Which encapsulation best describes how Teredo carries IPv6 traffic over an IPv4 network?

Which encapsulation best describes how Teredo carries IPv6 traffic over an IPv4 network?

• A. IPv4 traffic wrapped in IPv6 UDP packets
• B. IPv6 traffic wrapped in IPv4 TCP packets
• C. IPv6 traffic wrapped in IPv4 UDP packets
• D. IPv6 traffic wrapped in IPv4 ICMP packets

Answer: (C)

Teredo carries IPv6 traffic by tunneling it inside IPv4 datagrams that use UDP as the transport. This setup is chosen specifically to navigate NAT devices more reliably: UDP is stateless and easier to punch through NATs than TCP, so IPv6 packets can be wrapped in IPv4 UDP packets and traverse an IPv4 network to reach IPv6 peers. The result is IPv6 payload encapsulated within an IPv4 header, then a UDP header, and finally the IPv6 data. Other wrapping methods (such as IPv6 inside TCP, or inside ICMP) aren’t how Teredo operates, so they don’t describe its behavior.

Teredo carries IPv6 traffic by tunneling it inside IPv4 datagrams that use UDP as the transport. This setup is chosen specifically to navigate NAT devices more reliably: UDP is stateless and easier to punch through NATs than TCP, so IPv6 packets can be wrapped in IPv4 UDP packets and traverse an IPv4 network to reach IPv6 peers. The result is IPv6 payload encapsulated within an IPv4 header, then a UDP header, and finally the IPv6 data. Other wrapping methods (such as IPv6 inside TCP, or inside ICMP) aren’t how Teredo operates, so they don’t describe its behavior.