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IPv6-Centric Networking: Innovation Without Constraints

Over the last several months, I’ve been pleased to invite Mark Townsley, Cisco Fellow and recognized expert on Internet Protocol (IP), to discuss IPv6 as a key enabler of the Internet of Everything (IoE). In his series of guest blogs, Mark has explained the basics of IPv6 and why it is important (“Demystifying IPv6”), and discussed some of the technical challenges of moving to this latest version of IP (“Moving to IPv6: Rebuilding the Heart of the Internet Without Missing a Beat”). In this installment, Mark takes a look into the future at some of the things IPv6 will make possible. I’m particularly excited about this, because the unlimited addressing scheme of IPv6 is what will enable the exponential growth of connections among people, process, data, and things that will drive $14.4 trillion in IoE private-sector value over the next decade, and dramatically impact our daily lives. This is Mark’s third and final blog on IPv6.


townsleyIn my last blog, I explored various ways that IPv4 and IPv6 can coexist on the same network —each vital during the global IPv6 transition period, which began in earnest after the World IPv6 Launch last year. Today, I want to highlight new network deployments and designs that I like to call “IPv6-centric.” These architectures go beyond the more conservative approach of a congruent dual-stack IP network. Instead, they are designed and operated from the ground up with IPv6 at the base. While these networks can accommodate IPv4, IPv6 takes center stage.


IPv6-Centric Mobile Networks: Beginning last month, T-Mobile and Metro PCS users in the United States running the latest version of Android software are now provisioned with IPv6 by default, with no IPv4 address from the ISP network. Traffic to IPv6-enabled destinations such as Google, Facebook, Yahoo!, and Wikipedia will simply use IPv6. Traffic to non-IPv6-enabled sites will be translated to IPv4 after traversing the ISP network. If there are any remaining applications on the device that simply do not know how to handle IPv6, the Android device itself performs and IPv4-to-IPv6 translation internally, so the access network doesn’t see IPv4 at all.

“4G speeds and IoE are driving ‘scale-up’ and ‘scale-out’ in mobile networks. The scarcity of globally routable IPv4 addresses forces a series of compromises that an IPv6-only infrastructure alleviates, providing a solid bedrock to build upon.”

—    Cameron Byrne, T-Mobile Wireless, USA

IPv6-Centric Home Networks: Home networks are among the most challenging types of networks to operate. Today, many users connect to websites all over the world yet struggle to connect the devices in their own home. The Homenet Working Group in the Internet Engineering Task Force (IETF), of which I am co-chair, is leveraging the capabilities of IPv6 to improve home networks. For example, IPv6 allows many addresses per interface, while IPv4 allows only one active address at a time. This fundamental difference between IPv4 and IPv6 allows the network to direct or load-balance specific application traffic among multiple service providers, VPNs, or other types of exit points from the home network. These new capabilities, combined with enterprise-class routing adapted to the home environment, allow applications running IPv6 have an inherently more seamless view of the network to which they are connected.

IPv6-Centric Data Centers: Deep inside the whirring corridors of massively scaled data centers lie millions of virtual machines (VMs), all tied to their own virtual network adapters, each running IP. An IPv6-centric data center enables the VMs to run IPv6 without IPv4 alongside. Any required legacy IPv4 access is pushed to the edge of the data center and translated on entry and exit. This frees the provisioning system, VMs, and network to consider only IPv6, which can provide a vast number of VMs with unique values, with clean aggregation for routing and forwarding.

“Automated provisioning simply isn’t possible as we move along the IPv4 depletion curve, since we’re pushing uphill against allocation fragmentation and competition for scarce resources. The key advantage of an IPv6-centric design is that we’ve removed 90 percent-plus of the engineering cycles required for cloud.”

— Paul Zawacki, Distinguished Engineer, Oracle IT

IPv6-Centric Enterprise Networks: In the early days of the Internet, when IPv4 was developed, a device connected to the Internet was a big stationary computer running just one kind of traffic—data. Each computer had a separate IP address, and all was well. Today, enterprise networks must be able to handle voice and video as well as data, and they often do this by deploying separate virtual LANs (vLANs) to support each type of traffic, thus creating artificial network boundaries that are difficult to cross—a growing issue as more multimedia software is deployed across different types of devices. In an IPv6-centric network, each device on the network can have multiple addresses, each corresponding to prefixes that are routed and optimized for voice, video, or data. This enables full or limited access to each type of service in an optimal manner, without separate vLANs.

This is only a taste of the types of innovation being developed throughout the Industry. There are also incredible advances in “Low-Power” networks that are embracing IPv6 from the start, without even considering IPv4. Privacy addresses, now in wide use with IPv6, allow devices to run server-based applications on a publicly advertised IPv6 address while other “client-based” applications are limited to short-lived, partially random IPv6 addresses.

These network designs all use the capabilities of IPv6 in different ways, but fundamentally with the same IP technology. The best part is that advances driven in one area can spark innovation in another, while increasing scale across the ever-growing reach of IP. It’s exciting to see these new IPv6-centric approaches crossing so many environments and reaching economies of scale to enable truly ubiquitous connectivity. This is the heart of the Internet of Everything.

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  1. December 12, 2013 at 1:00 pm

    AT&T Uverse is deploying IPv6 to end users now here in South Florida with some of the newer modems. It appears to be via a 6rd tunnel on the back end, but it’s transparent for the end users. This is an exciting and low pressure way to get familiar with it for engineers at home ( or tinkerers ). It has a stateful firewall by default, but can be disabled so you can use your ISR G1/G2 to gain more control over it :)


  2. Incidentally, today was my first time accessing the Internet with an IPv6 address. This week my company was allocated a /48 IPv6 block by our ISP and last night we finished setting up our network. I can’t help but to remember the first time I surfed the web back in 1997.

    The first thing I noticed is that there are much more websites that are not yet accessible through IPv6 than those that are. Cisco, Google and Yahoo! are, of course, among the ones that are accessible. But I was shocked when I couldn’t access Amazon or HP.

    For some people, this move to an “infinite” address space may be just a technical issue. But I believe it has great significance, in particular for the IoE. Starting tomorrow I’m assigning an IPv6 address to every single device that will allow it, starting with my Raspberry Pi.