Last Call for IPv4

It's time to start planning your transition to IPv6.

By Anthony Christie, Chief Technology and Information Officer, Global Crossing

Although concerns about IPv4 address depletion are warranted, the transition to IPv6 is likely to go on for at least another year, so it's important that you get on board because this affects everything that touches the Internet. More important, a successful migration to IPv6 requires proper planning.

When ISPs and carriers begin filling requests for new IP addresses exclusively with IPv6 addresses, new servers, switches, firewalls and other network infrastructure will need to be IPv6 compliant. Web sites that interface with IPv6 networks will need to ensure they perform and provide your customers with the same overall experience that they get on IPv4 networks. This is like your cable TV company delivering both standard and HDTV programming. Eventually, broadcasters will grow weary of the expense of running two parallel networks and you will have to buy that HD-capable TV.

Why the move to IPv6? As you probably know, we just exhausted 4.3 billion possible 32-bit IPv4 addresses. No one thought we'd use them up, but they are all deployed. In contrast, IPv6 addresses are 128-bit numbers, so the number of possible addresses jumps to 340 trillion trillion trillion.

Why do we need so many addresses? In the future, not only will the number of people connecting to the network increase, but each of us will possess more devices that need to be connected – more smartphones, tablets and eBook readers; appliances such as refrigerators, televisions, and alarm clocks; and even my daughter's clothes might have IP addresses. In fact, military strategists foresee the day when every single asset in the field – humans as well as weapons – will have an IP address. Additionally, 4G wireless rollouts will send many more address-hungry wireless devices into the field.

IPv6 not only ensures plenty of addresses for everyone, it allows enterprises to reduce the cost of managing internal address space; it simplifies network designs while allowing for easier remote configuration. It provides better security and authentication; and it allows for much larger data packets. This larger address space will open the door to a new generation of devices. It also provides an improved degree of connectivity where individuals will be able to interact directly with devices anywhere on the network, i.e., anywhere in the world.

Last Call Stall Tactics

The lack of a sense of urgency many may be feeling about transitioning is justified by the following delaying tactics, which so far have worked well but which have inherent problems:

Network Address Translation (NAT): Many rely on Network Address Translation to prolong the life of IPv4. It allows one outside IP address to be shared among a number of computers and other devices, but it is tough to set up peer-to-peer connections; intermediate routing devices introduce complexity, points of failure, and communication delays; and NAT can obscure useful information, such as the general physical location of a person on the Internet who might want local services.

In addition, NAT does not support multiple applications running over a single connection, negating the benefits of IP convergence. Inbound connections, such as file-sharing applications or voice over IP (VoIP), require special attention. Operating servers from within a NAT environment is particularly awkward. Although NAT's low cost makes the system attractive, it comes with management expenses of its own – especially for ISPs and carriers managing large numbers of devices connecting to the Internet.

Tunneling: Where network hardware does not adequately support IPv6 traffic, IT pros rely on tunneling, a technique in which IPv6 packets can be placed within IPv4 "wrappers" to pass through networks without a problem. Addresses are transformed from IPv4 to IPv6 by adding leading zeroes. However, this makes it more likely that bits of information will get dropped, and in the long term, you will invest more resources in an aging network while missing out on new applications and services.

Trading Markets: Some hope that hoarded IPv4 address space will still be available through some sort of new "trading market" model or from companies sitting on unused assets. Although there are still-unused IPv4 addresses, you will have to find them and get them transferred into your name. Supply and demand will make these IPv4 addresses increasingly expensive.

Get Ahead of the Pack

The most important thing is to understand that IPv6 is coming and we must be prepared for it.

Make sure you choose a network provider that operates a dual-stack network. A dual-stack network has the ability to route IPv6 and IPv4 side by side on the network, so that your wide area network or Internet connection behaves as an IPv4 and IPv6 path simultaneously. Network operators do this for their customers because it allows the customer to test a fully-functioning IPv6 implementation without turning off any of their old IPv4 setup. This also allows the customer to retain access to the parts of the Internet that have not yet transitioned to IPv6.

If your equipment is not IPv6-capable today, make a minimal investment to get some IPv6-capable equipment, develop an addressing plan, and test your architecture and your design with a dual-stack network provider to make sure it is going to meet your specifications.

You have time to make the switch from IPv4 to IPv6, but don't put your enterprise in jeopardy by delaying further. Preparing now is easier than trying to catch up later.

Anthony Christie is the chief technology and information officer at Global Crossing, where he is responsible for implementing and operating a global technology and IT strategy []. You can contact the author at

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