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:-
CLASSES Range
Class A 1.0.0.0 to 127.255.255.255
Class B 128.0.0.0 to 191.255.255.255
Class C 192.0.0.0 to 223.255.255.255
Class D 224.0.0.0 to 239.255.255.255
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.
Internet protocol Version 4 (IPv4): Internet protocol is glue that holds the internet together. It transfers the datagrams from source to destination without considering that whether the machines are on the same network or not. IP is the main transport mechanism used by TCP/IP suit of protocols. IP provides connectionless, unreliable services.
This means, it will try its best to transfer the packets but it provides no guarantee for this. The packets transmitted through IP can be lost due to a number of reasons which includes noise that cause bit errors, congestion that cause loss of packets, router failure or host failures etc.
For reliability, IP is paired with some reliable protocol like TCP. IP provides service similar to the conventional postal service in which each letter is marked with full source and destination address. The mails are routed from post office of the sender to that of the receiver. Although, the postal department does its best to deliver a mail but it may not be able to deliver the mail due to many reasons.
The postal system is not responsible for this and the communication is carried on the risk of sender. For reliability, the sender may attach an acknowledgement card with the letter. If the receiver receives the letter, it detaches the acknowledgement and sends it back to the address of the sender. This way, the sender knows that the letter has reached the receiver, if the acknowledgement is received by him. The same purpose is achieved by attaching a packet of IP with some reliable protocol.
In internet protocol, the data packets are called as datagrams. Each of these datagrams is routed by using datagram packet switching. This way, every packet can take different route to the destination and each one is different from the other. These packets may reach out of order at the receiving end. The upper layer protocols are given with the job of reordering the packets.
INTERNET PROTOCOT VERSION 6
The numbers of users of the internet are increasing day by day and the services offered to these users are also increasing. A huge number of addresses are needed to accommodate such vast number of hosts. The internet not only transmits textual data. It also allows us to transmit audio and video data. In such data, the high speed data transfer is desired.
The internet protocol version 4 is being used in the current internet. The internet protocol version 6 has been designed for the future needs of the internet. IPv6 has following new features to make the network ready for next generation of the internet.
(i) IPv6 address is 128 bits long. This is far more than 32 bit long addresses used by Ipv4. This provides 296 more unique addresses
(ii) Ipv6 header has got separate options field. This speeds up the routing as most of the times, options are not needed.
(iii) Several new options have been added to set of options.
(iv) To accommodate the real time traffic, the Ipv6 uses Flow Label field instead of Type of Service field of Ipv4. With this field, a user can request for the type of service to be given to the datagram.
(v) The Ipv6 contains options for encryption and decryption of data. This provides additional security to the information.
In this protocol, the IP address is of 128 bits long. The address is divided into eight sections of 16 bits in length. Each 16 bit section is represented by four hexadecimal digits. A colon is used to separate every four hexadecimal digits. This way, the address consists of 32 hexadecimal digits.
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