standard,      minimal MIBs have been defined, and vendors often have Private      enterprise MIBs.  In theory, any SNMP manager can talk to any SNMP      agent with a properly defined MIB.  See also: client-server model,      Simple Network Management Protocol.      [Source: BIG-LAN]   Martian      A humorous term applied to packets that turn up unexpectedly on      the wrong network because of bogus routing entries.  Also used as      a name for a packet which has an altogether bogus (non-registered      or ill-formed) internet address.      [Source:RFC1208]   Maximum Transmission Unit (MTU)      The largest frame length which may be sent on a physical medium.      See also: frame, fragment, fragmentation.   mbone      The Multicast Backbone is based on IP multicasting using class-D      addresses.  The mbone concept was adopted at the March 1992 IETF      in San Diego, during which it was used to audiocast to 40 people      throughout the world.  At the following meeting, in Cambridge, the      name mbone was adopted.  Since then the audiocast has become full      two-way audio/video conferencing using two video channels, four      audio channels, and involving hundreds of remote users.  See also:      multicast, Internet Engineering Task Force.   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 inRFC 1319; MD-4, described inRFC 1320; and MD-5,      described inRFC 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 switchingMalkin                       Informational                     [Page 37]

RFC 1983                        Glossary                     August 1996   Metropolitan Area Network (MAN)      A data network intended to serve an area approximating that of a      large city.  Such networks are being implemented by innovative      techniques, such as running fiber cables through subway tunnels.      A popular example of a MAN is SMDS.  See also: Local Area Network,      Switched Multimegabit Data Service, Wide Area Network.      [Source: NNSC]   MIB      See: Management Information Base   Microcom Networking Protocol (MNP)      A series of protocols built into most modems which error-check or      compress data being transmitted over a phone line.   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.   MIME      See: Multipurpose Internet Mail Extensions   MNP      See: Microcom Networking Protocol   moderator      A person, or small group of people, who manage moderated mailing      lists and newsgroups.  Moderators are responsible for determining      which email submissions are passed on to list.  See also:      Electronic Mail, mailing list, Usenet.   MOSPF      Multicast Open Shortest-Path First. See: Open Shortest-Path First.   MTU      See: Maximum Transmission Unit   MUD      See: Multi-User Dungeon   multicast      A packet with a special destination address which multiple nodes      on the network may be willing to receive.  See also: broadcast,      unicast.Malkin                       Informational                     [Page 38]

RFC 1983                        Glossary                     August 1996   multihomed host      A host which has more than one connection to a network.  The host      may send and receive data over any of the links but will not route      traffic for other nodes.  See also: host, router.      [Source: MALAMUD]   Multipurpose Internet Mail Extensions (MIME)      An extension to Internet email which provides the ability to      transfer non-textual data, such as graphics, audio and fax.  See      also: Electronic Mail   Multi-User Dungeon (MUD)      Adventure, role playing games, or simulations played on the      Internet.  Devotees call them "text-based virtual reality      adventures."  The games can feature fantasy combat, booby traps      and magic.  Players interact in real time and can change the      "world" in the game as they play it.  Most MUDs are based on the      Telnet protocol.  See also: Telnet.      [Source: LAQUEY]   MX Record      See: Mail Exchange Record   NAK      See: Negative Acknowledgment   name resolution      The process of mapping a name into its corresponding address.  See      also: Domain Name System.      [Source:RFC1208]   namespace      A commonly distributed set of names in which all names are unique.      [Source: MALAMUD]   National Institute of Standards and Technology (NIST)      United States governmental body that provides assistance in      developing standards.  Formerly the National Bureau of Standards.      [Source: MALAMUD]   National Research and Education Network (NREN)      The NREN is the realization of an interconnected gigabit computer      network devoted to Hign Performance Computing and Communications.      See also: HPPC, IINREN.      [Source: HPCC]Malkin                       Informational                     [Page 39]

