The TCP/IP model is a fundamental framework for computer networking. It stands for Transmission Control Protocol/Internet Protocol, which are the core protocols of the Internet. This model defines how data is transmitted over networks, ensuring reliable communication between devices. It consists of four layers: the Link Layer, the Internet Layer, the Transport Layer, and the Application Layer. Each layer has specific functions that help manage different aspects of network communication, making it essential for understanding and working with modern networks.
TCP/IP was designed and developed by the Department of Defense (DoD) in the 1960s and is based on standard protocols. The TCP/IP model is a concise version of the OSI model. It contains four layers, unlike the seven layers in the OSI model. In this article, we are going to discuss the TCP/IP model in detail.
TCP/IP model was developed alongside the creation of the ARPANET, which later became the foundation of the modern internet. It was designed with a focus on the practical aspects of networking at the time. The lower-level hardware details and physical transmission medium were largely abstracted away in favor of higher-level networking protocols.
The main work of TCP/IP is to transfer the data of a computer from one device to another. The main condition of this process is to make data reliable and accurate so that the receiver will receive the same information which is sent by the sender. To ensure that, each message reaches its final destination accurately, the TCP/IP model divides its data into packets and combines them at the other end, which helps in maintaining the accuracy of the data while transferring from one end to another end. The TCP/IP model is used in the context of the real-world internet, where a wide range of physical media and network technologies are in use. Rather than specifying a particular Physical Layer, the TCP/IP model allows for flexibility in adapting to different physical implementations.
| Feature | TCP (Transmission Control Protocol) | IP (Internet Protocol) |
|---|---|---|
| Purpose | Ensures reliable, ordered, and error-checked delivery of data between applications. | Provides addressing and routing of packets across networks. |
| Type | Connection-oriented | Connectionless |
| Function | Manages data transmission between devices, ensuring data integrity and order. | Routes packets of data from the source to the destination based on IP addresses. |
| Error Handling | Yes, includes error checking and recovery mechanisms. | No, IP itself does not handle errors; relies on upper-layer protocols like TCP. |
| Flow Control | Yes, includes flow control mechanisms. | No |
| Congestion Control | Yes, manages network congestion. | No |
| Data Segmentation | Breaks data into smaller packets and reassembles them at the destination. | Breaks data into packets but does not handle reassembly. |
| Header Size | Larger, 20-60 bytes | Smaller, typically 20 bytes |
| Reliability | Provides reliable data transfer | Does not guarantee delivery, reliability, or order. |
| Transmission Acknowledgment | Yes, acknowledges receipt of data packets. | No |
Whenever we want to send something over the internet using the TCP/IP Model, the TCP/IP Model divides the data into packets at the sender’s end and the same packets have to be recombined at the receiver’s end to form the same data, and this thing happens to maintain the accuracy of the data. TCP/IP model divides the data into a 4-layer procedure, where the data first go into this layer in one order and again in reverse order to get organized in the same way at the receiver’s end.
The diagrammatic comparison of the TCP/IP and OSI model is as follows:
It is a group of applications requiring network communications. This layer is responsible for generating the data and requesting connections. It acts on behalf of the sender and the Network Access layer on the behalf of the receiver. During this article, we will be talking on the behalf of the receiver.
The packet’s network protocol type, in this case, TCP/IP, is identified by network access layer. Error prevention and “framing” are also provided by this layer. Point-to-Point Protocol (PPP) framing and Ethernet IEEE 802.2 framing are two examples of data-link layer protocols.
This layer parallels the functions of OSI’s Network layer. It defines the protocols which are responsible for the logical transmission of data over the entire network. The main protocols residing at this layer are as follows:
The Internet Layer is a layer in the Internet Protocol (IP) suite, which is the set of protocols that define the Internet. The Internet Layer is responsible for routing packets of data from one device to another across a network. It does this by assigning each device a unique IP address, which is used to identify the device and determine the route that packets should take to reach it.
