What you need to know about IPv6

Computerworld -

The world is running out of IP addresses. The current version of the Internet Protocol relies on unique addresses for each device that connects to a network. In the case of the Internet, public IP addresses that enable devices to communicate directly with one another over the global network are becoming scarcer each day. As more and more devices come online in the future, IPv4 will run out of capacity to accommodate our communication needs.

Thus, IPv6 was introduced and has steadily undergone testing and deployment in a variety of international locations. In this explainer, I'll take a look at the benefits of IPv6, including the differences in IP addressing and inherent security advantages, and then look at how IPv6 and IPv4 can coexist and how the global transition to IPv6 is going.

Differences in addressing

Of course, the primary benefit of IPv6 is its increased addressing capacity. IPv6 addresses are 128 bits to IPv4's 32-bit addresses. This is the single most significant improvement between the different versions and provides for a radically expanded address space. IPv6 supports 340,282,366,920,938,463,463,374,607,431,768,
211,456 addresses -- that's 2 to the 128th power. IPv6 addresses are typically described as eight groups of four hexadecimals -- for example, 2006:0db8:0000:0000:0000:0000:0714:57ff. Briefly, there are a couple of tricks and shortcuts to managing these addresses as well:

1. A group of four zeros can be left out of an address; just leave the separating colons in place. The above address in shortened form would read 2006:0db8::0714:57ff. The network equipment automatically detects the omitted parts and internally recognizes the shortened address. However, only one double colon is permitted, as more than one would make it difficult to detect which group was omitted.
2. Leading zeroes in a group can left out. In the previous shortened example, this would read 2006:db8::714:57ff.

Better security

The other significant improvement between IPv6 and IPv4 is the security baked into the protocol. IPsec, the time-proven standard for securing IP communications by encrypting and/or authenticating all IP packets at the network layer, is an integral part of the base protocol suite in IPv6. IPsec is more flexible than other encryption standards such as Transport Layer Security and Secure Sockets Layer because it operates at the network layer and thus is able to protect both TCP and UDP-based protocols. Such flexibility, however, comes at a cost of increased complexity and processing overhead.

Coexistence

How might IPv6 packets coexist and route over networks still using IPv4? Using a technique called tunneling, IPv6 packets are put within IPv4 headers to pass through networks without a problem. First, addresses are transformed from IPv4 to IPv6 by adding leading zeroes, and then the IPv6 packet itself is inserted into the header area of an IPv4 packet. The data is then sent out and travels normally through existing infrastructure. At the end of the transmission, an IPv6-aware router can strip the IPv6 packet out of the IPv4 header and route it appropriately to its destination.