global group—A group on a Windows Server 2003 network that allows members of one domain to access resources within that domain as well as resources from other domains in the same forest.
Trang 1gateway—A combination of networking hardware and software that connects two dissimilar kinds of
networks Gateways perform connectivity, session management, and data translation, so they must ate at multiple layers of the OSI Model
oper-gateway router—See border router.
GEO (geosynchronous orbit or geostationary orbit)—The term used to refer to a satellite that
main-tains a constant distance from a point on the equator at every point in its orbit Geosynchronous lites are the type used to provide satellite Internet access
satel-geostationary orbit—See GEO.
geosynchronous—See GEO.
ghost—A frame that is not actually a data frame, but rather an aberration caused by a device
misinter-preting stray voltage on the wire Unlike true data frames, ghosts have no starting delimiter
giant—A packet that exceeds the medium’s maximum packet size For example, any Ethernet packet that
is larger than 1518 bytes is considered a giant
Gigabit Ethernet—A type of Ethernet network that is capable of 1000 Mbps, or 1 Gbps, throughput.
Examples of Gigabit Ethernet include 1000BASE-T and 1000BASE-CX
global group—A group on a Windows Server 2003 network that allows members of one domain to
access resources within that domain as well as resources from other domains in the same forest
globally unique identifier—See GUID.
GNU—The name given to the public software project to implement a complete, free source code
imple-mentation of UNIX It also refers to the collection of UNIX-inspired utilities and tools that are includedwith Linux distributions The term “GNU” is an acronym within an acronym that stands for “GNU’s NotUNIX.”
grandfather-father-son—A backup rotation scheme that uses daily (son), weekly (father), and monthly
(grandfather) backup sets
graphical user interface—See GUI.
group—A means of collectively managing users’ permissions and restrictions applied to shared resources.
Groups form the basis for resource and account management for every type of network operating system,not just Windows Server 2003 Many network administrators create groups according to department or,even more specifically, according to job function within a department
GroupWise—An application from Novell that runs on NetWare servers and provides e-mail,
messag-ing, schedulmessag-ing, and collaboration services
Guest—A user account with very limited privileges that is created during the installation of a network
operating system
GUI (graphical user interface)—A pictorial representation of computer functions and elements that, in
the case of network operating systems, enables administrators to more easily manage files, users, groups,security, printers, and other issues
GUID (globally unique identifier)—A 128-bit number generated and assigned to an object upon its
creation in the Windows Server 2003 Active Directory Network applications and services use an object’sGUID to communicate with it
Trang 2hacker—A person who masters the inner workings of operating systems and utilities in an effort to
bet-ter understand them A hacker is distinguished from a cracker in that a cracker attempts to exploit a work’s vulnerabilities for malicious purposes
net-half-duplex—A type of transmission in which signals may travel in both directions over a medium, but
in only one direction at a time
handshake protocol—One of several protocols within SSL, and perhaps the most significant As its
name implies, the handshake protocol allows the client and server to authenticate (or introduce) eachother and establishes terms for how they securely exchange data during an SSL session
hardware address—See MAC address.
Hardware Compatibility List—See HCL.
hardware RAID—A method of implementing RAID that relies on an externally attached set of disks
and a RAID disk controller, which manages the RAID array
HCL (Hardware Compatibility List)—A list of computer components proven to be compatible with
Windows Server 2003 The HCL appears on the same CD as your Windows Server 2003 software and
on Microsoft’s Web site
head-end—A cable company’s central office, which connects cable wiring to many nodes before it
reaches customers’ sites
hertz (Hz)—A measure of frequency equivalent to the number of amplitude cycles per second.
heuristic scanning—A type of virus scanning that attempts to identify viruses by discovering “virus-like”
behavior
HFC (hybrid fiber-coax)—A link that consists of fiber cable connecting the cable company’s offices to
a node location near the customer and coaxial cable connecting the node to the customer’s house HFCupgrades to existing cable wiring are required before current TV cable systems can provide Internetaccess
HFS+—The primary file system used in Mac OS X Server.
hierarchical file system—The organization of files and directories (or folders) on a disk in which
direc-tories may contain files and other direcdirec-tories When displayed graphically, this organization resembles atreelike structure
High-Speed Token Ring—See HSTR.
home directory—A directory on a server associated with a particular user account A user has full access
privileges to files and subdirectories within his home directory
hop—A term used to describe each trip a unit of data takes from one connectivity device to another
Typ-ically, “hop” is used in the context of router-to-router communications
host—A computer that enables resource sharing by other computers on the same network.
host file—A text file that associates TCP/IP host names with IP addresses.
host name—A symbolic name that describes a TCP/IP device.
