The excess requirement of efficient and error-free data transmission over communication channels leads us to the discussion of the topic - what is the TCP/IP model? This tutorial will easily help to make you understand the basis and need for the TCP/IP model in the network domain. The TCP/IP is needed for implementing various network applications during the transmission of data and information over the communication channel.

What is TCP/IP Model?

The TCP/IP model refers to the Transmission Control Protocol/Internet Protocol Model. This model is a part of the network domain designed specifically for overseeing efficient and error-free transmission of data.

The model works on a four-layered architecture model, where each layer implicit the required network protocols on the data to be transmitted, which remodels the data to the most optimum structure for efficient transmission over the network.

In this tutorial on what is TCP/IP model is, you will understand the working of each layer in detail to better understand the functioning of the model.

The History of TCP/IP

The Internet Protocol Suite, or TCP/IP for short, is the set of protocols that make up the network layer of the Internet.

• TCP/IP was developed during the Cold War as a way for the U.S. Department of Defense to connect computers within their networks and with each other across national boundaries. It’s been used since the late 1960s when it was formalized by DARPA and later adopted by government agencies and universities worldwide as a common networking standard.
• The first version of TCP/IP was ARPANET (1975), which stands for Advanced Research Projects Administration Network. The name changed to TCP/IP in 1983, when it became an open standard that could be used on any network.
• To give researchers access to each other’s equipment, they needed to send messages quickly over long distances without having them re-transmitted by any intermediate nodes along the way. This necessity led to the development of the Transmission Control Protocol (TCP) and Internet Protocol (IP). These protocols were intended for machine-to-machine connections, such as between computers over local area networks or wide-area networks.

Prerequisite Layers of OSI Model

To understand the OSI model, it is first necessary to understand the concept of layering. Layering is a technique used in computer programming to divide a complex problem or system into smaller, more manageable parts. The OSI model is a seven-layer model that divides the complexity of network communications into seven smaller, more manageable parts, each responsible for a different aspect of the communication process.

The seven layers of the OSI model are:

• Physical layer,
• Data link layer,
• Network layer,
• Transport layer.
• Session layer,
• Presentation layer,
• Application layer.

Each OSI model layer is responsible for a different aspect of the communication process.

Features of the TCP/IP Model

Below mentioned are some of the features that make the TCP/IP model stand out in the network concepts:

• The TCP/IP model is among one of the most important network concepts that contributed to the working of ARPANET.
• The TCP/IP model comprises four layers: the network access layer, the internet layer, the transport layer, and the application layer (going from bottom to top).
• The network model is implemented during network and communication-related issues.
• Communication between different modes of network devices is possible through the application of various layers.
• The layers in the model provide maintenance of communication channels, flow control, and reliability check format, among other applications in the form of protocols.

Now go ahead and continue with the next topic in this tutorial on ‘what is the TCP/ IP model’, which includes the layers of the TCP/IP model.

Layers of the TCP/IP Model

In this section, you will understand the different layers of the model and their functionality in the network concept:

The TCP/IP model is divided into four different layers:

• Application layer
• Transport layer
• Internet layer
• Network Access layer

Each layer performs a specific task on the data that is being transmitted over the network channel, and data moves from one layer to another in a preset pattern as mentioned below:

The above model represents the flow of data when it is being transmitted from the sender side. In the case of data being received, the layers of the model work in reverse order.

Now, take a look at each of the layers in detail:

Application Layer

This is the topmost layer which indicates the applications and programs that utilize the TCP/IP model for communicating with the user through applications and various tasks performed by the layer, including data representation for the applications executed by the user and forwards it to the transport layer.

The application layer maintains a smooth connection between the application and user for data exchange and offers various features as remote handling of the system, e-mail services, etc.

Some of the protocols used in this layer are:

• HTTP: Hypertext transfer protocol is used for accessing the information available on the internet.
• SMTP: Simple mail transfer protocol, assigned the task of handling e-mail-related steps and issues.
• FTP: This is the standard protocol that oversees the transfer of files over the network channel.

Now, move on to the next layer,

Transport Layer

This layer is responsible for establishing the connection between the sender and the receiver device and also performs the task of dividing the data from the application layer into packets, which are then used to create sequences.

It also performs the task of maintaining the data, i.e., to be transmitted without error, and controls the data flow rate over the communication channel for smooth transmission of data.

