T-Rex Versus the Elephant

T-Rex Versus the Elephant

Why bother mentioning the OSI model at all? As it turns out, some of the terminology used by the OSI model ends up being used a lot today. In particular, the names of the layers of the OSI model are used to describe other networking models, TCP/IP included. To talk about networking, you need to know the names of the OSI model's seven layers.

OSI uses a seven-layer model, instead of the four (or five) layers in the TCP/IP model. Figure 3-10 depicts how the layers in the two models match up. For instance, OSI defines that error recovery between end user computers should be implemented by transport layer protocols. So, the TCP/IP transport layer, which also defines how end user computers do error recovery with TCP, equates to OSI Layer 4.