On Mon, Aug 9, 2021 at 9:24 AM Masataka Ohta <mo...@necom830.hpcl.titech.ac.jp> wrote: > William Herrin wrote: > > I did some math on this years ago and it worked out to about 8.5 > > million IPv4 routes. > > It should be 14M.
Doubtful. Like I said, I did the math. The question I asked at the time was: If: IPv6 fails to overtake IPv4 and IPv4 continues to be divided and redistributed to progressively higher-value uses and the /24 public Internet announcement boundary holds then What will the terminal size of the IPv4 Internet BGP table be? There are 2^24 = 16.8M /24s in the IPv4 address space. Many of these are reserved for non-unicast uses, e.g. 224/3, 0/8 Many of the unicast addresses are reserved for non-public uses, e.g. 10/8, 127/8 Some portion of the assigned address space is used off-Internet in valuable enough ways that its owners are unlikely to release it for use on the Internet. Some portion of the address space won't be disaggregated to /24 because their owners won't find it convenient Some portion of the address space will have overlapping announcements (/24s and the overlapping the /20, that sort of thing) I no longer have the exact formula but I made some reasonable assumptions for each of these factors and it worked out to 8.5 million as the probable terminal size of the IPv4 table. There were error bands too, I forget what they were, but nothing came even close to 14M. Regards, Bill Herrin -- William Herrin b...@herrin.us https://bill.herrin.us/