RFC 1983                        Glossary                     August 1996   National Science Foundation (NSF)      A U.S. government agency whose purpose is to promote the      advancement of science.  NSF funds science researchers, scientific      projects, and infrastructure to improve the quality of scientific      research.  The NSFNET, funded by NSF, was once an essential part      of academic and research communications.  It was a highspeed,      hierarchical "network of networks."  At the highest level, it had      a backbone network of nodes, interconnected with T3 (45Mbps)      facilities which spaned the continental United States.  Attached      to that were mid-level networks, and attached to the mid-levels      were campus and local networks.  See also: backbone network, mid-      level network.   Negative Acknowledgment (NAK)      Response to the receipt of either a corrupted or unnexpected      packet of information.  See also: Acknowledgement.   netfind      A research prototype to provide a simple Internet "white pages"      user directory.  Developed at the University of Colorado, Boulder,      it tries to locate telephone and email information given a      person's name and a rough description of where the person works.      See also: Knowbot, whois, white pages, X.500.      [Source: Ryan Moats]   netiquette      A pun on "etiquette" referring to proper behavior on a network.RFC 1855 (FYI 28) contains a netiquette guide produced by the User      Services area of the IETF.  See also: Acceptable Use Policy,      Internet Engineering Task Force.   Netnews      See: Usenet   network      A computer network is a data communications system which      interconnects computer systems at various different sites.  A      network may be composed of any combination of LANs, MANs or WANs.      See also: Local Area Network, Metropolitan Area Network, Wide Area      Network, internet.   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 areMalkin                       Informational                     [Page 40]

RFC 1983                        Glossary                     August 1996      globally unique.  See also: Internet, IP address, subnet address,      host address, Internet Registry.   Network File System (NFS)      A protocol developed by Sun Microsystems, and defined inRFC 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 inRFC 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]   NFS      See: Network File System   NIC      See: Network Information CenterMalkin                       Informational                     [Page 41]

RFC 1983                        Glossary                     August 1996   NIC.DDN.MIL      This is the domain name of the DDN NIC.  See also: Defense Data      Network, Domain Name System, Network Information Center.   NIS      See: Network Information Services   NIST      See: National Institute of Standards and Technology   NNTP      See: Network News Transfer Protocol   NOC      See: Network Operations Center   Nodal Switching System (NSS)      Main routing nodes in the NSFnet backbone.  See also: backbone,      National Science Foundation.      [Source: MALAMUD]   node      An addressable device attached to a computer network.  See also:      host, router.   NREN      See: National Research and Education Network   NSF      See: National Science Foundation   NSS      See: Nodal Switching System   NTP      See: Network Time Protocol   OCLC      See: Online Computer Library Catalog   octet      An octet is 8 bits.  This term is used in networking, rather than      byte, because some systems have bytes that are not 8 bits long.   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 thanMalkin                       Informational                     [Page 42]

RFC 1983                        Glossary                     August 1996      10,000 libraries worldwide.  Libraries use the OCLC System for      cataloging, interlibrary loan, collection development,      bibliographic verification, and reference searching.      [Source: OCLC]   Open Shortest-Path First (OSPF)      A link state, as opposed to distance vector, routing protocol.  It      is an Internet standard IGP defined in RFCs 1583 and 1793.  The      multicast version, MOSPF, is defined inRFC 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.   OSI      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      Standardization.      [Source: NNSC]   OSPF      See: Open Shortest-Path First   packet      The unit of data sent across a network.  "Packet" a generic term      used to describe unit of data at all levels of the protocol stack,      but it is most correctly used to describe application data units.      See also: datagram, frame.   Packet InterNet Groper (PING)      A program used to test reachability of destinations by sending      them an ICMP echo request and waiting for a reply.  The term is      used as a verb: "Ping host X to see if it is up!"  See also:      Internet Control Message Protocol.      [Source:RFC1208]Malkin                       Informational                     [Page 43]

