Chapter 3: Protocols and network communications

Chapter 3: Protocols and network communications

1. A network can be as complex as devices connected through the Internet, or as simple as two PCs connected directly to each other through a single cable, or can have any degree of intermediate complexity

   • Basic aspects of communication

2. Establishment of rules

   • Before communicating with each other, people must use established rules or agreements that govern the conversation.

3. Coding of messages

   • One of the first steps to send a message is to code it.
   • Coding is the process by which information is converted into another form acceptable for transmission.
   • The decoding will reverse this process to interpret the idea.

4. Format and encapsulation of the message

   • An identifier of the recipient a greeting The content of the message A closing phrase An identifier of the emission

5. message size

   • Another communication rule is size. When people communicate, the messages they send are usually divided into smaller fragments or sentences.

6. Synchronization of the message

   • Access method The access method determines when someone can send a message. If two people talk at once, there is a collision of information and it is necessary that both stop and restart, as shown in the animation.
   • Waiting time for the response If a person asks a question and does not hear an answer before an acceptable time, the person assumes that there will be no response and reacts accordingly.
   • flow control Synchronization also affects the amount of information that can be sent and the speed at which it can be delivered.

7. TCP / IP protocol set

   • Currently, the TCP / IP protocol suite includes many protocols.

8. TCP / IP communication process

9. Open standards

   • Open standards encourage interoperability, competition and innovation.

10. Internet standards

    • Standardization organizations are generally non-profit institutions and neutral with regard to suppliers, which are established to develop and promote the concept of open standards.

11. Benefits of using a layered model

    • It helps in the design of protocols, since the protocols that operate in a specific layer have defined information according to which they act, and a defined interface for the upper and lower layers. It encourages competition, since products from different suppliers can work together. Prevents changes in technology or functionalities of one layer affect other upper and lower layers. It provides a common language to describe network functions and capabilities.

12. The reference model OSI

    • The OSI model provides an extensive list of functions and services that can be presented in each layer.

13. Comparison between the OSI model and the TCP / IP model

    • The protocols that make up the TCP / IP protocol suite can be described in terms of the OSI reference model. In the OSI model, the network access layer and the application layer of the TCP / IP model are subdivided to describe discrete functions that must occur in these layers.

14. Message segmentation

    • In theory, a simple communication, such as a music video or an email can be sent over the network from a source to a destination as a massive and continuous bit transmission.

15. Protocol data units

    • While the application data goes down to the protocol stack and is transmitted through the network media, various protocol information is added at each level.