Trang 3hosts—Name of the host file used on UNIX, Linux, and Windows systems On a UNIX- or
Linux-based computer, hosts is found in the /etc directory On a Windows-Linux-based computer, it is found in the
%systemroot%\system32\drivers\etc folder
hot site—A place where the computers, devices, and connectivity necessary to rebuild a network exist,
and all are appropriately configured, updated, and connected to match your network’s current state
hot spare—In the context of RAID, a disk or partition that is part of the array, but used only in case one
of the RAID disks fails More generally, “hot spare” is used as a synonym for a hot swappable nent
compo-hot spot—An area covered by a wireless access point that provides visitors with wireless services,
includ-ing Internet access
hot swappable—A characteristic that enables identical components to be interchanged (or swapped)
while a machine is still running (hot) After being installed, a hot swappable component automaticallyassumes the functions of its counterpart
HSTR (High-Speed Token Ring)—A standard for Token Ring networks that operate at 100 Mbps HTML (Hypertext Markup Language)—The language that defines formatting standards for Web doc-
uments
HTTP (Hypertext Transfer Protocol)—An Application layer protocol that formulates and interprets
requests between Web clients and servers
HTTP over Secure Sockets Layer—See HTTPS.
HTTP Secure—See HTTP over Secure Sockets Layer.
HTTPS (HTTP over Secure Sockets Layer)—The URL prefix that indicates that a Web page requires
its data to be exchanged between client and server using SSL encryption HTTPS uses the TCP portnumber 443, rather than port 80 (the port that normal HTTP uses)
hub—A connectivity device that retransmits incoming data signals to its multiple ports Typically, hubs
contain one uplink port, which is used to connect to a network’s backbone
hybrid fiber-coax—See HFC.
hybrid topology—A physical topology that combines characteristics of more than one simple physical
topology
Hypertext Markup Language—See HTML.
Hypertext Transfer Protocol—See HTTP.
IAB (Internet Architecture Board)—A technical advisory group of researchers and professionals
inter-ested in overseeing the Internet’s design, growth, standards, and management
IANA (Internet Assigned Numbers Authority)—A nonprofit, U.S government-funded group that was
established at the University of Southern California and charged with managing IP address allocationand the domain name system The oversight for many of IANA’s functions was given to ICANN in 1998;however, IANA continues to perform Internet addressing and domain name system administration
ICA (Independent Computing Architecture) client—The software from Citrix Systems, Inc that,
when installed on a client, enables the client to connect with a remote access server and exchange
Trang 4key-strokes, mouse clicks, and screen updates Citrix’s ICA client can work with virtually any operating tem or application.
sys-ICANN (Internet Corporation for Assigned Names and Numbers)—The nonprofit corporation
cur-rently designated by the U.S government to maintain and assign IP addresses
ICMP (Internet Control Message Protocol)—A core protocol in the TCP/IP suite that notifies the
sender that something has gone wrong in the transmission process and that packets were not delivered
ICS (Internet Connection Sharing)—A service provided with Windows 98, Me, 2000 and 32-bit
ver-sions of XP operating systems that allows one computer, the ICS host, to share its Internet connectionwith other computers on the same network
ICS host—On a network using the Microsoft Internet Connection Sharing service, the computer whose
Internet connection other computers share The ICS host must contain two network interfaces: one thatconnects to the Internet and one that connects to the LAN
IEEE (Institute of Electrical and Electronics Engineers)—An international society composed of
engi-neering professionals Its goals are to promote development and education in the electrical engiengi-neeringand computer science fields
IEEE 1394—See FireWire.
IETF (Internet Engineering Task Force)—An organization that sets standards for how systems
com-municate over the Internet (for example, how protocols operate and interact)
ifconfig—A utility that establishes and allows management of TCP/IP settings on UNIX-type of
sys-tems
IGMP (Internet Group Management Protocol or Internet Group Multicast Protocol)—A TCP/IP
protocol used to manage multicast transmissions Routers use IGMP to determine which nodes useIGMP to join or leave a multicast group
IKE (Internet Key Exchange)—The first phase of IPSec authentication, which accomplishes key
man-agement IKE is a service that runs on UDP port 500 After IKE has established the rules for the type
of keys two nodes use, IPSec invokes its second phase, encryption
iManager—A browser-based tool for managing eDirectory in NetWare 6.x.
