I don't know if my question is clear. But, this is what I know now.

Ethernet MAC sublayer is part of NIC (but I'm unclear of LLC sublayer). PPP, HDLC and frame relay can be implemented on the same serial link. Therefore, I assume PPP, HDLC and frame relay are not part of NIC.

What other data link layer protocols that are not part of NIC?

Please correct me if I am wrong.

1 Answer 1


I think the best way to answer that is to answer the reverse question- what protocols are part of NIC (sic)?

The network interface card handles (primarily, exceptions below) Layer1 and Layer2 of the OSI protocol stack; namely, physical/electrical signals, and HDLC/Ethernet-style framing of other data used in Layer3 (typically these days, IP).

Read up on this wikipedia page- http://en.wikipedia.org/wiki/Data_link_layer

And anything not listed there is what's not included ;)

CAVEAT- most modern NIC's can now perform some sort of feature-set generally-known as 'offloading'- this can apply to Layer2 but typically involves Layer3 activities that would normally be handled by the CPU/OS-network-stack. Instead of burdening the operating system's network stack (and thus the CPU it runs on) most network interface cards have the ability to do things like processing checksums and other mundane activities, freeing the CPU to do more funstuff. Those mundane tasks, per the particular network interface card you are dealing with, might handle some Layer3 work. That's the only caveat, otherwise NIC's deal with Layer1 and Layer2, that's it.

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