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PP2P (Peer-To-Peer) - Ability of arbitrary pairs of network nodes to manage communication mutual information (by trading off between being clients and servers) in contrast to the master/slave communication scheme. Packet: A sequence of data, with associated control information, that is switched and transmitted as a whole; refers mainly to the field structure and format defined with the ITU-T X.25 recommendation. Synonym for data unit in the OSI model and used on the network layer. Packet sizes normally varies from 40 to 65,535 (ATM) bytes, depending on network hardware and media, but normally less than 1500. "Packet" is also a generic term used to describe unit of data at all levels of the protocol stack, but it is most correctly used to describe network layer data units. Packet Filter: Firewall technique that looks at each packet entering or leaving the network and accepts or rejects it based on user-defined rules. Packet filtering is fairly effective and transparent to users, but it is difficult to configure. In addition, it is susceptible to IP spoofing. Operates on the Network Layer. Packet Lifetime: The number of stations a packet can visit before being discarded. Packet Loss: Describes an event in which packets or units of information are lost in the exchange between sender and receiver, thereby resulting in no data or incomplete data. Packet Switching: A process where messages are broken into finite-sized packets that are always accepted by the network. The message packets are sent across different circuit paths. The packets are reassembled into the original message at the end of the circuit. See also X.25, Frame Relay, ATM. PAD (Packet Assembler/Dissembler): A device that connects a dumb terminal to an X.25 network. PAM (Pulse Amplitude Modulation): is used as the physical layer in HDSL and ISDN. The modulation consists of sending discrete amplitude levels (symmetric about 0 volts) at a regular rate. Both use the two binary one quaternary (2B1Q) line code. Four analog voltages (called quaternary symbols) are used to represent the four possible combinations of two bits (the "two binary"). These symbols are assigned the names +3, +1, -1, and -3. Each amplitude level being held for one symbol time communicates two bits. PAP (Password Authentication Protocol): One of two primary methods of being authenticated to connect to the Internet through PPP. CHAP is the other. PAP uses clear text authentication making it less secure than CHAP. Password: A secret code assigned to a user. Knowledge of the password associated with the user ID is considered proof of authorization. Password Creation Policy: Good password create policy usually requires the following rules to be followed:
Path Vector Routing: Enhancement of distance vector routing that includes complete path information. See BGP. PC (Personal Computer): Term coined by IBM describing an IBM PC compatible desktop computer. Today also refers to other personal computers, such as Apple's Macintosh. PCS (Personal Communications System): is used for digital cellular telephones. PDN (Public Data Network): A network established and operated by a PTT, common carrier, or private operating company for the specific purpose of providing data communications services to the public. May be a packet-switched network or a digital network such as DDS. Peak Demand: The maximum load during a specified period of time. [DOE Glossary of Electricity Terms] Peaking Capacity: Capacity of generating equipment normally reserved for operation during the hours of highest daily, weekly, or seasonal loads. Some generating equipment may be operated at certain times as peaking capacity and at other times to serve loads on an around-the-clock basis. [DOE Glossary of Electricity Terms] Peak Load Plant: A plant usually housing old, low-efficiency steam units; gas turbines; diesels; or pumped-storage hydroelectric equipment normally used during the peak-load periods. [DOE Glossary of Electricity Terms] Peak Load Set: [603-04-22] Generating set whose purpose is to run under discontinuous load conditions and to respond rapidly to peaks in the power demand of the network. [IEC_Glossary_1929b.pdf] PEM: Privacy Enhanced Mail Performance: A major factor in determining the overall productivity of a system, performance is primarily tied to availability, throughput and response time. Perimeter-based Security: The technique of securing a network by controlling access to all entry and exit points of the network. Peripheral: Any separate device: such as a printer or modem: that connects to and is controlled by a computer. Perl: Open source high-level programming language with an eclectic heritage written by Larry Wall et al. It derives from the ubiquitous C programming language and to a lesser extent from sed, awk, the Unix shell, and at least a dozen other tools and languages. . PGP (Pretty Good Privacy): A publicly available implementation of a public-key encryption system using no trusted third party. Note: PGP can be used to apply a digital signature to a message without actually encrypting the text of the message. This is normally used in public postings where the user wants all readers to be able to see the message text and also wants the reader to be able to confirm that the message is unaltered from its original form. Once a digital signature is created with PGP, it is impossible for anyone to modify either the message or the signature without the modification being detected by PGP. [2382-pt.35] Physical Device Model: A Physical Device model defines exactly one device. One or more Physical Device models are contained in a Logical