N
N-type SiliconSilicon that is negatively charged by doping with an element, such as Boron, which contains an extra electron. The extra electron enables electric current to flow through the material. See Semiconductors for more info.
NAS
Network Access Server
NFAS
Non-Facility Associated Signaling. A special case of ISDN signaling in which two or more T1 PRI lines use the same D channel, and you can add a backup D channel. NFAS is required for Switched-1536 data service; because all 24 channels of the T1 PRI line carry user data, the D channel must be on another line.
NFS
Network File System
NHRP
Next Hop Resolution Protocol
NIC
Network Information Center
NIS
Network Information Service
NOC 1 System
The operations system that functions as the network operations center for small telecommunications networks.
NOT Logic Gate
in semiconductor technology, a type of logic gate which uses NOT logic. The output of a NOT logic gate inverts the input from on to off or off to on. Semiconductors for more info.
NSFNET-IGP
National Science Foundation Network Interior Gateway Protocol
NT1 (Network Terminator Type 1)
An ISDN BRI line terminating device at the subscriber's location that provides line maintenance access, timing, and echo cancellation. NT1s may be built into other pieces of equipment or stand alone.
NTSC
National Television Systems Committee. Sets television standards in the United States. Also the video format used in the United States.
NVP-II
Network Voice Protocol II
NVRAM
Nonvolatile random access memory. Nonvolatile storage that can be erased and reprogrammed electronically, allowing software images to be stored, booted, and rewritten as necessary.
NVT ASCII
Network Virtual Terminal ASCII Nailed Line
Nailed Group
A group of nailed channels designated in an X.25 or frame relay profile.
Nailed-up Channel
A channel on a line rented from the phone company for exclusive use, 24 hours per day, seven days per week.
Nailed-up Circuit
A permanent connection between endpoints over which two parties exchange data. The number of nailed-up channels must be the same at both ends of the connection. For example, if there are five nailed-up channels at the local end, there must be five nailed-up channels at the remote end. However, channel assignments do not have to match. For example, channel 1 can be switched at the local end and nailed up at the remote end. A nailed-up circuit is also known as a private circuit or a leased circuit.
Nailed-up Line
A line rented from the phone company for exclusive use, 24 hours per day, seven days per week. The connection exists between two predetermined points and cannot be switched to other locations. A nailed-up line is also called a leased line.
Name Binding Protocol (NBP)
NBP is an AppleTalk protocol that enables you to make your application visible to users on an AppleTalk network. NBP associates the socket address assigned to a process or application to a name that contains three parts—the object, type, and zone fields. The object and type can be chosen by the developer, but the zone field specifies the zone in which the node resides.
Name Service
A distributed database service that maintains a single set of system configuration files for multiple systems on a network.
Name server
In data communications, a server connected to a network that transforms host names into network addresses.
Narrowband
In communications technology, digital communication at the rate of 64,000 bits per second or lower.
National ISDN-1 (NI-1)
NI-1 is a standard service type for an ISDN phone line. It was created so that users would not have to know what kind of switch they were connected to in order to buy compatible equipment. All the Regional Bell Operating Companies (RBOCs) support NI-1, though a new standard, National ISDN-2 (NI-2), was recently adopted.
National ISDN-2 (NI-2)
NI-2 is a new switch type that represents a more comprehensive standard than National ISDN-1 (NI-1).
National Security Computer Association (NSCA)
National Security Computer Association.
National Television Standards Committee
The TV standard used primarily in North America and Japan with 525 lines transmitted at 60 interlaced half-frames per second.
NavisAccess
An application that delivers superior management for the dial-up and dedicated portions of the network, providing extensive support for discovery and mapping, configuration, fault and performance management, and security.
NavisCore
An application that operates in conjunction with HP OpenView to provide multiservice IP, frame relay, asynchronous transfer mode (ATM) and switched multimegabit data service (SMDS) configuration and management of Lucent core switches from a single platform.
NavisXtend
An application that extends the capabilities of NavisCore to bring additional features and cost efficiencies to switch network operations, such as provisioning automation, intelligent fault handling, and historical statistics storage.
Negative Acknowledgment (NAK)
A NAK is a packet sent from a receiver to a sender, informing the sender that data is missing or corrupt. When a device receives a packet, it sends back a packet to the sending device. If all the data arrived without corruption, the packet is an acknowledgment (ACK). If some of the data is missing or corrupt, a NAK results requests that the sender retransmit the data.
NetWare Call Filter
A NetWare call filter is used to prevent Service Advertising Protocol (SAP) packets originating on the local IPX network from resetting the idle timer or initiating a call.
Network
A collection of computers, terminals, and other devices and the hardware and software that enable them to exchange data resources.
Network Access Server
Network access server.
