MAC MAC address MAC-layer address
MAC sublayer MacTCP mail bridge
mail exploder mail gateway Mail Header
Mail Path mail server mailing list
MAN managed object management services
Mancester Encoding MAP MAPI
Mark Martian MASM
Master-clock MAU maxdata
MB MCA MCGA
MCI MCI MDA
MDI MDS media
medium media types Megabyte
message message switching message unit
metacharacter MFLOPS MFM
MFS MGS MHS
MIB MIB variables MIC
microwave mid-level network MIDAS
MIDI midsplit MILNET
MIMD MIME MIS
MMU MNP Modem
Modem Eliminator moderator Modulation
MPC MPEG MPU
MPW MRCI MSAU
MSB MSI MSM
MSU MTA MTBF
MTU mu-law MUD
multicast multicast address Multidrop
multidrop line multihomed host
multihoming multimode fiber multiple domain network
multiplex Multiplexer (Mux) multiplexing
Multipoint Line Multitasking multivendor network
MUSE MVS MX Record
MAC (Media Access Control).
The lower portion of the datalink layer. The MAC differs for various physical
media. See also: MAC Address, Ethernet,
Logical Link Control, Token
MAC address The hardware
address of a device connected to a shared media. See also: Media
Access Control, Ethernet, token
ring. [Source: MALAMUD]
MAC-layer address See
hardware address and physical
MAC sublayer (Media
Access Control sublayer). As defined by the IEEE
, the lower portion of the OSI
reference model data link layer. The MAC sublayer is concerned with media
access issues, such as whether token passing or contention will be used.
MacTCP software from Apple
Computer that allows Macintoshes to talk with other computers via TCP/IP.
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 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 header Information
contained in every mail message which is used by mail programs to provide
the user with a summary of the origin and contents of each message.
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. [Source: RFC1392]
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.
mailing list A possibly
moderated discussion group, distributed via email from a central computer
maintaining the list of people involved in the discussion. [Source: ZEN]
MAN (Metropolitan Area Network).
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]
managed object In network
management, a network device that can be managed by a network management
management services SNA
functions distributed among network components to manage and control an
Mancester Encoding A
digital encoding technique in which each bit period is divided into two
complementary halves a negative-to-positive transition in the middle of
the bit period designates a binary 1 and a positive-to-negative transition
represents the 0. This encoding technique is self-clocking.
Automation Protocol). A network architecture created by General Motors
to satisfy the specific needs of the factory floor. MAP specifies a token-passing
LAN similar to IEEE
MAPI (Messaging API).
Mark In telecommunications,
this means the presence of a signal. A mark is equivalent to a binary "1".
A mark is the apposite of a space ("0").
Martian 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:
MASM (MacroASseMbler) Microsoft.
source of timing signals (or the signals themselves) that all network stations
use for synchronization.
MAU (Medium Attachment
Unit). (IEEE 802.3) or Multistation
Access Unit (IEEE 802.5). In IEEE
802.3, a device that performs IEEE 802.3 Layer 1 functions, including collision
detection and injection of bits onto the network. A MAU is referred to
as transceiver in the Ethernet specification. IEEE 802.5 MAUs (sometimes
called MSAUs so as not to confuse them with IEEE 802.3 MAUs) are wiring
concentrators to which Token Ring lobes attach.
maxdata Maximum data
size for frame on a link.
MCA (Micro Channel Architecture).
IBM's 32-bit expansion bus design found in PS/2s and other high-end computers.
MCGA (MultiColor Graphics
Array). The video adapter of the PS/2s, capable of adding 64-gray-scale
shades to the CGA standard and providing
EGA resolution with 16 colors.
MCI (Media Control Interface).
MCI A telecomunications
company that competes with AT&T and U.S. Sprint for long distance telephone
subscribers. For information about Cisco's MCI interface card, see CSC-MCI.
MDA (Monochrome Display Adapter).
MDI (Multiple Document Interface).
MDS (Macintosh Development
System).or (Microprocessor Development System).
media Plural of medium.
The physical environment through which transmission signals pass. Common
network media include twisted pair, coaxial and fiber optic cable, and
the atmosphere (through which microwave,
LASER, and infrared transmission
medium The material used
to support the transmission of data. This can be copper wire, coaxial cable,
optical fiber, or electromagnetic wave (as in microwave).[Source:
Media Types Specifies
that Content Types, Content Subtypes, Character Sets, Access Types, and
Conversion values for MIME mail will
be assigned and listed by the IANA.
You can see the document in html format or
you can download the original document in text format at ftp.isi.edu/in-notes/iana/assignments/media-types
Megabyte A million bytes.
