| Mechanism | Scenario | Targeted Environment | Design Concern |
| Dual Stack | End-to-End IPv6 + IPv4 | Any Environment that ultimately needs to move to end-to-end IPv6 | IPv6 support in all L3 ware platforms is required.
Increased control plane complexity.
May introduce scalability weaknesses when both IP versions are running together (depends on available hardware resources and memory) |
| Tunneling: Point to Point (P2P) (L2TPv3, GRE RFC 2473) | Transit IPv6 over IPv4-only network | A small number of IPv6 islands that need to interconnect over IPv4-network | Scalability and encapsulation overhead increased control plane complexity. |
| Tunneling: ISATAP (RFC 5214) | Host-source tunnel that terminate at IPv6-enabled modules or services | For trial IPv6 services or incase of IPv6 enable partially (for example, only at the data center); mostly enterprise networks. | Affects the overall network architecture. QoS, multicast, and NAT issues.
Adds control plane complexity.
Increases operational complexity. |
| Tunneling: mGRE | Interconnect IPv6 over IPv4 in a hub-and-spoke topology. | Interconnects IPv6-enabled remote sites in hub-and-spoke topology over IPv4 WAN.
Interconnects provate IPv6 island across public IPv4 clouds. | Multicast Traffic has to go via the hub.
Adds control plane complexity.
Increasses operational complexity. |
| Tunneling: 6rd (RFC 5969) | Used to extend IPv6 deployment to customer sites (ussually residential gateway), with limited impact on existing IPv4 infrastructure. | Service Provider Networks that offer IPv6 services.
Internet access over IPv4 service provider network to residential customer. | Whether the network equipment support 6rd.
Adds control plane complexity.
Increasses operationl complexity. |
| Tunneling: IPv6 over L2TP software | To offer IPv6 access for residential gateways. | Digital subscriber line (DSL)/ residential service providers with limited investment.
Stateful architecture on L2TP network Server (LNS). | Dual-Stack IPv4/IPv6 service on residential gateway LAN side.
Increases operational complexity. |
| Translation 64: NAT/SLB | Allows IPv6 handset / endpoint access to access IPv4 Internet over LTE/4G/5G or IPv4 services. | Green-field IPv6 service providers or enterprise networks that need to be interconnected to legacy / existing IPv4 network services. | Does not support every application type or protocol today.
Performance may not match dual-stack design, depending on traffic load. |
| Translation : DNS | DNS in this scenario offers the translation between the IPv4 and IPv6based on the source and targeted host. | Access Applications or services by name. | Limited to services applications that can be reached by name, not IP.
NAT64 is ussually required to leverage DNS64. |
| Translation: LISP | LISP encapsulation can facilitate the IPv6 communication over IPv4 transport. | Enterprise Edge, data center, or WAN with a mix of IPv4 and IPv6 networks. | High operational complexity.
Increased control plane complexity.
Network devices must support LISP. |
| MPLS: 6PE | Facilitate enabling IPv6 over an existing MPLS and MP-BGP IPv4 network. | Large enterprises or ISP that want to provide IPv6 over their IPv4 infrastructure. | Does not support provide traffic separation between different customer networks (no MPLS VPN support).
Increases control plane complexity. |
| MPLS: 6VPE | Facilitate enabling IPv6 over an existing MPLS and MP-BGP IPv4 network for VPN customer. | MPLS VPN providers or enterprises with MPLS VPN networks. | Increases control plane complexity.
May introduce scalability limitation because a separating routing information base RIB and FIB are required per sutomer. |
