Final answer:
The correct order of the TCP/IP model layers, starting with the layer closest to the network media, is Network Access, Internetwork, Transport, and Application, which corresponds to option (a). Each layer has specific responsibilities, from handling physical transmission to providing application-specific communication protocols.
Step-by-step explanation:
The TCP/IP model is a conceptual framework used in computer networking to provide end-to-end data communication specifying how data should be packetized, addressed, transmitted, routed, and received at the destination. The correct order of the layers of the TCP/IP model, starting with the layer closest to the network media/medium, is:
- Network Access
- Internetwork
- Transport
- Application
This order corresponds to option (a), which represents the sequence from the lowest layer interacting directly with the physical transmission media, up to the highest layer where application-specific communication occurs.
The Network Access layer (also known as the Link or Network Interface layer) is responsible for the physical and data link protocols, such as Ethernet for local area networks or PPP for point-to-point connections.
The Internetwork layer, often referred to as the Internet layer, is where packets are addressed and routed to their destination across multiple networks. IP (Internet Protocol) is the core protocol of this layer.
The Transport layer is responsible for providing end-to-end communication services for applications. It includes protocols like TCP (Transmission Control Protocol) and UDP (User Datagram Protocol), which ensure that data is delivered reliably and in the correct order, if required by the application.
The Application layer consists of protocols that are used by end-user applications to communicate over the network, such as HTTP for web browsing, SMTP for email, and FTP for file transfer.