I/O

Input/Output.

i486

An Intel 80386-compatible microprocessor that includes an onboard floating point unit for increased mathematical speed and operates at higher clock speeds than the 80386. See also 80386, Pentium, and Microprocessor.

IAB (Internet Activities Board)

The technical body that oversees the development of the Internet suite of protocols (commonly referred to as TCP/IP). It has two task forces (the IRTF and the IETF), each charged with investigating a particular area.

Iasparse

A utility (included in the Windows 2000 Resource Kit) that will digest an RRAS log, in IAS or database formats, and then produce a readable summary.

IBM Cabling

Another name for STP cabling.

ICD

See International Code Designator.

ICMP

See Internet Control Messaging Protocol.

Icon

A small graphic image that represents a function. Clicking on an icon produces an action. See also Graphical User Interface.

ICS

See Internet Connection Sharing.

IDE

A simple mass storage device interconnection bus that operates at 5 Mbps and can handle no more than two attached drives. IDE devices are similar to but less expensive than SCSI devices. See also Small Computer Systems Interface and Mass Storage Device.

IEEE

See Institute of Electrical and Electronic Engineers.

IEEE 802 Family

A set of networking standards developed by the IEEE.

IEEE 802.1

The IEEE committee specification that defines the bridging group. The specification for STP (Spanning-Tree Protocol) is IEEE 802.1.d. The STP uses SPA (spanning-tree algorithm) to find and prevent network loops in bridged networks. The specification for VLAN trunking is IEEE 802.1q.

IEEE 802.3

The IEEE committee specification that defines the Ethernet group, specifically the original 10Mbps standard. Ethernet is a LAN protocol that specifies Physical layer and MAC sublayer media access. IEEE 802.3 uses CSMA/CD to provide access for many devices on the same network. Fast Ethernet is defined as 802.3u, and Gigabit Ethernet is defined as 802.3q. See also Carrier Sense Multiple Access Collision Detect.

IEEE 802.5

IEEE committee that defines Token Ring media access.

IESG (Internet Engineering Steering Group)

The executive committee of the IETF.

IETF (Internet Engineering Task Force)

One of the task forces of the IAB. The IETF is responsible for solving short-term engineering needs of the Internet. It has over 40 Working Groups.

IGMP

See Internet Group Management Protocol.

IGP

See Interior Gateway Protocol.

IIS

See Internet Information Server.

ILMI

See Integrated Local Management Interface.

ILS_Anonymous_User

A special domain user account that is used by the ILS service. ILS supports telephony applications that use features such as caller ID, video conferencing, conference calling, and faxing. In order to use ILS, Internet Information Services (IIS) must be installed.

Import Utility

A Microsoft Exchange utility that enables the copying (i.e., importing) of directory information into the Exchange directory. This utility is accessed through the Tools menu of Microsoft Exchange Administrator. See also Export Utility.

Importing

The process of copying foreign message resources, such as mailboxes, messages, etc. into Exchange.

In-Band Management

In-band management is the management of a network device “through” the network. Examples include using Simple Network Management Protocol (SNMP) or Telnet directly via the local LAN. See also Out-of-Band Management.

Inbound Connections

Connections that allow incoming access to an RAS server.

Inbound Port Mapping

Controls where requests from outside your network should be routed.

Inbox

The storage folder that receives new incoming messages.

Incremental Backup

A backup type that backs up only the files that have changed since the last normal or incremental backup. It sets the archive attribute on the files that are backed up.

Incremental Zone Transfer (IXFRs)

Supported in Windows 2000 Server and higher and under BIND version 8.2.1 and higher. Just like an incremental backup, an incremental transfer enables the secondary server to pull only the changes it needs in order to synchronize its copy of the zone data with its configured source. Zone transfers are completed much more quickly and with far less network traffic generated. See also Active Directory Replication, Multimaster Replication Model, and Full Zone Transfers.

