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Learning From Successful IPv6 Upgrade Projects

I wrote about upgrading to IPv6 in the past, but I have more to say.

The wrong way: I've heard a number of people say they are going to try to convert all of their desktops to IPv6. I think they are picking the wrong project. While this is a tempting project, I think it is a mistake (well-intentioned, but not a good starter project). Don't try to convert all your desktops and servers to IPv6 as your first experiment. There's rarely any immediate value to it (annoys management), it is potentially biting off more than you can chew (annoys you), and mistakes affect people that you have to see in the cafeteria every day (annoys coworkers).

Instead copy the success stories I've detailed below. Some use a "outside -> in" plan, others pick a "strategic value".

Story 1: Work from the outside -> in

The goal here is to get the path from your ISP to your load balancer to use IPv6; let the load balancer translate to IPv4 for you. The web servers themselves don't need to be upgraded; leave that for phase 2.

It is a small, bite-sized project that is achievable. It has a real tangible value that you can explain to management without being too technical: "the coming wave of IPv6-only users will have faster access to our web site. Without this, those users will have slower access to our site due to the IPv4/v6 translaters that ISPs are setting up as a bandaid.". That is an explanation that a non-technical executive will understand.

It also requires only modest changes: a few routers, some DNS records, and so on. It is also a safe place to make changes because your external web presence has a good dev -> qa -> production infrastructure that you can leverage to test things properly (it does, right?).

Technically this is what is happening:

At many companies web services are behind a load balancer or reverse proxy.

ISP -> load balancer -> web farm

If your load balancer can accept IPv6 connections but send out IPv4 connections to the web farm, you can offer IPv6 service to external users just by enabling IPv6 the first few hops into your network; the path to your load balancer. As each web server becomes IPv6-ready, the load balancer no longer needs to translate for that host. Eventually you're entire web farm is native IPv6. Doing this gives you a throttle to control the pace of change. You can make small changes; one at a time; testing along the way.

The value of doing it this way is that it gives customers IPv6 service early, and requires minimal changes on your site. We are about 280 days away from running out of IPv4 addresses. Around that time ISPs will start to offer home ISP service where IPv6 is "normal" and attempts to use IPv4 will result in packets being NATed at the carrier level. Customers in this situation will get worse performance for sites that aren't offering their services over IPv6. Speed is very important on the web. More specifically, latency is important.

[Note: Depending on where the SSL cert lives, that load balancer might need to do IPv6 all the way to the frontends. Consult your load balancer support folks.]

Sites that are offering their services over IPv6 will be faster for new customers. Most CEOs can understand simple, non-technical, value statements like, "new people coming onto the internet will have better access to our site" or "the web site will be faster for the new wave of IPv6-only users."

Of course, once you've completed that and shown that the world didn't end, developers will be more willing to test their code under IPv6. You might need to enable IPv6 to the path to the QA lab or other place. That's another bite-sized project. Another path will be requested. Then another. Then the desktop LAN that the developer use. Then it makes sense to do it everywhere. Small incremental roll-outs FTW!

During Google's IPv6 efforts we learned that this strategy works really well. Most importantly we've learned that it turned out to be pretty easy and not expensive. Is IPv6 code in routers stable? Well, we're now sending YouTube traffic over IPv6. If you know of a better load test for the IPv6 code on a router, please let me know! (Footnote: "Google: IPv6 is easy, not expensive Engineers say upgrading to next-gen Internet is inexpensive, requires small team")

Story 2: Strategic Upgrades

In this story we are more "strategic".

Some people run into their boss's office and say, "OMG we have to convert everything to IPv6". They want to convert the routers, the DNS system, the DHCP system, the applications, the clients, the desktops, the servers.

These people sound like crazy people. They sound like Chicken Little claiming that the sky is falling.

These people are thrown out of their boss's office.

Other people (we'll call these people "the successful ones") go to their boss and say, "There's one specific thing I want to do with IPv6. Here's why it will help the company."

These people sound focused and determined. They usually get funding.

Little does the boss realize that this "one specific thing" requires touching many dependencies. That includes the routers, the DNS system, the DHCP system, and so on. Yes, the same list of things that the "crazy" person was spouting off about.

The difference is that these people got permission to do it.

