Here, we will learn about the TCP/IP model of a Computer Network in detail with its characteristics, layers, protocols, advantages, and disadvantages.
What is the TCP/IP Model?
TCP/IP model is a Transmission Control Protocol/Internet Protocol model which is a concise version of the OSI (Open System Interconnection) model.
This model was designed in 1960 by the Department of Defense (DoD). This model has a set of rules which helps in interconnecting the computers or network devices to the Internet.
It also specifies how the data should be transferred over long distances. Unlike seven layers of the OSI model, this model only has 4 layers.
Characteristics of TCP/IP Model
Following are the characteristics of the Transmission Control Protocol/Internet Protocol (TCP/IP) Model:
1. TCP/IP model is connection-oriented, i.e., the network devices should establish a connection before they transfer data to each other.
2. Reliability is the most important characteristic of the TCP/IP model.
3. This model ensures that the data reaches the destination in the same sequence it was sent.
4. It allows you to implement the flow control, error checking, and recovery mechanism.
5. This model provides the full-duplex facility, i.e., the data can be transferred in both directions.
Layers of TCP/IP Model
The functionality of the TCP/IP model is divided into four tasks. And, each task is performed by the different layers. Each layer has a defined set of methods and protocols for performing that task.
The four different layers of the TCP/IP model are mentioned below:
1. Network Layer
2. Internet Layer
3. Transport Layer
4. Application Layer
Network Layer
Network Layer of TCP/IP model is the lowest layer and the combination of physical and data link layer of OSI reference model.Sometimes, this layer is also referred to as the host-to-network layer.
This TCP/IP layer helps you to define how the data should be transferred physically using the network. It encapsulates the IP datagram into frames and maps the Internet Protocol (IP) addresses into the physical addresses.
This layer does not define any protocol but supports all the standard protocols.
Internet Layer
The Internet Layer of the TCP/IP model is the second layer and sends the data packets to the destination over the network.
This layer routes each data packet from the sender to the receiver using the optimal route and handles the errors in the transmission.
This layer uses the following three protocols:
1. IP protocol
2. ARP protocol
3. ICMP protocol
Transport Layer
The Transport Layer of the TCP/IP model is the third layer and provides the reliability, flow control, and correction of the data which is being sent by the source over the network.
This layer of the TCP/IP model is similar to the transport layer of the OSI reference model. The main function of this layer is that it makes the delivery of data error-free.
It also does functions like segmenting, multiplexing, and splitting of the data to be transferred over the network.
This layer uses the following two protocols:
1. TCP (Transmission Control Protocol)
2. UDP (User Datagram Protocol)
Application Layer
The Application Layer of the TCP/IP model is the uppermost layer and allows you to interact with the application.
This layer makes the node-to-node communication and controls the user-application interface. File transfer, e-mail services, and remote login are the best examples of the Application layer.
This layer uses the following multiple protocols:
1. Simple Mail Transfer Protocol (SMTP)
2. Domain Name System (DNS)
3. File Transfer Protocol (FTP)
4. TELNET
5. HyperText Transfer Protocol (HTTP)
6. Simple Network Management Protocol (SNMP)
Protocols of TCP/IP Model
Following are the most common TCP/IP protocols:
1. TCP
2. IP
3. HTTP
4. FTP
5. SMTP
6. SNMP
7. DNS
TCP
TCP is an abbreviation of Transmission Control Protocol.This protocol of the TCP/IP model divides the message into the small units called TCP segments and resembles all the segments based on the sequence number at the destination side.
This protocol also ensures that the data is successfully transmitted from one device to another over the network. This protocol retransmits those frames which are damaged in the previous transmission.
IP
IP is an abbreviation of Internet Protocol.This protocol of the TCP/IP model is the most essential protocol which decides the route for transmitting the data.
It is also responsible for implementing the logical host address.
HTTP
HTTP is an abbreviation of HyperText Transfer Protocol. This protocol of the TCP/IP model transfers the web pages and other web resources from the HTTP server to the HTTP client.
It allows users to access the data over the World Wide Web and also transfers the plain text, audio, and videos over WWW.
FTP
FTP is an abbreviation of File Transfer Protocol. This protocol of the TCP/IP model allows you to transfer the files from one device to another device over the network via the physical medium.
FTP also allows you to download the files to your computers from the other servers. It is mainly used for sharing files.
SMTP
SMTP is an abbreviation of Simple Mail Transfer Protocol.This protocol of the TCP/IP model allows you to transfer the mail messages to other email addresses over the Internet.
It exchanges the mail between the different email users on the same device or different device. You can easily send text messages, images, videos, audio, files, and graphics to one or more recipients.
SNMP
SNMP is an abbreviation of Simple Network Management Protocol. This protocol of the TCP/IP model manages the network devices on the Internet. Sometimes, it also provides a set of methods to monitor the network and detects the faults that occurred on the network.
DNS
DNS is an abbreviation of Domain Name System.This protocol of the TCP/IP model maps the names of the computers, devices, and services connected to the Internet.
As we know, IP addresses are used to identify the connection of a computer or device to the Internet. But, some people use names instead of IP addresses. That’s why DNS maps the names to the address.
Advantages of TCP/IP Model
Following are the advantages or benefits of the Transmission Control Protocol/Internet Protocol (TCP/IP) model:
1. The main advantage of this model is that it is used to make a connection between the two different computers.
2. This model supports multiple networking routing protocols.
3. Scalability is a big advantage of this model because it allows networks to be added or removed without disrupting the current network service.
4. This model uses control mechanisms such as flow control and error control.
5. TCP/IP model is an open protocol suite. So, any user or any organization can easily use this model, because it does not belong to the particular institute or company.
6. When this model is used on modem or LAN then it provides better performance.
7. The last and final advantage is that it offers internetworking among different organizations.
Disadvantages of TCP/IP Model
Following are the disadvantages or limitations of the Transmission Control Protocol/Internet Protocol (TCP/IP) model:
1. The TCP/IP model is complex. So, it is difficult to implement and manage.
2. In this TCP/IP model, the transport layer is not responsible for the delivery of packets.
3. This model is not the best choice for LAN and PAN networks. It was only implemented for the WAN networks.
4. The TCP/IP model does not replace the TCP/IP protocols easily.
5. This model is not suitable for describing the new technologies, because it has not clearly separated the concepts of interfaces, services, and protocols.