In that case, I recommend watching the OSI Model Demystified video by Eli the Computer Guy.
What is the OSI Model?
The Open Systems Interconnection (OSI) model is a reference guide to help manufacturers make sure components could communicate with each other. Its a useful tool in troubleshooting. Having a checklist to work through helps prevent people from making minor errors due to forgetfulness or complacency. Go through the layers of the OSI, and you’ll likely have identified where the deficiencies are.
What are the OSI layers and what should my team do with this?
Each OSI layer is an abstraction of a component. Think of the OSI model as a guide, these general layers help to thoroughly investigate your device.
For each layer your team deals with, you should develop documentation and troubleshooting checklists to improve their turnaround time on defects.
Application: The Top Layer - Interfaces to obtain access to services. Commonly the end-user interface.
Presentation: Formats the transferred data. Data is formatted so it can be understood by different devices.
Session: Ongoing communications between connected apps/devices. The session can allow data to be shared one direction at a time or simultaneously.
Transport: Data from the Session layer is accepted and packaged into smaller parts to pass through the Network layer. This layer acknowledges if data was received and corrects errors.
Network: This layer is concerned with the connection. Routers and IP protocols operate on this layer. Confirmation that the same number of packets sent were received. This layer corrects for issues including congestion of too many data packets.
Data Link: The layer switches operate on. Switches are the controllers that enable devices to communicate. Packet switching is used to receive, process, and forward data.
Physical: The mechanical, electrical, functional and procedural interfaces that transmit data. One example is the cabling system.
Detailed information can be read in the SANS Institute InfoSec Reading Room’s The OSI Model: An Overview.
There’s lots of acronyms to help remember the OSI model. Here is mine:
Picard Doesn’t Need To Set Phasers Again