can you pls help me understand what the instructor is trying to convey in the following slide.

from what I understand:- network address and link address are independent in the protocol layers but when it comes to the assignment of these addresses they are in some sense dependent in a way that for each link-layer address we need to have a network-layer address.

enter image description here

  • 1
    IMO this is a poorly written example. While technically correct, it’s confusing and it’s something you’d never see in real networks.
    – Ron Trunk
    Mar 18 '20 at 10:31

for each link-layer address we need to have a network-layer address

It's the other way around: the network layer (IP) uses the link layer (MAC) to deliver packets inside a local subnet. For IPv4, ARP is used to translate the local destination IP to the destination MAC address. The IP packet is encapsulated by a link-layer frame (usually Ethernet) and transported across the link-layer network.

The question which IP address belongs to MAC address xyz doesn't usually need an answer.

You only need a network-layer address if you use a protocol that requires those. Alternatively, you could use a protocol without network-layer addressing (like NETBIOS) but that is confined to a local segment and not routable in general.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.