AS195

AS195 is a low-numbered legacy autonomous system registered under ARIN to the San Diego Supercomputer Center (SDSC), an organized research unit of the University of California, San Diego. SDSC was founded in 1985 as one of the five original NSF-funded national supercomputing centers and today operates national high-performance-computing infrastructure including the Expanse, Voyager, and Triton Shared Computing Cluster systems, along with the National Research Platform. The ASN is the institutional home of CAIDA, the Center for Applied Internet Data Analysis, which runs the Archipelago measurement infrastructure and the Network Telescope; research-class scanning and measurement traffic originating from SDSC address space is therefore expected and consistent with academic internet-measurement norms rather than abuse. AS195 is actively routed: RIPEstat reports roughly 31 IPv4 prefixes (~156,416 addresses) and 2 IPv6 prefixes (2001:48d0::/32 and a more-specific /35), with full v4 visibility across RIS peers. CAIDA AS Rank places it around 3,686 globally and lists it as a clique/core member with three upstream providers, one settlement-free peer, and five customers; upstreams include CENIC (AS2152) and Cox Communications (AS22773). The ARIN RDAP autnum top-level registration event dates the allocation to 1988-05-26, last changed 2023-06-01. No notable public abuse signal was found as of June 2026 — the only documented historical incident is a 2004 intrusion in which SDSC was a victim, not a source — consistent with a clean, long-established R&E operator.

Operator

San Diego Supercomputer Center (SDSC), an organized research unit of UC San Diego; ARIN org handle SDSC-Z, ASN name SDSC-AS [Confirmed] — ARIN RDAP autnum/195, whois.arin.net/rest/asn/AS195

Country / RIR

US, ARIN [Confirmed] — rdap.arin.net/registry/autnum/195

Allocated

1988-05-26 (ARIN autnum top-level registration event, a first-party RIR fact — NOT an IEEE date); last changed 2023-06-01 [Confirmed] — rdap.arin.net/registry/autnum/195

Org status

active; founded 1985 as one of five original NSF supercomputing centers; affiliated with the UC San Diego Halıcıoğlu Data Science Institute; director (as of July 2021) Frank Würthwein [Confirmed] — sdsc.edu, en.wikipedia.org/wiki/San_Diego_Supercomputer_Center

Contacts

abuse@sdsc.edu, hostmaster@sdsc.edu, security@sdsc.edu; +1-858-534-5090; 9836 Hopkins Dr / 9500 Gilman Drive MS-0505, La Jolla, CA 92093-0505, US [Confirmed for abuse/hostmaster via RDAP + RIPEstat; address Likely via RDAP contacts] — rdap.arin.net/registry/autnum/195, RIPEstat abuse-contact-finder

Security/abuse context (NEUTRAL, DATED)

no notable public abuse signal found as of 2026-06-19 — not in Spamhaus listings, threat feeds, or NANOG archives. Sole documented incident: an April 2004 intrusion in which SDSC was a victim (no data compromised), not a source of abuse. Research-class scanning from CAIDA is expected, not malicious

Network & routing

Network type

research and education (academic); HPC / data-intensive scientific research network [Confirmed] — ipinfo.io/AS195, bgp.tools/as/195, en.wikipedia.org/wiki/San_Diego_Supercomputer_Center

Size

~31 IPv4 prefixes (~156,416 addresses) and 2 IPv6 prefixes; CAIDA customer cone 6 ASNs / 72 prefixes / 262,080 addresses [Confirmed] — RIPEstat routing-status, api.asrank.caida.org/v2/graphql

Routing/peering

actively announced — 327/327 RIS peers see v4 (100%), ~322/323 see v6; CAIDA AS degree 9 total (5 customers, 1 peer, 3 providers) [Confirmed]. No official peering policy page found on sdsc.edu; policy Unknown [Likely/Unknown] — ipinfo.io/AS195, api.asrank.caida.org/v2/graphql

Upstreams

CENIC (AS2152) and Cox Communications (AS22773); CAIDA counts 3 providers [Confirmed for the two named upstreams via ipinfo.io; the third provider AS not named in this pass] — ipinfo.io/AS195, api.asrank.caida.org/v2/graphql

RPKI

not assessed in this pass (no per-prefix RPKI validation performed) [Unknown] — no source

Notable usage

operates Expanse, Voyager, and the Triton Shared Computing Cluster; manages the National Research Platform; institutional home of CAIDA and the Archipelago / Network Telescope measurement infrastructure; historically hosted the Protein Data Bank and participated in TeraGrid

[Confirmed] — sdsc.edu, en.wikipedia.org/wiki/San_Diego_Supercomputer_Center, caida.org/about/research

Related ASNs

AS1909 (SDSC), AS7377 / AS46985 (UC San Diego), AS2641 (Scripps Research) appear in the routing neighborhood [Likely] — ipinfo.io/AS195

Peers/downstreams

peers observed include ESnet (AS293), CENIC (AS2152), UC San Diego (AS7377), Scripps Research (AS2641); downstreams include SDSC (AS1909), Scripps Research (AS2641), Clemson University (AS12148), Salk Institute (AS22213), UC San Diego (AS46985) [Likely] — ipinfo.io/AS195

Analyst note

low-numbered legacy ASN registered to a historically significant NSF supercomputing center and CAIDA's host; actively routed, clean abuse posture. Named upstream/peer ASNs beyond CENIC and Cox were not all resolved in this pass; RPKI not checked.