so I have just stared to learn OSI model and I can't understand why do we need IP on the third layer AND MAC addresses on the second layer.

From what I understand MAC addresses are used to move frames between nodes of a network (routers change source MAC address and destination MAC address as frame go through network)

1.Why do we need MAC addresses to do that? Can't we just use IP addresses of routers along the way? 2.Are MAC addresses just a redundancy? 3.Is it possible to somehow create a network model which would only use IP addresses? Just a single id number for each device in network


  • I just created a video which will help explain why you need both IP and MAC addresses: youtube.com/watch?v=LkolbURrtTs
    – Eddie
    Commented Jan 8, 2021 at 17:19
  • 1
    @Eddie thats funny because i spent my whole day today trying to understand networking more and I found your channel couple of hours ago, and ofc subscibed, and you answer my questions nice Commented Jan 8, 2021 at 17:40
  • I think originally there was Ethernet which didn't have IP addresses and there was IP (over serial lines) which didn't have MAC addresses. The combination is because we run IP over Ethernet. Why do we run IP over Ethernet instead of just running IP by itself? That's a very good question... Commented Jan 8, 2021 at 21:23


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