Index

A data structure that provides a mechanism for resolving queries more efficiently by working through a subset of the data rather than all of it. A full table scan can be avoided by using an index. In SQL Server, each table is allowed one clustered index. This index is the actual sort order for the data in the table. Nonclustered indexes consist of a list of ordered keys that contain pointers to the data in the data pages. Up to 249 nonclustered indexes can be created per table, but these occupy more space than clustered indexes do.

Indexed Sequential Access Method (ISAM)

A method of data access that uses file I/O routines with indexing and a few enhanced features. This type of data access is normally found when using flat-file databases like dBASE, FoxPro, and Access or DB2.

Indexing Service

A Windows service that creates an index based on the contents and properties of files stored on the computer’s local hard drive. A user can then use the Windows Search function to search or query through the index for specific keywords.

Industry Standard Architecture (ISA)

The design standard for 16-bit Intel-compatible motherboards and peripheral buses. The 32/64-bit PCI bus standard is replacing the ISA standard. Adapters and interface cards must conform to the bus standard(s) used by the motherboard in order to be used with a computer.

Infection

The action a virus carries out when it enters a computer system or storage device.

Information Event

An Event Viewer event that informs you that a specific action has occurred, such as when a system shuts down or starts. See also Event Viewer.

Information Flow

A description of the traffic generated on the network, its point of origin, its purpose, and the amount of bandwidth it uses.

Information Service

A group of service providers for a specific product or environment. The information service for Exchange Server includes service providers for an address book, message store, and message transport.

Infrared Transmissions

Infrared transmissions typically are limited to 100 feet. Within this range, however, infrared is relatively fast. Infrared’s high bandwidth supports transmission speeds of up to 10 Mbps.

Infrastructure

The physical aspects of a network such as the wiring, network links (LAN, MAN, WAN), and connectivity devices such as routers, hubs, and switches.

Infrastructure Manager

The Windows 2000 domain controller that is responsible for managing group memberships and transferring this information to other domain controllers within the Active Directory environment.

Infrastructure Master

A Windows server that is responsible for updating group-to-user references when group members are renamed or relocated. It updates the group object so that it knows the new name or location of its members.

Inheritance

The process by which settings and properties defined on a parent object implicitly apply to a child object.

Inherited Permissions

Parent folder permissions that are applied to (or inherited by) files and subfolders of the parent folder. In Windows, the default is for parent folder permissions to be applied to any files or subfolders in that folder.

Initialization Files

Files used to specify parameters that are used by an application or a utility. Initialization files are often used by setup programs to determine application installation information.

Initial User Account

The account that uses the name of the registered user and is created only if the computer is installed as a member of a workgroup (not into the Active Directory). By default, the initial user is a member of the Administrators group. See also Active Directory.

Injector

See Dropper.

Ink-Jet Printers

Output devices that create paper copies of computer data by squirting microscopic ink dots onto the paper from a rapidly moving ink-jet nozzle. Ink-jet printers create very high quality, inexpensive documents that have replaced most forms of mechanical impact printers. See also Laser Printers and Printers.

Installable Filing System (IFS)

See Web Storage System.

Instant Messaging (IM)

The Exchange 2000 service that allows for real-time messaging and collaboration between users. Clients generally use the MSN Messenger client to log on to Instant Messaging and subscribe to other users.

Instant Messaging Presence Protocol (IMPP)

The standards-based protocol clients use to interact with an Instant Messaging server. IMPP is being developed by leading vendors, including Microsoft anD Lotus. The Instant Messaging service in Exchange 2000 uses a Microsoft published protocol called RVP while IMPP is being ratified.

Institute of Electrical and Electronic Engineers (IEEE)

A professional organization that, among other activities, defines standards in a number of fields within computing and electronics, including networking and communications. IEEE standards are the predominant LAN standards used today throughout the industry. Many protocols are commonly known by the reference number of the corresponding IEEE standard.

Institute of Electrical and Electronic Engineers (IEEE) 1394 Standard

A standard that supports data transfer at speeds up to 400Mbps. Some of the trademark names for this standard are FireWire, I-link, and Lynx.

Insured Burst

In an ATM network, it is the largest, temporarily permitted data burst exceeding the insured rate on a PVC and not tagged by the traffic policing function for being dropped if network congestion occurs. This insured burst is designated in bytes or cells.

