What are the various address Translation schemes? Explain which scheme is used in Internet?
Translation from a computer's protocol address to a corresponding hardware address is termed as address resolution. Address resolution algorithms can be grouped in three fundamental categories:
Table lookup-
Bindings or mapping are stored in a table in memory, which the software searches when it requires resolving an address.
Closed Form Computation-
The protocol address assigned to a computer is selected carefully therefore the computer's hardware address can be calculated from the protocol address using fundamental Boolean and arithmetic operations.
Message Exchange-
Computer exchange messages across a network to solve an address. One computer sends a message which requests an address binding (that is translation), and other computer sends a reply which contains the requested information.
TCP/IP can utilize any of the three methods; the method selected for an exact network depends upon the addressing scheme used through under lying hardware.
Usually third scheme is used over internet. The TCP/IP suite includes a standard address resolution protocol (ARP). Address resolution protocol defines the format of the messages that computers exchange to solve an address with rules for handling ARP messages.