TCP/IP Model Explained | Cisco CCNA 200-301

Summary

In this video, CertBros explains the TCP/IP model, a fundamental framework for computer networking. The video compares the TCP/IP model with the OSI model, highlighting the differences in layers and their functions. It covers the four layers of the TCP/IP model—application, transport, internet, and link—while introducing a new updated model with split layers and renamed layers. The video also dives into the process of encapsulation, where data is transformed through each layer with added headers and trailers. The final part of the video shows how the receiving system decapsulates the data, ensuring accurate transmission to the intended application.

Takeaways

• 😀 The TCP/IP model is a framework used to standardize computer networking.
• 😀 Unlike the OSI model, the TCP/IP model is widely used in the real world.
• 😀 The original TCP/IP model consists of four layers: application, transport, internet, and link.
• 😀 The updated TCP/IP model has one extra layer and one renamed layer, splitting the link layer into data link and physical layers.
• 😀 The internet layer in the TCP/IP model has been renamed the network layer.
• 😀 The TCP/IP model has five layers, whereas the OSI model has seven, with some layers combining functionality.
• 😀 At the application layer, protocols such as HTTP, FTP, and SMTP operate.
• 😀 The transport layer uses TCP and UDP as common protocols and includes port numbers.
• 😀 Routers operate at the network layer, using IP to route data between devices.
• 😀 The physical layer handles hardware like cables and network interface cards, while switches operate at the data link layer.
• 😀 Encapsulation is the process of adding headers and trailers to data as it moves down the layers, with the final data transmitted in the form of frames.

Q & A

What is the primary purpose of the TCP/IP model?

The primary purpose of the TCP/IP model is to standardize computer networking, ensuring that different devices can communicate with each other over a network.

How does the TCP/IP model compare to the OSI model?

The TCP/IP model has four layers, while the OSI model has seven. Despite this difference, both models serve similar functions in networking, with the TCP/IP model being more commonly used in real-world applications.

What is the difference between the link layer and the internet layer in the updated TCP/IP model?

In the updated TCP/IP model, the link layer has been split into two separate layers: the data link layer and the physical layer. Additionally, the internet layer is now called the network layer.

What protocols operate at the application layer of the TCP/IP model?

At the application layer of the TCP/IP model, common protocols include HTTP, FTP, and SMTP, which are used for tasks like web browsing, file transfer, and sending emails.

What is the role of TCP and UDP at the transport layer?

At the transport layer, TCP (Transmission Control Protocol) and UDP (User Datagram Protocol) are used to manage the communication between devices, with TCP ensuring reliable delivery and UDP being used for faster, less reliable transmissions.

Which devices operate at the network layer of the TCP/IP model?

Routers operate at the network layer of the TCP/IP model, helping to route data between different networks using IP addresses.

What is the role of the data link layer in the TCP/IP model?

The data link layer is responsible for defining the protocols used to move data between devices on the same network. Ethernet is a common protocol at this layer, and switches typically operate at this level.

What happens during the encapsulation process in the TCP/IP model?

During the encapsulation process, data is passed down through the layers of the TCP/IP model, with each layer adding its own header (and sometimes a trailer). This allows the data to be transmitted effectively across the network.

What is the final name of the data once it has passed through all layers and reaches the physical layer?

Once the data has passed through all layers, it reaches the physical layer as a 'frame,' which is then transmitted across the network to the receiving device.

How does decapsulation occur when the data reaches the receiving device?

When the data reaches the receiving device, the decapsulation process begins by checking the destination MAC address, then the IP address, followed by the transport layer information, until the original application data is passed to the receiving application.