CCNA Vocabulary_N_O_P.txt

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CCNA Vocabulary_N_O_P.txt
2011-07-12 11:22:28
CCNA Vocab

CCNA Vocab N
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  1. network
    • 1.collection of computers, printers, routers, switches, and other devices that can communication with each other over some transmission medium.
    • 2.command that assgins a NIC based address to which the router is directly connected.
  2. network address
    a dotted decimal number defined by the IPv4 protocol to represent a network or subnet. It represents the network that hosts reside in. Also called a network number or network ID.
  3. Network address translation (NAT)
    translation RFC 1918 addresses to public domain addresses. Because RFC 1918 addresses are not routerd on the Internet, hosts accessing the Internet must use public domain addresses.
  4. network baseline
    a collection of data that establishes a reference for network performance and behavior over a period of time. This reference data is used in the future to assess the health and relative growth of network utilization.
  5. network interface card
    computer hardware, typically used for LANS, that allows the computer to connect to some network cable. The NIC can then send and receive data over the cable at the direction of the computer.
  6. network segment
    a part of a computer network that every device communicates with using the same physical medium. Network segments are extended by hubs or repeaters.
  7. Network time protocol
    a protocol for synchronizing the clocks of computer systems over packet-switch data networks. NTP uses UDP port 123 as its transport layer.
  8. node
    data link layer term describing a device connected to a network.
  9. noise
    In networking, a general term referring to any energy signal on a transmission medium that is not part of the signal used to transmit data over that medium.
  10. nonreturn to zero
    line code in which 1s are represented by one significant condition and 0s are represented by another.
  11. nonvolatile RAM (NVRAM)
    random-access memory that does not lose its contents when the computer is shut down
  12. nslookup
    a service or a program to look up information in the DNS
  13. octet
    a group of 8 binary bits. It is similar to, but not the same as, a byte. One Application in computer network is to use octets to divide IPv4 addresses into four components
  14. Open systems interconnection
    International standardization program created by ISO and ITU-T to develop standards for data networking that facilitate multivendor equipment interoperability
  15. Optical time domain reflectometer
    a popular certification method for fiber systems. The OTDR injects light into the fiber and then graphically displays the results of the detected reflected light. The OTDR measures the elapsed transit time of reflected light to calculate the distance to different events. The visual display allows determination of loss per unit lenght, evaluation of splices and connectors, and fault location. OTDR zooms in to certain locations for a close-up picture of portions of the link.
  16. Organizational Unique Identifier
    The first half of a MAC address. Manufactures must ensure that the value of the OUI has been registered with the IEEE. This value identifies the manufacturer of any Ethernet NIC or interface.
  17. overhead
    resources used to manage or operate the network. Overhead consumes bandwidth and reduces the amount of application data that can be transported across the network.
  18. packet
    when used generically, this term refers to end-user data along with networking headers and trailers that are transmitted through a network. When used specifically, it is end-user data, along with the network or Internet layer headers and any higherlayer headers, but no lower layer headers or trailers.
  19. Packet Tracer
    a drag-and-drop network simulator developed by Cisco to design, configure and troubleshoot network equipment within a controlled, simulated program environment.
  20. Pad
    a part of the ethernet frame that fills in the data field to ensure that the data field meets the minimum size requirement of 46 bytes.
  21. peer
    a host or node that participates in some form of a group. For example, p2p technology defines a group of peers that participate jointly in the same activity, each one having a server and client component.
  22. physical address
    a data link layer address, for example a MAC address
  23. physical media
    the cabling and connectors used to interconnect the network devices.
  24. physical network
    the connection of devices on a common media. Sometimes a physical network is also referred to as a network segment.
  25. physical topology
    the arrangement of the nodes in a network and the physical connections between them. This is the representation of how the media is used to connect the devices.
  26. ping sweep
    a network scanning technique used to identify which host IP addresses are operational.
  27. pinout
    defines which wires in a cable should connect to each pin on the connectors on both ends of a cable. For example, a UTP cable used for ethernet, used for a straight-through cable pinout, connects the wire at pin 1 on one end with the pin 1 on the other end, the wire at a pin 2 on one end with pi2 on the other end and so on.
  28. plug-in
    In a web browser, an application the browser uses, inside the browser window to display some types of content. For example, a browser typically uses a plug-in to display video.
  29. port
    In networking, this term is used in several ways. With ethernet hub and switch hardware, port is simply another name for interface, which is a physical connector in the swithc into whic a cable can be connected. With TCP and UDP, a port is a software function that uniquely identifies a software process on a computer that uses TCP or UDP. With Pcs a port can be a physical connector on the PC, like a parallel or USB port.
  30. positional notation
    somtimes called place-value notation, this is a numeral system in which each position is related to the next by a constant multiplier, a common ration, called the base or radix of that numeral system.
  31. post office protocol
    a protocol that allows a computer to retrieve email from a server.
  32. prefix length
    in IP subnetting, this refers to the portion of a set of IP addresses whose value must be identical for the addresses to be in the same subnet.
  33. priority queing
    a routing feature in which frames in an interface output queue are prioritized based on various characteristics such as packet size and interface type.
  34. prviate address
    define in RFC 1918, an IP address that does not have to be globally unique because the address exists inside packets only when the packets are inside a single private IP internetwork. Private IP addresses are popularly used in most company today, with NAT translating the private IP addresses into globally unique IP addresses.
  35. protocol
    a written specification that defines what tasks a service or device should perform. Each protocol defines messages, often in the form of headers, plus the rules and processes by which these messages are used to achieve some stated purpose.
  36. protocol data unit
    a generic term from OSI that refers to the data, headers, and trailers about which a particular network layer is concerned.
  37. protocol suite
    a delineation of networking protocols and standards into different categories, called layers, along with definitions of which sets of standards and protocols need to be implemented to create products that can be used to create a working network
  38. proxy arp
    a process that uses the same ARP messages as a normal ARP, but by which a router replies instead of the host listed in the ARP request. When a router sees an ARP request that cannot reach the intended host, but for which the router knows a route to reach the host, the router acts on behalf of the host and responds to the ARP request with the router's MAC address listed in the ARP reply
  39. PSH
    a 1-bit flag in the TCP header that is used to request to the higher layers for immediate delivery of the packet.
  40. public address
    an IP address that has been registered with IANA or one of its member agencies, which guarantees that the address is globally unique. Globally unique public IP addresses can be used for packets sent through the Internet.
  41. pulse amplitude modulation
    a form of signal modulation where the message information is encoded in the amplitude of series of signal pulses. It transmits data by varying the aplitunes of the individual pulses. This is now obsolete and has been replaced by pulse code modulation