Layer 4 in the DoD model overlaps with which layer(s) of the OSI model?

Layer 7 of the OSI model (Application layer) is only one component of the combined functionality covered by the DoD model's Process/Application layer.

Layers 2, 3, and 4 of the OSI model correspond to the DoD model's Network Access, Internet, and Host-to-Host layers respectively, not its top-most application layer.

Layer 3 of the OSI model (Network layer) aligns with the Internet layer of the DoD model, which focuses on routing and logical addressing, distinct from application services.

The DoD model simplifies the OSI model's top three layers-Session (Layer 5), Presentation (Layer 6), and Application (Layer 7)-into a single Process/Application layer. This layer handles responsibilities such as interhost communication session management, data format conversion, encryption, and providing application-level services.