Bandwidth, Throughput, and Multiplexing

Bandwidth

The amount of data that could theoretically be transmitted during a given period of time.

Throughput

The measure of how much data is actually transmitted during a given period of time.

EMI (electromagnetic interference)

Caused by motors, power lines, televisions, copiers, fluorescent lights, microwave ovens, manufacturing machinery, and other sources of electrical activity.

crosstalk

Occurs when a signal traveling on one wire or cable infringes on the signal traveling over an adjacent wire or cable.

attenuation

The loss of a signal's strength as it travels away from its source.

full-duplex transmission

Transmissions that are free to travel in both directions over a medium simultaneously.

half-duplex transmission

Transmissions that may travel in both directions over a medium but in only one direction at a time.

simplex transmission

Signals that may travel in only one direction and are sometimes called one-way or unidirectional communication.

multiplexing

Allows multiple signals to travel simultaneously over one medium.

TDM (time division multiplexing)

Divides a channel into multiple intervals of time, or time slots.

FDM (frequency division multiplexing)

Assigns different frequencies to create multiple frequency bands, each used by a subchannel.

coaxial cable

Has a central metal core surrounded by an insulator, a braided metal shielding, and an outer cover.

twisted pair cable

Consists of color-coded pairs of insulated copper wires, each twisted around each other.

shielded twisted pair cable

Consists of twisted-pair wires that are individually insulated and surrounded by shielding made of a metallic substance.

UTP cable

Comprises one or more insulated wire pairs encased in a plastic sheath.

STP vs UTP

STP is shielded and less susceptible to interference, while UTP is not shielded and more affordable.

straight-through cable

Terminates the RJ-45 plugs at both ends of the cable identically, following one of the TIA/EIA 568 standards.

Gigabit Ethernet

A type of Ethernet network that is capable of 1000-Mbps, or 1-Gbps, throughput.