TCP/IP stands for Transmission Control Protocol/Internet Protocol. TCP/IP interconnects network devices across an extranet or the Internet. TCP and IP are the two main protocols through the exchange of data where TCP specifies how the application creates the mode of communication over the network. In order to send the data over the Internet, it splits the data into smaller packets and also reassembles it in a sequence manner at the destination point.
IP determines the address and route for each packet and verifies that there is the correct destination.
In this article we will learn in detail about TCP/IP protocol, layers in TCP/IP model, Internet protocol, advantages and disadvantages of TCP/IP, advantages of TCP/IP model over OSI.
History of TCP/IP: In 1970s the defence advanced research program agency of US has developed the TCP IP model. it is created for use in ARPANET. TCP IP was only designed for the Unix OS but it has built into all of the OSes that came after it.
The functions of the TCP/IP model are divided into 4 layers, with each layer having a specific function.
- Network Access Layer
- Internet Layer
- Transport Layer
- Application Layer
Table of Contents
Network Access Layer of TCP/IP Model
The network access layer is the lowest layer in the TCP IP model. The two-layer physical layer and the data link layer in the OSI model are combined in the TCP/IP model, which is named the network access layer. The network access layer is also known as network interface layer or physical layer or link layer. This layer is used to physically send data through the network. It also helps to define how bits should connect to hardware that interfaces directly to the network. Example – coaxial, optical, fiber etc.
The Network Access Layer does not specify any specific protocol but it supports all standard protocols.
Internet Layer of TCP/IP Model
The Internet layer, also known as the network layer, is the second layer of the TCP-IP model. The Internet layer sends packets to and from the network or computer. In this layer the data reaches the destination manually.
The protocols used in the layer are – IP and ICMP
What is an IP (Internet Protocol)?
IP stands for Internet Protocol. Through the IP protocol, the packet is routed to the destination by checking the correct IP address shown in the packet header. There are two types of IP ipv4 and ipv6.
What is ICMP (Internet Control Message Protocol)?
ICMP stands for Internet Control Messaging Protocol. ICMP is contained in IP datagrams. It provides information about any network problem.
What is Address Resolution Protocol (ARP)?
ARP stands for Address Resolution Protocol. ARP is used to find the hardware address of the host using the IP address.
Transport Layer of TCP/IP Model
The transport layer of the TCP IP model is also known as the host to host layer. The transport layer establishes the connection between the sender and the receiver. It is also responsible for the error-free distribution and ordering of data.
The two main protocols used by the transport layer are TCP and UDP.
What is TCP (Transmission Control Protocol)?
TCP protocol is used to provide reliable and error free communication. TCP also manages the correct sequence of data through a flow control mechanism.
What is UDP (User Datagram Protocol)?
Unlike TCP, UDP provides connectionless service. UDP detects the error but is not able to specify it so UDP is an unreliable protocol.
Application Layer of TCP/IP Model
The application layer is the top layer of the TCP/IP model. The application layer establishes a seamless relationship between the application and the user. This layer provides email service and logon service to the remote host.
Various protocols are used in the application layer which are http, https, FTP, TFTP, Telnet, SSH, SNMP, NTP, DNS, DHCP, NFS, X Window and LPD.
- HTTP – HTTP stands for Hypertext Transfer Protocol. It is used to establish communication between the web browser and the server.
- SSH – SSH stands for secure shell. While it is comparable to Telnet, SSH is more reliable since it has the ability to maintain an encrypted connection.
- NTP – NTP stands for Network Time Protocol. The clock of our computer is synchronized with the help of NTP using a single source of precise time.
- FTP – FTP is used to transfer files over a network channel. FTP stands for File Transfer Protocol.
- SMTP – SMTP stands for Simple Mail Transfer Protocol. It is used to handle the task of email related issues.
- DNS – DNS stands for Domain Name System. It is used instead of IP address. IP address uniquely identifies a host but host name is more preferable than address so Domain Name System (DNS) refers to the system that associates a name with an address.
Advantages of TCP/IP model
The TCP/IP model has the following advantages:
- The TCP/IP model can be operated independently.
- It has the characteristic of a good failure recovery.
- It can add more networks without disturbing existing services.
- If data is lost using one route then another route is available to deliver the data, so it has the ability to handle higher error rates.
- It is platform independent which means that the client can be Windows, Unix etc.
- The TCP IP model is reliable, efficient and fast.
Disadvantages of TCP/IP model
The TCP/IP model has the following disadvantages:
- It is used for wide area networks (WAN). This is not good for LAN and PAN.
- The TCP/IP model is complex because the setup and management of this model is not easy.
- The protocol of the TCP/IP model cannot be changed.
- In this model the delivery of packets is not confirmed by the transport layer.
- The concepts of service, interface and protocol are not separated so new technologies may not be suitable in this model.
- The data will not be delivered until all images have been loaded, this means that if the web page contains more than one image, and if one of them is missing then the other components of the stream cannot be sent via TCP. As a result, if there is a problem with one picture the other will not load.