Example: Imagine that you are using a computer to send an email to a friend. When you click “send,” the email is broken down into smaller packets of data, which are then sent to the Internet Layer for routing. The Internet Layer assigns an IP address to each packet and uses routing tables to determine the best route for the packet to take to reach its destination. The packet is then forwarded to the next hop on its route until it reaches its destination. When all of the packets have been delivered, your friend’s computer can reassemble them into the original email message.
In this example, the Internet Layer plays a crucial role in delivering the email from your computer to your friend’s computer. It uses IP addresses and routing tables to determine the best route for the packets to take, and it ensures that the packets are delivered to the correct destination. Without the Internet Layer, it would not be possible to send data across the Internet.
The TCP/IP transport layer protocols exchange data receipt acknowledgments and retransmit missing packets to ensure that packets arrive in order and without error. End-to-end communication is referred to as such. Transmission Control Protocol (TCP) and User Datagram Protocol are transport layer protocols at this level (UDP).
This layer is analogous to the transport layer of the OSI model. It is responsible for end-to-end communication and error-free delivery of data. It shields the upper-layer applications from the complexities of data. The three main protocols present in this layer are:
The host-to-host layer is a layer in the OSI (Open Systems Interconnection) model that is responsible for providing communication between hosts (computers or other devices) on a network. It is also known as the transport layer.
Some common use cases for the host-to-host layer include:
Example: Consider a network with two hosts, A and B. Host A wants to send a file to host B. The host-to-host layer in host A will break the file into smaller segments, add error correction and flow control information, and then transmit the segments over the network to host B. The host-to-host layer in host B will receive the segments, check for errors, and reassemble the file. Once the file has been transferred successfully, the host-to-host layer in host B will acknowledge receipt of the file to host A.
In this example, the host-to-host layer is responsible for providing a reliable connection between host A and host B, breaking the file into smaller segments, and reassembling the segments at the destination. It is also responsible for multiplexing and demultiplexing the data and providing end-to-end communication between the two hosts.
The physical layer is not covered by the TCP/IP model because the data link layer is considered the point at which the interface occurs between the TCP/IP stock and the underlying network hardware. Also, it is designed to be independent of the underlying physical media. This allows TCP/IP to be flexible and adaptable to different types of physical connections, such as Ethernet, Wi-Fi, fiber optics, or even older technologies like dial-up modems. The physical layer is typically handled by hardware components and standards specific to the physical medium being used, like Ethernet cables or radio waves for Wi-Fi.
TCP/IP Model covers many Internet Protocols. The main rule of these Internet Protocols is how the data is validated and sent over the Internet. Some Common Internet Protocols include:
| TCP/IP | OSI |
|---|---|
| TCP refers to Transmission Control Protocol. | OSI refers to Open Systems Interconnection. |
| TCP/IP uses both the session and presentation layer in the application layer itself. | OSI uses different session and presentation layers. |
| TCP/IP follows connectionless a horizontal approach. | OSI follows a vertical approach. |
| The Transport layer in TCP/IP does not provide assurance delivery of packets. | In the OSI model, the transport layer provides assurance delivery of packets. |
| Protocols cannot be replaced easily in TCP/IP model. | While in the OSI model, Protocols are better covered and are easy to replace with the technology change. |
| TCP/IP model network layer only provides connectionless (IP) services. The transport layer (TCP) provides connections. | Connectionless and connection-oriented services are provided by the network layer in the OSI model. |
In conclusion, the TCP/IP model is the backbone of modern internet communication, allowing different devices and networks to connect and share information reliably. Despite some complexity and security concerns, its flexibility, scalability, and widespread adoption make it essential for both small and large networks. Overall, the TCP/IP model is crucial for ensuring efficient and effective network communication.
TCP/IP generally works with both the IP that is, IPv4 and IPv6 . If you are using IPv4 or IPv6, it seems that you are already working on TCP/IP Model.
The OSI Model has seven layers, while the TCP/IP Model has four layers. The TCP/IP Model is simpler and more practical, making it more widely used in real-world networking.
IP addresses identify devices on a network, enabling data to be routed to the correct destination.
