IP ADDRESS

IP stands for Internet protocol. An IP address is a unique 32-bits logically assigned binary number of four octets (8-bits), which is represented in decimal notation, designed for a particular device. Hosts and routers used in the TCP/IP protocol suite are identified by the IP addresses. The IP address is also divided into classes and each class has its specific range. The IP address consists of two parts, which are Network ID and Host ID.
a) Network ID: Identifies the network to which the hosts is connected. Network ID is the same for the hosts on a particular network.
b) Host ID: Identifies the host on a network Host ID is different hosts on the network. Each pair of numbers written in decimal notation in an IP address is called an octet.

• An IP address can’t be duplicated.
• All Host bits can’t be set to Zero.
• All Host bits can’t be set to 1.
• 127 can’t be taken as the first octet because it is reserved as a Ioopback address (the address that acts as a test mechanism for network devices and protocol)

Dynamic IP Address: It refers to the IP address assigned to the devices that requires temporary connectivity to the network or device communication through the network for a short period. It uses Dynamic Host Configuration Protocol (DHCP) for assigning the IP address.

Static IP address: It refers to the IP address assigned to a device that requires permanent connectivity on the network. It is the semi-permanent IP address.
That means it cannot be changed.

Classification of IP address:
IP defines five types of classes, i.e. A,B,C,D and E. The first four bits of an IP address determines the class in which an IP address fits.

Types of IP Addresses
      

Class	Network ID		Host ID	Purpose
A	0	7-bits	24-bits	LAN & WAN
B	10	14-bits	16-bits
C	110	21-bits	8-bits
D	1110			Multicast
E	11110			Future Use or R&D (Research and Development) purpose

Class A
Class A addresses are used when there are several hosts communicating on a large network. It uses the first octet, in which first bit is  set to zero and the other seven bits are all set to 1.These networks use the first 8-bits of the IP address to identify the network address and the remaining 24-bits are used to identify the individual host. Class A has up to 2^24 different host, which means that the networks can have up to 16,777,214 hosts.

Class B
Class B addresses use the first two octets or 16-bits of an IP address to identify the network address and the remaining 16-bits or the last two octets to identify the Host ID or address. Class B has up to 2^16 different Host IDs, which means a network can have a maximum of 16,384 class B and 65,534 Hosts on each class B. class B addresses are used in medium to large scale organizations.

Class c
Class C addresses use the first three octets or 24-bits of an IP address for the  network address and the remaining last octet or 8-bits to identify the Host address. Class C has up to 2^8 different Host IDs, so the network can have up to 254 hosts. Class C addresses are used in LAN's.

Class D
Class D addresses are not assigned to Host but are designed for Multicasting (one-to-many) communication each class in class D defines a particular group of Hosts on the Internet.

Class E
Class E addresses are also not assigned to Hosts. These types of addresses are not used for general applications, but are reserved for experimental purpose.

Unicast IP Addresses
Unicast helps in one-to-one communication. Unicast IP address uniquely identifies a host in a particular network when a data packet is sent from a host to the destination address.

Multicast IP Addresses
Multicast address helps in one-to-many communication, when a data packet from a host is sent to a group of hosts and not to a single destination address.

Broadcast IP Addresses
Broadcast address help in one-to-all communication. A Broadcast IP address allows a data packet to be sent from a host to all other hosts on the network.