Integrated Local Management Interface (ILMI)

A specification created by the ATM Forum, designated for the incorporation of network-management capability into the ATM UNI. Integrated Local Management Interface cells provide for automatic configuration between ATM systems. In LAN emulation, ILMI can provide sufficient information for the ATM end station to find an LECS. In addition, ILMI provides the ATM NSAP (Network Service Access Point) prefix information to the end station.

Integrated Security

A SQL Server security mode in which SQL Server accepts, or trusts, the Windows NT validation of a user. The Windows NT account information is used to validate the user to SQL Server. These connections are referred to as trusted connections.

Integrated Services Digital Network (ISDN)

A group of ITU (CCITT) standards designed to provide voice, video, and data transmission services on digital telephone networks. ISDN uses multiplexing to support multiple channels on high-bandwidth circuits. See also Public Switched Telephone Network, Data Link Layer, and Modem.

Intel Architecture

A family of microprocessors descended directly from the Intel 8086, itself descended from the first microprocessor, the Intel 4004. The Intel architecture is the dominant microprocessor family. It was used in the original IBM PC microcomputer adopted by the business market and later adapted for home use.

Intelligent Hub

A hub that can allow management and/or the ability to perform switching.

Interactive Group

A Windows 2000 special group that includes all the users who use the computer’s resources locally.

Interactive Logon

A logon when the user logs on from the computer where the user account is stored on the computer’s local database. Also called a local logon. See also Logon.

Interactive User

The user who physically logs on to a computer is considered interactive, as opposed to a user who logs on over the network.

Interarea Routing

Routing between two or more logical areas. See also Area and Intra-Area Routing.

Interconnectivity Devices

Devices that connect independent networks. They include routers, brouters, gateways, and CSUs/DSUs.

Interfaces

All of the different connections on your server, whether they are internal or external, that physically join your server to the network. These could be a network interface card (NIC), modem, or other mechanism.

Interface Processor

Any of the several processor modules used with Cisco 7000 series routers. See also ATM Interface Processor, Channel Interface Processor, Ethernet Interface Processor, Fast Ethernet Interface Processor, HSSI Interface Processor, Multichannel Interface Processor, and Token Ring Interface Processor.

Inter-Forest Restructuring

The process of moving users, groups, and computer objects from a Windows domain in a separate AD forest to a new Windows domain.

Interior Gateway Protocol (IGP)

Any protocol used by the Internet to exchange routing data within an independent system. Examples include RIP, IGRP, and OSPF.

INTERLNK

Connects two computers via parallel or serial ports.

Intermediate Data Facility (IDF)

A room or closet separate from the Main Data Facility (MDF) that houses switches, patch panels, hubs, cabling, and other network interconnecting equipment. IDFs are usually found in outlying areas of a building or campus and server as a connecting point between users and the MDF.

Internal Command

One of a set of many commands available to you at any time as they are loaded into memory every time you start your PC.

Internal Interface

The connection or connections on your ISA Server that join it to your private network.

Internal Network Number

An identification for NetWare file servers. An internal network number is also used if the network is running File and Print Services for NetWare or is using IPX routing. This option must be configured to run the NWLink IPX/SPX/NetBIOS Compatible Transport protocol on a Windows 2000 computer. Normally, the internal network number should be left at its default setting.

Internal Routing

Term that refers to the process of moving packets around on your own internetwork.

International Code Designator (ICD)

Adapted from the subnetwork model of addressing, this assigns the mapping of Network layer addresses to ATM addresses. HSSI is one of two ATM formats for addressing created by the ATM Forum to be utilized with private networks. See also Data Country Code.

International Model

A business model that crosses international borders.

International Standards Organization (ISO)

International body responsible for setting standards for many things, including certain network standards.

International Telecommunication Union (ITU)

The U.N. umbrella organization that develops and standardizes telecommunications worldwide. The ITU also contains the CCITT, the International Frequency Registration Board (IFRB), and the Consultative Committee on International Radio (CCIR). In popular usage, CCITT standards are being referred to as ITU standards. For more information on ITU, see www.itu.ch.