The protocols used in this layer are:

• TCP: Transmission Control Protocol is responsible for the proper transmission of segments over the communication channel. It also establishes a network connection between the source and destination system.
• UDP: User Datagram Protocol is responsible for identifying errors, and other tasks during the transmission of information. UDP maintains various fields for data transmission such as:
• Source Port Address: This port is responsible for designing the application that makes up the message to be transmitted.
• Destination Port Address: This port receives the message sent from the sender side.
• Total Length: The total number of bytes of the user datagram.
• Checksum: Used for error detection of the message at the destination side.

Moving on to the next layer, you have:

Internet Layer

The Internet layer performs the task of controlling the transmission of the data over the network modes and enacts protocols related to the various steps related to the transmission of data over the channel, which is in the form of packets sent by the previous layer.

This layer performs many important functions in the TCP/IP model, some of which are:

1. It is responsible for specifying the path that the data packets will use for transmission.
2. This layer is responsible for providing IP addresses to the system for the identification matters over the network channel.

Some of the protocols applied in this layer are:

• IP: This protocol assigns your device with a unique address; the IP address is also responsible for routing the data over the communication channel.
• ARP: This protocol refers to the Address Resolution Protocol that is responsible for finding the physical address using the IP address.

The last layer in the network model is the network access layer.

Network Access Layer

This layer is the combination of data-link and physical layer, where it is responsible for maintaining the task of sending and receiving data in raw bits, i.e., in binary format over the physical communication modes in the network channel.

• It uses the physical address of the system for mapping the path of transmission over the network channel.
• Till this point in this tutorial on what is TCP/IP model, you understood the basic idea behind the model and details about its layers, now compare the model with another network model.

How Does TCP/IP Work?

The TCP/IP protocol suite is the set of communication protocols used to connect hosts on the Internet. TCP/IP allows computers on the same network to identify and communicate with each other. TCP/IP is a two-layer protocol, with the transport layer (TCP) responsible for reliable end-to-end communication and the Internet layer (IP) accountable for routing packets from the host to the host.

• At the transport layer, TCP provides a reliable byte-stream service to applications. TCP guarantees the delivery of data and that data will be delivered in the same order in which it was sent. TCP uses several mechanisms to provide this service, including sequence numbers, acknowledgments, and timeouts.
• At the Internet layer, IP is responsible for routing datagrams (packets) from host to host. IP does not guarantee the delivery of datagrams, but it tries to deliver them as best. If a datagram cannot be delivered, IP will return an error message to the source host.

The TCP/IP protocol suite is the most commonly used protocol suite on the Internet today, and it is also the protocol suite used by most LANs and WANs.

Why is TCP/IP Important?

TCP/IP is essential because it provides an architecture that allows for virtually instantaneous communication across all types of network media, such as copper, fiber, or wireless. It does this using the Internet Protocol Suite, which encompasses both the TCP and UDP protocols.

In turn, the TCP Protocol governs how packets move from one place to another on a network, and the UDP Protocol governs how packets move within a single machine or between two devices on a local area network (LAN). Without TCP/IP, there would be no way for computers to communicate over the internet.

OSI Model vs. TCP IP Model

The TCP/IP model was designed in the 1960s to maintain and explain the transmission of data, whereas the OSI model is a network concept specifically for explaining the communication and working of data and protocols during the transmission of information.

### OSI Model	### TCP/IP Model
The OSI model consists of 7 layers.	TCP/IP model comprises 4 layers.
The OSI model has separate session and presentation layers.	This model comprises a session and presentation layer in the application layer.
The transport layer in this model provides a packet delivery protocol.	In this model, the transport layer does not have any such protocols.
This model is implemented during network communication.	This model is used as a reference model for the network channel.

How are TCP/IP and IP Different?

• The Transmission Control Protocol (TCP) is a communication protocol responsible for ensuring that data is transferred reliably and in order between the two devices.
• On the other hand, IP is the network layer protocol responsible for routing network traffic.

While TCP/IP are both crucial protocols on the internet, they serve different purposes.

Functions of TCP/IP Layers

The TCP/IP model is a four-layer model that divides network communications into four distinct categories or layers. The model is often referred to as the TCP/IP stack. The four important layers are the application layer, the transport layer, the network layer, and the link layer.