IMAP (Internet Message Access Protocol)—A mail retrieval protocol that improves on the
shortcom-ings of POP The single biggest advantage IMAP4 has relative to POP is that it allows users to store sages on the mail server, rather than always having to download them to the local machine The mostcurrent version of IMAP is version 4 (IMAP4)
mes-IMAP4 (Internet Message Protocol, version 4)—The most commonly used form of the Internet
Mes-sage Access Protocol (IMAP)
impedance—The resistance that contributes to controlling an electrical signal Impedance is measured
in ohms
incremental backup—A backup in which only data that has changed since the last full or incremental
backup is copied to a storage medium After backing up files, an incremental backup unchecks the archivebit for every file it has saved
Trang 5Industry Standard Architecture—See ISA.
information node—See i-node.
infrared—A type of data transmission in which infrared light signals are used to transmit data through
space, similar to the way a television remote control sends signals across the room Networks may use twotypes of infrared transmission: direct or indirect
Infrared Data Association—See IrDA.
infrastructure WLAN—A type of WLAN in which stations communicate with an access point and not
directly with each other
inherited—A type of permission, or right, that is passed down from one group (the parent) to a group
within that group (the child)
i-node (information node)—A UNIX-type file system information storage area that holds all details
about a file This information includes the size, the access rights, the date and time of creation, and apointer to the actual contents of the file
Institute of Electrical and Electronics Engineers—See IEEE.
Integrated Services Digital Network—See ISDN.
integrity—The soundness of a network’s files, systems, and connections To ensure integrity, you must
protect your network from anything that might render it unusable, such as corruption, tampering, ural disasters, and viruses
nat-integrity checking—A method of comparing the current characteristics of files and disks against an
archived version of these characteristics to discover any changes The most common example of integritychecking involves a checksum
intelligent hub—A hub that possesses processing capabilities and can therefore monitor network traffic,
detect packet errors and collisions, poll connected devices for information, and gather the data in base format
data-interior router—A router that directs data between nodes on an autonomous LAN.
International Organization for Standardization—See ISO.
International Telecommunication Union—See ITU.
Internet—A complex WAN that connects LANs and clients around the globe.
Internet Architecture Board—See IAB.
Internet Assigned Numbers Authority—See IANA.
Internet Connection Sharing—See ICS.
Internet Control Message Protocol—See ICMP.
Internet Corporation for Assigned Names and Numbers—See ICANN.
Internet Engineering Task Force—See IETF.
Internet Group Management Protocol—See IGMP.
Internet Group Multicast Protocol—See IGMP.
Trang 6Internet Key Exchange—See IKE.
Internet Message Access Protocol—See IMAP.
Internet Message Access Protocol, version 4—See IMAP4.
Internet Protocol—See IP.
Internet Protocol address—See IP address.
Internet Protocol Security—See IPSec.
Internet Relay Chat—See IRC.
Internet Service Provider—See ISP.
Internet services—The services that enable a network to communicate with the Internet, including
World Wide Web servers and browsers, file transfer capabilities, Internet addressing schemes, securityfilters, and a means for directly logging on to other computers
Internet Society—See ISOC.
Internet telephony—The provision of telephone service over the Internet.
internetwork—To traverse more than one LAN segment and more than one type of network through a
router
Internetwork Packet Exchange—See IPX.
Internetwork Packet Exchange/Sequenced Packet Exchange—See IPX/SPX.
interrupt—A circuit board wire through which a device issues voltage, thereby signaling a request for the
processor’s attention
interrupt request—See IRQ.
interrupt request number—See IRQ number.
intranet—A network or part of a network that uses browser-based services to exchange information
within an enterprise Intranets may be contained within a LAN or may be accessible via a WAN or theInternet
intraNetWare—Another term for NetWare version 4.11, the version in which support for Internet
ser-vices was first introduced
IP (Internet Protocol)—A core protocol in the TCP/IP suite that operates in the Network layer of the
OSI Model and provides information about how and where data should be delivered IP is the tocol that enables TCP/IP to internetwork
subpro-IP address (Internet Protocol address)—The Network layer address assigned to nodes to uniquely
iden-tify them on a TCP/IP network IP addresses consist of 32 bits divided into four octets, or bytes
IP datagram—The IP portion of a TCP/IP frame that acts as an envelope for data, holding information
necessary for routers to transfer data between subnets
IP next generation—See IPv6.
