AS9991 SHUDO-U Hiroshima Shudo University

AS9991 (SHUDO-U) is held by Hiroshima Shudo University (広島修道大学), a private university in Asaminami-ku, Hiroshima, Japan. It traces its lineage to the domain school of the Hiroshima Domain and took its present form as a four-year university in the twentieth century; today it runs several faculties across a single Hiroshima campus.

What it's used for

This is a campus network with a legacy allocation that dwarfs its actual need. RIS sees a single announced IPv4 prefix — 150.32.0.0/16, a full class-B-sized block of 65,536 addresses — plus one IPv6 prefix, 2001:df2:b340::/48, and 2 observed BGP neighbours.

The /16 is the historically interesting part. Japanese universities were early and generous recipients of address space, and a single institution of this size holding an entire /16 is a survival of that era rather than a reflection of demand. The university does not need 65,000 public addresses; what it needs is a stable, portable block for its campus subnets, wireless, labs, and its public web, mail and DNS. Two BGP neighbours is the confirming signal: this network buys connectivity (in Japan, typically a commercial upstream alongside the SINET research network) and sells none.

The IPv6 /48 out of 2001:df2::/32 is a downstream assignment rather than an independent allocation, which is consistent with the university taking v6 from a provider or the national research network rather than holding its own.

Notable

• A /16 announced as a single prefix with no deaggregation is a good marker of untouched legacy space: nothing has forced the university to split it.
• Address count is a poor proxy for network size here. Judged on addresses this looks like a mid-sized ISP; judged on neighbours and prefixes it is plainly a single campus.