IPv4 & IPv6

What is Internet Protocol -- IP?

The Internet Protocol (IP) is the method or protocol by which data is sent from one computer to another on the Internet.

What is Internet Protocol address ?

An Internet Protocol address (IP address) is a numerical label assigned to each device (e.g., computer, printer) participating in a computer network that uses the Internet Protocol for communication. An IP address serves two principal functions: host or network interface identification and location addressing.

Most networks combine IP with a higher-level protocol called Transmission Control Protocol (TCP), which establishes a virtual connection between a destination and a source. IP by itself can be compared to something like the postal system. It allows you to address a package and drop it in the system, but there's no direct link between you and the recipient. TCP/IP, on the other hand, establishes a connection between two hosts so that they can send messages back and forth for a period of time.

What is IPv4?

 IPv4 stands for Internet Protocol version 4. It is the underlying technology that makes it possible for us to  connect our devices to the web. Whenever a device access the Internet (whether it’s a PC, Mac,  smartphone or other device), it is assigned a unique, numerical IP address such as 99.48.227.227. To send data from one computer to another through the web, a data packet must be transferred across the network containing the IP addresses of both devices.

Without IP addresses, computers would not be able to communicate and send data to each other. It’s essential to the infrastructure of the web.

What is IPv6?

 IPv6 is the sixth revision to the Internet Protocol and the successor to IPv4. IPv6 is often referred to as the "next generation" Internet standard and has been under development now since the mid-1990s. IPv6 was born out of concern that the demand for IP addresses would exceed the available supply. It functions similarly to IPv4 in  that it provides the unique, numerical IP addresses necessary for Internet-enabled devices to communicate.  However, it does sport one major difference: it utilizes 128-bit addresses.

Why are we running out of IPv4 addresses?

In IPv4 an address consists of 32 bits (4 bytes) which limits the address space to 4294967296 (2^32) possible unique addresses. That means it can support 2^32 IP addresses in total — around  4.29 billion. That may seem like a lot, but all 4.29 billion IP addresses have now been assigned to various institutions, leading to the crisis we face today.

Though we haven’t run out of addresses quite yet. Many of them are unused and in the hands of institutions like MIT and companies like Ford and IBM. More IPv4 addresses are available to be assigned and more will be traded or sold (since IPv4 addresses are now a scarce resource), but they will become a scarcer commodity over the next two years until it creates problem for the web.

 How does IPv6 solve this problem?

 As previously stated, IPv6 utilizes 128-bit (16 bytes) Internet addresses. Therefore, it can support 2^128 Internet addresses — 340,282,366,920,938,000,000,000,000,000,000,000,000 of them to be exact. That’s a lot of addresses, so many that it requires a hexadecimal system to display the addresses. In other words, there are more than enough IPv6 addresses to keep the Internet operational for a very, very long time.

 While increasing the pool of addresses is one of the most important benefit of IPv6, there are other important technological changes in IPv6 that will improve the IP protocol,they are :

• No more NAT ( Network Address Translation (NAT) is a method of connecting multiple computers to the Internet using one IP address because of shortage of IP addresses. This allows home users and small businesses to connect their network to the Internet cheaply and efficiently.) 

• Auto-configuration

• No more private address collisions

• Better multicast routing

• Simpler header format

• Simplified, more efficient routing

• True quality of service (QoS), also called "flow labeling"( Flow label field in the IPv6 header can be used by a source to label a set of packets belonging to the same flow.)

• Built-in authentication and privacy support

• Flexible options and extensions

• Easier administration (say good-bye to DHCP)

So why don’t we just switch?

The depletion of IPv4 addresses was predicted years ago, so the switch has been in progress for the last decade. However, progress has been slow — only a small fraction of the web has switched over to the new protocol. In addition, IPv4 and IPv6 essentially run as parallel networks — exchanging data between these protocols requires special gateways. 

To make the switch, software and routers will have to be changed to support the more advanced network. This will take time and money. 

How will this affect us?

 Initially, it won’t have a major impact.Most operating systems actually support IPv6, including Mac OS X 10.2 and Windows XP SP 1. However, many routers and servers don’t support it, making a connection between a device with an IPv6 address to a router or server that only supports IPv4 impossible. IPv6 is also still in its infancy; it has a lot of bugs and security issues that still need to be fixed, which could result in one giant mess.

Nobody is sure how much the transition will cost or how long it will take, but it has to be done in order for the web to function as it does today.