Abbreviation for Internal Organization of the Network Layer. The OSI standard for the detailed architecture of the Network Layer.
Note: Basically, it partitions the Network layer into subnetworks interconnected by convergence protocols (equivalent to internetworking protocols), creating what is called a catenet or internet.

That part of the atmosphere, extending from about 70 to 500 kilometers, in which ions and free electrons exist in sufficient quantities to reflect and/or refract electromagnetic waves. [After JP1]

A device that transmits signals for the purpose of determining ionospheric conditions. [NTIA] [RR]

Absorption occurring as a result of interaction between an electromagnetic wave and free electrons in the ionosphere.

An increase in the ionization of the ionosphere, caused by solar activity, which results in greatly increased radio wave absorption.

Synonym ionospheric scatter.

Of electromagnetic waves propagating in the ionosphere, a redirection, i.e., bending--by a complex processing involving reflection and refraction--of the waves back toward the Earth.
Note: The amount of bending depends on the extent of penetration (which is a function of frequency), the angle of incidence, polarization of the wave, and ionospheric conditions, such as the ionization density.

The propagation of radio waves by scattering as a result of irregularities or discontinuities in the ionization of the ionosphere. [NTIA] [RR] Synonym forward propagation ionospheric scatter.

A technique that provides real-time data on high-frequency ionospheric-dependent radio propagation, using a basic system consisting of a synchronized transmitter and receiver.
Note: The time delay between transmission and reception is translated into effective ionospheric layer altitude. Vertical incident sounding uses a collocated transmitter and receiver and involves directing a range of frequencies vertically to the ionosphere and measuring the… (Read More →)

Ongoing disturbances of the ionosphere that scatter incident electromagnetic waves.
Note: Ionospheric turbulence results in irregularities in the composition of the ionosphere that change with time. This causes changes in reflection properties. These, in turn, cause changes in skip distance, fading, local intensification, and distortion of the incident waves. [From Weik '89]