Device model. For example, one RTU may contain models of three DR units within it, while handling all communications to the SCADA system. The RTU is acting as a Logical Device, while the 3 DR unit models are the Physical Devices. Physical Layer: Within the OSI model, the lowest level (Layer 1) of network processing, below the data link layer; concerned with the electrical, mechanical, and handshaking procedures over the interface that connects a device to a transmission medium. PING: (Packet InterNet Groper). A program used to test reachability of destinations by sending them an ICMP echo request and waiting for a reply. PKI: see Public Key Infrastructure. PKCS: The Public-Key Cryptography Standards (PKCS) is a set of standards for public-key cryptography, developed by RSA Laboratories in cooperation with an informal consortium, originally including Apple, Microsoft, DEC, Lotus, Sun and MIT. PKCS has been cited by the OIW (OSI Implementors' Workshop) as a method for implementation of OSI standards. PKCS is compatible with PEM but extends beyond PEM. For example, where PEM can only handle ASCII data, PKCS is designed for binary data as well. PKCS is also compatible with the ITU-T X.509 standard. The published standards are PKCS #1, #3, #5, #6, #7, #8, #9, #10 and #11. http://www.rsa.com/ Plaintext: Plaintext is an un-encrypted message. Planned Generator: A
proposal by a company to install electric generating equipment at an
existing or planned facility or site. The proposal is based on the
owner having obtained (1) all environmental and regulatory approvals,
(2) a signed contract for the electric energy, or (3) financial
closure for the facility. [DOE
Glossary of Electricity Terms] Plenum Cable: Cable with a special Teflon coating designed for use in suspended ceilings, in inside walls, or between floors. The Teflon coating provides low flame-spread and low, nontoxic smoke in the case of an accident. Plenum cables should meet the CMR (Communications Riser Cable) or CMP (Communications Plenum Cable) specifications of the National Electric Code and are often used for cable runs in air-return areas. Plug-in: A (usually small) piece of software that adds features to a larger piece of software. Common examples are plug-ins for the Netscape® browser and web server. Adobe Photoshop® also uses plug-ins. The idea behind plug-ins is that a small piece of software is loaded into memory by the larger program, adding a new feature, and that users need only install the few plug-ins that they need, out of a much larger pool of possibilities. Plug-ins are usually created by people other than the publishers of the software the plug-in works with. PMS (Power Management System): See EMS. Point of Common Coupling (PCC): The point where a Local Electric Power System (EPS) is connected to an Area Electric Power System. This term is used in the context of Distributed Resources (DR) that are interconnected with the power system. [IEEE P1547 Standard for Interconnecting Distributed Resources with Electric Power Systems] Point of Presence (POP): The physical location within a LATA where an inter-exchange carrier's circuits interconnect with the local lines of telephone companies in that LATA. Policy: Organizational-level rules governing acceptable use of computing resources, security practices, and operational procedures. Polling: Communications access control procedure where a primary (master) station systematically invites secondary stations, one at a time, to transmit data. POP3 (Post Office Protocol, version 3): The protocol used by an e-mail client to get e-mail from a users mailbox on the mail server. Port: (1) The place where the various protocols send and receive data on a particular computer. Most protocols have standard ports and users rarely have to worry about those ports. Users will have to specify ports in certain types of client/server applications such as MUDS and IRC. In TCP/IP; an integer identifying a process. A port number and an IP address defines a socket address. (2): One of a computer's physical input/output channels. Postmaster: The person responsible for taking care of mail problems, answering queries about users, and other related work at a site. POTS: Plain Old Telephone Service. Power: The rate at which energy is
transferred. Electrical energy is usually measured in watts. Also used
for a measurement of capacity. [DOE
Glossary of Electricity Terms] PPP (Point to Point Protocol): PPP provides a standard method for transporting multi-protocol datagrams over point-to-point links. PPP is also the Internet Standard for transmission of IP packets over serial lines; i.e., the communication using a standard telephone line and a high-speed modem. (Replaces SLIP). PQ: 1. Real and Reactive Power; 2. Power Quality Presentation Layer: In the OSI model, the layer of processing that provides services to the Application Layer, allowing it to interpret the data exchanged, as well as to structure data messages for transmission in a specific display and control format. PRI (Primary Rate Interface): ISDN primary-rate service consisting of B Channels and one 64 Kbps D Channel. Overhead is 8 kbps which adds up to 1.544 Mbps (same as DS-1/T-1 Line). See also 23B+D. Primary Control - Power control of the generating unit, done using an individual speed governor, according to the grid frequency and depending on the governor setting. Prime Mover:
The engine, turbine, water wheel, or similar machine that drives an
electric generator; or, for reporting purposes, a device that converts
energy to electricity directly (e.g., photovoltaic solar and fuel
cell(s)). [DOE
