The ChorusOS operating system provides TCP/IP and UDP/IP stacks (POSIX_SOCKETS), both over IPv4 and IPv6.
IPv4 and IPv6 can be used simultaneously.
Consult "Networking" in ChorusOS 5.0 Features and Architecture Overview to see the RFC list of the IPv4 and IPv6 protocols that are supported
See ip6(7P) man page for further information.