AS15204 ITC-SD-01 - INTERSTATE TELECOMMUNICATIONS COOPERATIVE, INC.

The IPv6 announcements double in size, block after block, all the way up.

What it's used for

• A rural telephone cooperative. Ten IPv4 prefixes and thirty-eight IPv6 prefixes announced from the United States, covering twenty-five thousand IPv4 addresses.

Notable

• The IPv6 prefixes tile one allocation in a doubling ladder: two /48 blocks, then a /47, a /45, a /44, a /43, a /42, a /41, each twice the size of the last and sitting immediately above it.
• Several netnames spell the cooperative out as a telephone company, while the registrant on the same block calls it a telecommunications company. The two words are in the same record.
• Those netnames end in a run of digits that is the block's address with the separators removed.
• One registrant field is the company name followed by a semicolon and nothing after it; another appends an abuse handle whose capitalisation matches no other spelling of the name.
• One block's registrant is a three-letter abbreviation repeated three times with spaces between.
• Sixteen of eighteen sampled addresses answered, under one domain, with a two-character code between the address and the domain that takes one of two values.

Interesting

• A doubling ladder is what an allocation looks like when it is carved by an algorithm that always takes the next aligned block big enough. It is correct, it is efficient, and it produces dozens of routes where one would carry the same traffic.
• A cooperative that renamed itself from telephone to telecommunications left both names in the registry, which is how these records date themselves.