• Request for Comments: 2529 - Transmission of IPv6 over IPv4 Domains without Explicit Tunnels
• Request for Comments: 3056 - Connection of IPv6 Domains via IPv4 Clouds
• Request for Comments: 4213 - Basic Transition Mechanisms for IPv6 Hosts and Routers
• Request for Comments: 4380 - Teredo: Tunneling IPv6 over UDP through Network Address Translations (NATs)
• Request for Comments: 4554 - Use of VLANs for IPv4-IPv6 Coexistence in Enterprise Networks
• Request for Comments: 4659 - BGP-MPLS IP Virtual Private Network (VPN) Extension for IPv6 VPN
• Request for Comments: 4798 - Connecting IPv6 Islands over IPv4 MPLS Using IPv6 Provider Edge Routers (6PE)
• Request for Comments: 5158 - 6to4 Reverse DNS Delegation Specification