This document provides an applicability statement for the use of UDP
transport checksums with IPv6. It defines recommendations and
requirements for the use of IPv6 UDP datagrams with a zero UDP
checksum. It describes the issues and design principles that need to
be considered when UDP is used with IPv6 to support tunnel
encapsulations, and it examines the role of the IPv6 UDP transport
checksum. The document also identifies issues and constraints for
deployment on network paths that include middleboxes. An appendix
presents a summary of the trade-offs that were considered in
evaluating the safety of the update to RFC 2460 that changes the use
of the UDP checksum with IPv6.