In order to provide computer to computer communication via Internet, we need a global addressing scheme. Such an addressing is provided by Internet Protocol (IP) at the network layer.
It is a 32-bit address This is called an IP address or logical address. Which is made up of the network ID, plus a unique host ID. This address is typically represented with the decimal value of each octet separated by a period (for example, 192.168.7.27). Every Host and router on the internet has an IP Address. This IP address is unique and no two devices on the Internet can have the same address at the same time.
These numbers are assigned by ISP (Internet Service Provider), and IP address can be used to identify the country or region from which a computer is connecting to the WEB. The IP address can either be Static or dynamic.
In static address is to be given manually. But in dynamic a DHCP server is to be configured to give ip address to the connected hosts automatically. This address is used to uniquely identify each Network host over the network. p address is divided into 5 category usually called classes. This allocation has come to be called class full addressing.
Following are the classes of ip:-
Class A 188.8.131.52 to 127.255.255.255
Class B 184.108.40.206 to 220.127.116.11
Class C 192.0.0.0 to 18.104.22.168
Class D 22.214.171.124 to 126.96.36.199
Class E 240.0.0.0 to 255.255.255.255
a Router has more than one IP address because router connects two or more different networks. But A computer or host can only have one and a unique ip address. A routers function is to inspect incoming packet and determine whether it belongs to local network or to a Remote Network, if a local packet is determined then there is no need of routing and if a Remote packet is determined then it will route that packet according to the routing table other wise the packet will be discarded.
In the virtual hosting environment, a single machine can act like multiple machines (with multiple domain names and IP addresses.
IP address format
• The 32-bit IP address is grouped eight bits at a time, separated by dots and represented in decimal format. This is known as dotted decimal notation as shown in fig.
• Each bit in the octet has a binary weight (128,64,32, 16,8,4,2, 1).
• The minimum value for an octet is 0, and the maximum value for an octet is 255.