I read on the Internet that the NIC resides on the physical layer of the OSI model so what about the other 6 layers. I know what they actually do but i want to know how it's done. In other wards, what hardware components they use to complete their jobs

  • 1
    The OSI model is just a model. The real world doesn't actually follow the OSI model. The IP model is much closer to what actually happens, but it is still just a model, and things don't fall completely in line with it either.
    – Ron Maupin
    Aug 9 '18 at 20:24
  • Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you can provide and accept your own answer.
    – Ron Maupin
    Dec 25 '18 at 9:12

Traditionally, a NIC (and its driver) handles the physical (PHY) and the data link layers (MAC). The network and (the common) transport layers are part of the operating system and the rest is handled by the application.

Technology advances and today many NICs also handle various layer-3 and layer-4 functions (offloading) while applications heavily use libraries and frameworks that may be part of the operating system.

Additionally, decent firewalls offload most functions to content processors, so nearly everything may be done in hardware.

So, while the functionality stays the same, the exact locations of processing move down the system stack, improving processing speed and capabilities.


In other wards, what hardware components they use to complete their jobs

Simple answer: None.

The OSI model describes how the data being transmitted is structured. It does not describe the hardware in any kind.

In the times of analogue modems for example everything that has been done in hardware was located in "layer 1". All other layers were completely handled in software.

When Ethernet or WLAN is used the hardware does things that are belonging to layers 1 and 2 according to the OSI model; layers 3-7 are still a pure software thing (at least when talking about a normal PC).


Usually when people refer to the NIC as layer one they are talking about the hardware. The other 6 layers are represented by software. As an application sends data to the network, that data moves though the network stack hitting each layer once by one, starting at layer 7 and moving down towards layer 1. different snippets of code in various protocols until the data is sent to the hardware NIC. The protocols do something with the data at each stack layer and add their own meta data into headers at each layer so that the same protocols on the other end of transmission know what to do with the data.

You can see from this image how data passes though each layer though a "virtual interface". But its important to know that these virtual interfaces are just code, the only thing physical is at the bottom of the stack when the processed data finally hits the NIC and sent over the wire or send over the air via Wifi.

Data flow though the OSI model


The hardware inside a NIC is basically the same asa radio as that is what it really is. It is a electromagnetic wave generator(transmitter) and receiver/decoder with a interface to a computer where the signals are sent and received in binary as opposed to , say sound waves in an FM radio.

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