When troubleshooting network issues it’s helpful to understand if the issue is occurring at Layer 2 or Layer 3 of the OSI model.

When reading technical information or preparing for a network-analysis effort, it helps to have certain issues and concepts in mind. These items serve that purpose regarding TCP/IP and the OSI Model: ...

The Internet Protocol layer is comparable to layer 3 in the OSI model. The host-to-host layer is equivalent to OSI layer 4. These are the TCP and UDP (user datagram protocol) functions.

This is a good example of de-cerebralisation in action. The 4-7 layer band in the OSI 7-layer network model covers some important tasks, such as load-balancing.