The Open Systems Interconnection (OSI) model gives people a shared way to describe how network communication works. It is a reference framework, not a requirement that every network use a particular set of protocols.
In the 1970s, computer networks were built by governments, research organizations, and technology vendors. Many used different designs and proprietary protocols, so devices from different systems could not always communicate. As public data networks began to emerge, the need for common standards became increasingly clear.
All flashcards
What is a reference model?
A conceptual framework that organizes functions and provides shared terminology without requiring specific protocols.
What are peer entities in networking?
Entities at the same layer on different devices that follow a shared protocol.
What is a service data unit (SDU)?
Data passed to a lower layer for that layer to process or carry.
What does the MAC sublayer do?
It controls how devices access a shared medium and gain permission to transmit.
What is a cross-layer function?
A function that affects more than one layer rather than belonging exclusively to one.
Quiz questions
Which task is primarily performed by the OSI physical layer?Answer: Transmitting raw bits as electrical, radio, or optical signals.
What is the primary scope of data-link delivery in the OSI model?Answer: Frame transfer between directly connected nodes on a link.
Which function is associated with the OSI network layer?Answer: Using addressing and routing to move packets between networks.
Which statement describes TCP as a transport protocol?Answer: It can provide ordered, reliable delivery using acknowledgments and retransmission.
Why is mapping TCP/IP layers to OSI layers considered approximate?Answer: Real protocols may cross layer boundaries or combine functions.
Based on the Wikipedia article OSI model, licensed CC BY-SA 4.0. Adapted into a summary, flashcards and quizzes.