BGP in 2025#

Geoff Huston — APNIC

• Why: The annual ground truth on DFZ health — directly relevant to FIB sizing, deaggregation trends, and (this year) a genuinely new datapoint: the IPv4 routing table and the advertised address span are now moving in opposite directions.
• What: IPv4 FIB passed 1M entries for all peers, yet the advertised address span shrank by 11M /32s during 2025 (3.1B advertised vs 580M unadvertised, +10M) — IPv4 use declining in access networks (notably the US) while cloud use still grows. Biggest movers: China Mobile (+13,382 prefixes), Amazon (+14,004), AT&T (−2,605, echoing its consolidation described in the Ukraine talk), IPXO broker growth visible. Amazon's super-aggregate games through the year (+4.3M, −15.8M, +15.1M address swings). IPv6: ~20k entries/year (~10%) growth with 45% of prefixes being /48s; 2,096 new IPv6 advertisers vs 956 departing. Projections: best 5-year fit still polynomial for IPv4 but a 3-year linear fit is competing; IPv6 growth model highly uncertain.
• How: Longitudinal analysis across Route-Views/RIPE RIS peers; churn (updates/withdrawals) notably stable — the IPv4 network is "surprisingly stable" with withdrawals flat for ~15 years.
• Where applicable: Universal for capacity planning and RIB/FIB trend work. The headline nuance — prefix count growing while address span shrinks — matters for anyone modeling router table growth or arguing about IPv4 scarcity.