According to a presentation I saw them give in 2008, Comcast found their 'one thing" to be: Settop box management. Every settop box needs an IP address so they can manage it. That's more IP addresses than they could reasonably get from ARIN. So, they used IPv6. If you get internet service from Comcast, the settop box on your TV set is IPv6 even though the cable modem sitting next to it providing you internet service is IPv4. They had to get IPv6 working for anything that touches the management of their network: provisioning, testing, monitoring, billing. Wait, billing? Well, if you are touching the billing system, you are basically touching a lot of things. Ooh, shiny dependencies. (There used to be a paper about this at but the link isn't working. I found this interview with the author but not the original paper.)

Nokia found their "one thing" to be: power consumption. Power consumption, you say? Their phones waste battery power by sending out pings to "keep the NAT session alive". By switching to IPv6 they didn't need to send out pings. No NAT, no need to keep the NAT session alive. Their phones can turn off their antenna until they have data to send. That saves power. In an industry where battery life is everything, any CxO or VP can see the value. A video from Google's IPv6 summit details Nokia's success in upgrading to IPv6.

Speaking of phones, T-Mobile's next generation handset will be IPv6-only. Verizon's LTE handsets are required to do IPv6. If you have customers that access your services from their phone, you have a business case to start upgrading to IPv6 now.

In the long term we should be concerned with converting all our networks and equipment to IPv6. However the pattern we see is that successful projects have picked "one specific thing to convert", and let all the dependencies come along for the ride.


In summary, IPv6 is real and real important. We are about a year away from running out of IPv4 addresses at which point ISPs will start offering IPv6 service with translation for access to IPv4-only web sites. Successful IPv6 deployment projects seem to be revealing two successful patterns and one unsuccessful pattern. The unsuccessful pattern is to scream that the sky is falling and ask for permission to upgrade "everything". The sucessful patterns tend to be one of:

  • Find one high-value (to your CEO) reason to use IPv6: There are no simple solutions but there are simple explanations. Convert just that one thing and keep repeating the value statement that got the project approved. There will be plenty of dependencies and you will end up touching many components of your network. This will lead the way to other projects.
  • Work 'from the outside -> in": A load balancer that does IPv6<->IPv4 translation will let you offer IPv6 to external customers now, gives you a "fast win" that will bolster future projects, and gives you a throttle to control the speed at which services get native support.

I'd love to hear from readers about their experiences with convincing management to approve IPv6 projects. Please post to the comments section!


P.S. Material from the last Google IPv6 conference is here:

Posted by Tom Limoncelli in Technical Tips

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3 Comments | Leave a comment

I am sysadmin for university, and working with IPv6 is essential in R&E community. Our experience starts with deploying dual-stack network, after that we provide "interesting" service, such as ipv6 web cache proxy with less stringent for user (no Internet quota), but with best-effort SLA (you can't complain). As long as critical service is running, management is okay with that.

Do you have recommendation of opensource ipv6 load balancer? Currently I am evaluating Brocade ServerIron ADX1000.

I'd be interested in seeing your source for the claim that the next generation T-Mobile phones being IPv6 only.

Good post!

Great post Tom.

I'm doing exactly the opposite of what you suggest, but I've got a good reason, honest!

I am working as a lab manager and integration engineer for a product development group. For a year now, IPv6 compatibility shows up in planning meetings, then is pushed to the low priority stack, not because it's actually low priority, but because the perceived risk/reward ratio is so bad... people don't know anything about it, so they assume it's horribly difficult, and no customers are asking for it (though senior VPs are) and so... it just sort of doesn't get done.

I sold my bosses on the following plan: using a fun tutorial and some other motivational tricks, we get people to turn on IPv6 on their desktops themselves, and debug it a bit, etc. When everyone has earned their "IPv6 driver's license", we get a party! Whoo hoo for parties!

Then take something so important they can't do their work and make it IPv6 only (like the source code server). This is the stick, which only comes out after the carrot has done it's work.

The idea is that if people Live and Love IPv6 every day on their desktops (and can debug it themselves, and ask a cube-mate for help, and...), then they will be less afraid to commit to putting "get product feature X tested under IPv6" onto the roadmap.

I'm in the middle of this approach, and I'll come back and tell you how it went once the stick falls and our Mercurial server is IPv6 only.

Muah hah hah.


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