NOTES ON INTERNET PROTOCOL AND ITS DIAGRAM

INTERNET PROTOCOL

• IP is responsible for moving data from computer to computer.
• The Internet Protocol ( IP ) is a protocol used for communicating data across a packet-switched internetwork using the Internet Protocol Suite , also referred to as TCP/IP.
• IP uses gateways to help move data from point "a" to point "b". Early gateways were responsible for finding routes for IP to follow.

The internet protocol(ip) is a network layer protocol.

* it host and getways process packets called internet datagrams(ip datagrams)

* ip provides connectionless, best effort delivery service to the layers above it.

* The goal of IP is to interconnect networks of diverse technologies and create a single, virtual network to which all hosts connect.

* Hosts communicate with other hosts by handing datagrams to the IP layer;

    * The sender doesn't worry about the details of how the networks are actually interconnected.

    * IP provides unreliable, connectionless delivery service.

    * IP defines a universal packet called an Internet Datagram.

INTERNET PROTOCOL  ADDRESS:

Every machine on the Internet has a unique identifying number, called an IP Address. A typical IP address looks like this:

• 216.27.61.137

To make it easier for us humans to remember, IP addresses are normally expressed in decimal format as a "dotted decimal number" like the one above. But computers communicate in binary form. Look at the same IP address in binary:

• 11011000.00011011.00111101.10001001

C

The four numbers in an IP address are called octets, because they each have eight positions when viewed in binary form. If you add all the positions together, you get 32, which is why IP addresses are considered 32-bit numbers. Since each of the eight positions can have two different states (1 or 0) the total number of possible combinations per octet is 2⁸ or 256. So each octet can contain any value between 0 and 255. Combine the four octets and you get 2³² or a possible 4,294,967,296 unique values.

There are five classes of available IP ranges: Class A, Class B, Class C, Class D and Class E, while only A, B and C are commonly used.

 Each class allows for a range of valid IP addresses.

Class A - This class is for very large networks, such as a major international company might have. Class A networks have a beginning octet of 1 - 126. Class A's default mask is 255.0.0.0, or /8. The Class A network mask 255.0.0.0 means the first octet of the address is the network portion, and the final three octets are the host portion.

Class B - Class B is used for medium-sized networks. A good example is a large college campus. Class B networks have a beginning octet of 128-191. Class B's default mask is 255.255.0.0, or /16.
The Class B network mask 255.255.0.0 means the first two octets of the address are the network portion, and the final two octets are the host portion.

Class C - Class C addresses are commonly used for small to mid-size businesses. Class C networks have a beginning octet of 192 - 223. Class C's default mask is 255.255.255.0, or /24. The Class C network mask 255.255.255.0 means the first three octets of the address are the network portion, and the final octet is the host portion.

Class D - Used for multicasts, Class D is slightly different from the first three classes. It has a first bit value of 1, second bit value of 1, third bit value of 1 and fourth bit value of 0.

Class E - Class E is used for experimental purposes only. Like Class D, it is different from the first three classes. It has a first bit value of 1, second bit value of 1, third bit value of 1 and fourth bit value of 1.