IP phone—See IP telephone.
Trang 7IP spoofing—A security attack in which an outsider obtains internal IP addresses, then uses those
addresses to pretend that he has authority to access a private network from the Internet
IP telephone—A telephone used for VoIP on a TCP/IP-based network IP telephones are designed to
transmit and receive only digital signals
IP telephony—See Voice over IP.
ipconfig—The utility used to display TCP/IP addressing and domain name information in the Windows
NT, Windows 2000, and Windows XP operating systems
IPng—See IPv6.
IP-PBX—A private switch that accepts and interprets both analog and digital voice signals (although
some IP-PBXs do not accept analog lines) It can connect with both traditional PSTN lines and datanetworks An IP-PBX transmits and receives IP-based voice signals to and from other network connec-tivity devices, such as a router or gateway
IPSec (Internet Protocol Security)—A Layer 3 protocol that defines encryption, authentication, and key
management for TCP/IP transmissions IPSec is an enhancement to IPv4 and native to IPv6 IPSec isunique among authentication methods in that it adds security information to the header of all IP packets
IPv4 (IP version 4)—The current standard for IP addressing that specifies 32-bit addresses composed of
four octets
IPv4LL (IP version 4 Link Local)—A protocol that manages automatic address assignment among
locally connected nodes IPv4LL is part of the Zeroconf group of protocols
IPv6 (IP version 6)—A newer standard for IP addressing that will replace the current IPv4 (IP version
4) Most notably, IPv6 uses a newer, more efficient header in its packets and allows for 128-bit sourceand destination IP addresses The use of longer addresses will allow for many more IP addresses to be incirculation
IPX (Internetwork Packet Exchange)—A core protocol of the IPX/SPX suite that operates at the
Net-work layer of the OSI Model and provides routing and internetNet-work services, similar to IP in the TCP/IPsuite
IPX address—An address assigned to a device on an IPX/SPX-based network.
IPX/SPX (Internetwork Packet Exchange/Sequenced Packet Exchange)—A protocol originally
developed by Xerox, then modified and adopted by Novell in the 1980s for the NetWare network ating system
oper-IRC (Internet Relay Chat)—A protocol that enables users running special oper-IRC client software to
com-municate instantly with other participants in a chat room on the Internet
IrDA (Infrared Data Association)—A nonprofit organization founded in 1994 to develop and promote
standards for wireless communication using infrared signals IrDA is also used to denote the type of less technology this group has developed
wire-IRQ (interrupt request)—A message sent to the computer that instructs it to stop what it is doing and
pay attention to something else IRQ is often used (informally) to refer to the interrupt request number
IRQ number—The unique number assigned to each interrupt in a computer Interrupt request numbers
range from 0 to 15, and many PC devices reserve specific numbers for their use alone
Trang 8ISA (Industry Standard Architecture)—The original PC bus type, developed in the early 1980s to
sup-port an 8-bit and later 16-bit data path and a 4.77-MHz clock speed
ISDN (Integrated Services Digital Network)—An international standard that uses PSTN lines to
carry digital signals It specifies protocols at the Physical, Data Link, and Transport layers of the OSIModel ISDN lines may carry voice and data signals simultaneously Two types of ISDN connections areused in North America: BRI (Basic Rate Interface) and PRI (Primary Rate Interface) Both use a com-bination of bearer channels (B channels) and data channels (D channels)
ISO (International Organization for Standardization)—A collection of standards organizations
rep-resenting 146 countries with headquarters located in Geneva, Switzerland Its goal is to establish national technological standards to facilitate the global exchange of information and barrier-free trade
inter-ISOC (Internet Society)—A professional organization with members from more than 180 countries
that helps to establish technical standards for the Internet
ISP (Internet Service Provider)—A business that provides organizations and individuals with Internet
access and often other services, such as e-mail and Web hosting
ITU (International Telecommunication Union)—A United Nations agency that regulates
interna-tional telecommunications and provides developing countries with technical expertise and equipment toadvance their technological bases
J1—A digital carrier standard used in Japan that offers 24 channels and 1.544-Mbps throughput.
