AS9631 YSU-AS-KR youngsan university

AS9631 (YSU-AS-KR) is registered to Youngsan University (영산대학교), a private university in South Korea with campuses in Yangsan, South Gyeongsang Province, and the Haeundae district of Busan. It is a campus network: the AS exists to carry students, staff, labs and university services, not to sell connectivity.

What it's used for

The routing evidence is exactly what a self-hosted campus looks like. RIS shows 33 IPv4 prefixes covering 8,448 addresses, no IPv6, and 2 observed neighbours. Two adjacencies means the university is dual-homed to a pair of upstreams — enough for redundancy, and nothing more. There is no peering fabric and no downstream cone, which is the difference between an institution that runs its own AS for resilience and a network that sells transit. At roughly 8,000 addresses, the estate is sized for a campus population rather than a service provider's pool.

The prefixes themselves are all /24s, scattered across many unrelated blocks (61.75.198–201, 221.164.x, 211.220.22x–23x, 210.110.4x, 220.119.24x, 121.67.137, 220.77.177), with no aggregation anywhere. That is the fingerprint of an institution that accumulated small assignments from Korean carriers over a long period, one building, lab or campus expansion at a time, rather than receiving a single contiguous allocation. Announcing them separately keeps each assignment independently routable across the two upstreams.

Notable

• All 33 prefixes are /24s. Nothing has ever been aggregated into anything larger.
• No IPv6 is announced, which is common for Korean campus networks of this vintage even though the national research network has long supported it.