1.1 Purpose of the Physical Layer

Question 1

PHYSICAL CONNECTION

Answer 1

A physical connection can be a wired connection using a cable or a wireless connection using radio waves.

Question 2

AP

Answer 2

Devices on a wireless network must be connected to a wireless access point (AP) or wireless router.

There are the components of an access point:

1. The wireless antennas (These are embedded inside the router version shown in the figure above.)
2. Several Ethernet switchports
3. An internet port

Question 3

NIC

Answer 3

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

Ethernet NICs are used for a wired connection.
Wireless local area network (WLAN) NICs are used for wireless.

Question 4

PHYSICAL LAYER

Answer 4

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.

The physical layer encodes the frames and creates the electrical, optical, or radio wave signals that represent the bits in each frame. These signals are then sent over the media, one at a time.

The destination node physical layer retrieves these individual signals from the media, restores them to their bit representations, and passes the bits up to the data link layer as a complete frame.