International Telecommunication Union Telecommunication Standardization Sector (ITU-T)

This is a group of engineers that develops worldwide standards for telecommunications technologies.

Internet

A global network made up of a large number of individual networks interconnected through the use of TCP/IP protocols. The individual networks comprising the Internet are from colleges, universities, businesses, research organizations, government agencies, individuals, and other bodies. The governing body of this global network is the Internet Activities Board (IAB). When the term Internet is used with an upper-case I, it refers to the global network, but with a lower-case i, it simply means a group of interconnected networks. See also File Transfer Protocol, Telnet, UseNet, World Wide Web, Transmission Control Protocol/Internet Protocol, and Multicast Backbone.

internet

Before the rise of the Internet, this lowercase form was shorthand for “internetwork” in the generic sense. Now rarely used. See also Internetwork.

Internet Address

A 32-bit value displayed in numbers that specifies a particular network and a particular node on that network.

Internet Connection Sharing

A Windows feature that allows a small network to be connected to the Internet through a single connection. The computer that dials into the Internet provides network address translation, addressing, and name resolution services for all of the computers on the network. Through Internet connection sharing, the other computers on the network can access Internet resources and use Internet applications, such as Internet Explorer and Outlook Express.

Internet Control Message Protocol (ICMP)

ICMP enhances the error control provided by IP. Connectionless protocols, such as IP, cannot detect internetwork errors, such as congestion or path failures. ICMP can detect such errors and notify IP and upper-layer protocols.

Internet Explorer

A World Wide Web browser produced by Microsoft and included free with Windows. See also
World Wide Web and Internet.

Internet Group Management Protocol (IGMP)

Employed by IP hosts, the protocol that reports their multicast group memberships to an adjacent multicast router.

Internet Information Server (IIS)

Serves Internet higher-level protocols like HTTP and FTP to clients using Web browsers. See also Hypertext Transfer Protocol, File Transfer Protocol and World Wide Web.

Internet Layer

The layer in the DoD model that relates to the Network layer of the OSI model.

Internet Locator Server (ILS)

A Microsoft server that monitors which users are online and available for collaboration, such as participating in a chat, a whiteboarding session, or even a videoconference.

Internet Message Access Protocol 4 (IMAP4)

An Internet retrieval protocol that enables clients to access and manipulate messages in their mailbox on a remote server. IMAP4 provides additional functions over POP3, such as access to subfolders (not merely the Inbox folder), and selective downloading of messages.

Internet Print Protocol (IPP)

A Windows protocol that allows users to print directly to a URL. Printer- and job-related information are generated in HTML format. See also Uniform Resource Locator and Hypertext Markup Language.

Internet Printer

A Windows feature that allows users to send documents to be printed through the Internet.

Internet Protocol (IP)

A connectionless protocol that provides datagram service, and IP packets are most commonly referred to as IP datagrams. IP is a packet-switching protocol that performs the addressing and route selection. IP operates at the Network layer of the OSI model. See also Transmission Control Protocol/Internet Protocol and Internet.

Internet Protocol Security (IPSec)

A suite of encryption services and security protocols that allow you to protect the traffic on your network, not only between remote sites but within the local area network as well. IPSec allows for confidentiality through encryption, authentication through digital signatures or shared keys, and data integrity by incorporating a checksum for verification.

Internet Relay Chat (IRC)

An Internet protocol used to enable real-time, text-based conversations on a network or networks. Conversations are called chats or sessions, and the organization of a number of chats on a particular topic is called a channel.

Internet Server Application Programming Interface (ISAPI) Filter

A method for directing Web browser requests for specific URLs to specific ISAPI applications, which are then run. ISAPI filters are commonly used to manage customized logon authentication.

Internet Service Provider (ISP)

A company that provides dial-up connections to the Internet. See also Internet.

Internet Services Manager

A Windows utility used to configure the protocols that are used by Internet Information Services (IIS) and Personal Web Services (PWS).