• The Application Layer: The application layer is closest to the end user. And this is the layer that users interact with directly, including protocols such as HTTP, FTP, and SSH. This layer is responsible for providing applications with access to the network.
• The Transport Layer: The transport layer ensures that data is delivered reliably and efficiently from one point to another. This layer handles data transmission between hosts, including protocols like TCP and UDP.
• The Internet Layer: The network layer is responsible for routing data through the web. This layer delivers data packets from one host to another, including the IP protocol.
• The Link Layer: The link layer provides reliable data links between the two nodes — for example, protocols like ethernet and Wi-Fi.

Protocols Used

There are four main protocols used in TCP/IP: the Transmission Control Protocol (TCP), the User Datagram Protocol (UDP), the Internet Protocol (IP), and the Internet Control Message Protocol (ICMP).

• TCP ensures that data is delivered reliably and in order.
• UDP is used for applications where data doesn’t need to be delivered reliably or needs to be delivered quickly without the overhead of TCP.
• IP is the protocol that routes data from one computer to another.
• ICMP is used for error-checking and for managing traffic congestion.

All four of these protocols are essential for the proper functioning of the internet. They work together to ensure that data is delivered quickly, reliably, and in the appropriate order.

There are some other protocols also notable, and there are,

• Address Resolution Protocol (ARP)
• File Transfer Protocol (FTP)
• Hypertext Transfer Protocol (HTTP)
• Simple Mail Transfer Protocol (SMTP)
• Domain Name System (DNS)

TCP Characteristics

• TCP is a connection-oriented protocol that establishes a connection between two nodes before transmitting any data. All data sent over a TCP connection is checked for accuracy and retransmitted until the data is received correctly. This reliability makes TCP well-suited for applications that require a high degree of error-checking and for large data transfers. And also, TCP operates at the lowest level of the OSI model, transmitting data in segments, which are then reassembled into whole frames by the receiver.
• TCP also provides congestion control, which helps prevent network congestion by regulating the rate at which data is sent.
• Additionally, TCP can control the flow of data, allowing data to be sent at different rates depending on the application’s needs.

Advantages and Disadvantages of the TCP/IP Model

With tons of benefits, there are also some potholes here with these models.

Advantages of TCP/IP:

• Scalability: The TCP/IP model is highly scalable and can accommodate small and large networks.
• Reliability: The model is robust and reliable, making it suitable for mission-critical applications.
• Flexibility: It is very flexible, allowing for interoperability between different types of networks.
• Security: The various protocols in the model provide robust security measures.
• Cost-effectiveness: TCP/IP is relatively inexpensive to implement and maintain.

Disadvantages of TCP/IP:

• Complexity: The model is quite complex and requires a certain degree of expertise to configure and maintain.
• Vulnerability: Because of its complexity, it is vulnerable to attack.
• Performance: Performance can be degraded due to network congestion and latency.

Uses of TCP/IP

Here are some of the most valuable uses of TCP/IP models:

• World Wide Web: TCP/IP transfers data between web browsers and servers.
• Email: Applications such as Outlook, Thunderbird, and Gmail use TCP/IP protocols to send and receive emails.
• File Transfer: FTP, SFTP, and other file transfer services rely on TCP/IP to move files from one computer to another.
• Networking: TCP/IP links computers together in a network.
• Virtual Private Networks: VPNs use TCP/IP to encrypt data before it travels across a public or private network.
• Internet of Things: Many smart home devices use TCP/IP to communicate and transfer data.
• Voice Over Internet Protocol: VOIP services such as Skype and Google Voice use TCP/IP to transmit calls over the internet.

Conclusion

In this ‘What is TCP/IP model’ tutorial, you understood the network communication details about data, which includes the basic idea behind the working of the model, the functioning of each layer in the model, and also how the data is restructured to achieve efficient transmission over the communication channel.

To better understand the working of each layer and the different steps they take during the data transmission over the network from a professional point of view, you can refer to Simplilearn’s Cyber Security Expert course, Cyber Security Course, and PGP in Cyber Security, which will allow you to gain in-depth knowledge about the network functions and working of the model at a whole new level.

Do you have any questions related to this tutorial on ‘What is TCP/IP model?’ If yes, feel free to mention them in the comments section at the bottom of this page. Our team will help you solve your queries ASAP.