RFC1983 - Internet Users Glossary

Network Working Group G. Malkin, Editor

Request for Comments: 1983 Xylogics

FYI: 18 August 1996

Obsoletes: 1392

Category: Informational

Internet Users' Glossary

Status of this Memo

This memo provides information for the Internet community. This memo

does not specify an Internet standard of any kind. Distribution of

this memo is unlimited.

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 . . . . . . . 46

A . . . . . . . 2 J . . . . . . . 33 S . . . . . . . 49

B . . . . . . . 7 K . . . . . . . 33 T . . . . . . . 52

C . . . . . . . 10 L . . . . . . . 33 U . . . . . . . 55

D . . . . . . . 14 M . . . . . . . 35 V . . . . . . . 57

E . . . . . . . 18 N . . . . . . . 39 W . . . . . . . 57

F . . . . . . . 20 O . . . . . . . 42 X . . . . . . . 59

G . . . . . . . 22 P . . . . . . . 43 Y . . . . . . . 60

H . . . . . . . 23 Q . . . . . . . 46 Z . . . . . . . 60

References . . . . . . . . . . . . . . . . . . . . . . . . . . 61

Security Considerations . . . . . . . . . . . . . . . . . . . . 62

Editor's Address . . . . . . . . . . . . . . . . . . . . . . . 62

Glossary

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: RFC822

:-)

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.

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.

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 standards

(e.g., ANSI C is the version of the C language approved by ANSI).

ANSI is a member of ISO. See also: International Organization for

Standardization.

[Source: NNSC]

American Standard Code for Information Interchange (ASCII)

A standard character-to-number encoding widely used in the

computer industry. See also: EBCDIC.

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]

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 RFCis updated periodically and, in any

case, current information can be oBTained from the Internet

Assigned Numbers Authority (IANA). If you are developing a

protocol or application that will require the use of a link,

socket, port, protocol, etc., please contact the IANA to receive a

number assignment. See also: Internet Assigned Numbers Authority,

STD.

[Source: STD2]

Asynchronous 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]

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. The

Big-Endian and Little-Endian parties debated over whether soft-

boiled eggs should be opened at the big end or the little end.

See also: little-endian.

[Source: RFC1208]

binary

11001001

BIND

See: Berkeley Internet Name 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 in RFC1542, is used for booting

diskless nodes. See also: Dynamic Host Configuration Protocol,

Reverse Address Resolution Protocol.

Border Gateway Protocol (BGP)

The Border Gateway Protocol is an exterior gateway protocol

defined in RFC1771. It's design is based on experience gained

with EGP, as defined in RFC904, 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.

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.

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 in RFC1519, 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]

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.

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 check

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 destination

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.

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]

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 Agent

dynamic adaptive routing

Automatic rerouting of traffic based on a sensing and analysis of

current actual network conditions. NOTE: this does not include

cases of routing decisions taken on predefined information.

[Source: J. Postel]

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 address

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 in RFC904. See also:

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.

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 in RFC1288, 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.

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.

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 in RFC1436, 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.

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.

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.

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 Report

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.

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 RFCactivities, 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.

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.

internet number

See: internet address

Internet Protocol (IP, IPv4)

The Internet Protocol (version 4), defined in RFC791, 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.

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 in RFC791.

It is usually represented in dotted decimal notation. See also:

dot address, internet address, Internet Protocol, network address,

subnet address, host address.

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 Union

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,

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. See

also: Electronic Mail, mailing list, Usenet.

[Source: LAQUEY]

Lycos

Lycos, Inc. is a new venture formed in late June 1995, to develop

and market the Lycos technology originally developed under the

direction of Dr. Michael ("Fuzzy") Mauldin at Carnegie Mellon

University. The part of Lycos you see when you do a search is the

search engine. "Lycos" comes from Lycosidae, a cosmopolitan

family of relatively large active ground spiders (Wolf Spiders)

that catch their prey by pursuit, rather than in a web.

