What is TCP IP Model? How does TCP ID Model Works? Layers & Protocols

Understanding the TCP/IP model in computer networks is essential for network managers, developers, and anyone interacting with computer networks. It takes a rational approach to network communication and enables fast and dependable data transfer across the internet. 

This blog will discuss the layers and protocols of the TCP/IP model and how it works.

What Is TCP/IP Model?

The TCP/IP model in computer networks governs data interchange between computers and other devices through networks, most notably the internet. It takes its name from its two main protocols, TCP and IP. The present internet architecture heavily relies on the five-tiered TCP/IP framework. 

The Function of TCP/IP

Here are some of the things that TCP/IP does:

• Provides a collection of standardised communication protocols that allow devices to communicate over the internet.
• Breaks data into packets and reassembles them at the destination.
• Provides error detection and repair to guarantee data integrity.
• Provides flow management to prevent data loss due to congestion.
• Provides addressing and routing to guarantee that data is delivered to the proper destination.
• Provides a dependable, connection-oriented transport layer (TCP) with an unstable, connectionless network layer (IP)
• Enables communication across devices with varied hardware and software setups
• Provides a basis for many other internet protocols and applications, such as HTTP, FTP, and SMTP

Comparing TCP and IP 

Here is a table that summarises the main differences between TCP and IP:

TCP/IP’s Evolution

The US Department of Defense (DoD) created the TCP/IP protocol stack as a part of the ARPANET initiative in the 1970s. It comprises the application layer, the transport layer, the internet layer, and the network access layer. The framework’s open, scalable, and extendable nature makes it possible to introduce new protocols as required. The OSI model, a seven-layer standard for computer system communication, serves as its foundation. TCP/IP has undergone several changes, with IPv6 being the most recent. IPv6 surpasses IPv4’s restrictions, enabling a bigger address space, increased security, and better interoperability with mobile devices.

Layers Required for the OSI Model

Here are the seven layers of the OSI model:

• Layer 1: Application Layer – provides services to the user and applications
• Layer 2: Presentation Layer – translates data between the application and network formats
• Layer 3: Session Layer – manages communication sessions between applications
• Layer 4: Transport Layer – provides reliable data transfer between hosts
• Layer 5: Network Layer – routes data between networks
• Layer 6: Data Link Layer – provides reliable data transfer between adjacent nodes
• Layer 7: Physical Layer – transmits raw bit streams over physical media

Characteristics of the TCP/IP Model

Here are some of the features of the TCP/IP model:

• A layered framework dividing the diverse functions of networking into distinct levels
• A protocol stack defining the transportation of data across the internet.
• An open standard widely used and supported by many companies and organisations.
• A flexible model that can be modified to numerous sorts of networks and applications
• A scalable approach accommodating networks of varied sizes and complexities
• A trustworthy model containing error detection and repair procedures to maintain data integrity.
• A connection-oriented approach building a virtual circuit between two endpoints for reliable data transfer (in the case of TCP)
• A connectionless framework that does not construct a virtual circuit and enables quicker data transfer (in the case of UDP)

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The TCP/IP Model Layers

There are four layers of the TCP/IP reference model:

1. Application Layer: Network services for apps are provided by the application layer. The HTTP, FTP, SMTP, and DNS protocols are among them. 
2. Transport Layer: The transport layer ensures that data is reliably and effectively sent between devices. Among the protocols included are TCP (Transmission Control Protocol) and UDP (User Datagram Protocol). 
3. Internet Layer: Data packets are addressed, routed, and fragmented over various networks via the Internet layer. Logical addressing and routing are provided via IP (Internet Protocol). 
4. Network Access Layer: This layer, sometimes called the link layer or data link layer, handles the physical transfer of data over the network. It consists of protocols that outline data transmission through physical media like Ethernet or Wi-Fi.

Importance of TCP/IP

TCP/IP is essential for several reasons:

• Standardisation: TCP/IP gives a set of standard methods ensuring all devices on the internet can interact with one another.
• Reliability: TCP/IP ensures that data is sent in the correct order and that lost packets are re-transmitted to provide stable contact between devices. 
• Scalability: TCP/IP can handle large amounts of data and be used in networks of any size, courtesy of its scalable nature. 
• Security: To protect data while it is being moved across the internet, TCP/IP includes several security features, such as encryption and authentication. 

