Question

Consider a scenario in which Elsa who is a researcher in the Computer Science department of CSUDH needs to order a scientific journal related to her research from an online bookseller. Explain the communications that happen at Network, Data-link, and Physical Layers.

Answer 1

The network layer responds to requests from transport layer and issues requests to the data link layer.

The Data Link layer performs two basic services: Allows the upper layers to access the media using techniques such as framing. Controls how data is placed onto the media and is received from the media using techniques such as media access control and error detection.

The physical layer deals with transmission of individual bits from one node to another over a physical medium. It defines the physical characteristics and functions of the physical devices and interfaces so that transmission can occur.

When a book is ordered online the request is sent to the network layer first . The network layer will process this request and send request to the data link layer.

The data link layer will process the media and the request is now sent to the physical layer . The physical layer is concerned with actual transfer of data bits across a transmission medium between 2 devices. So the physical layer will send the request of ordering the book to the online bookseller.