Tunneling IPv6 Packets Over Existing IPv4 Networks
This section explains the rationale of tunneling data over the network. Then it describes how IPv6 packets are tunneled over IPv4 networks. Finally, it presents protocols and mechanisms standardized by the IETF to establish and deploy IPv6-over-IPv4 tunnels between dual-stack nodes.
Tunnels are generally used on the network to carry incompatible protocols or specific data over an existing network. For example, Distance Vector Multicast Routing Protocol (DVMRP) tunnels carry multicast datagrams over unicast networks. IPSec in tunnel mode, Layer 2 Tunneling Protocol (L2TP), and other Virtual Private Network (VPN) mechanisms transfer sensitive data over public IP networks using secure ...