Distinction Between OSI Model and TCP/IP Model

Here is a tabular comparison between the OSI and TCP/IP model:

What Do the TCP/IP Layers Do?

Here are the functions of four TCP/IP protocol layers:

• Application Layer: Provides applications with standardised data transfer. The HTTP, FTP, SMTP, and SNMP protocols are used.
• Transport Layer: The transport layer of a network handles data dependability, flow management, and data correction. Among its protocols are TCP and UDP.
• Internet Layer: The internet layer transports packets across networks. The IP, ARP, and ICMP protocols are used.
• Network Access Layer: The network access layer handles data transfer between devices linked to the same network. Its protocols include Ethernet and Wi-Fi.

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TCP/IP Protocols 

The main protocols used in TCP/IP are:

• User Datagram Protocol (UDP)
• Hypertext Transfer Protocol (HTTP)
• File Transfer Protocol (FTP)
• Simple Mail Transfer Protocol (SMTP)
• Address Resolution Protocol (ARP)
• Internet Control Message Protocol (ICMP)
• Network File System (NFS)
• Domain Name System (DNS)
• Telnet
• Simple Network Management Protocol (SNMP)

Features of TCP

Here are the characteristics of TCP:

• Connection-oriented: Establish a connection before transferring data.
• Bidirectional: Provides for two-way communication.
• Reliable delivery: Resends missing data to guarantee reliable delivery.
• Order preservation: Assures that data reaches the destination in the same order it was transmitted.
• Error-checking and recovery: Includes methods for error-checking and recovery.
• Flow control: Includes flow control to prevent overloading the recipient with data.
• Full duplex communication: Can execute both receiver and transmitter’s functions.
• Header length: The TCP header is a minimum of 20 bytes and a maximum of 60 bytes long.

The Benefits and Drawbacks of the TCP/IP Model

Benefits of the TCP/IP Model

• Industry-standard model: The TCP/IP protocol suite is extensively used and accepted in real networking situations.
• Interoperability: TCP/IP provides cross-platform communications among heterogeneous networks, making it compatible with diverse devices and operating systems.
• Open protocol suite: TCP/IP is not held by any institute, making it freely available.
• Scalable client-server architecture: The TCP/IP framework enables a scalable design, allowing networks to be added without interrupting present services.
• Identification and address resolution: TCP/IP allocates an IP address to each computer on the network, making each device recognisable via the network.

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Drawbacks of the TCP/IP model

• Lack of strict layer separation: Unlike the OSI model, which has strict layer separation, the TCP/IP framework lacks a clear border between the layers. 
• Limited scalability: The TCP/IP framework was not built for the current internet’s scale and was intended for smaller networks. As a result, scaling TCP/IP-based networks to accommodate the enormous volumes of data and devices observed today can be challenging.
• Security flaws: Security was not a top priority in creating the TCP/IP framework. Therefore, the technologies and protocols employed in the framework have built-in security weaknesses. 
• Lack of integrated QoS techniques: The TCP/IP framework lacks integrated quality of service (QoS) techniques, such as guaranteed bandwidth or latency. This can challenge high QoS applications like real-time communication or video streaming.
• There is little support for multimedia applications: The TCP/IP framework lacks built-in functionality for multimedia applications since it was created primarily for data transport. 
• Limited assistance with mobility: Mobile devices and network transit were not initially intended to be managed by the TCP/IP framework. As a result, maintaining connectivity and switching between networks seamlessly can be difficult.

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TCP/IP Applications

A few applications of the TCP/IP model are:

• End-to-end communication: It is made possible by TCP/IP, which outlines how data should be addressed, transported, routed, and received at the destination.
• Remote login: TCP/IP can be used to provide remote login through a network, enabling users to access the file system of a server host.
• Transmission of files: It enables interactive file transmission over a network.
• Email transmission: TCP/IP transmits email messages over networks.
• Delivery of web pages: TCP/IP distributes webpages throughout the network.
• Data transfer: It provides secure data transmission between the server and client while upholding the sent data’s integrity.
• Dynamic routing: TCP/IP allows data packets to be routed in real-time along the fastest and safest path, enhancing data security.

Conclusion

The TCP/IP architecture outlines the protocols and standards for each level to facilitate reliable and successful data transport. The concept’s layered technique permits the modular architecture, compatibility, and freedom of network protocol invention. 

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