User's Manual

B222s User’s Guide 179
APPENDIX A
IP Addresses and Subnetting
This appendix introduces I P addresses and subnet m asks.
I P addr esses ident ify individual devices on a net work. Every net working device (such as com put ers,
servers, rout ers, and printers) needs an I P addr ess t o com m unicat e across t he net work. These
networking devices are also known as hosts.
Subnet m asks det erm ine the m axim um num ber of possible hosts on a net work. You can also use
subnet m asks t o divide one network into m ult iple sub- net works.
Introduction to IP Addresses
One part of t he I P address is t he net work num ber, and t he ot her part is the host I D. I n t he sam e
way t hat houses on a street share a com mon street nam e, t he hosts on a net work share a com m on
network num ber. Sim ilarly, as each house has it s own house num ber, each host on t he network has
it s own unique ident ifying num ber - t he host I D. Rout ers use t he net work num ber t o send packet s
to t he correct network, while the host I D determ ines t o which host on t he network t he packet s are
delivered.
Structure
An I P address is m ade up of four part s, writ ten in dot t ed decim al notat ion (for exam ple,
192.168.1.1) . Each of t hese four part s is known as an octet. An octet is an eight - digit binary
num ber ( for exam ple 11000000, which is 192 in decim al not at ion).
Therefore, each octet has a possible range of 00000000 to 11111111 in binary, or 0 t o 255 in
decim al.