Internetwork

A network made up of multiple network segments that are connected with some device, such as a router. Each network segment is assigned a network address. Network layer protocols build routing tables that are used to route packets through the network in the most efficient manner.

Internetworking

Broadly, anything associated with the general task of linking networks to each other. The term encompasses technologies, procedures, and products. When you connect networks to a router, you are creating an internetwork.

Internetwork Packet Exchange (IPX)

The Network and Transport layer protocol developed by Novell for its NetWare product. IPX is a routable, connection-oriented protocol similar to TCP/IP but much easier to manage and with lower communication overhead. See also Internet Protocol, NetWare, and NetWare Link.

InterNIC

The agency that is responsible for assigning IP addresses. See also Internet Protocol and IP Address.

Interoperability

The ability of different systems to work together (for example, the ability of two different messaging systems to exchange messages).

Interpersonal Messaging (IPM)

The X.400 standard for the format of an e-mail message.

Interprocess Communications (IPC)

A generic term describing any manner of client/server communication protocols, specifically those operating in the Application layer. Interprocess communications mechanisms provide a method for the client and server to trade information. See also Named Pipes, Remote Procedure Call, Network Basic Input/Output System, Mailslots, Network Dynamic Data Exchange, and Local Procedure Call.

Interrupt Request (IRQ)

A hardware signal from a peripheral device to the microprocessor indicating that it has I/O traffic to send. If the microprocessor is not running a more important service, it will interrupt its current activity and handle the interrupt request. IBM PCs have 16 levels or interrupt request lines. Under Windows each device must have a unique interrupt request line. See also Microprocessor, Driver, and Peripheral.

Interrupts

Inputs to the CPU in a PC that allow devices to get its attention – to interrupt it – if it is performing another task. Interrupts are also called IRQs (for interrupt requests).

Intersite

Transfer of information across site boundaries.

Intersite Replication

AD replication between domain controllers that are located in different AD sites.

InterSite Topology Generator (ISTG)

Windows server that generates the connection objects between sites within an AD forest.

INTERSVR

Starts the Interlnk server.

In The Wild (ITW)

A virus is “in the wild” if it is verified as having caused an infection outside a laboratory situation. Most viruses are in the wild and differ only in prevalence. See also Zoo Virus.

Intra-Area Routing

Routing that occurs within a logical area. See also Interarea Routing.

Intra-Forest Restructuring

The process of moving security principals between domains within the same Active Directory forest.

Intranet

A privately owned network based on the TCP/IP protocol suite. See also Transmission Control Protocol/Internet Protocol.

Intrasite

Transfer of information within one site.

Intrasite Replication

AD replication between domain controllers with the same AD site.

Intrusion Detection Filter

Special packet or application filters designed to look for specific intrusion methods, and stop them.

Inverse ARP

See Inverse Address Resolution Protocol.

Inverse Address Resolution Protocol

A technique by which dynamic mappings are constructed in a network, allowing a device such as a router to locate the logical network address and associate it with a permanent virtual circuit (PVC). Commonly used in Frame Relay to determine the far-end node’s TCP/IP address by sending the Inverse ARP request to the local DLCI.

I/O (Input/Output)

The process of reading and writing data back and forth from cache to disk. The smallest unit of I/O in SQL Server is the 8KB page. All I/O happens in page increments. Logical I/O is defined as a data read or write operation that is made to cache or disk. Physical I/O is subclassified as a data read or write that is made to disk only.

IP

See Internet Protocol.

IP Address

A four-byte number that uniquely identifies a computer on an IP internetwork. InterNIC assigns the first bytes of Internet IP addresses and administers them in hierarchies. Huge organizations like the government or top-level Internet service providers (ISP) have Class A addresses, large organizations and most ISPs have Class B addresses, and small companies have Class C addresses. In a Class A address, InterNIC assigns the first byte, and the owning organization assigns the remaining three bytes. In a Class B address, InterNIC or the higher level ISP assigns the first two bytes, and the organization assigns the remaining two bytes. In a Class C address, InterNIC or the higher level ISP assigns the first three bytes, and the organization assigns the remaining byte. Organizations not attached to the Internet can assign IP addresses as they please. See Internet Protocol and Internet.

