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New Member

ARP

I have read in a book that ARP and RARP work on the top of datalink layer.Actually where do these two protocols work ,in the Network layer or the datalink layer ?

  • Other Network Infrastructure Subjects
4 REPLIES
Cisco Employee

Re: ARP

ARP operates at the same layer as IP (Layer 3) and has its own Ether Type (0x0806), whereas IP is 0x0800.

Hope this helps,

New Member

Re: ARP

ARP maps ip address (layer 3)to mac addresses and rarp does the reverse so they work on network layer so I guess the author is mentoning a layer top on data link layer that is network layer

New Member

Re: ARP

Thankyou for your information.

Bronze

Re: ARP

ARP is often considered to work "in between" Ethernet and IP, at layer 2.5 if you will. That's probably what the author means. Though since it does run on top of Ethernet, it can also be considered layer 3.

When you get more and more involved in this stuff it becomes clearer that the OSI layers aren't something to be taken too too seriously -- they can help from a conceptual level, but that's about it. A lot of protocols don't exactly fit into one layer or another. Consider ICMP, for example. It runs over IP, but no one ever calls it a layer 4 protocol. It's generally considered layer 3.5.

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