By now we all know that IPv6 is a powerful solution to a pressing problem. The world has run out of new IPv4 addressing space, and the internet needs IPv6 to grow. What’s less widely discussed—but potentially more exciting—is how the modern version of the internet protocol won’t just make the internet bigger, but it will make it smarter.
For years, IPv6 was a tough sell. Few organizations were eager to invest in something that just made the addressing space bigger, particularly if IPv4 was already meeting their needs. Now that the pool of IPv4 addresses has run dry, the pace of transition has increased significantly. And it will only accelerate as we start to explore the full potential for network innovation that IPv6 brings to the table.
Comcast is a major user of IP addressing space, which led the company to go all-in on IPv6 nearly a decade ago. The company became the first major U.S. ISP to deploy dual-stack IPv4 and IPv6 connectivity throughout 100 percent of its network in 2014. Today, over 80 percent of Comcast's customers are actively provisioned with IPv6 support. Before the end of 2016, the ISP expects more than half of its traffic will use IPv6. By 2017, more than 90 percent of its customers will be provisioned with IPv6. And by 2020, it expects IPv4 traffic growth to all but stop.
It wasn't easy. IP addresses permeate everything you do as a network operator, and upgrading can be a time- and resource-intensive process. What I will say is that the commitment and investment Comcast made years ago has opened the floodgates to innovations that are expected to make its network faster, smarter and more efficient.
The internet of a trillion, trillion, trillion things
One of the easiest ways to think of this is in the context of the Internet of Things. Gartner Research estimates that there will be 6.4 billion “things” connected to the internet this year. That’s exciting, until you realize there are only 4.3 billion IPv4 addresses in the world, and virtually all of them are already spoken for.
Networking technology has evolved over the years to meet this large and growing disparity between the number of connected things and the number of available internet addresses, but the solution has made networking more complex and less efficient. For example, Network Address Translation (NAT) technology allows one dynamically assigned IP address to serve dozens (hundreds or even thousands) of internet-connected things. The cost of that complexity, however, is felt in performance and network flexibility, and it hinders some internet applications.
Compare that to IPv6, which supports 340 trillion, trillion, trillion addresses, and you start to see what makes my fellow network engineers so excited. As ISPs, device manufacturers, content creators, consumers and others in the internet ecosystem increasingly transition to IPv6-compatible devices, we have enough addressing space to provision every single thing in a customer’s house. More than that, one could use an IP address for every component, memory location, software process, disk drive block, etc. Every Comcast IPv6 home has more IP space than the entire IPv4 internet to the power of two. You can virtually name everything that exists, existed or will exist with an IP address.
But IPv6 is far more than “more addresses.” Even today, in a world largely dominated by NAT devices, we’ve begun to witness measureable speed and performance advantages from IPv6-compatible internet devices. As we begin moving to a world where IPv6 replaces IPv4, we can be even more creative about how the IoT functions and reap even greater performance and functional benefits.
For consumers, this will mean better performance and potentially even more pinpoint control over how their connected home devices work. For network operators, it means that even as the ecosystem of connected devices becomes vastly more complex, the network that reaches them can actually get simpler, more lightweight and more efficient.
Smarter Packets = Smarter Networks
Something network engineers realized early on with IPv6 is that the larger size of IPv6 addresses opens up some interesting possibilities. Compared to an IPv4 header, which is 32 binary numbers, an IPv6 header is 128 binary numbers. That means we can put information into an IPv6 packet in a way that was never before possible with IPv4.
Simply put, IPv6 addresses can be made “smarter,” so that they play a more active role in determining their path through the network. Back to the IoT example, rather than relying on complex network machines to make all the routing decisions associated with a packet, applications themselves will be able to choose paths and services in the network.
This concept—called IPv6 Segment Routing (IPv6 SR)—is the next major frontier in network architecture, and it holds the key to networks keeping pace with ever greater, more complex traffic flows.
We hear a lot of discussion about software-defined networking (SDN), but what’s less widely talked about is how essential IPv6 is to unlocking the true potential of SDN to transform networks. We’ve been software-defining core functions of our network for several years, but it is only with tools like IPv6 Segment Routing and service chaining that we begin to really witness the true benefits of a software-first network architecture.
Of course you can benefit from SDN in an IPv4 MPLS environment, but you’re still software-defining essentially complex, potentially inefficient functions and limiting your capabilities to a single MPLS network vs. cross networks, in the home, data centers, etc. When you overlay powerful SDN orchestration on top of a simplified IPv6-powered core, you begin to recognize the real boosts to efficiency, performance and reliability that SDN can provide.
For many years, the narrative about IPv6 was that organizations should upgrade because it was the right thing to do for the internet. Lately, that narrative has shifted to a realization that IPv4 is gone and upgrading is no longer optional. Those two things may be true, but from the perspective of a network engineer, the real reason to act is that IPv6 holds the key to the next step in the evolution of a smarter network.
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