IP

IP address

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.
In computer networking , an IP address ( internet protocol address ) is a unique number that devices use in order to identify and communicate with each other on a network utilizing the Internet Protocol standard. (Sometimes this is shortened to just "IP" as in "My IP is A.B.C.D".) Any participating device including routers , computers , time-servers, printers, internet fax machines, and some telephones must have its own globally unique communicable address. In other words, an IP address is like a full address for postal mail like 123 Main Street, Anytown, California , United States.
Since IP addresses are not easy to remember, the Domain Name System provides the ability to map domain names (e.g. www.wikipedia.org ) to an IP address ( 207.142.131.248 ).

IP version 4

IPv4 uses 32- bit (4 byte ) addresses which limits the address space to 4,294,967,296 possible unique addresses. However, many are reserved for special purposes such as private networks (~18 million addresses) or multicast addresses (~1 million addresses). This reduces the number of addresses that can be allocated as public Internet addresses and as the number of addresses available is consumed, an IPv4 address shortage appears to be inevitable in the long run.

IP version 6

In IPv6 , the new (but not yet widely deployed) standard protocol for the Internet, addresses are 128 bits wide, which, even with generous assignment of netblocks, should suffice for the foreseeable future. In theory, there would be exactly 2 128 , or about 3.403 × 10 38 unique host interface addresses.
A version 6 address is written as eight 4-digit hexadecimal numbers separated by colons. For readability, addresses may be shortened in two ways. Within each colon-delimited section, leading zeroes may be truncated. Secondly, one string of zeroes (and only one) may be replaced with two colons (::). For example, all of the following addresses are equivalent:

• 1080:0000:0000:0000:0000:0034:0000:417A
• 1080:0:0:0:0:34:0:417A
• 1080::34:0:417A