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1. Autonomous Systems & BGP Path Vector Protocol
Autonomous System Numbers & Path Vector Principles
The global Internet is a collection of over 70,000 Autonomous Systems (AS)—networks under a single administrative domain identified by a unique ASN. BGP (Border Gateway Protocol) is the path-vector protocol that ties these systems together across peering points and Internet Exchange Points (IXPs).
Unlike IGP protocols like OSPF, BGP makes routing decisions based on network policies, AS-PATH length, and path attributes rather than raw link metrics.
Security Operator Note: 32-bit ASNs range from 1 to 4,294,967,295. Always verify ASN authorization before establishing external BGP peerings.
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# Querying BGP ASN information for an IP using whois whois -h whois.radb.net 1.1.1.1
Visual Architecture: Global BGP AS Peering & RPKI ROV Topology
AS 13335 (Cloudflare)
Prefix: 1.1.1.0/24
ROA Signed: VALID
Tier-1 Transit Provider (AS 7018)
BGP Path Vector Routing
ROV Filter: Drops Invalid Origins
Rogue AS 99999 (Attacker)
Spoofed Prefix: 1.1.1.0/24
ROA Mismatch: INVALID (Dropped)
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