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Why MAC address is used and not only IP Address for Networking

Though A very basic Question but asked by CCNA Beginners!MAC address(Identifier) or Hardware Address that is burnt on the Network Interface Cards by its manufacturing companies is used for communication because devices on a LAN must also be uniquely and individually identified or they, like humans sharing the same name, will receive data not intended for them.When data is to be delivered on a LAN, it is encapsulated within an entity called a Frame, a kind of binary envelope.
Think of data encapsulation as being the digital equivalent of placing a letter inside an envelope. A destination address and a return (source) address are written on the outside of the envelope. Without a destination address, the postal service would have no idea where to deliver the letter.
Likewise, when a frame is placed on a data link, all devices attached to the link “see” the frame; therefore, some mechanism must indicate which device should pick up the frame and read the enclosed data, and rest of the device should ignore and discard the data. And here is the MAC address that come into action and identifies itself for the reception of data.
This also helps to prevent excessive data processing by all of the Networked devices for whom the data is not intended for.
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