iSACA Cybersecurity Fundamentals Certification Practice Exam

What does the term "Encapsulation" refer to in networking?

1. The division of data into packets

2. The addition of addressing information to data as they are transmitted

3. The compression of data before transmission

4. Concealing data within a secure environment

The correct answer is: The addition of addressing information to data as they are transmitted

Encapsulation in networking refers to the process of adding addressing information to data as it is transmitted over a network. This process occurs at various layers of the OSI or TCP/IP models, where data from the application layer gets wrapped in headers (and sometimes trailers) as it passes down through the layers. When data is prepared for transmission, each layer adds its own control information. For example, the transport layer adds a TCP or UDP header that includes source and destination port information, while the network layer adds IP addressing information to route the data properly. This layering and wrapping of data ensures that packets contain all necessary information for the receiving devices to understand where the data is coming from and where it needs to go. In contrast, the other options relate to aspects of data transmission but do not accurately capture the essence of encapsulation. Dividing data into packets is part of the data transmission process but does not involve adding addressing. Compression is a method to reduce the size of data, often used for efficiency, but it does not involve addressing. Concealing data within a secure environment refers to security practices, not the encapsulation process itself.