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RFC 8950 carries IPv4 routes over IPv6 next hops without tunnels

anuragbhatia.com 5 min read Editor score 7/10

The setup lets IPv6-only network cores exchange IPv4 routes over IPv6 BGP sessions, leaving IPv4 at network edges without tunnels. It offers a practical path to reduce IPv4 configuration across backbones and IXPs.

What: - RFC 8950 lets MP-BGP announce IPv4 routes with IPv6 next-hops, carrying IPv4 over an IPv6 network without tunnels.
How: - IPv6 reachability uses NDP, while IPv4 packets remain IPv4 on the wire and travel over Ethernet to the MAC found by NDP.
Why it matters: - This lets backbone operators run IPv6-only cores while continuing to exchange IPv4 routes with customers and peers.

The lab’s route path connects IPv4-only edges through an IPv6-only provider core. Sketched from the article's own text.

Read on anuragbhatia.com → Hacker News · 63 comments

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