Help Me ------ Addressing

auos

Hi,

I want some one answer me about below question,
Why Layer 2 using MAC (Physical address) while Layer 3 using IP (Logical address), why using two addressing, what is different.


BR,
Auos

Sie

I havent done this exam of studied for it by my guess is that the IP Address is a Software Address whereas the MAC Address is a Physical Address specific to the NIC.

Layer 3 as I understand it deals with providing the means of transfering the data from one point to another. (Breaking up the packets etc)

Cisco Guru's feel free to correct me..... :

sir_creamy_

"One key feature of network layer addresses is that they were designed to allow logical grouping of addresses."
- Odom

In a word, subnetting.

bluesjunior23

Because in order to route an ip packet from one point to another it may pass through a multitude of devices therefore you need an address format to keep track of the end to end source and destination (ip address) and an address format to keep track of the specific device to device source and destination address's (mac). So while a packets destination ip address stays the same through out its entire journey towards its destination, the frame's (which contains the packet) mac address changes depending on where it is on its route to the destination. This was a confusing point for me and i would recommend perhaps reading up on the osi layers specifically 1 though 4 to get a better handle on how this works.