TCP / IP and OSI layers overview

Let's talk about the fundamentals of the TCP/IP network and OSI models. Let's keep in mind that each layer has its own protocol, which will be listed below. The first difference at a glance is that the TCP/IP model consists of 5 layers, whereas the OSI model has 7: Application, Transport, Network, Data-link, Physical vs. Application, Presentation, Session, Transport, Network, Data-link, Physical

Application layer - Provides an interface for communication between software and applications that need to communicate.

Presentation layer - Defines and negotiates data formats. Also includes encryption.

Session layer - Defines how to start, control, and end sessions. It also includes message management.
Protocols: Telnet, FTP, DNS, TFTP, etc.

Transport layer - Provides data delivery, error recovery, and flow control.
Protocols: TCP, UDP.

Network layer - Defines addressing, forwarding, and path determination.
Protocols: IP, ARP, RARP.

Data-link layer - Defines the rules for when a device can send data to a particular medium.

Physical layer - Sets the standards for the physical characteristics of data transmission.
Protocols: Ethernet, Token Ring, etc.

Benefits of OSI:
- Less complex - breaking it down into more layers makes it easier to understand.
- Standard interfaces - additional layers allow different companies to integrate different solutions and architectures, which is beneficial for the market and competition.
- Easier to catch up - a more detailed and structured breakdown allows for a faster understanding of application communication.
- Easier to develop using OSI because of fewer complications; updating the architecture will be less complex.
- Multi-vendor availability - by using the same standards, different computers and networking gear can interact with each other in the same network.
- Modular engineering - different vendors and companies can write software for various layers. For example, Company A writes software for the Application layer, while Company B focuses on Network layers.

Benefits of TCP/IP:
- Independent from the operating system.
- A good choice for scalable infrastructure.
- Helps establish connections between two types of computers.
- Provides and establishes connections between organizations.
- Supports a wide range of protocols.
- And more!

Difference between TCP/IP and OSI:
I can point out the most simple and fundamental differences between them:
- Different header sizes: 5 bytes in OSI vs. 20 bytes in TCP/IP.
- OSI is good for setting and standardizing motherboards, routers, and switches (hardware), whereas TCP/IP helps establish communication between two computers.

If you are interested in networking architecture and its concepts, I would recommend the CISCO certification. There are a lot of things to learn and explore in this field. With this brief information on the TCP/IP and OSI models, you should now have a better understanding of which model to use and when!