The Link Layer
The TCP/IP model lumps together the OSI model’s layer 1 and layer 2 into a single layer called the Link layer (or Network Interface layer).
A nice way to separate layers in the TCP/IP model is to think about packets and frames. Any part of the network that deals with complete frames is in the Link layer. The moment the frame information is stripped away from an IP packet, we move out of the Link layer and into the Internet layer.
Travel Advisory
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At the Link layer, just about every network tech reverts back to the OSI model for troubleshooting. It’s important to distinguish between problems happening at the Physical layer, ...

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