RFC 1983                        Glossary                     August 1996   Packet Switch Node (PSN)      A dedicated computer whose purpose is to accept, route and forward      packets in a packet switched network.  See also: packet switching,      router.      [Source: NNSC]   packet switching      A communications paradigm in which packets (messages) are      individually routed between hosts, with no previously established      communication path.  See also: circuit switching, connection-      oriented, connectionless.   PD      Public Domain   PDU      See: Protocol Data Unit   PEM      See: Privacy Enhanced Mail   PGP      See: Pretty Good Privacy   PING      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      routers.   Point-to-Point Protocol (PPP)      The Point-to-Point Protocol, defined inRFC 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]   POP      See: Post Office Protocol and Point Of Presence   port      A port is a transport layer demultiplexing value.  Each      application has a unique port number associated with it.  See      also: Transmission Control Protocol, User Datagram Protocol.Malkin                       Informational                     [Page 44]

RFC 1983                        Glossary                     August 1996   Post Office Protocol (POP)      A protocol designed to allow single user hosts to read electronic      mail from a server.  Version 3, the most recent and most widely      used, is defined inRFC 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.   postmaster      The person responsible for taking care of electronic mail      problems, answering queries about users, and other related work at      a site.  See also: Electronic Mail.      [Source: ZEN]   PPP      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.   Prospero      A distributed filesystem which provides the user with the ability      to create multiple views of a single collection of files      distributed across the Internet.  Prospero provides a file naming      system, and file access is provided by existing access methods      (e.g. anonymous FTP and NFS).  The Prospero protocol is also used      for communication between clients and servers in the archie      system.  See also: anonymous FTP, archie, archive site, Gopher,      Network File System, Wide Area Information Servers.   protocol      A formal description of message formats and the rules two      computers must follow to exchange those messages.  Protocols can      describe low-level details of machine-to-machine interfaces (e.g.,      the order in which bits and bytes are sent across a wire) or      high-level exchanges between allocation programs (e.g., the way in      which two programs transfer a file across the Internet).      [Source: MALAMUD]Malkin                       Informational                     [Page 45]

RFC 1983                        Glossary                     August 1996   protocol converter      A device/program which translates between different protocols      which serve similar functions (e.g. TCP and TP4).   Protocol Data Unit (PDU)      "PDU" is internationalstandardscomitteespeak for packet.  See      also: packet.   protocol stack      A layered set of protocols which work together to provide a set of      network functions.  See also: layer, protocol.   proxy ARP      The technique in which one machine, usually a router, answers ARP      requests intended for another machine.  By "faking" its identity,      the router accepts responsibility for routing packets to the      "real" destination.  Proxy ARP allows a site to use a single IP      address with two physical networks.  Subnetting would normally be      a better solution.  See also: Address Resolution Protocol      [Source:RFC1208]   PSN      See: Packet Switch Node.   PTT      See: Postal, Telegraph and Telephone   queue      A backup of packets awaiting processing.   RARE      Reseaux Associes pour la Recherche Europeenne.  See: Trans-      European Research and Education Networking Association.   RARP      See: Reverse Address Resolution Protocol   RBOC      Regional Bell Operating Company   Read The F*cking Manual (RTFM)      This acronym is often used when someone asks a simple or common      question.   Read The Source Code (RTSC)      This acronym is often used when a software developer asks a      question about undocumented code.Malkin                       Informational                     [Page 46]

RFC 1983                        Glossary                     August 1996   reassembly      The IP process in which a previously fragmented packet is      reassembled before being passed to the transport layer.  See also:      fragmentation.   recursive      See: recursive   regional      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]   repeater      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 inRFC 903, which provides the reverse      function of ARP.  RARP maps a hardware (MAC) address to an      internet address.  It is used primarily by diskless nodes when      they first initialize to find their internet address.  See also:Malkin                       Informational                     [Page 47]

