| 信息安全, 航空 |
номер автономной системы (a unique numeric identifier assigned to every autonomous system—the collection of one or more IP networks that share a single, clearly defined routing policy on the public Internet. When two networks exchange routes with the Border Gateway Protocol (BGP), they do so under their ASNs, which let routers know "who" is announcing a particular IP prefix and where traffic should be delivered next. Large organisations such as Google (AS 15169) or Cloudflare (AS 13335) operate their own autonomous systems, while many smaller companies rely on their upstream Internet service provider's ASN.
The numbers themselves are allocated in two ranges (original 16-bit values up to 65 535 and modern 32-bit extensions that reach into the four-billion range). The Internet Assigned Numbers Authority (IANA) delegates blocks to the five Regional Internet Registries (RIPE, ARIN, APNIC, LACNIC, AfriNIC), which in turn assign individual ASNs to network operators that can demonstrate a distinct routing policy.) |
