WLAN AP ROUTER 802.11N207B IP Addresses, Network Masks, andSubnetsIP AddressesNoteThis section refers only to IP addresses for IPv4 (version 4 of theInternet Protocol). IPv6 addresses are not covered.This section assumes basic knowledge of binary numbers, bits,and bytes.IP addresses, the Internet's version of telephone numbers, areused to identify individual nodes (computers or devices) on theInternet. Every IP address contains four numbers, each from 0to 255 and separated by dots (periods), e.g. 20.56.0.211. Thesenumbers are called, from left to right, field1, field2, field3, andfield4.This style of writing IP addresses as decimal numbersseparated by dots is called dotted decimal notation. The IPaddress 20.56.0.211 is read "twenty dot fifty-six dot zero dottwo-eleven."Structure of an IP addressIP addresses have a hierarchical design similar to that oftelephone numbers. For example, a 7-digit telephone numberstarts with a 3-digit prefix that identifies a group of thousands oftelephone lines, and ends with four digits that identify onespecific line in that group.Similarly, IP addresses contain two kinds of information:• Network IDIdentifies a particular network within the Internet or intranet• Host IDIdentifies a particular computer or device on the networkThe first part of every IP address contains the network ID, andthe rest of the address contains the host ID. The length of thenetwork ID depends on the network's class (see followingsection). The table below shows the structure of an IP address.Field1 Field2 Field3 Field4Class A Network ID Host IDClass B Network ID Host IDClass C Network ID Host IDHere are some examples of valid IP addresses:Class A: 10.30.6.125 (network = 10, host = 30.6.125)Class B: 129.88.16.49 (network = 129.88, host = 16.49)Class C: 192.60.201.11 (network = 192.60.201, host = 11)Network classesThe three commonly used network classes are A, B, and C.(There is also a class D but it has a special use beyond the