A thousand kilobytes. See also: Byte,
message An application-layer
logical grouping of information. See also Packet,
message switching Switching
technique involving transmission of messages from node to node through
a network. The message is stored at each node until such time as a forwarding
path is available. See also Packet
Switching and Circuit Switching.
message unit Unit of
data processed by any layer.
metacharacter A single
character that is used in place of another character or set of characters.
MFLOPS (Million Floating-point
Operation Per Second).
MFM (Modified Frequency Modulation).
A method of recording data on disks that eliminates redundant or blank
areas. This recording techhnique provides double-density storage.
MFS (Metropolitan Fiber Systems).
They are perhaps most known in our circles for operating the physcal infrastructure
of the MAE- East internet exchange, and are also involved in MAE-West.
This is a PNO-style organization with its outspring in the US, however
they are beginning to establish themselves with a presence in cities in
europe as well ...
MGS (Midsize Gateway
Server). Cisco 4-slot bridge/router.
MHS (Message Handling System).
The system of message user agents, message transfer agents, message stores,
and access units which together provide OSI electronic mail. MHS is specified
in the CCITT X.400 series
MIB (Management Information
Base). 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]
MIB variables (Management
Information Base variables). A database of information on managed objects
that can be accessed via network management protocols such as SNMP
MIC (Media Interface
Connector). FDDI de facto standard
waves in the range 1 to 30 gigahertz. Microwave-based networks are a nascent
technology gaining favor due to high bandwidth and relatively low cost.
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. [Source: RFC1392]
MIDAS An Australian
MIDI (Musical Instrument
Digital Interface). For more information see: LexiCat
cable system in which the available frequencies are split into two groups:
one for transmission and one for reception.
MILNET (MILitary NETwork).
Originally part of the ARPANET, MILNET
was partitioned in 1984 to make it possible for military installations
to have reliable network service, while the ARPANET continued to be used
for research. See DDN
MIMD (Multiple Instruction,
Internet Mail Extensions). An extension to Internet
email which provides the ability to transfer non-textual data, such as
graphics, audio, video and fax . It is defined in RFC1341.
Now obsoleted by RFC1521.
(Updated by RFC1590)
See also: Electronic Mail. [Source:
MIS (Management Information
System). A computer system that provides management with information on
MMU (Memory Management Unit).
The hardware used to translate virtual memory addresses into physical memory
MNP (Microcom Network Protocols).
Protocols for error correction and data compression from Microcom-Inc..
Modem (Modulator- Demodulator).
A device used to convert serial digital data from a transmitting DTE
to a signal suitable for transmission over telephone lines. It also reconverts
the transmitted signal to serial digital data for acceptance by a receiving
Modem Eliminator A
device used to connect a local terminal and a computer port. The modem
eliminator replaces the pair of modems ordinarily required.
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.
by which signal characteristics are transformed to represent information.
Types of modulation include frequency modulation (FM), in which signals
of different frequencies represent different data values, and amplitude
modulation (AM), in which signal amplitude is varied to represent different
MOO (Mud, Object Oriented)
-- one of several kinds of multi-user role-playing environments, so far
only text-based. See also: MUD, MUSE
MOP Maintenance Operation
Protocol. Digital Equipment Corporation
protocol, a subset of which is supported by Cisco Systems, that provides
a way to perform primitive maintenance operations on DECnet systems. For
example, MOP can be used to download a system image to a diskless station.
MOSS (MIME Object
Security Services). A protocol that uses the multipart/signed
and multipart/encrypted framework to apply digital signature and encryption
services to MIME objects. Source: [RFC
MPC Multimedia PC). A set
of rules that provides personal computerswith multimedia capabilities.
MPEG (Moving Pictures Experts
Group). A movie format
MPU (MicroProcessor Unit).
MPW (Macintosh Programmer's
MRCI (Microsoft Real-Time
Access Unit). See MAU.
MSB (Most-Significant Bit
MSI (Medium-Scale Integration)..
MSM Cisco's M chassis-based
Moscow State University's network
MTA (Message Transfer Agent).
An OSI application process used to
store and forward messages in the X.400
Message Handling System. Equivalent to Internet mail.
MTBF (Mean Time Between
Failures). The average length of time a system or component will work without
MTU (Maximum Transmission
Unit). The largest frame length which may be sent on a physical medium.
See also: Fragmentation,
Frame. [Source: RFC1392]
mu-law North American
companding standard used in conversion between analog and digital signals
in PCM systems. Similar to the European
MUD (Multi-User Dungeon).
