Talk about the physical link 【arp】

Today I learned about the knowledge about the TCP/IP ,we all know the internet include 7 arrangement .I won’t say much about that!now let’s talk about the knowledge about physical link arp. arp all name is called address resolution protocol !The effects of it is resolution the goal computer’s mac accroding goal IP in the data package !
In the internet ,data is send as a form of frame to the goal computer !if a computer want to send a frame to other computer! it’s can’t achieve if only konw the goal computer’s IP! then it must needs ARP to get the goal computer mac address ! <the mac address is the computer’s exclusive identification number,all over the word has only one!>,so after the send part must the accept part’s mac ,then data can be send on the internet! arp provided dynamic mapping from internet ip to physical mac ! why is dynamic ? because it will automatic execute and change by the time !a computer can change its network card to change its mac!
Now we know the arp help the send computer get the receive computer mac then the data frame can be send to the goal computer !Though the peocess is dynamic ,we don’t have to care about it ! but it is necessary to know the peocess to our server developer !
At first , if the access part computer is linked with the accessed part computer directly! The access part computer can mapping the accessed computer mac directly accroding to accessed computer’s IP! Otherwise ,the access part computer will send broadcast to internet ! Ask all the internet computers who‘s physic link network segment same as access computer if the IP which the access computer wants to access same as the someone!if get it ! the successful matching computer will reply its mac to the access computer ,and record the access computer’s mac and ip,then the two computer can send dataeach other !if not find the corresponding computer ,the arp package will be
abandon on the internet !so the data can’t be send to the internet!
so there are only the not resolutioned arp packages on the internet ! there never are no IP/TCP on the internet!