In my last column (IPv6: Prepare for the possibilities), I talked about current users of IPv6, ranging from military applications to mobile technologies in Asia and Europe. IPv6 is no longer just an idea or new standard waiting for technology to catch up. It is real and it is here now.
Change is always hard and migrating your IPv4 network to IPv6 may be the most challenging project ever undertaken by your networking staff. The primary issue facing many CIOs and CTOs is whether or not the migration should even happen. After all, if my IPv4 network is working fine and there does not seem to be a rush by other organizations to migrate, then why force a painful change? It is easy to stay put with a working IPv4 network and not force a change – but on the other hand, can you risk being behind in planning if your competitors start a mass movement towards IPv6 or your agency is required to implement IPv6 in a relatively short time frame?
As we all know, the Internet and the technologies that are part of the Internet are in a continuous state of transformation due to the constant arrival of new ideas, new techniques and improvements over old methods. How much of your current IPv4 network was physically in place just five or ten years ago? If we can agree that change is inevitable and that even your IPv4 networks will change over the coming years to adapt to changes in your organization, then we have begun to build a good basis for considering a migration plan to IPv6.
Fortunately the physical infrastructure - the wires, connectors, cabinets and racks – are identical for both networking standards. A migration to IPv6 does not mean that you have to remove expensive fiber optic or twisted-pair cables, engineer new equipment storage rooms, or install new wall plates and jacks. At the application level, IPv6 is transparent to the human-machine interface, meaning that your employees and customers will continue to use their familiar applications as before.
Where IPv6 does have an impact are the middle layers – the addressing and routing mechanisms of your network. Once the migration is complete, all of the devices on your network will have new addresses. A fortunate fact about IPv6 is that it is backwards compatible with existing IPv4 installations. This means that you can run both IPv4 and IPv6 at the same time on the same network while the migration is taking place.
The key advantage to IPv6 is the vast increase in available addresses over what is offered via IPv4. In today's Internet, the IP address is contained in a four-byte (32 bits) field of the IP header portion of a datagram. Those 32 bits limit the range of IPv4 to a maximum of 4.3 billion addresses. That sounded like a very large number in the early 1980s when IPv4 came into popular use. Unfortunately, we've done such a poor job of managing the address allocations that we have nearly run out of available IP ranges for future network growth.
This shortage has lead to quick-fix solutions like Network Address Translation (NAT) and other means of getting more mileage out of the shrinking pool of available IP addresses. In IPv6, the address field is increased to sixteen bytes (128 bits) which pushes the limit to a whopping 3.4 x 1038 unique addresses. Within that vast space are the original 4.3 billion IPv4 addresses, a feature that ensures current IP addresses will work on future IPv6-based networks.
The best time to start planning an IPv6 migration is now. If you intend to expand or upgrade a portion of your existing IPv4 network, consider specifying the expansion with IPv6 as the networking protocol. Likewise, if new computers, networking equipment, or software are in your future, ensure that all purchase orders specify IPv6 compliance. You don't have to immediately turn on the IPv6 features of new products, but you should not purchase any new hardware or software that is not IPv6 compliant. Likewise, include IPv6 compliance as a mandatory performance item in the development of any unique hardware or software solutions that support your business.
Once the decision has been made to migrate to IPv6, it's time to start building a migration plan and strategy. Begin by looking for easy areas to start the migration:
- New facilities or buildings
- Expansions to existing networks
- New equipment or software acquisitions
- Outsourced software development
Once the new projects are on track for IPv6, turn to your existing network installation and look for areas that are outdated or scheduled for routine upgrades. If you notice a common theme here, it's that a migration from IPv4 to IPv6 does not need to be a "rip it all out and install something new" approach. It will be many years before IPv4 is obsolete, so the best approach is to time your transition to coincide with normal expansions and upgrades. Before you know it, your entire organization will be IPv6 end-to-end and you'll be ready to take full advantage of all the new features that IPv6 brings to the Internet.
About the author:
Dubhe Beinhorn is vice president, Juniper Federal Systems. She can be contacted at Beinhorn@juniper.net.