Physical Layer

Connections

Wired

Wireless

Network interface cards (NICs) connect a device to the network.

connected to a wireless access point (AP) or wireless router

The OSI physical layer provides the means to transport the bits that make up a data link layer frame across the network media. This layer accepts a complete frame from the data link layer and encodes it as a series of signals that are transmitted to the local media. The encoded bits that comprise a frame are received by either an end device or an intermediate device.

functional areas

Encoding

Physical Components

Signaling

is a method of converting a stream of data bits into a predefined "code”

In other words, encoding is the method or pattern used to represent digital information

This is similar to how Morse code encodes a message using a series of dots and dashes.

The physical layer must generate the electrical, optical, or wireless signals that represent the "1" and "0" on the media.

The way that bits are represented is called the signaling method

Bandwidth

is typically measured in kilobits per second (kbps)

is the capacity at which a medium can carry data

Latency refers to the amount of time, including delays, for data to travel from one given point to another.

Throughput is the measure of the transfer of bits across the media over a given period of time.

factors that influence throughput

The amount of traffic

The type of traffic

The latency created by the number of network devices encountered between source and destination