A Bound End-to-End Tunnel (BEET) mode for ESP

This document specifies a new mode, called Bound End-to-End Tunnel (BEET) mode, for IPsec ESP. The new mode augments the existing ESP tunnel and transport modes. For end-to-end tunnels, the new mode provides limited tunnel mode semantics without the regular tunnel mode overhead. The mode is intended to support new uses of ESP, including mobility and multi-address multi-homing.