Preparing for IPv6, a New System for Internet Addressing

In this era of the World Wide Web, we often use the term "hyper" to describe mega or massive scale: Hyperlinking, hyperspeed, and hyperthreading all spring to mind. Yet there's one area of hypergrowth we all need to take seriously, even with all the hyperbole surrounding it, and that's the double-edged sword of hyperconnectivity.

The number of connected devices -- especially video-equipped devices -- is growing exponentially: Estimates range from 5 billion to 7 billion connected devices in use in 2012 alone, with a growth curve beyond 20 billion connected devices within 3 years.

Seems like a good opportunity to monetize content and move more video bits to all these connected devices, right? True, if all the devices could be connected at the same time.

The internet, however, as you've probably already heard, is running out of IP addresses, the essential numbering scheme required for a connected device to, well, get connected.

How to Read an IP Address

First, a sanity check: Even if the world is running out of the IP addresses needed to keep your local home network -- via cable modem or DSL -- connected to the broader world, your local home network is probably in no danger of running out of connectivity. Home routers work on the premise that they share a single, external IP address, but internally they use one of three network class designations (A, B, C) to connect devices. Each of these classes has an assigned IP range set aside for local area network (LAN) connections, which is why you may see IP addresses on your Apple TV or Wi-Fi-equipped iDevice that start with 10.0.NNN.NNN or 192.168.NNN.NNN.

The farthest right set of three N's, above, can be considered a subnetwork, or subnet, and a single subnet can have up to 256 connected devices (think 192.168.1.0-255). The second set of three N's, moving to the left in the numbering scheme, shows that there can be up to 256 subnets. So the average home not only falls well below the 65,536 IP address limit of but also falls below the 256 device address limit of a single subnet.

If every device were behind a home network router, we might have years to go until we reach the maximum threshold of the octect-based IPv4 addressing scheme. Yet many devices need a direct connection to the internet, not one hidden -- or masked -- behind a router's IP address. Mobile devices need their own unique IP address to roam from network point to network point, for instance, as do mission-critical industrial control devices. Discrete IP addresses are often safer, too, than the blanket security requirements often used on home and even enterprise routers.

Tick-Tock

So exactly how great is the need? According to Google, it turns out that the need is so great that we should've come up with a better scheme yesterday.

"[T]he current Internet addressing system, IPv4, only has room for about 4 billion addresses," notes a Google blog post commemorating the June 2012 IPv6 Launch Day, adding that the available 4,300,000,000 IP addresses are "not nearly enough for the world's people, let alone the devices that are online today and those that will be in the future: computers, phones, TVs, watches, fridges, cars, and so on. More than 4 billion devices already share addresses. As IPv4 runs out of free [available] addresses, everyone will need to share."

Google notes that the number of potential users worldwide is well over 4.3 billion users -- and growing -- so even if each user only had one connected device, we'd run out of IP addresses around 2015. But it turns out we passed that threshold for available IP addresses back in 2011, as the average number of devices owned by a single internet user jumped to 2.5 devices per user.

To compensate for a limited number of IP addresses, network operators share IP addresses, on the assumption that not all devices will be simultaneously connected. They do this through limiting the time-to-live (TTL) settings on a device's IP address request to shorter and shorter durations. For a DSL modem, the TTL may be set to renew its IP address lease every day (24 hours), but for a mobile network cell tower the IP address lease renewal may be as short as 20 minutes on the assumption that only a certain number of devices may attempt to connect to the network during that short time duration.

Yet that sharing model bought only a few years of temporary relief, and many times network operators are faced with having too many devices requesting IP address leases at the same time.

A classic microscale case of this problem was Wi-Fi connectivity at the Macworld San Francisco event or the Apple World Wide Developer Conferences (WWDC) that I've covered for Streaming Media. Over the years, the number of WWDC attendees grew, yet the number of devices per attendee grew even faster: At one particular WWDC, around the time that Steve Jobs introduced the iPhone and iPod touch devices, I remember noticing that some reporters in the press section had three or four Wi-Fi-connected devices. This was the same event where Jobs famously asked users to turn off their Wi-Fi so he could demonstrate the latest Apple gizmo's Wi-Fi connection capability. No one obliged -- after all there were tweets and liveblogs to write since Apple had chosen not to live stream the keynote -- so the next year Apple created a private, nonbroadcast Wi-Fi network for Jobs to show off the next shiny object in a more controlled environment.

A much more important example, though, comes from the world of mobile newsgathering. Several companies that make portable electronic news gathering (ENG) transmission units -- a number of these are covered elsewhere in this year's Sourcebook -- include data transmission units from multiple cellular service providers, as well as the ability to boost the signal strength to reach beyond the closest mobile provider towers to find those towers with fewer connected users. This lesson came from experience, during the Arab Spring protests, especially during the days of Egypt's Tahrir Square protests, where cell towers were overwhelmed both with video content uploads as well as IP address requests.

Short-Term Thinking

The problem in fixing the IP address shortage is somewhat akin to Bill Gates' often-misquoted statement about computer users never needing more than 640KB of RAM.

IPv4 wasn't designed to last forever, yet it was planned to last for decades, and even that hasn't panned out. Comprising four sets of numbers, IPv4 was deliberately planned to accommodate for hyper-growth. It turns out "hyper" is a mathematical prefix used to denote four or more dimensions, so the nod to hyper in the IPv4 world was to use four groups numbers to represent a theoretical 4,300,000,000 IP addresses.

IPv4 uses a base eight numbering system -- a set of eight numbers that can represent up to 256 possible combinations. Base eight is known to most people as 8 bit, for the eight numbers, when it comes to computing. Memory or processor speeds use base eight in increments such as 8, 16, 32, 64, 128, 256. Base eight is used for computing, as it has the ability to be represented in binary (e.g., 0 or 1, on or off) and you may recall that 8 bits make up one byte.

IPv4 used four groups of three numbers, with each group of three numbers considered an octet and limited to 256 at its upper end. To get to the 256 possible combinations, one should understand that the eight numbers are represented this way: NNNN NNNN.

The left and right groups of four digits (bits) are each considered a nibble, with all eight considered a byte. I'm not making this up: someone had a great sense of humor when it came to early computing.