Unified Transition Overlay (UTO): A Gateway-Based IPv4/IPv6 Translation Proxy

Unified Transition Overlay (UTO) is a gateway-based IPv4/IPv6 translation proxy that enables cross-version connectivity without requiring encapsulation, new protocol headers, or modifications to end-host stacks. UTO operates exclusively at transition gateways, which translate packet headers between IPv4 and IPv6 and update transport-layer checksums to preserve end-to-end correctness. By confining translation logic to gateways, UTO allows the underlying network to remain purely IPv4 or purely IPv6, facilitating incremental deployment within existing routing and forwarding infrastructures. UTO also supports incremental checksum update to reduce processing overhead for TCP and UDP traffic.