[Source: Lycos's FAQ]

MAC

See: Media Access Control

MAC address

The hardware address of a device connected to a shared media. See

also: Media Access Control, Ethernet, token ring.

[Source: MALAMUD]

mail bridge

A mail gateway that forwards electronic mail between two or more

networks while ensuring that the messages it forwards meet certain

administrative criteria. A mail bridge is simply a specialized

form of mail gateway that enforces an administrative policy with

regard to what mail it forwards. See also: Electronic Mail, mail

gateway.

[Source: NNSC]

Mail Exchange Record (MX Record)

A DNS resource record type indicating which host can handle mail

for a particular domain. See also: Domain Name System, Electronic

Mail.

[Source: MALAMUD]

mail exploder

Part of an electronic mail delivery system which allows a message

to be delivered to a list of addresses. Mail exploders are used

to implement mailing lists. Users send messages to a single

address and the mail exploder takes care of delivery to the

individual mailboxes in the list. See also: Electronic Mail,

email address, mailing list.

[Source: RFC1208]

mail gateway

A machine that connects two or more electronic mail systems

(including dissimilar mail systems) and transfers messages between

them. Sometimes the mapping and translation can be quite complex,

and it generally requires a store-and-forward scheme whereby the

message is received from one system completely before it is

transmitted to the next system, after suitable translations. See

also: Electronic Mail.

[Source: RFC1208]

mail path

A series of machine names used to direct electronic mail from one

user to another. This system of email addressing has been used

primarily in UUCP networks which are trying to eliminate its use

altogether. See also: bang path, email address, UNIX-to-UNIX

CoPy.

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 Network

Management Information Base (MIB)

The set of parameters an SNMP management station can query or set

in the SNMP agent of a network device (e.g. router). Standard,

minimal MIBs have been defined, and vendors often have Private

enterprise MIBs. In theory, any SNMP manager can talk to any SNMP

agent with a properly defined MIB. See also: client-server model,

Simple Network Management Protocol.

[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 in RFC1319; MD-4, described in RFC1320; and MD-5,

described in RFC1321 all produce a 128-bit signature. They

differ in their operating speed and resistance to crypto-analytic

attack. Generally, one must be traded off for the other.

message switching

See: packet switching

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.

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]

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.

RFC1855 (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 are

globally unique. See also: Internet, IP address, subnet address,

host address, Internet Registry.

Network File System (NFS)

A protocol developed by Sun Microsystems, and defined in RFC1094

(RFC1813 defines Version 3), which allows a computer system to

access files over a network as if they were on its local disks.

This protocol has been incorporated in products by more than two

hundred companies, and is now a de facto Internet standard.

[Source: NNSC]

Network Information Center (NIC)

A NIC provides information, assistance and services to network

users. See also: Network Operations Center.

Network Information Services (NIS)

A set of services, generally provided by a NIC, to assist users in

using the network. See also: Network Information Center.

Network News Transfer Protocol (NNTP)

A protocol, defined in RFC977, 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 Center

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 than

10,000 libraries worldwide. Libraries use the OCLC System for

cataloging, interlibrary loan, collection development,

bibliographic verification, and reference searching.

[Source: OCLC]

Open Shortest-Path First (OSPF)

A link state, as opposed to distance vector, routing protocol. It

is an Internet standard IGP defined in RFCs 1583 and 1793. The

multicast version, MOSPF, is defined in RFC1584. 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]

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 in RFC1661, 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.

Post Office Protocol (POP)

A protocol designed to allow single user hosts to read electronic

mail from a server. Version 3, the most recent and most widely

used, is defined in RFC1725. 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]

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.

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 RFCseries of documents is unusual in

that the proposed protocols are forwarded by the Internet research

and development community, acting on their own behalf, as opposed

to the formally reviewed and standardized protocols that are

promoted by organizations such as CCITT and ANSI. See also: BCP,

FYI, STD.

