In OSI Networking Model, why is Network layer above Data-link layer

Question

I always had a feeling that in OSI, the Data-link layer and the Networking layers should switch places because overall, the layers in the model seem to move from the user specific (Application layer) towards network specific (physical layer). Now, given that MAC address in data-link layer is an artifact that is closer to the user than the network layer, I think the data-link layer should be above network layer.

Now, I'm sure there is a good and logical reason for Network layer being above data-link layer; but that reasoning escapes me; can anyone give me the reason for it? I mean the reason why network layer is above data-link layer.

Thanks, Dan

Answer 1

Now, given that MAC address in data-link layer is an artifact that is closer to the user than the network layer, I think the data-link layer should be above network layer.

The MAC address is closer to the hardware, not the user, and is not always present at all, being specific to the IEEE 802 LAN architecture.

The data link layer encapsulates communication between adjacent nodes on a network. It is between the network layer and the physical layer because it uses services provided by the physical layer and provides services needed by the network layer.

The network layer encapsulates communication between arbitrary nodes on the network, adding the routing information needed to coordinate forwarding through a sequence of nodes adjacent to eachother to reach the final destination.