The OSI model divides the networking process into seven logical layers, each of which has unique functionality and to which are assigned specific services and protocols. In this model, information is passed from one layer to the next, starting at the Application layer ISO OSI on the transmitting host, proceeding down the hierarchy to the Physical layer, then passing over the communications channel to the destination host, where the information proceeds back up the hierarchy, ending at the Application layer. The figure depicts the steps in this process.
Message notifying an operator or administrator of a network problem. See also event and trap. A-law is used primarily in European telephone networks and is similar to the North American mu-law standard.
See also companding and mu-law. Algorithm A set of rules and decision structures for actions in a specifically defined set of circumstances. Alias A file whose sole purpose is to represent another file.
Alignment errors are usually caused by frame damage due to collisions. All-rings Explorer Packet See all-routes explorer packet. All-routes Explorer Explorer Packet packet that traverses an entire SRB network, following all possible paths to a specific destination.
Sometimes called all-rings explorer packet, See also explorer packet, local explorer packet, and spanning explorer packet. AppleTalk Low Overhead Encapsulation.
Alphanumeric Referring to Origin of osi model group of printable characters that includes the letters of the alphabet in both upper and lower case, the numerals plus a limited group of additional symbols and punctuation marks.
Modulation technique whereby information is conveyed through the amplitude of the carrier signal. Ambient Referring to a set of conditions that exist independently of the system of interest.
AMI Alternate mark inversion. Line-code type used on T1 and E1 circuits. In AMI, zeros are represented by 01 during each bit cell, and ones are represented by 11 or 00, alternately, during each bit cell.
AMI requires that the sending device maintain ones density. Ones density is not maintained independent of the data stream. Sometimes called binary coded alternate mark inversion.
See also ones density. A standard unit of measurement for electrical current flow. Amplitude In the terminology of wave motion, the height of the wave. Amplitude is usually measured from a reference point of 0.
In electrical waves, amplitude is typically expressed in volts. Analog Referring to a system or component that uses a system of measurement, response or storage in which values are expressed a s a magnitude using a continuous scale of measurement. Analog Transmission Signal transmission over wires or through the air in which information is conveyed through variation of some combination of signal amplitude, frequency, and phase.
Anomaly An unusual instance or circumstance. The principle group in the US. A system of higher- level protocols used for the transmission of data and authentication between applications. APaRT recognizes specific data link layer encapsulation packet types and, when these packet types are transferred from one medium to another, translates them into the native format of the destination device.
A set of tools and procedures provided by the programmer of an application so that other programmers can control, exchange data with, or extend the functionality of an application. Apollo Domain Proprietary network protocol suite developed by Apollo Computer for communication on proprietary Apollo networks.
IBM SNA system software that allows high-speed communication between programs on different computers in a distributed computing environment. APPC establishes and tears down connections between communicating programs, and consists of two interfaces, a programming interface and a data-exchange interface.
The former replies to requests from programs requiring communication; the latter establishes sessions between programs. See also LU 6. AppleScript A programming language that can call tasks within Macintosh applications.
Application An independently executable set of algorithms and data structures that perform a specific set of functions. This layer provides services to application processes such as electronic mail, file transfer, and terminal emulation that are outside of the OSI model.
The application layer identifies and establishes the availability of intended communication partners and the resources required to connect with themsynchronizes cooperating applications, and agreement on procedures for error recovery and control of data integrity.
Corresponds roughly with the transaction services layer in the SNA model. See also data link layer, network layer, physical layer, presentation layer, session layer, and transport layer. APPN handles session establishment between peer nodes, dynamic transparent route calculation, and traffic prioritization for APPC traffic.regardbouddhiste.com 2 data-flow model can node 1 can node 2 can node 3 receive-only node n data filter data filter data filter data filter local intelligence local.
The Internet protocol suite is the conceptual model and set of communications protocols used on the Internet and similar computer regardbouddhiste.com is commonly known as TCP/IP because the foundational protocols in the suite are the Transmission Control Protocol (TCP) and the Internet Protocol (IP).
It is occasionally known as the Department of Defense (DoD) model because the development of the. CIDR REPORT for 3 Sep This report was generated at Mon Sep 3 AEST.
Report Sections: Status Summary. Summary of total route table size for the past 7 days, a listing of possibly bogus routes seen and summary information on ASes.
Lists of numerous resources supporting both X3D Graphics and Virtual Reality Modeling Language (VRML). Traditional SNA Environments. SNA was developed in the s with an overall structure that parallels the OSI reference model. With SNA, a mainframe running Advanced Communication Facility/Virtual Telecommunication Access Method (ACF/VTAM) serves as the hub of an SNA network.
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