Reseaux IP Europeens (RIPE)

A collaboration between European networks which use the TCP/IP

protocol suite.

Reverse Address Resolution Protocol (RARP)

A protocol, defined in RFC903, which provides the reverse

function of ARP. RARP maps a hardware (MAC) address to an

internet address. It is used primarily by diskless nodes when

they first initialize to find their internet address. See also:

Address Resolution Protocol, BOOTP, internet address, MAC address.

RFC

See: Request For Comments

RFC822

The Internet standard format for electronic mail message headers.

Mail experts often refer to "822 messages." The name comes from

RFC822, 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.

Routing Information Protocol (RIP)

A distance vector, as opposed to link state, routing protocol. It

is an Internet standard IGP defined in RFC1058. 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 in RFC1055, 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.

Simple Mail Transfer Protocol (SMTP)

A protocol used to transfer electronic mail between computers. It

is specified in RFC821, 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, RFC822.

Simple Network Management Protocol (SNMP)

The Internet standard protocol developed to manage nodes on an IP

network. The first version is defined in RFC1157 (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.

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 in RFC1155

(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.

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.

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 in RFC854 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]

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 in RFC1393.

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 in RFC793.

It is connection-oriented and stream-oriented, as opposed to UDP.

See also: connection-oriented, stream-oriented, User Datagram

Protocol.

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 in RFC1738. 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.

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 in RFC768.

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.

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. The

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 To

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 System

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.

References

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", RFC1325

(FYI 4), Xylogics, SRI, May 1992.

HACKER "THIS IS THE JARGON FILE", Version 2.9.8, January 1992.

HPCC "Grand Challenges 1993: High Performance Computing and

Communications", Committee on Physical, Mathmatical and

Engineering Sciences of the Federal Coordinating Council for

Science, Engineering and Technology.

MALAMUD Malamud, Carl, "Analyzing Sun Networks", Van Nostrand

Reinhold, New York, NY, 1992.

NNSC "NNSC's Hypercard Tour of the Internet".

LAQUEY LaQuey, Tracy, with Jeanne C. Ryer, "The Internet Companion:

A Beginner's Guide to Global Networking", Addison-Wesley,

Reading, MA, 1992.

NWNET Kochmer, Jonathan, and NorthWestNet, "The Internet Passport:

NorthWestNets Guide to Our World Online", NorthWestNet,

Bellevue, WA, 1992.

RFC1208 Jacobsen, O., D. Lynch, "A Glossary of Networking Terms", RFC

1208, Interop, Inc., March 1991.

STD1 Postel, J., "INTERNET OFFICIAL PROTOCOL STANDARDS", RFC1920

(STD 1), March 1996.

STD2 Reynolds, J., J. Postel, "ASSIGNED NUMBERS", RFC1700 (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.

Security Considerations

While security is not explicitly discussed in this document, some of

the glossary's entries are security related. See the entries for

Access Control List (ACL), authentication, Computer Emergency

Response Team (CERT), cracker, Data Encryption Key (DEK), Data

Encryption Standard (DES), encryption, Kerberos, Message Digest (MD-

2, MD-4, MD-5), Pretty Good Privacy (PGP), Privacy Enhanced Mail

(PEM), RSA, Trojan Horse, virus, and worm.

Editor's Address

Gary Scott Malkin

Xylogics/Bay Networks

53 Third Avenue

Burlington, MA 01803

Phone: (617) 238-6237

EMail: gmalkin@Xylogics.COM

• ·RFC1977 - PPP BSD Compr
• ·RFC1979 - PPP Deflate P
• ·RFC1978 - PPP Predictor
• ·RFC1981 - Path MTU Disc
• ·RFC1980 - A Proposed Ex
• ·RFC1982 - Serial Number
• ·RFC1985 - SMTP Service
• ·RFC1989 - PPP Link Qual
• ·IPv6地址以及IPv6DNS的研究
• ·RFC1990 - The PPP Multi