Key Concepts in Data Communication and Networking

A signal is a limited form of inter-process communication used in Unix and other operating systems that support POSIX.

Duplex Communication

Duplex is used in telecommunications to define a system that is able to maintain two-way communication, sending and receiving messages simultaneously.

Modulation Techniques

Modulation involves a set of techniques for transporting information over a carrier wave, typically a sine wave. Differentiation includes:

• Double Side Band (DSB)
• Amplitude Modulation (AM)
• Phase Modulation (PM)
• Frequency Modulation (FM)
• Single Sideband Modulation (SSB, or SSB)
• Vestigial Sideband Modulation (VSB, VSB-AM, or BLV)
• Quadrature Amplitude Modulation (QAM)
• Orthogonal Frequency Division Multiplexing (OFDM), also known as "Discrete Multi Tone" (DMT) modulation
• Wavelength modulation
• Ring modulation

Multiplexing Defined

Multiplexing is the combination of two or more channels of information in a single transmission medium using a device called a multiplexer. The reverse process is called demultiplexing.

International Organization for Standardization (ISO)

The International Organization for Standardization (ISO) is an international organization composed of national standardization bodies. Governmental in nature, it creates and promotes industry standards for commercial use worldwide. These rules are known as ISO standards and aim at the coordination of national rules in line with the Final Act of the World Trade Organization, in order to facilitate trade, exchange of information, and assist with the development and common use of technologies. You can find more information at ISO's official website.

Communication Protocols

A protocol is the standard set of rules for representation, signaling, authentication, and error detection required to send information through a communication channel. An example of a simple communications protocol adapted to voice communication is the case of a radio broadcaster talking to listeners. Examples of standardized protocols include:

TCP/IP, AppleTalk, NetBEUI, NetBIOS, IPX/SPX.

IP Addressing and Subnetting

An IP address is a number that identifies a logical, hierarchical interface of a device (usually a computer) within a network using the IP protocol (Internet Protocol), which corresponds to the network layer of TCP/IP.

Netmask Function

The netmask is a combination of bits used to define the scope of a computer network. Its function is to indicate which part of the device IP address represents the network number, including the subnet, and which part is designated for the host.