IP Address

IP Addressing in Brief

What is ip address ?

An Internet Protocol address (IP address) is a numerical label assigned to each device connected together. IP addresses allow hosts to participate on IP based networks.  An IP address serves two main functions: host or network interface identification and location addressing. They are of two type

IPv4 and IPv6

IPv4:-

•  It is a 32 bit binary number represented as four octets (four 8-bit values).
•  Each octet is separated by a period.
•  There are three types of IPv4 addresses:

o   Network address, i.e  ...192.168.1.0

o    Host address, i.e …….192.168.1.1 to 192.168.1.254 and

o   Broadcast address……192.168.1.255

• IP addresses can be represented in one of two ways:

Decimal:-. In decimal notation, each octet must be between 0 and 255, i.e  192.168.1.1

Binary :-In binary notation, each octet is an 8-digit number.

(for example 10000011.01101011.00000010.11001000)

                           8 bit...…8  bit……8 bit………8 bit

• The IP address includes both the network and the host address.
• The subnet mask is a 32-bit number that is associated with each IP address which play master roll in  identifying the network portion/batch of the address. In binary form, the subnet mask is always a series of 1's followed by a series of 0's (1's and 0's are never mixed mask might be decimal -255.255.255.0 Binary  - 11111111.11111111.11111111.00000000)

In later section we will learn in detail about IPv4 and IPv6

  

Now the big question arise in your mind is that ,

What is Network address?

Host address?

What is broadcast address?

Network Address – while talking about the network address the only thing to have  in mind is that 

• It is  The portion of  address which we referred+ as  network is
• Uses the first address in the network batch,
• The network address is reserved and is not usable by a host
• All hosts in a network batch will have the same network address or say
• All hosts in a network will have the same network bits or network portion/batch 

Broadcast Address – For a given network batch/ portion broadcast address is

·         used to send data to all of the hosts/user on a network

·         Uses the highest (last) address in the network,

·         The broadcast address is reserved and is not usable by a host

·         The bits in host portion are all 1’s

·         Also called a directed broadcast.

Host Address – these are The addresses

•  Assigned to the end devices in the network
•  Each and every device in the network needs a unique ip address,
• The host addresses lie between the network and broadcast address

There are some default classless of ip address based on there subnet mask which could be classified as:-

Class	Range of address	Default Mask	No. of Network	No. of Usable hosts/Network
Class A	1.0.0.0  to 126.255.255.255	255.0.0.0	126	2^24-2=16777216
Class B	128.0.0.0 to 191.255.255.255	255.255.0.0	2^14=65384	2^16-2=65534
Class C	192.0.0.0 to 223.255.255.255	255.255.255.0	2^21=2097152	2^8-2  =254
Class D	224.0.0.0 to 239.255.255.255	NA		Reserve for Multicast
Class E	240.0.0.0 to 255.255.255.255	NA		Reserved for experimental use.

Addresses in the 127.0.0.0 (127.0.0.0 to 127.255.255.255) range are reserved for the local host (in other words "this" host or the host you're currently working at). The most commonly-used address is 127.0.0.1 which is the loopback address.

Privet ip address :-The following address ranges have been reserved for private use:

• 10.0.0.0 to 10.255.255.255
• 172.16.0.0 to 172.31.255.255
• 192.168.0.0 to 192.168.255.255

These range of ip address are not routable on internet. Routers connected to the Internet typically filter messages within these ranges and prevent them from being propagated to the Internet.

Basically the privet ip address are used at local network by any organization and the same address at the same time can be used by another organization. Since these address are not routable at internet so for sending information on internet with these addresses NAT is used , using NAT-PAT , a single public ip is needed to to translate any range of privet address.\/