J3—A digital carrier standard used in Japan that offers 480 channels and 32.064-Mbps throughput jabber—A device that handles electrical signals improperly, usually affecting the rest of the network A
network analyzer will detect a jabber as a device that is always retransmitting, effectively bringing the work to a halt A jabber usually results from a bad NIC Occasionally, it can be caused by outside elec-trical interference
net-jamming—A part of CSMA/CD in which, upon detecting a collision, a station issues a special 32-bit
sequence to indicate to all nodes on an Ethernet segment that its previously transmitted frame has fered a collision and should be considered faulty
suf-Java System Directory Server Enterprise Edition—The Sun Microsystems implementation of LDAP jumper—A small, removable piece of plastic that contains a metal receptacle that fits over a pair of pins
on a circuit board to complete a circuit between those two pins By moving the jumper from one set ofpins to another set of pins, you can modify the board’s circuit, thereby giving it different instructions onhow to operate
KDC (Key Distribution Center)—In Kerberos terminology, the server that runs the authentication
ser-vice and the Ticket-granting serser-vice to issue keys and tickets to clients
Kerberos—A cross-platform authentication protocol that uses key encryption to verify the identity of
clients and to securely exchange information after a client logs on to a system It is an example of a vate key encryption service
pri-kernel—The core of a UNIX-type of system and a NetWare NOS This part of the operating system is
loaded and run when you turn on your computer It mediates between user programs and the computerhardware
Trang 9kernel module—A portion of the kernel that you can load and unload to add or remove functionality on
a running UNIX or Linux system
key—A series of characters that is combined with a block of data during that data’s encryption To
decrypt the resulting data, the recipient must also possess the key
Key Distribution Center—See KDC.
key management—The method whereby two nodes using key encryption agree on common parameters
for the keys they will use to encrypt data
key pair—The combination of a public and private key used to decipher data that was encrypted using
public key encryption
L2TP (Layer 2 Tunneling Protocol)—A protocol that encapsulates PPP data, for use on VPNs L2TP
is based on Cisco technology and is standardized by the IETF It is distinguished by its compatibilityamong different manufacturers’ equipment, its ability to connect between clients, routers, and serversalike, and also by the fact that it can connect nodes belonging to different Layer 3 networks
label—A character string that represents a domain (either top-level, second-level, or third-level) LAN (local area network)—A network of computers and other devices that is confined to a relatively
small space, such as one building or even one office
LAN Emulation—See LANE.
LANE (LAN Emulation)—A method for transporting Token Ring or Ethernet frames over ATM
net-works LANE encapsulates incoming Ethernet or Token Ring frames, then converts them into ATMcells for transmission over an ATM network
last mile—See local loop.
late collision—A collision that takes place outside the normal window in which collisions are detected
and redressed Late collisions are usually caused by a defective station (such as a card, or transceiver) that
is transmitting without first verifying line status or by failure to observe the configuration guidelines forcable length, which results in collisions being recognized too late
latency—The delay between the transmission of a signal and its receipt.
Layer 2 Tunneling Protocol—See L2TP.
Layer 3 switch—A switch capable of interpreting data at Layer 3 (Network layer) of the OSI Model Layer 4 switch—A switch capable of interpreting data at Layer 4 (Transport layer) of the OSI Model.
LC (Local Connector)—A connector used with single-mode or multimode fiber-optic cable.
LDAP (Lightweight Directory Access Protocol)—A standard protocol for accessing network
directo-ries
leaf object—An object in an operating system’s directory, such as a printer or user, that does not contain
other objects
lease—The agreement between a DHCP server and client on how long the client can use a
DHCP-assigned IP address DHCP services can be configured to provide lease terms equal to any amount oftime
Trang 10LEO (low earth orbiting)—A type of satellite that orbits the earth with an altitude between 700 and
1400 kilometers, closer to the earth’s poles than the orbits of either GEO or MEO satellites LEO lites cover a smaller geographical range than GEO satellites and require less power
satel-Level 1—A form of UTP that contains two wire pairs satel-Level 1 is the type of wire used for older voice
networks and is unsuitable for transmitting data
license tracking—The process of determining the number of copies of a single application that are
cur-rently in use on the network and whether the number in use exceeds the authorized number of licenses
Lightweight Directory Access Protocol—See LDAP.
line printer daemon—See lpd.
line-of-sight—See LOS.
link segment—See unpopulated segment.