IPC

See Interprocess Communications.

IPCONFIG

A command used to display the computer’s IP configuration.

IPCONFIG Tool

Command-line tool provided by Windows used to configure, and to see the configuration of, TCP/IP interfaces on your local machine.

IP Control Program (IPCP)

The protocol used to establish and configure IP over PPP. See also Internet Protocol and Point-to-Point Protocol.

IPCP

See IP Control Program.

IP Datagram

The structure that enables a client and server to transfer other types of network traffic. The data is wrapped inside an IP datagram.

IP Fragment Filters

Filters designed to detect and drop fragmented packets to help protect against several well-known attacks. However, certain applications such as streaming audio also make use of fragments to deliver their large payload across the network.

IP Multicast

A technique for routing that enables IP traffic to be reproduced from one source to several endpoints or from multiple sources to many destinations. Instead of transmitting only one packet to each individual point of destination, one packet is sent to a multicast group specified by only one IP endpoint address for the group.

IPP

See Internet Print Protocol.

IPSec

See IP Security Extensions.

IPSec Client

The computer that attempts to establish a connection to another machine. See also IPSec Server.

IPSec Policy Agent

A service running on a Windows machine that connects to an Active Directory server and fetches the IPSec policy and then passes it to the IPSec code.

IPSec Server

The target of an IPSec client’s attempts.

IPSec Tunnel

See Tunnel Mode.

IP Security Extensions (IPSec)

A process that makes it possible to transfer sensitive information to other hosts across the Internet without fear of compromise. IPSec provides authentication and encryption for transmitted data.

IPTUNNEL

A software driver that permits the encapsulation of IPX packets inside of IP packets for transmission over an IP network. This allows NetWare servers to communicate through links that support only TCP/IP, such as UNIX machines.

IPX

See Internetwork Packet Exchange.

IPX Control Program (IPXCP)

The protocol used to establish and configure IPX over PPP. See also Internetwork Packet Exchange and Point-to-Point Protocol.

IPXCP

See IPX Control Program.

IPX External Network Number

A number that is used to represent an entire network. All servers on the network must use the same external network number.

IPX Internal Network Number

A number that uniquely identifies a server to the network. Each server must have a different internal network number.

IPX/SPX

A protocol suite developed by Xerox and used by Novell operating systems.

IPXWAN

Protocol used for new WAN links to provide and negotiate line options on the link using IPX. After the link is up and the options have been agreed upon by the two end-to-end links, normal IPX transmission begins.

IRQ

See Interrupt Request.

IRTF (Internet Research Task Force)

One of the task forces of the IAB. The group responsible for research and development of the Internet protocol suite.

ISA

See Industry Standard Architecture.

ISAPI Filter

See Internet Server Application Programming Interface Filter.

ISDN

See Integrated Services Digital Network.

ISDN Modem

An interconnectivity device that connects a computer to an ISDN line.

ISL Routing

Inter-Switch Link routing is a Cisco proprietary method of frame tagging in a switched internetwork. Frame tagging is a way to identify the VLAN membership of a frame as it traverses a switched internetwork.

ISO 10646

A 4-byte character encoding scheme that includes all the world’s national standard character
encodings, defined by the International Organization for Standardization (ISO). The 2-byte Unicode characters set maps into part of ISO 10646. See also American Standard Code for Information Interchange, Double-Byte Character Set, and Unicode.

Isochronous Transmission

Asynchronous data transfer over a synchronous data link, requiring a constant bit rate for reliable transport.

ISP

See Internet Service Provider.

Iteration

The incremental process by which DNS names are resolved to IP addresses.

ITU-T

See International Telecommunication Union Telecommunication Standardization Sector.

ITW

See In The Wild.

IUSR_computername

A special user account that is used for anonymous access for Internet Information Services (IIS) on a computer that has IIS installed.

IWAM_computername

A special user account that is used for Internet Information Services (IIS) to start from process applications on a computer that has IIS installed.