Q:
This is common question as ARP has two components:
1) MAC address
2) IP address
I know that you are knowledgable in this but please read the logic below:
Since MACs are important to send Frames from one local host to another(local means same collision domain). MACs are the physical component used make that one to one connection. IPs are the logical IDs assigned to the operating system(OS). Thus, a host may recieve a Frame intended for its MAC but when the Frame is unpacked to see the IP, the IP may or may not be intended for that OS. Thus, to send a fram on a local network (same collision domain) you really only need a MAC address. However, if your host system only has the IP address of the destination host ARP sends out a broadcast to see who responds with the same IP *and* MAC address. We can say that ARP is a layer two because it is a method of finding the destination MAC through a known IP address. ARP uses information from layer 3 to find its layer 2 functional component.
A:
Second: ARP processing occurs at Layer 3 of the OSI Model. If Host A attempts to contact Host B, it standardly only has an IP address by which to contact Host B. This is primarily due to the concepts of direct and indirect routing. Anyway, the steps below outline IP processing at Layer 3, which is the second reason that ARP resides at Layer 3 and not Layer 2.
|
ITpassZone is keeping researching the official CCNA syllabus 1 final 2 group certificate certification
exam pool to guarantee that ITpassZone CCNA syllabus 1 final 2 group certificate study guide
covers 100% of the CCNA syllabus 1 final 2 group certificate IT test knowledge and contain
extremely similar question style and content. 