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Dan's Blog Are We Running Out of Internet Address Space?
Dan's Blog Are We Running Out of Internet Address Space?
Are We Running Out of Internet Address Space?
Written by Dan Schaefer
The Number Resource Organization (NRO) recently announced that there is less than 10 percent resource remaining within the IPv4 address space. This means that as new people sign up for Internet access and as new Internet-based services are deployed, there will be a dwindling supply of precious address space to accommodate them. This will severely affect the availability of services in the near future.
So what’s the solution? Something called IPv6.
And what’s the difference between IPv4 and IPv6? The primary difference is that there is a lot more address space available with IPv6. When IPv4 was originally rolled out to the public, it was thought that its 32 bits of address space would be sufficient to accommodate world demand for the foreseeable future. Unfortunately, it was not foreseen that the Internet would quickly slip into the mainstream and explode.
Consider that the maximum number of permutations of a 32 bit address space is 2 taken to the power of 32, or about 4 billion addresses. You would think that would be sufficient, but there are some caveats to consider:
- Many addresses are reserved for special services. Chief among them is what’s known as “Class D” or “Multicast” addresses. Other addresses include familiar ranges that begin with 192.168.X.X and 10.X.X.X, which are reserved for local address space.
- In order to make world-wide routing a reality, the overall address space had to be carved into smaller contiguous address spaces and reserved. Though many of these addresses may not be used, they are reserved nevertheless and cannot be freed up.
- Large countries, like China, were late to the table when it came to reserving address space for their sizable populations, so competition for remaining space is fierce.
It’s good to know that there are a lot of people who saw this day coming, and they took initiative to create another Internet Protocol standard called IPv6. IPv6 reserves four times as many bits for addressing; that is, 2 taken to the power of 128. This is a huge number, roughly equivalent to 340 with 36 zeroes behind it. (In scientific notation, that’s 340E36 addresses) Consider that the total output power of the sun is a mere 4E26 Watts! Within IPv6, there are probably enough addresses to assign a unique number to all paramecium on the planet, should we choose to do so. Obviously, the large address space of IPv6 is a bit of overkill. But like IPv4, the address space of IPv6 is sectioned into different ranges, so the actual available address space is slightly less.
For example, the 48-bit hardware (MAC) address on your PC can “map into” the IPv6 address. This still leaves 2^128 / 2^48 or about 1.2E24 addresses. Ah … still a very large number. The IPv6 address space is parsed up into other sections as well, including a section that is reserved for carrying the 32 bit address space of IPv4. This helps when transitioning from IPv4 to IPv6.
IPv6 has been around for over 10 years, but still has not been widely deployed. The motivation for deployment has been slowed by innovations within IPv4 that have extended its life. These innovations include DHCP, Dynamic DNS, something called “Classless Inter-Domain Routing" (CIDR) and Network Address Translation (NAT). But even these innovations are hitting their limit, and the global supply of IPv4 addresses is simply coming to an end.
Many companies have already tested and deployed IPv6. This includes the newer Microsoft Operating systems as well as all recently developed hardware from the big network manufacturers, such as Cisco and Juniper. In short, the world is ready, but until someone hits the panic button, the switchover will not occur. That day is fast approaching, and when it arrives, there will be problems adapting to the newer technology. But in a relatively short period of time, the pain will be over, and everyone will be better off.
A final note regarding the transition to IPv6: Since the “IP” layer is below the “TCP” layer, the impact on most applications will not be noticeable. Most applications deal with the TCP layer, and as such, they will be insulated from what takes place below. A similar analogy exists with wireless; most applications are unaware of the underlying transport mechanism, whether it’s copper or wireless. They work the same regardless, and so it is with IPv6.
If you thirst for more knowledge in this area, leave a comment, and I will go into more depth.
Best,
Dan
PS: I apologize if you were waiting for the next installment of the Flash introduction series, which I previously indicated would be available today. Ironically, I ran out of time this week because I was too busy working on a Flash project. I plan to complete the next installment by Sunday night, however, so stay tuned!
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