RFC 1983                        Glossary                     August 1996      Address Resolution Protocol, BOOTP, internet address, MAC address.   RFC      See: Request For CommentsRFC 822      The Internet standard format for electronic mail message headers.      Mail experts often refer to "822 messages."  The name comes fromRFC 822, which contains the specification.  822 format was      previously known as 733 format.  See also: Electronic Mail.      [Source: COMER]   RIP      See: Routing Information Protocol   RIPE      See: Reseaux IP Europeenne   Round-Trip Time (RTT)      A measure of the current delay on a network.      [Source: MALAMUD]   route      The path that network traffic takes from its source to its      destination.  Also, a possible path from a given host to another      host or destination.   routed      Route Daemon.  A program which runs under 4.2BSD/4.3BSD UNIX      systems (and derived operating systems) to propagate routes among      machines on a local area network, using the RIP protocol.      Pronounced "route-dee".  See also: Routing Information Protocol,      gated.   router      A device which forwards traffic between networks.  The forwarding      decision is based on network layer information and routing tables,      often constructed by routing protocols.  See also: bridge,      gateway, Exterior Gateway Protocol, Interior Gateway Protocol.   routing      The process of selecting the correct interface and next hop for a      packet being forwarded.  See also: hop, router, Exterior Gateway      Protocol, Interior Gateway Protocol.   routing domain      A set of routers exchanging routing information within an      administrative domain.  See also: Administrative Domain, router.Malkin                       Informational                     [Page 48]

RFC 1983                        Glossary                     August 1996   Routing Information Protocol (RIP)      A distance vector, as opposed to link state, routing protocol.  It      is an Internet standard IGP defined inRFC 1058.  See also:      Interior Gateway Protocol, Open Shortest-Path First.   RPC      See: Remote Procedure Call   RSA      A public-key cryptographic system which may be used for encryption      and authentication.  It was invented in 1977 and named for its      inventors: Ron Rivest, Adi Shamir, and Leonard Adleman.  See also:      encryption, Data Encryption Standard, Pretty Good Privacy.   RTFM      See: Read The F*cking Manual   RTSC      See: Read The Source Code   RTT      See: Round-Trip Time   SDH      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 inRFC 1055, but is not an Internet Standard.  It is being      replaced by PPP.  See also: Point-to-Point Protocol.   server      A provider of resources (e.g. file servers and name servers).  See      also: client, Domain Name System, Network File System.   SGML      See: Standardized Generalized Markup Language   SIG      Special Interest Group   signature      The three or four line message at the bottom of a piece of email      or a Usenet article which identifies the sender.  Large signatures      (over five lines) are generally frowned upon.  See also:      Electronic Mail, Usenet.Malkin                       Informational                     [Page 49]

RFC 1983                        Glossary                     August 1996   Simple Mail Transfer Protocol (SMTP)      A protocol used to transfer electronic mail between computers.  It      is specified inRFC 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 inRFC 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.   SLIP      See: Serial Line IP   SMDS      See: Switched Multimegabit Data Service   SMI      See: Structure of Management Information   SMTP      See: Simple Mail Transfer Protocol   SNA      See: Systems Network Architecture   snail mail      A pejorative term referring to the U.S. postal service.   SNMP      See: Simple Network Management Protocol   SONET      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.   STD      A subseries of RFCs that specify Internet standards.  The official      list of Internet standards is in STD 1.  See also: Request For      Comments.Malkin                       Informational                     [Page 50]