Glossary of Electricity Terms] Program: See Application. Propagation delay: The time it takes a signal composed of electromagnetic energy to travel from one point to another over a transmission channel; usually most noticeable in communicating with satellites; normally, the speed-of-light delay. Propagation velocity (% of c): The speed at which an electrical signal travels in the cable. The value given typically must be multiplied by the speed of light (c) to obtain units of meters per second. For example, a cable that lists a propagation velocity of 78% gives a velocity of 0.78 * 300*106 = 234*106 meters per second. Protocol: A formal description of message formats and the rules two computers must follow to exchange messages. Standard protocols allow computers from different manufacturers to communicate, providing programs running on both ends agree on what the data means. Proxy: 1) A method of replacing the code for a service applications with an improved version that is more security aware. The preferred method is by "service communities". Proxies evolved from socket implementations. 2) A software agent that acts on behalf of a user. Typical proxies accept a connection from a user, make a decision as to whether or not the user or client address is permitted to use the proxy, perhaps does additional authentication, and then completes a connection on behalf of the user to a remote destination. Proxy Server: a proxy server is a server that acts as an intermediary between a workstation user and the Internet so that the enterprise can ensure security, administrative control, and caching service. A proxy server is associated with or part of a gateway server that separates the enterprise network from the outside network and a firewall server that protects the enterprise network from outside intrusion. PSK (Phase Shift Keying): A digital-to-analog modulation method in which the phase of the carrier signal is varied to represent a specific bit pattern. PSTN: Public Switched Telephone Network. Public Key: In cryptography, a public key is a value provided by some designated authority as an encryption key that, combined with a private key derived from the public key, can be used to effectively encrypt messages and digital signatures. In encryption a two-key system in which the key used to lock data is made public, so everyone can "lock." A second private key is used to unlock or decrypt. The use of combined public and private keys is known as asymmetric cryptography. A system for using public keys is called a public key infrastructure (PKI). Public Key Certificate: A public key certificate is a digitally signed document that serves to validate the sender's authorization and name. The document consists of a specially formatted block of data that contains the name of the certificate holder (which may be either a user or a system name) and the holder's public key, as well as the digital signature of a certification authority for authentication. The certification authority attests that the sender's name is the one associated with the public key in the document. A user ID packet, containing the sender's unique identifier, is sent after the certificate packet. There are different types of public key certificates for different functions, such as authorization for a specific action or delegation of authority. Public key certificates are part of a public key infrastructure that deals with digitally signed documents. The other components are public key encryption, trusted third parties (such as the certification authority), and mechanisms for certificate publication and issuing. Public Key Cryptography: Unlike secret key cryptography, public key cryptography uses two different keys - one public and one private. They are created simultaneously using the same algorithm (a popular one is known as RSA) by a certificate authority (CA). The keys are mathematically related, yet it is computationally infeasible to deduce one from the other. The private key is given only to the requesting party and the public key is made publicly available (as part of a digital certificate) in a directory that all parties can access. Anyone with the public key can encrypt a message but not decrypt it. Only the person with the private key can decrypt the message. Public Key Infrastructure: PKI is the combination of software, encryption technologies, and services that enables the protection and the security of communications and transactions. Publish-Subscribe: The publish-subscribe concept is a method by which systems interact with each other. In this concept, one or more systems subscribe to data provided by another system. When some triggering event takes place, such as that data is updated, or a specific period of time has passed, or some alarm or significant event occurs, then the data is "published" to the subscribing systems. This concept has only recently begun to be implemented extensively. Another concept more commonly used is client-server. Pumped-Storage Hydroelectric Plant: A plant that usually generates electric energy during peak-load periods by using water previously pumped into an elevated storage reservoir during off-peak periods when excess generating capacity is available to do so. When additional generating capacity is needed, the water can be released from the reservoir through a conduit to turbine generators located in a power plant at a lower level. [DOE Glossary of Electricity Terms] Purchased Power Adjustment:
A clause in a rate schedule that provides for adjustments to the bill
when energy from another electric system is acquired and it varies
from a specified unit base amount. [DOE
Glossary of Electricity Terms] |
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