Networks and Communications
Layers in TCP/IP
What are the Layers in the TCP/IP model?
The purpose of the TCP/IP model is to protect data integrity maintain communications reliably. The TCP/IP model is organised into four layers, in which each layer is defined by its role in the data transmission process. The four layers of the TCP/IP model are: Internet layer Layer 1 – Network Access layer Note: the TCP/IP layers are often represented in a top-down manner from layer 4 to layer 1 but it is also possible to represent the model in the reverse order layer 1 to layer 4.
Layer 4: Application Layer
The Application Layer includes protocols that applications use in order to exchange data in a standardised way. For example: • Hypertext Transfer Protocol (HTTP) • File Transfer Protocol (FTP) • Simple Mail Transfer Protocol (SMTP)
Layer 3: Transport Layer
The Transport Layer consists of protocols concerned with the reliable and error-free end-to-end communication of data. For example: • Transmission Control Protocol (TCP) • User Datagram Protocol (UDP)
Layer 2: Internet Layer
The Internet Layer defines protocols that handle the packaging, addressing and routing of data before transmission across physical media. For example: • Internet Protocol (IP) – IP v4 and IP v6 • Address Resolution Protocol (ARP)
Layer One: Network Access Layer
The Network Access Layer consists of protocols that facilitate physical data transfer across network hardware (i.e cables and switches). For example: • CSMA/CA • CSMA/CD