RFC 1983                        Glossary                     August 1996   stream-oriented      A type of transport service that allows its client to send data in      a continuous stream.  The transport service will guarantee that      all data will be delivered to the other end in the same order as      sent and without duplicates.  See also: Transmission Control      Protocol.      [Source: MALAMUD]   Structure of Management Information (SMI)      The rules used to define the objects that can be accessed via a      network management protocol.  These rules are defined inRFC 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.   subnet      A portion of a network, which may be a physically independent      network segment, which shares a network address with other      portions of the network and is distinguished by a subnet number.      A subnet is to a network what a network is to an internet.  See      also: internet, network.      [Source: FYI4]   subnet address      The subnet portion of an IP address.  In a subnetted network, the      host portion of an IP address is split into a subnet portion and a      host portion using an address (subnet) mask.  See also: address      mask, IP address, network address, host address.   subnet mask      See: address mask   subnet number      See: subnet address  supernet      An aggregation of IP network addresses advertised as a single      classless network address.  For example, given four Class C IP      networks: 192.0.8.0, 192.0.9.0, 192.0.10.0 and 192.0.11.0, each      having the intrinsic network mask of 255.255.255.0; one can      advertise the address 192.0.8.0 with a subnet mask of      255.255.252.0.  See also: IP address, network address, network      mask, Classless Inter-domain Routing.Malkin                       Informational                     [Page 51]

RFC 1983                        Glossary                     August 1996   Switched Multimegabit Data Service (SMDS)      An emerging high-speed datagram-based public data network service      developed by Bellcore and expected to be widely used by telephone      companies as the basis for their data networks.  See also:      Metropolitan Area Network.      [Source:RFC1208]   Synchronous Digital Hierarchy (SDH)      The European standard for high-speed data communications over      fiber-optic media.  The transmission rates range from 155.52Mbps      to 2.5Gbps.   Synchronous Optical NETwork (SONET)      SONET is an international standard for high-speed data      communications over fiber-optic media.  The transmission rates      range from 51.84Mbps to 2.5Gbps.   Systems Network Architecture (SNA)      A proprietary networking architecture used by IBM and IBM-      compatible mainframe computers.      [Source: NNSC]   T1      A term for a digital carrier facility used to transmit a DS-1      formatted digital signal at 1.544 megabits per second.   T3      A term for a digital carrier facility used to transmit a DS-3      formatted digital signal at 44.746 megabits per second.      [Source: FYI4]   TAC      See: Terminal Access Controller (TAC)   talk      A protocol which allows two people on remote computers to      communicate in a real-time fashion.  See also: Internet Relay      Chat.   TCP      See: Transmission Control Protocol   TCP/IP Protocol Suite      Transmission Control Protocol over Internet Protocol.  This is a      common shorthand which refers to the suite of transport and      application protocols which runs over IP.  See also: IP, ICMP,      TCP, UDP, FTP, Telnet, SMTP, SNMP.Malkin                       Informational                     [Page 52]

RFC 1983                        Glossary                     August 1996   TELENET      The original name for what is now SprintNet.  It should not be      confused with the Telnet protocol or application program.   Telnet      Telnet is the Internet standard protocol for remote terminal      connection service.  It is defined inRFC 854 and extended with      options by many other RFCs.   TERENA      See: Trans-European Research and Education Networking Association   Terminal Access Controller (TAC)      A device which was once used to connect terminals to the Internet,      usually using dialup modem connections and the TACACS protocol.      While the device is no longer in use, TACACS+ is a protocol in      current use.   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]   TLA      See: Three Letter Acronym   TN3270      A variant of the Telnet program that allows one to attach to IBM      mainframes and use the mainframe as if you had a 3270 or similar      terminal.      [Source: BIG-LAN]Malkin                       Informational                     [Page 53]

