Application Delivery Controllers Can Ease the IPv6 MigrationApplication Delivery Controllers Can Ease the IPv6 Migration

The role of an ADC is to bridge the application and network environments, which positions it well to ease the move to the address-rich v6.

It seems after a long hiatus, IPv6 is back in the news. Now as Gary Audin pointed out in his blog (http://www.nojitter.com/blog/229300740), the impending transition IPv6 has been something we have been talking about for years. In fact, I wrote my first IPv6 report in 2001 when I thought we were on the verge of a large migration, which of course never happened.

Part of the reason adoption has been slow is that the value proposition for IPv6 is all about more addresses. Early in the development of IPv6, the protocol did a whole bunch of things from a management and security perspective that IPv4 did not do. Since then, all of the vendors have added pretty much all those features to v4, leaving the value proposition to solely be more IP addresses. Even that value proposition has been limited since things like NAT (network address translation) has evolved, making the limited number of IP addresses no longer an issue for many companies.

However, recently there’s been more interest due to a combination of government mandates, growth of IPv6 in Japan and other parts of Asia and a general interest level due to the exploding number of IP enabled endpoints. I’m not sure if any one of these outweighs any other, it depends greatly on the business.

This did get me thinking though about how an organization could migrate to IPv6 while minimizing the risk. It’s not likely that a company will do a hot cut over to IPv6, so a migration plan is essential. And, even if the company were either crazy enough or small enough to do a hot cut over, the companies and networks that it interfaces with would likely not be IPv6, again making migration important.

One of the most important pieces of infrastructure in an IPv6 migration plan is the application delivery controller (ADC). Gary made mention of this in his blog but referred to it as a “load balancer” which is where ADCs came from--but they’re so much more today. ADCs live at the intersection of applications and networks and bridge those two worlds together. In fact, recently two ADC solution providers, data center specialist Brocade and market leader F5 have started to market around IPv6 because of increasing customer demand.

ADCs can provide several key functions in an IPv6 transition. The ADC can be dual stacked which provides a v4 to v6 translator in the network. By placing the dual stack capabilities next to the application, developers can modify the application to be v6 compliant without modifying the network, since the application talks to the ADC. Similarly, a network manager could modify the network without the applications being touched. The ADC would handle translating to both sides of it. The ADC can deliver simultaneous v6 to v4 translation at the application layer. An IP “rosetta stone” is a good way of thinking about it. Most would think to use a router for this functionality, but routers operate at layer 3, not at the application layer like ADCs do.

Other than the gateway function, each vendor has a number of product specific features that can facilitate IPv6 transitions. For example:

Brocade updated its application resource broker to be IPv6 compliant as well as enabling third party integration through a software API. The application resource broker combined with Brocade’s ADC can help transition applications that utilize the specific IP addresses.

F5’s version 10.0 of its TMOS operating system brought with it a number of IPv6 transition features including:

The ADC can be used as a v4 to v6 gateway by configuring a virtual server using either a v4 and/or a v6 version of the address and then the other network nodes using the other version. Companies can then run in a mixed mode environment and migrate to v6 on a schedule that that business deems important rather than being forced to migrate. This could prolong the migration cycle, but on the plus side, does de-risk it.

F5’s global traffic manager (GTM) can act as a DNS by receiving a v4 or v6 query and then doing a translation with a properly formatted address. Additionally, the GTM-based DNS can reject queries that have no v6 information available, instead of waiting for a timeout, which can add a long delay to the DNS process.

These are just a few examples of the role that ADCs can play in an IPv6 migration. ADCs can also provide virtual server, virtual IP, NAT, Secure NAT and other functions that bridge v4 to v6.

IPv6 may not be on the near term roadmap for many organizations right now but it will be eventually. Instead of trying to make drastic network changes, application delivery controllers can be used for an easier transition. The role of an ADC is to bridge the application and network environments and the case of IPv6 is no exception.