Glossary

address resolution protocol (ARP)

A method for finding a host's Ethernet address from its Internet address. The sender broadcasts an ARP packet containing the Internet address of another host and waits for it (or some other host) to send back its Ethernet address. Each host maintains a cache of address translations to reduce delay and loading. ARP enables the Internet address to be independent of the Ethernet address, but this works only if all hosts support it.

ARP

See address resolution protocol.

ATM address

A 20-byte (the bytes are often referred to as octets) number that uniquely identifies an asynchronous transfer mode (ATM) endpoint. The first 13 bytes are assigned by the switch and are called the switch prefix; the remaining 7 bytes (made up of a 6-byte end system identifier and a 1-byte selector) are assigned by the local host.

DHCP

See dynamic host configuration protocol.

DNS

See Domain Name System.

domain name

A name that identifies a logical group of computers. It is a text string that can include letters (a-z and A-Z), digits (0-9), and hyphens (-) (for example, eng). A fully qualified domain name is composed of the local domain and all of its ancestor domains leading to the root domain, separated by periods and ending in a period (for example, eng.sun.com.). A partially qualified domain name is the local domain name and some number of ancestor domains separated by periods (for example, eng.sun). When a partial domain name is used, it is assumed to be within the current domain or within one of the ancestor domains of the current domain.

Domain Name System (DNS)

A network information service that provides information about hosts within the domain name system. It is mainly used for name resolution, that is, it is used to provide host addresses that correspond to host names. It can also be used to provide other information about hosts such as aliases or mail servers.

Dynamic Host Configuration Protocol (DHCP)

A protocol that provides a host with an Internet protocol (IP) address and other Internet configuration parameters without any need for preconfiguration by the user.

dynamic router

A router that relies on information broadcast from other routers to update its routes to reflect changes in the network topology. The router also broadcasts this information to other dynamic routers.

email address

An electronic mail address, which is composed of three parts: the user name (the name of the person who receives the mail), the host name (the system on which that user has an account) and the domain name (the domain in which the system resides). The user name is separated from the host name by an "at" sign (@). The host name and domain name are separated by a period (for example, user@host.domain.com).

Ethernet

A network protocol that broadcasts information to all the hosts on the network. The information is accepted by the intended recipients and discarded by the other hosts.

firewall

A logical border that protects the local network against intrusion from other networks. A firewall can monitor or prohibit connections to and from specified services or hosts.

file transfer protocol (FTP)

A protocol that enables files to be copied between systems connected to a TCP/IP network independent of the operating systems or architectures of the hosts involved in the file transfer.

FTP

See file transfer protocol.

hexadecimal number

A number expressed in base 16. It is composed of the characters 0-9, a-f, and A-F.

host address (IP address)

An assigned number that uniquely identifies each computer connected to a TCP/IP network. The address consists of two parts: a network number and a host number. The network number identifies the network to which the computer is connected, and the host number identifies the computer on that network. The host address is composed of four integers separated by periods. The first integer must be in the range 0-223, the second and third integers in the range 0-255, and the fourth integer in the range 1-254 (for example, 129.144.0.1).

host name

The name of a computer within the local domain. It is a text string of up to 24 characters composed of letters (a-z and A-Z), digits (0-9), and hyphens (-). The last character cannot be a hyphen.

HTML

See hypertext markup language.

HTTP

See hypertext transport protocol.

HTTPD

See hypertext transport protocol daemon.

hypertext markup language (HTML)

A language used to format hypertext documents. Hypertext documents have text that contains links to other documents or to images, sound, graphics, or video files.

hypertext transport protocol (HTTP)

A way used to transmit and display hypertext documents. HTTP capitalizes on the fact that navigation information can be embedded directly in the documents. Thus, the protocol does not need to support full navigation features like the FTP protocols do. Because HTTP has low overhead, HTTP servers are commonly used for serving hypertext documents.

hypertext transport protocol daemon (HTTPD)

The software component of a Web server. Using the HTTPD, the Netra server makes its administration tools available to clients on the LAN.

