We just posted a tech report “Understanding Address Usage in the Visible Internet” at <ftp://ftp.isi.edu/isi-pubs/tr-656.pdf>.
The abstract summarizes the tech report:
Although the Internet is widely used today, there are few sound estimates of network demographics. Decentralized network management means questions about Internet use cannot be answered by a central authority, and firewalls and sensitivity to probing means that active measurements must be done carefully and validated against known data. Building on frequent ICMP probing of 1% of the Internet address space, we develop a clustering algorithm to estimate how Internet addresses are used. We show that adjacent addresses often have similar characteristics and are used for similar purposes (61% of addresses we probe are consistent blocks of 64 neighbors or more). We then apply this block-level clustering to provide data to explore several open questions in how networks are managed. First, the nearing full allocation of IPv4 addresses makes it increasingly important to estimate the costs of better management of the IPv4 space as a component of an IPv6 transition. We provide about how effectively network addresses blocks appear to be used, finding that a significant number of blocks are only lightly used (about one-fifth of /24 blocks ha
ve most addresses in use less than 10% of the time). Second, we provide new measurements about dynamically managed address space, showing nearly 40% of /24 blocks appear to be dynamically allocated, and dynamic addressing is most widely used in countries more recently to the Internet (more than 80% in China, while less then 30% in the U.S.).
Xue Cai and John Heidemann. Understanding Address Usage in the Visible Internet. Technical Report N. ISI-TR-2009-656, USC/Information Sciences Institute, February, 2009. http://www.isi.edu/~johnh/PAPERS/Cai09b.html