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]
multicast A packet
with a special destination address which multiple nodes on the network
may be willing to receive. See also: Broadcast.
multicast address An
address that refers to multiple network devices. Synonymous with group
Multidrop A communications
arrangement in which multiple devices share a common transmission channel,
although generally only one may transmit at a time.
multidrop line See
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.
scheme in IS-IS routing that supports
assignment of multiple area addresses.
multimode fiber Optical
fiber supporting propagation of multiple frequencies of light.
multiple domain network An
SNA network with multiple SSCPs.
multiplex The division
of a single transmission medium into multiple logical channels supporting
many simultaneous sessions. For example, one network may have simultaneous
rlogin, and SMTP
connections, all going at the same time. [Source: ZEN]
A device allowing two or more signals to pass over and share a common transmission
multiple signals on a single channel.
Multipoint Line A
single communications line or circuit interconnecting several stations.
Usually used with some kind of polling mechanism to address each connected
terminal with a unique address code. Also called a multidrop
execution of two or more processes at the same time.
multivendor network Network
using equipment from more than one vendor. Multivendor networks pose many
more compatibility problems than single-vendor networks.
MUSE One kind of MUD - usually
with little or no violence. See also: MOO,
MVS Multiple Virtual Storage.
MX Record (Mail eXchange
Record). A DNS resource record type indicating which host can handle mail
for a particular domain. See also: Domain
Name System, Electronic Mail. [Source:
NACSIS Nagle's algorithm
NAK name caching name resolution
namespace name server NAPLPS
narrowband NASK NAU
NBNS NBS NC
NCC NCCF NCP
NCSA NCSA Mosaic NDIS
neighboring routers NET
net.citizen netiquette NetNews
Netscape NETSERV NetView
NetWare Network Network Address
network administrator network analyzer Network Information Center
Network interface network layer Network Management System
network numbers Newbie
NIC.DDN.MIL NIKHEF NIS
N-ISDN NIST NIU
NLM NLDM NMI
NMS NMVT NN
NNI NNTP NOC
Node noise NORDUnet
Northwest Net NOS NPDA
NPDN NREN NRM
NRZ NRZI ns
NSAP NSF NSS
NT1 NT2 NTP
NTSC null modem Numeris
NVRAM Nyquist Sampling Theorem
N-1 An intra-university
network in Japan, connecting mainframes via X.25.
N-ISDN (Narrowband ISDN).
same as ISDN.
NACSIS (National Center
for Science Information Systems). Japanese network that is considered the
successor to N-1.
Nagle's algorithm Actually
two separate congestion control algorithms that can be used in TCP-based
networks. One algorithm reduces the sending window: the other limits small
NAK (Negative Acknowledgement).
Response to receipt of a corrupted packet of information. See also: Acknowledgement
name caching Method
by which remotely discovered hast names are stored by a router for use
in future packet-forwarding decisions for quick access.
name resolution The
process of mapping a name into the corresponding address. See also: Domain
Name System. [Source: RFC1208].
namespace A commonly
distributed set of names in which all names are unique. [Source: MALAMUD]
name server A server
provided on the network that risolves network names into network locations
NAPLPS (North American
Presentation-Level Protocol Syntax).
narrowband See baseband.
(Naukowa i Akademicka Siec Komputerowa). Research and Academic
Network in Poland.
NAU (Network Addressable
Unit). SNA term for an addressable entity, Examples include PUs,
LUs, and SSCPs.
Also: (Network Access Unit)
NAUN (Nearest Active
Upstream Neighbor). In Token Ring
or IEEE 802.5 networks, the closest
upstream network device from the device acting as reference point that
is still active.
NBFCP (PPP NetBIOS
Frames Control Protocol). The NBF protocol was originally
called the NetBEUI
protocol. This document defines the Network Control Protocol for establishing
and configuring the NBF protocol over PPP Source: [RFC
Name Server). Windows Internetworking uses its own name server.
NBS (National Bureau
of Standards). See NIST
NC (Network Computer).
Is a set of appliances based upon open standards for networked computing
and communications like HTML, HTTP,
the Java Virtual Machine etc. The
NC should be: small, inexpensive, easy to use, and without the complexity
and cost associated with today's personal computers (PCs).
NCC (Network Coordination
Centre). See NOC.
NCCF (Network Communications
Control Facilities). Netwiew/IBM.
NCP (Network Control Program).
In SNA, a program that routes and controls
the flow of data between a communications controller (in which it resides)
and other network resources.
NCSA National Center for
Supercomputing Applications at the University of Illinois at Urbana-Champaign;
developers of NCSA Mosaic.