Linux—A freely distributable implementation of a UNIX-type of system Finnish computer scientist
Linus Torvalds originally developed it
LLC (Logical Link Control) sublayer—The upper sublayer in the Data Link layer The LLC provides
a common interface and supplies reliability and flow control services
load balancing—An automatic distribution of traffic over multiple links, hard disks, or processors
intended to optimize responses
local account—A type of user account on a Windows Server 2003 network that has rights to the
resources managed by the server the user has logged on to
local area network—See LAN.
local collision—A collision that occurs when two or more stations are transmitting simultaneously.
Excessively high collision rates within the network can usually be traced to cable or routing problems
Local Connector—See LC.
local loop—The part of a phone system that connects a customer site with a telecommunications
car-rier’s switching facility
logical address—See network address.
Logical Link Control layer—See LLC (Logical Link Control) sublayer.
logical topology—A characteristic of network transmission that reflects the way in which data is
trans-mitted between nodes (which may differ from the physical layout of the paths that data takes) The mostcommon logical topologies are bus and ring
loopback adapter—See loopback plug.
loopback address—An IP address reserved for communicating from a node to itself (used mostly for
troubleshooting purposes) The loopback address is always cited as 127.0.0.1, although in fact, ting to any IP address whose first octet is “127” will contact the originating device
Trang 11transmit-loopback plug—A connector used for troubleshooting that plugs into a port (for example, a serial,
par-allel, or RJ-45 port) and crosses over the transmit line to the receive line, allowing outgoing signals to beredirected back into the computer for testing
loopback test—An attempt to contact one’s own machine for troubleshooting purposes In
TCP/IP-based networking, a loopback test can be performed by communicating with an IP address that beginswith an octet of 127 Usually, this means pinging the address 127.0.0.1
LOS (line-of-sight)—A wireless signal or path that travels directly in a straight line from its
transmit-ter to its intended receiver This type of propagation uses the least amount of energy and results in thereception of the clearest possible signal
low earth orbiting—See LEO.
lpd (line printer daemon)—A UNIX service responsible for printing files placed in the printer queue by
thelpr command.lpr
lpr—The UNIX command This command simply places files in the printer queue The files are
subse-quently printed with lpd, the print service
MAC (Media Access Control) sublayer—The lower sublayer of the Data Link layer The MAC
appends the physical address of the destination computer onto the frame
MAC address—A 12-character string that uniquely identifies a network node The manufacturer
hard-codes the MAC address into the NIC This address is composed of the Block ID and Device ID
Mac OS X Server—A proprietary network operating system from Apple Computer that is based on a
version of UNIX
Mach—A UNIX-type of operating system kernel developed by researchers at Carnegie Mellon
Univer-sity in Pittsburgh, PA Mach is the basis for the kernel in Mac OS X Server
macro virus—A virus that takes the form of an application (for example, a word-processing or
spread-sheet) program macro, which may execute when the program is in use
mail server—A server that manages the storage and transfer of e-mail messages.
mail services—The network services that manage the storage and transfer of e-mail between users on a
network In addition to sending, receiving, and storing mail, mail services can include filtering, routing,notification, scheduling, and data exchange with other mail servers
main bus—See bus.
MAN (metropolitan area network)—A network that is larger than a LAN, typically connecting clients
and servers from multiple buildings, but within a limited geographic area For example, a MAN couldconnect multiple city government buildings around a city’s center
man pages—See manual pages.
managed hub—See intelligent hub.
Management Information Base—See MIB.
management services—The network services that centrally administer and simplify complicated
man-agement tasks on the network Examples of manman-agement services include license tracking, security ing, asset management, address management, software distribution, traffic monitoring, load balancing,and hardware diagnosis
Trang 12audit-manual pages—The online documentation for any variety of the UNIX operating system This
docu-mentation describes the use of the commands and the programming interface
map—The action of associating a disk, directory, or device with a drive letter.
MAU (Multistation Access Unit)—A device on a Token Ring network that regenerates signals;
equiv-alent to a hub
maximum transmission unit—See MTU.
MCSE (Microsoft Certified Systems Engineer)—A professional certification established by Microsoft
that demonstrates in-depth knowledge about Microsoft products, including Windows 2000, Windows
XP, and Windows Server 2003
Mechanical Transfer Registered Jack—See MT-RJ.
