TCP/IP Protocol Model
The OSI Model isn’t a practical model but just a reference model to represent the functions of the communication system. Compared to it, the TCP/IP model seems condensed as it has only 4 layers but it works through all the functionalities regardless.
The various layers present in it are listed below.
- Network Access Layer
It is similar to Data Link and Physical layers of OSI model working together. It implements hardware addresses and facilitates data transmission through its protocols. It is the bottom-most layer of the TCP/IP Protocol Suite.
- Internet Layer
It is similar to the Network Layer of the OSI model. It looks after the logical transmission of data through a set of protocols. The major protocols are :
- IP : Internet Protocol is responsible for transporting data packets from source to destination host by analyzing IP addresses in packet headers.
- ICMP : Internet Control Message Protocol provides information to hosts regarding network issues.
- ARP : Address Resolution Protocol checks for a host’s hardware addresses from a set of IP addresses.
- Host-to-Host Layer
Similar to the transport layer in OSI model, Host-to-Host layer handles end-to-end communication and error-free transmission of data. The protocols found in this layer are :
- TCP – Transmission Control Protocol facilitates flawless communication between systems. It also manages the flow of data, its sequence and segmentation.
- UDP – User Datagram Protocol is just a backup protocol that is inexpensive but isn’t reliable.
- Application Layer
It mimics the functionalities of the three top-most layers of the OSI model, namely Session, Presentation and Application Layer. It is the top-most layer in the TCP/IP Protocol Suite. It handles node-to-node communication. Some major protocols of this layer are :
- HTTP and HTTPS – Hypertext transfer protocol is implemented by the World Wide Web to handle interaction between browsers and servers. HTTPS stands for HTTP-Secure and is a mixture of HTTP and Secure Socket Layer (SSL) which is used in authentication processes.
- SSH – Secure Shell is similar to TELNET, another protocol in Application Layer, but handles encryption better and is used as terminal emulations software.
- NTP – Network Time Protocol controls the synchronization of clocks on computers to one standard source.