RFC 1983                        Glossary                     August 1996   token ring      A token ring is a type of LAN with nodes wired into a ring.  Each      node constantly passes a control message (token) on to the next;      whichever node has the token can send a message.  Often, "Token      Ring" is used to refer to the IEEE 802.5 token ring standard,      which is the most common type of token ring.  See also: 802.x,      Local Area Network.   topology      A network topology shows the computers and the links between them.      A network layer must stay abreast of the current network topology      to be able to route packets to their final destination.      [Source: MALAMUD]   traceroute      A program available on many systems which traces the path a packet      takes to a destination.  It is mostly used to debug routing      problems between hosts.  There is also a traceroute protocol      defined inRFC 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]   transceiver      Transmitter-receiver.  The physical device that connects a host      interface to a local area network, such as Ethernet.  Ethernet      transceivers contain electronics that apply signals to the cable      and sense collisions.      [Source:RFC1208]   transit network      A transit network passes traffic between networks in addition to      carrying traffic for its own hosts.  It must have paths to at      least two other networks.  See also: backbone, stub network.   Transmission Control Protocol (TCP)      An Internet Standard transport layer protocol defined inRFC 793.      It is connection-oriented and stream-oriented, as opposed to UDP.      See also: connection-oriented, stream-oriented, User Datagram      Protocol.Malkin                       Informational                     [Page 54]

RFC 1983                        Glossary                     August 1996   Trojan Horse      A computer program which carries within itself a means to allow      the creator of the program access to the system using it.  See      also: virus, worm.   TTFN      Ta-Ta For Now   TTL      See: Time to Live   tunnelling      Tunnelling refers to encapsulation of protocol A within protocol      B, such that A treats B as though it were a datalink layer.      Tunnelling is used to get data between administrative domains      which use a protocol that is not supported by the internet      connecting those domains.  See also: Administrative Domain.   twisted pair      A type of cable in which pairs of conductors are twisted together      to produce certain electrical properties.   UDP      See: User Datagram Protocol   unicast      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 inRFC 1738.  See also: World Wide Web.   Universal Time Coordinated (UTC)      This is Greenwich Mean Time.      [Source: MALAMUD]   UNIX-to-UNIX CoPy (UUCP)      This was initially a program run under the UNIX operating system      that allowed one UNIX system to send files to another UNIX system      via dial-up phone lines.  Today, the term is more commonly used to      describe the large international network which uses the UUCP      protocol to pass news and electronic mail.  See also: Electronic      Mail, Usenet.Malkin                       Informational                     [Page 55]

RFC 1983                        Glossary                     August 1996   urban legend      A story, which may have started with a grain of truth, that has      been embroidered and retold until it has passed into the realm of      myth.  It is an interesting phenonmenon that these stories get      spread so far, so fast and so often.  Urban legends never die,      they just end up on the Internet!  Some legends that periodically      make their rounds include "The Infamous Modem Tax," "Craig      Shergold/Brain Tumor/Get Well Cards," and "The $250 Cookie      Recipe."      [Source: LAQUEY]   URL      See: Uniform Resource Locators   Usenet      A collection of thousands of topically named newsgroups, the      computers which run the protocols, and the people who read and      submit Usenet news.  Not all Internet hosts subscribe to Usenet      and not all Usenet hosts are on the Internet.  See also: Network      News Transfer Protocol, UNIX-to-UNIX CoPy.      [Source: NWNET]   User Datagram Protocol (UDP)      An Internet Standard transport layer protocol defined inRFC 768.      It is a connectionless protocol which adds a level of reliability      and multiplexing to IP.  See also: connectionless, Transmission      Control Protocol.   UTC      See: Universal Time Coordinated   UUCP      See: UNIX-to-UNIX CoPy   uudecode      A program which reverses the effect of uuencode.  See also:      uuencode.   uuencode      A program which reversibly converts a binary file in ASCII.  It is      used to send binary files via email, which generally does not      allow (or garbles) the transmission of binary information.  The      original binary can be restored with uudecode.  The encoding      process generally creates an ASCII file larger than the original      binary, so compressing the binary before running uuencode is      highly recommended.Malkin                       Informational                     [Page 56]