Media Access Control sublayer—See MAC (Media Access Control) sublayer.
media converter—A device that enables networks or segments using different media to interconnect and
exchange signals
medium earth orbiting–See MEO.
member server—A type of server on a Windows Server 2003 network that does not hold directory
infor-mation and therefore cannot authenticate users
memory range—A hexadecimal number that indicates the area of memory that the NIC and CPU will
use for exchanging, or buffering, data As with IRQs, some memory ranges are reserved for specificdevices—most notably, the motherboard
MEO (medium earth orbiting)—A type of satellite that orbits the earth 10,390 kilometers above its
sur-face, positioned between the equator and the poles MEO satellites can cover a larger area of the earth’ssurface than LEO satellites while using less power and causing less signal delay than GEO satellites
mesh topology WAN—A type of WAN in which several sites are directly interconnected Mesh WANs
are highly fault-tolerant because they provide multiple routes for data to follow between any two points
message switching—A type of switching in which a connection is established between two devices in
the connection path; one device transfers data to the second device, then breaks the connection Theinformation is stored and forwarded from the second device after a connection between that device and
a third device on the path is established
Metaframe—A software package from Citrix Systems, Inc that supplies terminal services to remote
clients
metropolitan area network—See MAN.
MIB (Management Information Base)—A database used in network management that contains a
device’s definitions of managed objects and their data
Microsoft Certified Systems Engineer—See MCSE.
Microsoft Challenge Handshake Authentication Protocol—See MS-CHAP.
Microsoft Challenge Handshake Authentication Protocol, version 2—See MS-CHAPv2.
Microsoft Directory Synchronization Services—See MSDSS.
Trang 13Microsoft Management Console—See MMC.
Microsoft Windows Services for NetWare—A suite of tools for integrating Windows 2000 Server or
Windows Server 2003 servers with NetWare servers The suite includes a tool for synchronizing datafrom NetWare directories with Active Directory, a tool for migrating files from a NetWare server to aWindows Server 2003 server, and File and Print Services for NetWare, which allows a Windows Server
2003 computer to appear as a NetWare server to NetWare clients
middleware—The software that sits between the client and server in a 3-tier architecture Middleware
may be used as a messaging service between clients and servers, as a universal query language for bases, or as means of coordinating processes between multiple servers that need to work together in ser-vicing clients
data-milestone—A reference point that marks the completion of a major task or group of tasks in a project
and contributes to measuring the project’s progress
MIME (Multipurpose Internet Mail Extensions)—A standard for encoding and interpreting binary
files, images, video, and non-ASCII character sets within an e-mail message
mirroring—A fault-tolerance technique in which one component or device duplicates the activity of
another
MMC (Microsoft Management Console)—A customizable, graphical network management interface
used with Windows Server 2003
MMF (multimode fiber)—A type of fiber-optic cable that contains a core with a diameter between 50
and 100 microns, through which many pulses of light generated by a light-_emitting diode (LED) travel
at different angles
mobile—A type of wireless system in which the receiver can be located anywhere within the transmitter’s
range This allows the receiver to roam from one place to another while continuing to pick up its signal
modal bandwidth—A measure of the highest frequency of signal a multimode fiber-optic cable can
sup-port over a specific distance Modal bandwidth is measured in MHz-km
modem—A device that modulates analog signals into digital signals at the transmitting end for
trans-mission over telephone lines, and demodulates digital signals into analog signals at the receiving end
modular router—A router with multiple slots that can hold different interface cards or other devices so
as to provide flexible, customizable network interoperability
modulation—A technique for formatting signals in which one property of a simple carrier wave is
mod-ified by the addition of a data signal during transmission
Monitor—A NetWare NLM that provides a text-based menu for viewing and modifying server
para-meters, such as protocols, bindings, system resources, and loaded modules
motherboard—The main circuit board that controls a computer.
mount—The process of making a disk partition available.
MRTG (Multi Router Traffic Grapher)—A command-line utility that uses SNMP to poll devices,
col-lects data in a log file, and then generates HTML-based views of the data MRTG is freely distributedsoftware originally written by Tobias Oetiker, a networking professional who in the early 1990s saw aneed for a tool to regularly measure the status of his organization’s WAN link
Trang 14MS-CHAP (Microsoft Challenge Handshake Authentication Protocol)—An authentication protocol
offered by Microsoft with its Windows clients and servers Similar to CHAP, MS-CHAP uses a way handshake to verify a client’s credentials and encrypts passwords with a challenge text
three-MS-CHAPv2 (Microsoft Challenge Authentication Protocol, version 2)—An authentication
proto-col provided with Windows XP, 2000, and Server 2003 operating systems that follows the CHAP model,but uses stronger encryption, uses different encryption keys for transmission and reception, and requiresmutual authentication between two computers
MSDSS (Microsoft Directory Synchronization Services)—An application that, when installed on a
Windows Server 2003 server, can synchronize information between an Active Directory database and aNetWare eDirectory database
MT-RJ (Mechanical Transfer Registered Jack)—A connector used with single-mode or multimode
fiber-optic cable
MTU (maximum transmission unit)—The largest data unit a network (for example, Ethernet or Token
Ring) will accept for transmission
Multi Router Traffic Grapher—See MRTG.
