In the world of humans, for communication to take place between two individuals, it is required that both sides know the language that they want to communicate in. Similarly, in the world of computers, whenever two computers try to communicate, they must support the communication protocol.

To better understand the communication process between two computers, let's examine the example of communication between two individuals. When two people meet and begin to communicate, the following activities take place:

1. Person A formulates his/her opinion in their mind and utters the words through their mouth.
2. The air then acts as the transmission medium which transfers the words from person A to person B.
3. The transmitted words reach the ears of person B, who then, through the center of knowledge, understands the received words.

This works in almost the...

Communication preferences are different. Mostly, communication between people occurs in one-to-one, one-to-many, and one-to-all formats. So, depending on the importance of the transmitted message, this is when the sender of a message wants to know if the message has been successfully received by the recipient. Then, it is necessary that the recipient acknowledges the sender of the message.

In computer networks, one-to-one communication, as shown in Figure 2.4, represents a unicast message delivery option. Because in this type of communication, there is only one destination for the message:

If you have ever tried talking to your friend through a pipe by passing on the voice from your mouth straight to your friend's ear, then you have used a physical communication medium. Other than that, there are logical communication mediums as well. The two together, both the physical and logical mediums, make up the communication channel in the telecommunication and computer networks which are commonly used for transmitting information. The communication channel width is measured in Hertz (Hz), while its data rate is measured in bits per second (bps).

A simplex communication is often referred to as a one-way communication because the direction of the transmission is predetermined...

The fact that you are able to read and understand this book proves that you know the English language. Like any other language written and spoken around the globe, the English language also has its own rules of grammar, syntax, and spelling. Almost equally, even computers, in order to communicate with one another, must know the communication language. Like human languages, the computer communication language also contain standards and rules, which are called communication protocols. In the following sections, you will get acquainted with characteristics of the communication protocols, and will be introduced to some of the well-known communication protocols in computer networks.

In order to describe the functionality of the network, including communication between computers, a layered model is used. These layers facilitate the operating system's work whenever the computer is required to communicate with other computers. This concept dates back to the 1960s, known as the time of internet development. It consisted of two protocols, IP and TCP. At that time, the layered framework called the TCP/IP reference model was designed so that later on, it had set the standard of networking functionality on the internet, enabling computers to communicate through a layered format.

To understand the layered model, let's get familiar with the following concepts:

• The protocol suite is a communication protocol stack that is comprised of a set of communications protocols. Some of the most well-known protocol suites in the history...

As mentioned previously, the OSI reference model consists of seven layers in which certain network functions are performed by their respective protocols. In addition to describing the processes that happen within layers, the OSI reference model also describes the interaction of each layer with the neighboring layers above and below. To avoid confusion, you will often encounter situations in the literature where the layers of the OSI reference model are named with numbers instead of their respective names (for example, the physical layer as Layer 1).

Today, Ethernet is the communication technology that is widely used in LANs. Ethernet operates in the physical layer and data link layer of the OSI reference model. Thus, it defines both Layer 1 technologies and Layer 2 protocols. The data on an Ethernet network is carried on by a frame.

The merits for the invention of the Ethernet belong to Dr. Robert Metcalfe, who in 1973 while working at the Xerox Palo Alto Research Center (PARC) wrote a memo in which he described his finding. Metcalfe had built an Ethernet network system to interconnect workstations with laser printers, thus making it possible to transfer data up to 1 Mbps. Undoubtedly, being convinced of the potential...

Nowadays, a lot of effort is being made to advance the development of IP addressing technologies. IPv6 addressing is the best example of such an effort. Nevertheless, even though the IPv6 addressing technology is becoming more and more plausible, it still prefers the role of spectator in the great arena of the internet, where IPv4 addressing technology continues to be the norm.

To communicate with a device on the network, it must be equipped with an IP address. Currently, the addressing technology we use is Internet Protocol version 4 (IPv4) addressing. The label v4 represents the fourth version of IP addressing, as specified in IETF publication RCF 791. However, you will...

We can summarize the chapter with the following points:

• Coding and decoding of messages are very important processes of communication:
  • Coding converts the information to an acceptable form for the transmission.
  • Decoding converts the received message into an intelligible language.
• Packing bits into the frame so they can be transmitted represents the encapsulation.
• When the receiving computer receives the frame and unpacks it by taking out the bits, this accomplishes de-encapsulation.
• Communication between computers is very strict as far as the size of the message is concerned.
• Access method, flow control, and response timeout are essential parts of the message timing:
  • In unicast message delivery, there is only one destination for the message
  • In multicast message delivery, there are several reachable destinations for the message.
  • In broadcast message delivery, all computers...

1. Packing bits into the frame so they can be transmitted represents encapsulation. (True | False)
2. In _________________ message delivery, there are several reachable destinations for the message.
3. Which of the following are essential parts of the message timing? (Choose three)
   1. Access method
   2. Flow control
   3. Response timeout
   4. Simplex communication
4. The Ethernet MAC address is often known as a logical address, and it used for communication in the Network layer. (True | False)
5. _________________ represents a logical division of one large network into multiple smaller networks.
6. Which of the following are fields of an Ethernet frame? (Choose two)
   1. EtherType
   2. FCS
   3. Coding
   4. Decoding
7. The session layer (Layer 5) is responsible for establishing and maintaining the on-demand communication sessions between applications. (True | False)
8. _________________ is responsible for interacting with...