03 - Network Performance

Bandwidth in Hertz

Refers to the range of frequencies contained in a composite signal

Bandwidth in bps

The number of bits per second that a channel, a link, or even a network.

Throughput

The measure of how fast we can send data through a network, measured in bits per second.

Latency

The time required for data to travel from its origin to its destination in a system.

Propagation Delay

The time required for a bit to travel from the source to the destination across a communication medium.

PD = distance/vp

Formula for propagation delay use (vp) for speed.

Transmission Time

It is the time required for transmission of a message.

Ttrans = Message/Bandwidth

Formula for Transmission Time.

Bandwidth Delay Product

The product of the data links capacity and its round-trip delay time in seconds.

Jitter

The measure of the variation in latency over time.

Multiplexing

It is the set of techniques that allows simultaneous transmission of multiple signals across a data link.

Frequency Division Multiplexing

An analog technique that can be applied when the bandwidth of a link is greater than the combined bandwidths of the signals to be transmitted.

Wavelength Division Multiplexing

Designed to use the high data rate capability of fiber-optic cable. Involves optical signals. Combines multiple light sources into a single light.

Time Division Multiplexing

Digital process that allows several connections to share the high bandwidth of a link.

Synchronous TDM

Type of TDM. The time slots are assigned at the beginning, irrespective of the idea about the presence of data at the source.

Interleaving

TDM can be visualized as fast rotating switches. One MUX side and another deMUX side. The switches are synchronized at the same speed.

Multilevel MUX

A technique in MUX where the data rate of an input line is a multiple of others.

Multiple-Slot Allocation

A technique where one device is assigned more than one time slot per frame.

Pulse Stuffing

A technique used to handle small differences in data rates between input channels.

Asynchronous TDM

aka Statistical TDM, it allocates time slots dynamically to the data streams based on requirements.

Spread Spectrum (SS)

It is design to be used in wireless applications. A technique in digital communications that spreads a signal over a wider bandwidth to combat interference, enhance privacy, and enable multiple users to share a common channel.

Frequency Hopping SS

Short bursts of multiple frequencies. A type of SS

Direct Sequence SS

Original signal is multiplied by a high rate pseudorandom bit sequence. Type of SS.