Today’s residential home networks are quite simple. They usually have a single Internet connection, which is plugged in to the WAN port of a residential gateway. The gateway will typically feature a few wired Ethernet ports and a wireless access point, which are in most cases bridged together to form a single layer-2 LAN segment. The LAN segment is configured with private IPv4 addresses; in order to let the hosts and devices on the LAN segment to communicate with the IPv4 Internet, the gateway will perform IPv4 NAT.
If the requirements of the home network are equally simple, this will work well enough for most users. However, the moment you start adding more functionality, things get complicated quickly. For example, how does one go about introducing another Internet connection? Or another residential gateway? Or IPv6? Or all of the above? Someone competent in computer networking might well be able to set it up, but Joe Public will probably have to resort to trial and error. He might end up with a completely non-functional network, or he might get lucky and stumble across configuration that ostensibly works - but even in this case, it is very likely that the home network would suffer a loss of functionality and/or performance in the process.
Introducing the IETF Homenet working group
Fortunately, the fact that residential home networks were rapidly falling behind the technology curve wasn’t lost on the IETF. In 2011, the working group Home Networking - colloquially known as Homenet - was founded to create a set of standards that would allow even the most non-technical user to fully unleash the potential of his home network in a self-configuring «plug and play» manner. Quoting from the working group charter:
This working group focuses on the evolving networking technology within and among relatively small “residential home” networks. For example, an obvious trend in home networking is the proliferation of networking technology in an increasingly broad range and number of devices. […]
Home networks need to provide the tools to handle these situations in a manner accessible to all users of home networks. Manual configuration is rarely, if at all, possible, as the necessary skills and in some cases even suitable management interfaces are missing.
The purpose of this working group is to focus on this evolution, in particular as it addresses the introduction of IPv6, by developing an architecture addressing this full scope of requirements:
o prefix configuration for routers
o managing routing
o name resolution
o service discovery
o network security
The decision to base the new standards on an IPv6 foundation was likely an easy one to make. Not only is IPv6 the only future-proof option, it also comes with certain features that facilitate automatic and self-configuring networks (such as ubiquitous link-local addresses and SLAAC). That said, Homenet won’t deprive anyone of their IPv4 connectivity - the working group isn’t blind to the reality that IPv4 will remain a necessity for most users in the years to come:
The group should assume that an IPv4 network may have to co-exist alongside the IPv6 network and should take this into account insofar as alignment with IPv6 is desirable.
So far, the Homenet working group has published one RFC titled IPv6 Home Networking Architecture Principles, and is currently actively working on a number of other Internet-Drafts that describe the nitty-gritty details of how it all fits together.
Running code: the Hnet project
While it’s clearly important to have the Homenet standard properly documented in RFCs, these documents aren’t particularly useful on their own. At the end of the day, it’s the availability of functioning implementations of those RFCs, i.e., running code, that truly matters.
In spite of being a work in progress, the current draft specifications has proven mature enough for the Hnet project to build a working open-source Homenet implementation. The Hnet project is included in the latest stable OpenWrt release, version 15.05 Chaos Calmer.
That means that if you own a residential gateway device that’s amongst the several hundred models supported by OpenWrt (or are willing to spend something like €20-€30 on one), you can already **today** take Homenet for a spin and experience the future of home networking. In the past few weeks I’ve been doing just that, and I can say that I am pleasantly surprised at how well it actually works. It’s even fully integrated in OpenWrt’s web interface - no command line familiarity required. I’ve converted my own home network to be based exclusively on OpenWrt and Hnet, and I see no reason to going back to my old legacy setup.
In an upcoming post I will explain how to take a default installation of OpenWrt 15.05 Chaos Calmer, install the software from the Hnet project, and configure it to be a Homenet router. Stay tuned!