464XLAT
IPv4-on-IPv6-only-network transition-mechanism. RFC 6877 (2013). Combine client-side stateless-translation (CLAT) + network-side stateful-translation (PLAT/NAT64) för apps som hardcoded-IPv4-only.
Klient (phone): kör mini-NAT internally (CLAT) som maps app-IPv4-traffic till IPv6-source. Network: NAT64 maps IPv6-back-till-real-IPv4 vid edge. Resultat: legacy-IPv4-apps work transparent on IPv6-only-network. T-Mobile USA-cellular use 464XLAT — phones run CLAT internally. Modern Android (10+) has built-in CLAT. iOS native-IPv6-only-apps don't need CLAT, but legacy apps benefits. Performance-overhead: minimal (in-kernel translation), but adds complexity. Future-irrelevance: as IPv6-adoption climbs, fewer-apps need-IPv4, 464XLAT mostly handles legacy.