ICMP

See internet control message protocol.

IDE

See integrated development environment.

integer

A whole number composed of the digits 0-9.

Internet

A global collection of networks connecting a wide range of computers using a common protocol to communicate and share services.

Internet control message protocol (ICMP)

An extension to the Internet protocol (IP). It allows for the generation of error messages, test packets, and informational messages related to IP.

Internet protocol (IP)

Internet protocol. The network layer protocol for the Internet protocol suite.

integrated development environment (IDE)

integrated services digital network (ISDN)

A set of integrated telecommunications services available over public telecommunication networks.

Internet Service Provider

A company that provides an Internet connection by using its own computer system as a conduit to the Internet. The service provider generally has a direct Internet connection; the client typically connects to the service provider with a dial-up connection.

IP

See Internet protocol.

ISDN

See integrated services digital network.

local area network

A group of computer systems in close proximity that can communicate with one another via some connecting hardware and software.

LAN

See Local Area Network.

MAC address

The unique hardware address assigned to a system or interface board when it is manufactured.

multihomed host

A host that has more than one network interface connected to the same network.

netmask

A mask used to determine the network address from a host address. A netmask is composed of four integers in the range 0-255 separated by periods. When a netmask is expressed in binary notation, it must be a contiguous sequence of "ones" followed by a contiguous sequence of "zeroes" (for example, 255.255.128.0).

network address

A number that identifies the network in which a computer resides. A network address is composed of four integers separated by periods. The first integer must be in the range 0-223, the second and third integers must be in the range 0-255, and the fourth integer must be in the range 0-254 (for example, 129.144.0.0).

network interface

An access point to a system on a network. Each interface is associated with a physical device. However, a physical device can have multiple network interfaces.

Network Information Service (NIS)

A network information service containing key information about the systems and the users on the network.

network time protocol (NTP)

A protocol built on top of TCP/IP that ensures accurate local timekeeping with reference to radio, atomic or other clocks located on the Internet. This protocol is capable of synchronizing distributed clocks within milliseconds over long time periods.

NFS

Network File System. This Remote Procedure Call (RPC) service that enables machines to share files across the network. It permits the user to access remote files and hierarchies transparently as if they were local to the user's machine.

NIS

See Network Information Service.

NTP

See network time protocol.

point-to-point protocol (PPP)

This protocol enables two computers to be connected over a two-way communications link, such as a telephone line. The connection is established as needed.

PPP

See point-to-point protocol.

RARP

See reverse address resolution protocol.

Remote Procedure Call (RPC)

reverse address resolution protocol (RARP)

Thus protocol provides the reverse function of address resolution protocol (ARP). RARP maps a hardware address to an Internet address. It is used primarily by diskless nodes when they first initialize to find their Internet address.

route

A route specifies the next router on a message's path to its destination. A default route does not contain a specific destination; it has a general destination used for any destinations not specified in other routes.

router

A computer or other dedicated hardware that connects two or more networks and routes data between them.

static router

A router that relies on manual addition of routes. Routing information is not exchanged with other routers.

software package

A collection of files and directories required for a software product. A complete software product can be made up of several packages. A collection of packages required for a software product is called a software cluster.

software patch

A collection of files and directories that fix a set of problems associated with a software product. A patch can be installed on a system only if the software product being fixed is also installed.

TCP/IP

Transport Control Protocol/Interface Program. The protocol suite originally developed for the Internet. It is also called the Internet protocol suite.

uniform resource locator (URL)

The addressing system used by clients to request web documents from servers. The format of a URL is protocol://system:port/document (for example, http://www.sun.com/).

URL

See uniform resource locator.

user name

The name that the computer uses to identify a particular user. It is a text string of up to eight characters that can include letters (a-z and A-Z), digits (0-9), hyphens (-), and underscores (_). The first character must be a letter.

Web

A collection of systems on the Internet that contain hypertext documents that are accessible using HTTP and are displayed as web pages by web servers.