Is NIC layer 01 or layer 02?

I am asking this question because of I found both answers in different sources. Some-one says It is Layer 01. Someone says It is in layer 2. I am getting ready for advanced level IT exam and official book says it is in layer one. Answer for same question in official practice test is layer 2. My opinion it is a layer 01.

If i ask from you, Is NIC layer 01 or layer 02? what is your answer. please provide with reason.



A NIC provides physical layer connectivity (cable attachment, line encoding) as well as data link layer services (framing, addressing).

Edit: As Jörg has correctly pointed out in his comment, many NICs offer some some kinds of offloading or even application-level functions, from checksum offloading to a fully fledged iSCSI initiator. The "bare" or basic function of a NIC is L1 and L2 though.

  • It mean there is no exact answer for "is NIC in Layer 2 or layer 1"?
    – infra
    Mar 17 at 7:29
  • Either ... or ... is wrong. A NIC works in both layers. For OSI that is, other models have fewer layers.
    – Zac67
    Mar 17 at 8:39
  • 1
    There are also NICs that provide MACsec acceleration, IPSec accelaration, TCP Segmentation Offloading, IP / UPD / TCP Checksum Offloading, etc. I believe there are even NICs that do TLS Acceleration. The NICs in our products do RTP-over-UDP-over-IP-over-Ethernet in one go. Mar 18 at 18:28
  • @JörgWMittag Absolutely - NICs have grown into L4 and even L7 (e.g. iSCSI) in the meantime...
    – Zac67
    Mar 18 at 19:06

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