Physical Layer is the first layer in the OSI Reference Model.

Communication starts at the 7th Layer (Application).

Tangible parts that we can see which enables communication.

- Ex: end devices, intermediary devices

Before any network communications can occur, a physical connection is not needed to a local network for it to be established.

A PHYSICAL connection can be a ______ connection using a cable or a ______ connection using radio waves.

A _______________ connects a device to the network.

Some devices may have just one NIC, while others may have multiple NICs (Wired and/or Wireless, for example).

What are the components of an access point?

_____________ are used for a wired connection, whereas ___________________ are used for wireless.

An end-user device may include one or both types of NICs.

Ex: A network printer - only have an Ethernet NIC

Tablets and smartphones - only contain a WLAN NIC and must use a wireless connection.

All physical connections are equal, in terms of the performance level, when connecting to a network.

Transports bits across the network media.

PDU of the data link 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.

[Physical Layer]

Accepts a complete frame from the __________ and encodes it as a series of signals that are transmitted to the local media.

The physical layer is only concerned with wired network connections.

When a frame is encoded by the physical layer, all bits are sent over the media at the same time.

The physical layer of the receiving device passes bits up to which higher level layer?

What PDU is received by the physical layer for encoding and transmission?

The next device in the path to the destination receives the bits and re-encapsulates the frame, then decides what to do with it.

The Data Link Layer has 2 sublayers:

[2 sublayers of Data Link Layer]

- LLC - Logical Link Control (the higher sublayer)

- MAC - Media Access Control (the lower sublayer)

The TCP/IP standards are implemented in software and governed by the

______.

The protocols and operations of the upper OSI layers are performed using software designed by software engineers and computer scientists.

The physical layer consists of electronic circuitry, media, and connectors developed by engineers.

Therefore, it is not appropriate that the standards governing this hardware are defined by the relevant electrical and communications engineering organizations.

The physical layer standards are implemented in hardware and are

governed by many organizations including:

The physical layer standards are implemented in hardware and are

governed by many organizations including:

[National telecommunications regulatory authorities]

The physical layer standards are implemented in hardware and are

governed by many organizations including:

[Regional cabling standards groups]

ISO

What is the meaning of TIA/EIA?

ITU

ANSI

IEEE

FCC

ETSI

The physical layer standards address three functional areas:

Are the electronic hardware devices, media, and other connectors that transmit the signals that represent the bits.

The physical components are the electronic hardware devices, media, and other connectors that transmit the signals that represent the _____.

_____________ such as NICs, interfaces and connectors, cable materials, and cable designs are all specified in standards associated with the physical layer.

Converts the stream of bits into a format recognizable by the next device in the network path.

Encoding is also called line encoding.

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

Are groupings of bits used to provide a predictable pattern that can be recognized by both the sender and the receiver.

Is the method or pattern used to represent digital information.

Encoding is not similar to how Morse code encodes a message using a series of dots and dashes.

Examples of encoding methods include:

Is how the bit values, “1” and “0” are represented on the physical medium.

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

______________ must define what type of signal represents a "1" and what type of signal represents a "0".

The method of signaling will not vary based on the type of medium being used.

Is the capacity at which a medium can carry data.

Measures the amount of data that can flow from one place to another in a given amount of time; how many bits can be transmitted in a second.

Physical media properties, current technologies, and the laws of physics do not play a role in determining available bandwidth.

Bandwidth is typically measured:

Bandwidth is sometimes thought of as the speed that bits travel, however this is accurate.

1 bps (Bits per second) = fundamental unit of bandwidth

1 Kbps = ______ bps = _____ bps

1 Mbps = __________ bps = _____ bps

1 Gbps – _____________ bps = ____ bps

1 Tbps = __________________ bps = _____ bps

Amount of time, including delays, for data to travel from one given point to another.

 In an internetwork, or a network with multiple segments, throughput cannot be faster than the slowest link in the path from source to destination.

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

You can't reveal the throughput of an internet connection through online speed tests.

The measure of usable data transferred over a given period of time.

Goodput = _________ - __________

Goodput is always lower than throughput, which is generally lower than the bandwidth.

5 Factors why we can’t get the maximum speed:

The best time of the day to use the internet is early morning.

Our maximum speed depends on our devices, cabling, media.

(Ex: Switch can only accommodate 10 mbps, Fiber cable is faster)

Ex: downloading, streaming, gaming

2 combinations that determines the practical bandwidth of a network:

Which media uses patterns of microwaves to represent bits?

Which media uses patterns of light to represent bits?

Which media uses electrical pulses to represent bits?