1. V4 traversal for IPv6 mobility protocols - Scenarios Mip6trans Design Team MIP6 and NEMO WGs, IETF 63

2. Background MIPv6 and NEMO are both IPv6 mobility protocols Most access networks are still IPv4 only. When a mobile node attaches to an IPv4 access network, it needs to reach its IPv6 Home Agent and IPv6 services Using IPv6 transition protocols with MIPv6 is not very efficient. More details on this at http://people.nokia.net/vijayd/mip6trans/transition_mechanisms.txt http://people.nokia.net/vijayd/mip6trans/transition_mechanisms.txt The design team’s goal is to consider all scenarios and develop solutions that help a mobile node access its Home Agent and IPv6 services from an IPv4 access network. Will not address transitioning from MIPv4 to MIPv6

3. Scenario 1 The mobile node is attached to an IPv4 only access network and needs to reach its IPv6 Home Agent and services Assumptions The access network is IPv4-only The MN is dual stack capable The HA is reachable through a public IPv4 address and an IPv6 address The MN and HA support generic IPv6-over-IPv4 tunneling

4. Scenario 2 Same as scenario 1, but HA is behind an IPv4 NAT device Assumptions A gateway node in the DMZ is configured with an address that is known to the MN as the HA’s IPv4 address The HA is aware of the address configured on the gateway node The gateway node is configured to forward any UDP encapsulated messages from the MN to the HA

5. Scenario 3 Support for IPv4 sessions using MIP6 and NEMO protocols Most MNs are dual stack and might set up IPv4 sessions in addition to IPv6 sessions Running MIPv4 and MIPv6 at the same time has a lot of disadvantages and should be avoided More on this in draft-ietf-mip6-dsmip-problem-00.txt Session continuity for IPv4 sessions over the mip6trans tunnel Assumptions IPv4 traffic can be carried over the mip6trans tunnel

6. NAT Traversal The MN/MR may be behind a NAT box with respect to the HA in any of the 3 scenarios Any solution must include A NAT traversal mechanism NAT detection Overhead from UDP encapsulation should be avoided when a NAT is not present

7. Solution Requirements Connect an IPv6 mobile node to its IPv6 Home Agent and services from an IPv4- only access network Support NAT traversal, NAT detection and the ability to turn off the NAT traversal mechanism when not required Support the scenario where the Home Agent is behind a NAT and not accessible through a public address Support dynamic discovery of the HA’s IPv4 address Enable IPsec protection for the mip6trans tunnel. The Home Agent and the mobile node must be able to negotiate tunnel security associations for the mip6trans tunnel Enable the mobile node to use its IPv4 Home Address for IPv4 sessions over the mip6trans tunnel Support dynamic allocation of the IPv4 Home Address