multicast address—A type of address in the IPv6 that represents multiple interfaces, often on multiple
nodes An IPv6 multicast address begins with the following hexadecimal field: FF0x, where x is a
char-acter that identifies the address’s group scope
multicasting—A means of transmission in which one device sends data to a specific group of devices
(not necessarily the entire network segment) in a point-to-multipoint fashion Multicasting can be usedfor videoconferencing over the Internet, for example
multimeter—A simple instrument that can measure multiple characteristics of an electric circuit,
includ-ing its resistance and voltage
multimode fiber—See MMF.—
multipath—The characteristic of wireless signals that follow a number of different paths to their
desti-nation (for example, because of reflection, diffraction, and scattering)
multiplexer (mux)—A device that separates a medium into multiple channels and issues signals to each
of those subchannels
multiplexing—A form of transmission that allows multiple signals to travel simultaneously over one
medium
multiprocessing—The technique of splitting tasks among multiple processors to expedite the
comple-tion of any single instruccomple-tion
multiprotocol network—A network that uses more than one protocol.
Multipurpose Internet Mail Extensions—See MIME.
Multistation Access Unit—See MAU.
multitasking—The ability of a processor to perform multiple activities in a brief period of time (often
seeming simultaneous to the user)
mutual authentication—An authentication scheme in which both computers verify the credentials of
each other
Trang 15name server—A server that contains a database of TCP/IP host names and their associated IP addresses.
A name server supplies a resolver with the requested information If it cannot resolve the IP address, thequery passes to a higher-level name server
namespace—The complete database of hierarchical names (including host and domain names) used to
resolve IP addresses with their hosts
narrowband—A type of wireless transmission in which signals travel over a single frequency or within a
specified frequency range
NAS (network attached storage)—A device or set of devices attached to a client/server network,
dedi-cated to providing highly fault-tolerant access to large quantities of data NAS depends on traditionalnetwork transmission methods such as Ethernet
NAT (Network Address Translation)—A technique in which IP addresses used on a private network
are assigned a public IP address by a gateway when accessing a public network
nbtstat—A TCP/IP troubleshooting utility that provides information about NetBIOS names and their
addresses If you know the NetBIOS name of a workstation, you can use nbtstat to determine its IPaddress
NDS (NetWare Directory Services)—In NetWare 4.x and 5.x, the system of managing multiple servers
and their resources, including users, volumes, groups, profiles, and printers, used with NetWare versions4.x and 5.x The NDS model was the precursor to eDirectory
needs assessment—The process of clarifying the reasons and objectives for a proposed change to
deter-mine whether the change is worthwhile and necessary, and to elucidate the scope and nature of the posed change
pro-negative frame sequence check—The result of the CRC (cyclic redundancy check) generated by the
originating node not matching the checksum calculated from the data received It usually indicates noise
or transmission problems on the LAN interface or cabling A high number of (nonmatching) CRCs ally results from excessive collisions or a station transmitting bad data
usu-net mask—See subusu-net mask.
NetBEUI (NetBIOS Enhanced User Interface)—The Microsoft adaptation of the IBM NetBIOS
protocol NetBEUI expands on NetBIOS by adding a Transport layer component NetBEUI is a fast andefficient protocol that consumes few network resources, provides excellent error correction, and requireslittle configuration
NetBIOS (Network Basic Input Output System)—A protocol designed by IBM to provide Transport
and Session layer services for applications running on small, homogeneous networks
NetBIOS Enhanced User Interface—See NetBEUI.
NetDrive—The client software that enables Windows workstations to connect to a NetWare 6.5 server
using standard Internet protocols, such as FTP and HTTP After connecting through NetDrive, a usercan navigate the server’s directories and manage files as if navigating a Windows hard disk
NETMON—Novell’s network monitoring NLM NETMON is included in NetWare 5.x and 6.x.