15 IP A DDRESS C ONFIGURATIONIP Address OverviewIP Address Classificationand RepresentationAn IP address is a 32-bit address allocated to a device connected to the Internet. Itconsists of two fields: net-id and host-id. To facilitate IP address management, IPaddresses are divided into five classes, as shown in Figure 37.Figure 37 Five classes of IP addressesClass A, Class B, and Class C IP addresses are unicast addresses. Class D IPaddresses are multicast addresses and Class E addresses are reserved for futurespecial use. The first three types are commonly used.IP addresses are in the dotted decimal notation. Each IP address contains fourdecimal integers, with each integer corresponding to one byte (forexample,10.110.50.101).Some IP addresses are reserved for special use. The IP address ranges that can beused by users are listed in Table 73.0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 3101 01 1 01 1 1 01 1 1 1 0net-idnet-idnet-idMulticast addressReserved addresshost-idhost-idhost-idClass AClass BClass CClass DClass Enet-id: Network ID; host-id: Host ID0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 3101 01 1 01 1 1 01 1 1 1 0net-idnet-idnet-idMulticast addressReserved addresshost-idhost-idhost-idClass AClass BClass CClass DClass Enet-id: Network ID; host-id: Host ID
