2IPv4Internet Protocol addressing version 4 (IPv4) is the basis of Internet.Every connected host has a four octet address expressed in decimal:AAA.BBB.CCC.DDDFor example: (Google)A host can send a packet to an IP address and it will be delivered to the correct destination.
3CLASSFUL ADDRESSINGUnder IPv4 addressing scheme (classful addressing), the class of the network may be A, B or C. The class effects how the four number IP address is intrepreted. For all classes, the last byte is limited between: 1 – 254: reserved for network address- 255: reserved for broadcast address
5CLASS A (large network): the first byte identifies the network and the last 3 bytes represent an address range for hosts on the network.Byte 1: 1 – 126Byte 2 and 3: 0 – 255No. of hosts (max): 16,646,144CLASS B (medium network): the first two bytes identify the network and the last 2 bytes represent an address for hosts on the network.Byte 1: 128 – 191No. of hosts (max): 65,024CLASS C (small network): the first three bytes identify network and the last byte represent an address for hosts on the network.Byte 1: 192 – 223No. of hosts (max): 254 hostsCLASS D: Byte 1: 224 – 239CLASS E: Byte 1: 240 – 255
6Broadcast Address: broadcast address is intended to go to every host on the network. (host address bytes are replaced with 255 (all ones)Example: Class B network with a network address of would have a broadcast address of
7Network Address: is formed by replacing all host bytes with 0. Example: Class B IP address of , has network address ofNetwork Mask (netmask): a host must know if a received packet relates to the network to which the host is a member. Membership of a network is determined using netmask defined on every network host.netmask = all network bits set to 1, all hosts bitsset to 0Example: Class A = , Class B =
85 Different Classes of IP Address CLASS AtoCLASS BtoCLASS CtoCLASS DtoCLASS Eto
9PRIVATE IP ADDRESS (are not used anywhere on public internet, reserved for private LANs) Network ClassNetwork NumbersNetwork MaskNo. of NetworksNo. of Hosts per NetworkCLASS A12616,646,144CLASS Bto16,38365,024CLASS Cto2,097,151254LOOPBACK (localhost)to-