NCSA Mosaic A World
Wide Web client developed by NCSA's Software Development Group. The first
WWW browser that was available for the Macintosh, Windows and UNIX all
with the same interface. "Mosaic" really started the popularity of the
Web. The source-code to Mosaic has been licensed by several companies and
there are several other pieces of software as good or better than Mosaic,
most notably "Netscape". See also:
NDIS (Network Driver
Interface Specification). Produced by Microsoft, a specification for generic,
hardware-independent and protocol-independent device driver for NICs.
neighboring routers In
OSPF, two routers that have interfaces
to a common network. On multiaccess networks, neighbors are dynamically
discovered by OSPF's HELLO Protocol.
NET (Network Entity
Title). Network addresses, as defined by the ISO
network architecture and as used in CLNS-based
Netbeui (NetBios Extended
User Interface). Pronounced "net-booey," it is an enhanced version of the
Netbios protocol used by network operating systems such as LAN Manager,
LAN Server, Windows for Workgroups Windows 95 and Windows NT. It formalizes
the transport frame that was never standardized in Netbios and adds additional
functions. The transport layer driver frequently used by Microsoft's LAN
Manager, Windows for Workgroups and Windows NT. Netbeui implements the
OSI LLC2 protocol. More information are available here.
NetBIOS (Network Basic
Input/Output System). The standard interface to networks on systems using
DOS, OS/2, and some versions of Unix
that provides standard ways for applications to interact with a LAN
(e.g. request lower-level network services..
net.citizen An inhabitant
of Cyberspace. One usually tries to be a good net.citizen, lest one be
flamed. [Source: ZEN ]
netiquette A pun on
"etiquette" referring to proper behavior on a network. RFC
1855 (FYI 28) contains a netiquette guide produced by the User Services
area of the IETF. See also: Acceptable
Use Policy, Internet
Engineering Task Force. [Source: RFC1983]
Netnews See: Usenet
Netscape A World Wide
Web client developed by Netscape
NETSERV Is a server,
wich allows fast access to data files and programs of general interest.
The main functions of the server can be divided into three general categories:
File Server, Node Management and User Directory services. [Source: EARN
NetView IBM network
management architecture and related applications.
NetWare Developed and
marketed by Novell, Inc., the world's most popular distributed filer system.
NetWare provides transparent remote file access and numerous other distributed
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. [Source: RFC1392]
network administrator Person
who helps maintain a network.
network analyzer A
hardware/software device offering various network trubleshooting features,
including protocol-specific packet decodes, specific programmed troubleshooting
tests, packet filtering, and packet transmission.
Network Information Center A
location that provides access to RFCs
and other information about the Internet. Usually referred to as a NIC.
Network interface The
boundary between a carrier's network and a local installation.
network layer Layer
3 of the OSI reference model. Layer 3 is the layer at which routing occurs.
network management Generic
term used to describe systems or actions that help maintain, characterize,
or troubleshoot a network. Network management is an increasingly important
topic in the more general field of networking.
System A comprehensive system of equipment used in monitoring,
controlling, and managing a data communications network.
network number See:
Newbie A new participant
of a particular newsgroup or the internet as a whole. "listen you newbie,
read the FAQ before you post..."
NFS (Network File
System). As commonly used, a distributed file system protocol suite
developed by Sun Microsystems that allows remote file access across a network.
In actuality, NFS is simply one protocol in the suite. "NFS" protocols
include NFS, XDR
(External Data Representation), RPC
(Remote Procedure Call), and others. These protocols are part of a larger
architecture that Sun refers to as ONC
(Open Network Computing).
The NFS protocol provides access to shared filesystems across networks.
It is intended to be machine, operating system, network architecture, and
transport independent. The protocol currently exists in two versions: version
and version 3 [< ahref=http://www.cis.ohio-state.edu/htbin/rfc/rfc11813.html>RFC1813],
both built on Sun RPC [RFC1831] and its associated eXternal Data Representation
(XDR) [RFC1832]. Source: [
NIC (Network Information
Center). A NIC provides information, assistance and services to network
users. See also: Network Operations Center.
Also, the acronym NIC can expand to "Network Interface Card" and "Network
Interface Controller". See also adapter.
is the domain name of the DDN NIC. See also: Defense
Data Network, Domain Name System,
Network Information Center.
NIKHEF Nationaal Instituut
voor Kern- en Hoge-Energie Fysica (NL)
NIS (Network Information
Services). A set of services, generally provided by a NIC, to assist users
in using the network. See also: Network
Information Center. [Source: RFC1392]
N-ISDN Narrowband ISDN.
Contrast with B.ISDN.
