w5100 mask addrs

what is the diff b/w offset addrs, mask addrs, physical addrs, base addrs of a socket-n in w5100?
plz reply me as early as possible
i need clear difference please

Please refer to datasheet, it has all the information you need. At least before you ask such general questions, you should have some research done.

i saw data sheet,but i did not find the correct difference
can you help me plz