Which OSI model layers are combined in the TCP/IP network access layer?

The TCP/IP network access layer combines:

1. OSI Physical layer (L1 - Physical)
2. OSI Data Link layer (L2 - Data Link)

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#Why these specific layers?

The TCP/IP network access layer is responsible for how data is actually transmitted over the network: via cable, Wi-Fi, fiber optics, and so on. In other words, it includes:

• physical signals, frequencies, cables, connectors - this is OSI L1
• forming Ethernet frames, MAC addressing, VLANs, switch operation - this is OSI L2

In TCP/IP, it was decided not to separate them, because in practice they always work together.