At the 2011 IPv6 Summit, Oracle’s senior network engineer, Paul Zawacki, presented a session on IPv6 address planning considerations for the enterprise. He gave this advice on how to implement an internal IPv6 network successfully:
- Challenge your IPv4 experience: In the past, we had to custom-size every subnet. We may have given a /24 to a specific IPv4 network, and those choices came with consequences. It was rare that we guessed perfectly on the size and that that number was still valid eight or nine years out. We either guessed too high or too low. If we guessed too high, we wasted a lot of address space. If we guessed too low, we would be subjecting ourselves to a painful and costly re-addressing exercise. This custom sizing work in IPv4 is also required at the subnet, site and regional aggregation level—all of which is a tremendous burden on the network design teams and the backend registration functions. However, IPv6 eases this burden, which brings Zawacki to his next point.
- Look for new opportunities afforded in IPv6: With proper planning and choices in your design strategy and addressing plan, you have the potential to virtually eliminate most custom addressing design work at the site and subnet level. This opens up new opportunities for things like dense virtual environments, where you’re not at risk of running out of address space to satisfy the requirements for that group of applications. It might also mean that you can automate the backend registrations because of the vastness of the space that’s available to you.
- Standardize wherever possible: We could design an address scheme from scratch and eliminate the things that didn’t work well in IPv4, like that custom design work. If we could standardize the size of networks, sites (where possible) and regional route aggregations, then we could overcome that limitation in our IPv4 designs.
- Keep the math simple for success: If we properly design our addressing plan around some standards, we can keep the math simple. In example, if you stay on major bit boundaries wherever possible and choose to use a few of the right major bit boundaries for the needs of your organization, you’ve tremendously improved the odds for success.
- Just get started: Don’t ignore the fact that IPv4 addresses are coming to an end. Begin an IPv6 migration strategy, which is the very least enterprises should be doing, and don’t stop your IPv6 learning.
In the end, beginning an internal IPv6 migration strategy is a terrific opportunity to start anew, and one that likely only comes along once in a lifetime in your career, Zawacki said.
“It’s not uncommon for enterprises to have extremely fragmented routing tables because of a series of growth and acquisitions that have happened over the course of 20-25 years. Those things are not easily resolved without significant readdressing efforts on a global scale, and we now are presented with that opportunity [in IPv6],” Zawacki said, “It can be extremely liberating.”