Network Address Translation (NAT)
Hides the IP addresses of client stations in an internal network by presenting one IP address to the outside world. Performs the translation back and forth.
Network Alignment
A method of setting up IP address pools for pool summary. When you perform network alignment, you make sure that the first address in the pool is the first host address, and that the maximum number of entries you specify is two less than the total number of addresses in the pool.
Network Block Transfer (NETBLT )
A transport level, flow control, bulk data transfer protocol used in the Internet.
Network Channel Terminating Equipment
Hardware that links a user's premises to the network.
Network Element
A piece of equipment in a telecommunications network, such as cross-connects, multiplexers, and transmission gear.
Network Interface Unit
In telecommunications, the boundary point between the network and the customer. It separates wiring and equipment owned by the network service provider from that of customers.
Network Layer
A layer in the OSI Reference Model. The Network layer provides address resolution and routing protocols. Address resolution enables the Network layer to determine a unique network address for a node. Routing protocols allow data to flow between networks and reach their proper destination. Examples of Network-layer protocols are Address Resolution Protocol (ARP), Datagram Delivery Protocol (DDP), Internet Control Message Protocol (ICMP), Interior Gateway Protocol (IGP), Internet Protocol (IP), Internetwork Packet Exchange (IPX), and Packet Layer Protocol (PLP).
Network Management System
The system that controls network configuration, fault and performance management, and diagnostic analysis.
Network Operating System (NOS)
An operating system for networks or the software that runs on local area networks. It manages the continual conversation between all computers on a network.
Network Operations Center (NOC)
The work center that monitors the operations of a telecommunications network.
Network Service Provider (NSP)
An NSP is a company that provides Internet connectivity to Internet Service Providers (ISPs) and other organization requiring high-speed access to the Internet.
Network Switch
A network device that selects a path or circuit for sending data to its next destination.
Network Termination (NT )
The termination point of a virtual channel, virtual path, or virtual path/channel at the user-network interface (UNI).
Network Tone Cut-through
A feature that provides answer supervision support for Lucent unit gateways that use non-PRI trunks. Network tone cut-through enables each Lucent unit to pass call-progress tones across the IP network for voice-over-IP (VoIP) calls. Call-progress tones generated by a distant public switched telephone network (PSTN) are passed between the two Lucent unit gateways processing the call. When a Far End Gateway receives call progress tones from the PSTN, the tones are stored as voice frames, and then transmitted across the IP network in Real-Time Transport Protocol (RTP) packets. Upon receiving the RTP packets, the Near End Gateway decodes and sends these tones to the calling endpoint. Network tone cut-through is also known as far end cut-through PSTN, RTP, VoIP.
Network Virtual Terminal (NVT)
An NVT is a bi-directional character device with a printer and a keyboard. The printer responds to incoming data, and the keyboard produces outgoing data sent over a Telnet connection. The code set is seven-bit ASCII in an eight-bit field.
Network Virtual Terminal ASCII (NVT ASCII)
Network Virtual Terminal ASCII.
Network Voice Protocol (NVP)
NVP is a protocol developed to enable the communication of real-time interactive voice over disparate computer networks.
Network-Node Interface
The point where one network connects to another.
Network-side Address
The interface address of the line on which the Lucent unit sends an outgoing call. A call switched to a local ISDN BRI line is an example of a route to a network-side address.
Neural Network
Computer chips that mimic the way brain cells retrieve information and solve problems.
New Technology (NT)
Known as Windows NT, the operating system from Microsoft Corporation that lets Windows run on file servers and high-end workstations and provides multitasking, security, and network connectivity.
Next-generation Public Network
A packet-based infrastructure that integrates data, fax, video, and voice communications.
Node
A device, such as a PC, server, switching point, bridge, or gateway, connected to a network at a single location. A node can also be called a station.
Noise
On a communications channel, extraneous signals that degrade the quality or performance of the link.
Non-facility Associated Signaling
A special case of ISDN signaling in which two or more T1 PRI lines use the same D channel, and you can add a backup D channel. NFAS is required for switched-1536 data service; because all 24 channels of the T1 PRI line carry user data, the D channel must be on another line.
North American Numbering Plan
The system used to route calls through the public network in North America. It consists of 10 digits: area code, three-digit prefix or central office code, and subscriber code. For example, 212-555-5555
Null Modem
A device that connects two computers by emulating the characteristics of a modem. Similar to a modem eliminator.
Null Modem Cable
A cable that joins computing devices directly to each other instead of over a network. It's used to connect the console port or any asynchronous data terminal equipment (DTE) port to a terminal or other DTE.
Numbering Plan Area
Also called area code, the 3-digit NPA is the first part of every phone number in the North American Numbering Plan.
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