The Open Systems Interconnection model (OSI model) is a conceptual model that characterizes and standardizes the communication functions of a networka group or system of interconnected people or things.  You must understand this material. I've seen many different videos, these are some of the better videos:
- DescribeGive a detailed account or picture of a situation, event, pattern or process. how communication over networksa group or system of interconnected people or things. is broken down into different layers.
- ListGive a sequence of brief answers with no explanation. the stages in the OSI model