NIST (National Institute
of Standards and Technology). The United States governmental body that
provides assistance in developing standards. Formerly the National Bureau
of Standards. [Source: MALAMUD]
NIU (Network Interface Unit).
A physical network adapter (e.g. an Ethernet card)..
NLDM (Network Logical Data
NLM (NetWare Loadable Module).
NMI (NonMaskable Interrupt).
An emergency request by hardware for service from the microprocessor that
overrides all other request (e.g., commands made by the user via the keyboard).
NMS (Network Management System).
The system responsible for managing a (portion of a) network. The NMS talks
to network management agents, which reside in the managed nodes, via a
network management protocol. See agent.
NMVT (Network Management
Vector Transport). SNA message consisting of a series of vectors conveying
network management specific information.
NN (Network Node).
Intermediate node in an SNA network that performs route selection and provides
directory services to other APPN nodes.
NNI (ATM Network Node
Interface). The standard interface between ATM
Also: (Network-to-Network Interface) in Frame
Relay. In an SMDS network, an NNI
is referred to as Inter-Switching System Interface (ISSI).
NNTP (Network News Transfer
Protocol). A protocol, defined in RFC
977, for the distribution, inquiry, retrieval, and posting of news
articles. See also: Usenet. [Source:
NOC (Network Operations Center).
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]
Node An addressable device
attached to a computer network. See also: host,
router. In Data Communication a point
of interconnection to a network
noise Undesirable communications
International network operator, provides services the Nordic
national networks and to other networks of interest to the company and
its owners: DENet (Denmark), FUNET
(Finland), SURIS (Iceland), UNINETT
(Norway), SUNET (Sweden)
Northwest Net NSF-funded
regional network serving the Northwest, Alaska, Montana, and North Dakota.
Northwest Net connects all major universities in the region as well as
many leading industrial concerns such as Boeing and Sequent Computer.
NOS (Network Operating
System). Generic term used to refer to what are really distributed sile
systems. Examples of NOSs include NetWare,
Banyan VINES, NSF, and LAN
NPDA (Network Problem Determination
Application). Netview/IBM - also CISCO/ TCP/IP NM.
NPDN Low-speed circuit-switched
public network in the Nordic countries.
NREN (National Research
and Education Network). The NREN is the realization of an interconnected
gigabit computer network devoted to Hign Performance Computing and Communications.
See also: HPCC, IINREN.
NRM (Normal Response
Mode). HDLC mode for use on links
with one primary station and one or more secondary stations. In this mode,
secondary stations can only transmit if they first receive a poll from
the primary station.
NRZ (Non-return to Zero).
A binary encoding scheme representing ones and zeroes by opposite and alternating
high and low voltages, in which there is no return to a zero (reference)
voltage between encoded bits. See unipolar.
NRZI (Non-Return to Zero
Inverted). A binary encoding scheme which inverts the signal in a "1" and
leaves the signal unchanged for a "0". Also called transition coding.
ns (nanosecond). One-billionth
of a second.
NSAP (Network Service Access
Point). The point at which the OSI Network Service is made available to
a Transport entity. The NSAPs are identified by OSI
Network Addresses as specified by ISO 8348/Ad2. The point at which OSI
Network Service is made available to a Layer 4 entity.
NSF (National Science Foundation).
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,
is an essential part of academic and research communications. It is a highspeed
"network of networks" which is hierarchical in nature. At the highest level,
it is a backbone network currently comprising 16 nodes connected to a 45Mb/s
facility which spans the continental United States. Attached to that are
mid-level networks and attached to the mid-levels are campus and local
networks. NSFNET also has connections out of the U.S. to Canada, Mexico,
Europe, and the Pacific Rim. The NSFNET is part of the Internet. [Source:
NSS (Nodal Switching
System). Main routing nodes in the NSFnet backbone. See also: backbone,
National Science Foundation. [Source: MALAMUD]
NT1 Network Termination 1.
NT2 Network Termination 2.
NTP (Network Time Protocol).
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.
It is defined in STD
1119. See also: Internet. [Source:
NTSC (National Television
Standards Committee). U.S. video standard.
null modem Small box
or cable used to join computing devices directly, rather than over a network.
Numeris Public ISDN
network in France.
NVRAM Nonvolatile RAM.
Random access memory that retains its contents when a unit is powered off.
In Cisco products, NVRAM is used to store configuration information.
Nyquist Sampling Theorem Theorem
proved by H. Nyquist showing that it is possible to reconstruct analog
signals from samples if enough samples are taken.
NYSERNet New York state
network with a T1 backbone connecting
NSF, many universities, and several