P


packet filtering

A firewall method in which each packet that attempts to pass through the firewall is examined to determine its contents. The packet is then allowed to pass or it is blocked, as appropriate.



packet sniffer

A device or an application that allows data to be copied from the network and analyzed. In legitimate applications, it is a useful network troubleshooting tool.



PAN (Personal Area Network)

A network layout whereby devices work together in close proximity to share information and services, commonly using technologies such as Bluetooth or infrared.



passive hub

A hub that has no power and therefore does not regenerate the signals it receives. Compare with active hub.



passive termination

A SCSI bus terminator that uses a terminating resistor pack placed at the end of the bus. This resistor relies on the interface card to provide it with a consistent level of power.



password

A set of characters used with a username to authenticate a user on a network and to provide the user with rights and permissions to files and resources.



patch

A fix for a bug in a software application. Patches can be downloaded from the Internet to correct errors or security problems in software applications.



patch cable

A cable, normally twisted-pair, used to connect two devices together. Strictly speaking, a patch cable is the cable that connects a port on a hub or switch to the patch panel, but today, people commonly use the term to refer to any cable connection.



patch panel

A device in which the cables used in coaxial or twisted-pair networks converge and are connected. The patch panel is usually in a central location.



PCAnywhere

A software program that allows users to gain control of a computer remotely.



PCI (Peripheral Component Interconnect)

A relatively new high-speed bus designed for Pentium systems.



PCMCIA (Personal Computer Memory Card International Association)

An industry group organized in 1989 to promote standards for credit cardsized devices such as memory cards, modems, and network cards. Almost all laptop computers today have multiple PCMCIA slots. PCMCIA cards are now generally referred to simply as PC cards.



peer-to-peer networking

A network environment that does not have dedicated servers, where communication occurs between similarly capable network nodes that act as both clients and servers.



permissions

Authorization provided to users that allows them to access objects on a network. The network administrators generally assign permissions. Permissions is slightly different from but often used with rights.



physical address

The MAC address on every NIC. The physical address is applied to a NIC by the manufacturer and except for very rare occurrences, is never changed.



physical layer

Layer 1 of the OSI model, where all physical connectivity is defined.



physical topology

The actual physical layout of the network. Common physical topologies include star, bus, and ring. Compare with logical topology.



ping

A TCP/IP protocol stack utility that works with ICMP and uses echo requests and replies to test connectivity to other systems.



plenum

The space between the structural ceiling and a drop-down ceiling that is commonly used for heating, ventilation, and air-conditioning systems as well as for running network cables.



plug-and-play

An architecture designed to enable hardware devices to be detected by the operating system and for the driver to be automatically loaded.



polling

The media-access method for transmitting data in which a controlling device is used to contact each node to determine whether it has data to send.



PoP (point-of-presence)

The physical location where a long-distance carrier or a cellular provider interfaces with the network of the local exchange carrier or local telephone company.



POP (Post Office Protocol)

A protocol that is part of the TCP/IP protocol suite and is used for retrieving mail stored on a remote server. The most commonly used version of POP is POP3. POP is an application layer protocol.



port

In physical networking terms, a pathway on a networking device that allows other devices to be connected. In software terms, a port is the entry point into an application, system, or protocol stack.



port mirroring

A process by which two ports on a device, such as a switch, are configured to receive the same information. Port mirroring is useful in troubleshooting scenarios.



POTS (Plain Old Telephone Service)

The current analog public telephone system.

See also [PSTN]


PPP (Point-to-Point Protocol)

A common dial-up networking protocol that includes provisions for security and protocol negotiation and provides host-to-network and switch-to-switch connections for one or more user sessions.



PPPoE (Point-to-Point Protocol over Ethernet)

Internet connection authentication protocol that uses two separate technologies, Ethernet and the Point-to-Point Protocol (PPP), to provide a method for multiple users to share a common Digital Subscriber Line (DSL), cable modem, or wireless connection to the Internet.



PPTP (Point-to-Point Tunneling Protocol)

A protocol that encapsulates private network data in IP packets. These packets are transmitted over synchronous and asynchronous circuits to hide the underlying routing and switching infrastructure of the Internet from both senders and receivers.



presentation layer

Layer 6 of the OSI model, which prepares information to be used by the application layer.



PRI (Primary Rate Interface)

A high-level network interface standard for use with ISDN. PRI is defined as having a rate of 1.544Mbps, and consists of a single 64Kbps D channel plus 23 T1 B channels for voice or data.

See also [BRI]
See also [ISDN]


primary name server

The DNS server that offers zone data from files stored locally on the machine.



private network

A network to which access is limited, restricted, or controlled. Most corporate networks are private networks. Compare with public network.



proprietary

A standard or specification that is created by a single manufacturer, vendor, or other private enterprise.



protocol

A set of rules or standards that control data transmission and other interactions between networks, computers, peripheral devices, and operating systems.



protocol suite

Any two or more protocols that work together, such as TCP and IP or IPX and SPX. Also known as a protocol stack.



proxy

A device, an application, or a service that acts as an intermediary between two hosts on a network, eliminating the ability for direct communication.



proxy server

A server that acts as a go-between for a workstation and the Internet. A proxy server typically provides an increased level of security, NAT, caching, and administrative control.



PSTN (public switched telephone network)

A term that refers to all the telephone networks and services in the world. The same as POTS, PSTN refers to the world's collection of interconnected public telephone networks that are both commercial and government owned. All of the PSTN is digital, except the connection between local exchanges and customers (which is called the local loop or last mile), which remains analog.



public network

A network, such as the Internet, to which anyone can connect with the most minimal of restrictions. Compare with private network.



punchdown block

A device that is used to connect network cables from equipment closets or rooms to other parts of a building. Connections to networking equipment such as hubs or switches are established from the punchdown block. Also used in telecommunications wiring for distributing phone cables to their respective locations throughout the building.



punchdown tool

A hand tool that enables the connection of twisted-pair wires to wiring equipment such as a patch panel.





    Network+ Exam Cram 2
    Network+ Exam Cram 2
    ISBN: 078974905X
    EAN: N/A
    Year: 2003
    Pages: 194

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