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 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. 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. I'll explain why this is important in a moment.


Who created IPv6 and how long has IPv6 been available? It is new?

The Internet Engineering Task Force (IETF), an international group concerned with developing technical standards that make the Internet work better first published the basic IPv6 protocol in 1998. It has since seen a number of enhancements, such as the addition of mobile IPv6 specifications (in 2004).


What happened to IPv5?

Version 5 of the IP family was an experimental protocol developed in the 1980s. IPv5 (also called the Internet Stream Protocol) was never widely deployed. Since the number 5 was already allocated, this number was not considered for the successor to IPv4. Several proposals were suggested as the IPv4 successor, and each was assigned a number. In the end, it happened that the one with version number 6 was selected.


Why we are running out of IPv4 addresses?

IPv4 uses 32 bits for its Internet 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.

Let's be clear, 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 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.


Are there other advantages to IPv6 besides increased address space?

The main advantage of IPv6 is that it provides much more address space. Being a more recent protocol, IPv6 does have a few design improvements over IPv4, particularly in the areas of autoconfiguration, mobility, and extensibility. However, increased address space is the main benefit of IPv6.


What happens when IPv4 address pool is finally depleted?

Existing devices and networks connected to the Internet through IPv4 addresses will continue to work as they do now. In fact, IPv4-based networks are expected to co-exist with IPv6-based networks at the same time.

However, for network operators and other entities that rely on Internet numbering allocations, it will become increasingly difficult and expensive (and eventually prohibitively so) to obtain new IPv4 address space to grow their networks. The cost and complexity associated with keeping track of and managing remaining IPv4 address space efficiently will also increase.

Therefore, network operators and enterprises will need to implement IPv6 in order to ensure long-term network growth and global connectivity.


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. The first real test of the IPv6 network will come on June 8, 2011, World IPv6 Day. Google, Facebook and other prominent web companies will test drive the IPv6 network to see what it can handle and what still needs to be done to get the world switched over to the new network.


How will this effect me?

Initially, it won't have a major impact on your life. 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.

How much will the transition to IPv6 cost?

Since network needs and businesses differ, IPv6 transition strategies and related costs will also vary between organisations. Hardware and software vendors are increasingly integrating IPv6 as a standard feature in products, allowing organisations to deploy IPv6 as part of routine upgrade cycles. For many organisations, operational costs, including staff training, and one-time administrative costs to add IPv6 to management databases and documentation, are likely to constitute the majority of the cost of upgrading to IPv6. Organisations that run in-house customised software will experience additional costs to upgrade these programs to IPv6, and enterprises that have test/release processes will see a marginal additional cost for the IPv6 configuration tests.

For end-users, operating systems such as Mac OS X, Windows, and Linux now incorporate IPv6 within their latest releases and will automatically use IPv6 if it is available. Applications are expected to follow as the global demand for IPv6 increases.


Will IPv6 addresses run out eventually?

No. An enormous amount of IP address space exists under IPv6. IPv6, in fact, was specifically designed to fix the address limitations of IPv4. This addressing capacity will enable the trillions of new Internet addresses needed to support connectivity for a huge range of smart devices such as phones, household appliances and vehicles.


Without NAT, won't my network be less secure?

Translating addresses does not provide any security benefits. In many cases NATs require an outgoing connection to be present before they will allow an incoming connection to succeed. This 'stateful packet filtering' can be enabled for IPv6 in the absence of any address translation. The security properties of IPv6 are no different than those of IPv4.

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