RFC 1983                        Glossary                     August 1996   Veronica      A Gopher utility which effectively searches Gopher servers based      on a user's list of keywords.  The name was chosen to be a "mate"      to another utility named "Archie."  It later became an acronym for      Very Easy Rodent Oriented Netwide Index to Computer Archives.  See      also: archie, Gopher.   virtual circuit      A network service which provides connection-oriented service      without necessarily doing circuit-switching.  See also:      connection-oriented.   virus      A program which replicates itself on computer systems by      incorporating itself into other programs which are shared among      computer systems.  See also: Trojan Horse, worm.   W3      See: World Wide Web   WAIS      See: Wide Area Information Servers   WAN      See: Wide area network   WebCrawler      A WWW search engine.  The aim of the WebCrawler Project is to      provide a high-quality, fast, and free Internet search service.      The WebCrawler may be reached at "http://webcrawler.com/".      [Source: WebCrawler's "WebCrawler Facts"]   WG      See: Working Group   white 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.   whois      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.  TheMalkin                       Informational                     [Page 57]

RFC 1983                        Glossary                     August 1996      information stored includes a person's company name, address,      phone number and email address.  The latest version of the      protocol, WHOIS++, is defined in RFCs 1834 and 1835.  See also:      InterNIC, white pages, Knowbot, netfind, X.500.   Wide Area Information Servers (WAIS)      A distributed information service which offers simple natural      language input, indexed searching for fast retrieval, and a      "relevance feedback" mechanism which allows the results of initial      searches to influence future searches.  Public domain      implementations are available.  See also: archie, Gopher,      Prospero.   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      available.   worm      A computer program which replicates itself and is self-      propagating.  Worms, as opposed to viruses, are meant to spawn in      network environments.  Network worms were first defined by Shoch &      Hupp of Xerox in ACM Communications (March 1982).  The Internet      worm of November 1988 is perhaps the most famous; it successfully      propagated itself on over 6,000 systems across the Internet.  See      also: Trojan Horse, virus.   WRT      With Respect ToMalkin                       Informational                     [Page 58]

RFC 1983                        Glossary                     August 1996   WWW      See: World Wide Web   WYSIWYG      What You See is What You Get   X      X is the name for TCP/IP based network-oriented window systems.      Network window systems allow a program to use a display on a      different computer.   The most widely-implemented window system is      X11 - a component of MIT's Project Athena.   X.25      A data communications interface specification developed to      describe how data passes into and out of public data      communications networks.  The CCITT and ISO approved protocol      suite defines protocol layers 1 through 3.   X.400      The CCITT and ISO standard for electronic mail.  It is widely used      in Europe and Canada.   X.500      The CCITT and ISO standard for electronic directory services.  See      also: white pages, Knowbot, whois.   XDR      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]   XNS      See: Xerox Network SystemMalkin                       Informational                     [Page 59]

RFC 1983                        Glossary                     August 1996   Yahoo!      Yahoo! is a hierarchical subject-oriented guide for the World Wide      Web and Internet.  Yahoo! lists sites and categorizes them into      appropriate subject categories.  Yahoo! may be reached at      "http://www.yahoo.com/".      [Source: Yahoo's "What is Yahoo?"]   Yellow Pages (YP)      A historic (i.e., no longer in use) service used by UNIX      administrators to manage databases distributed across a network.   YP      See: Yellow Pages   zone      A logical group of network devices.Malkin                       Informational                     [Page 60]

RFC 1983                        Glossary                     August 1996References   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",RFC1208, Interop, Inc., March 1991.   STD1    Postel, J., "INTERNET OFFICIAL PROTOCOL STANDARDS",RFC 1920           (STD 1), March 1996.   STD2    Reynolds, J., J. Postel, "ASSIGNED NUMBERS",RFC 1700 (STD           2), ISI, October 1994.   TAN     Tanenbaum, Andrew S., "Computer Networks; 2nd ed.", Prentice           Hall, Englewood Cliffs, NJ, 1989.   ZEN     Kehoe, Brendan P., "Zen and the Art of the Internet",           February 1992.Malkin                       Informational                     [Page 61]

RFC 1983                        Glossary                     August 1996Security 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.COMMalkin                       Informational                     [Page 62]