# RFC 5572

RFC 5572 discusses using [TSP](/glossary/t/tsp) to set up [IP tunnels](/glossary/t/tunnel) with inner protocols, such as IPv6 or IPv4, inside various outer protocols packets, such as IPv4, IPv6, or UDP over IPv4 for IPv4 NAT traversal.


## More information

[https://tools.ietf.org/html/rfc2275](https://tools.ietf.org/html/rfc5572)