I recently came across an interesting piece about the use of IP addresses in the Tesla model S. The part that caught my attention and led to this post is that the car uses the private IPv4 address subnet 192.168.90.0/24 to address different nodes e.g. the centre console is 192.168.90.100 and the dashboard/navigation screen is 192.168.90.101.

Put your geek hat on for a moment as you ponder that! – anything in the car that you want to be able to communicate with individually can now have its own IP address. Here are some scenarios that are not too far-fetched.

• In-car wireless LANs to which devices can connect. Think of having an iPad or Galaxy Note III in the car, on the network making available its library of music, videos or books available to other devices in the car, or even the cards entertainment system. Apart from limiting the transmit power of the wireless radio for the LAN so as not to cause interference with nearby cars, all technologies required to achieve this already exist and are mature.
• Don’t stop at an IP address for the front console, the seat-back entertainment system are also good targets for their own IP addresses (that’s one way they’ll interact with the mobile device you connect for example).
• In the spirit of containing failure domains, there should be one IP subnet for different sub systems of the car—entertainment, system monitoring, sensors and climate control etc. (You really don’t want packets from say the proximity sensors contending with packets of the videos or audios being streamed from the media server in the hood to mobile devices in the car or seat-back screens.)

An interesting question for the industry is whether this address space be private or public? If it remains private as is apparently currently the case, it will mean that every Tesla dashboard has the exact same IP address 192.168.90.101. (I don’t know the internals of how Tesla architect this but I suspect that if they do run remote diagnostics on the car like they do, they are probably using a different private subnet for each car) . Public address space will mean that every dashboard in every car that is IP-enabled will have its own unique way of globally addressing. The globally unique public options is both exciting and terrifying. Exciting because the increase in the number of addressable devices in the global network (and thus the value of that network) will increase. Terrifying because that global addressability could be abused with consequences ranging from privacy violations (will an employee of the car company be able to access the feeds from the in-car video camera?), through potential for remote car-jacking to pervasive surveillance. Don’t forget that the same capability that will let the car manufacturer run diagnostics and fix your car remotely or get it to report its location when stolen is the same one that big brothers every where love.

Of course the public addressing option is only feasible in an IPv6 world. I also think it is a perfect opportunity, IP on such a scale in cars is pretty greenfield and users don’t yet have too many expectations, so starting with IPv6 will be perfect ... as it will define THE IP-in-cars experience and set the baseline. Ultimately though, I expect to see private addressing maintained some components (those that will only ever need to communicate with other subsystem in the car) and public addressing for other components.

Going for a moment with the premises that each car needs to have some publicly addressable space, the interesting question comes up—how will each car get this globally unique address space? Here are the possibilities for this addressing:

1. The car manufacturer (Tesla, Toyota, Honda, BMW etc) becomes an Local Internet Registry (LIR). That is it will get blocks of address space from the RIRs which it will then assign bits of that space to each car it makes and sells. This raises an interesting side-question. As the cars will be sold globally, which RIR would the car company get address space from? The simplest answer is they’ll get it from the RIR that serves the region where they currently have their manufacturing operations. If this is the case, I foresee problems ensuring that this space is globally routable as cars are sold in different countries. I don’t think this is an effective option.
2. The car manufacturer assigns private IPv6 ULAs to systems it needs to remotely access and then installs an in-car router which could get a public IPv6 prefix via 3G or 4G from the local ISP, and then provisions various /64s for different subsystems. In this scenario, the car manufacturer doesn’t become an LIR but can still uniquely address (via ULA) all cars it makes with very low probability of address space collision. Hey maybe they could even get IANA to reserve a block of IPv6 space for this purpose.

So how much address space should one car get? The answer, whatever it is , is most certainly not a /64. Because some some systems will need to have auto-provisioning (SLAAC or DHCPv6 .... the article indicates the dashboard runs off of Ubuntu), each car needs to have at least one /64 available. And just like the small home user, I see at least a /60 per car (yes I love my nibble boundaries).

Statistics from the International Organisation of Motor Vehicle Manufacturers of annual car production numbers from 1999 till date indicate that on average, the world produces about 48 million cars annually (This doesn’t include heavy trucks and light 2 wheeled vehicles). So if we plan to have a /60 for each of those cars, then that’s one /34 for all cars in the world. Which is quite small if you consider that RIRs give at least a /32 to an LIR.

And as the IP network of the car of the future becomes more complex, we might need to deploy more of the same IP technologies we plan to deploy for the home network of the future. Because unlike smartphones and tables where one would expect the users to be more technologically sophisticated, users of such cars will likely not want to configure stuff or even be able to hence the need for complete auto-configuration. In any case, exciting times ahead and this will be an interesting development to watch.