1. Booting up on the Home Link
MEXT WG, IETF 71
Vijay Devarapalli
(draft-devarapalli-mext-mipv6-home-link-01)
Presented by ?

2. Use of Mobile IPv6 in SDOs
A few SDOs are adopting the use of Mobile IPv6 in their next generation architectures
The architectures are being designed to make it appear to the MN that it is attached to the home link over certain access networks
Limited bandwidth
Desire to avoid Mobile IPv6 tunneling overhead
A point-to-point link is typically used between the MN and the HA to create a single hop home link
GTP, IPsec, PMIPv6 are used to create the point-to-point links
Neighbor discovery is not run on some of these p2p links
Booting up in the home link needs to be analyzed in more detail for this home link operation
Returning home over the p2p links is not considered here

3. Bootstrapping
Bootstrapping depends on the IKEv2 exchange and BU/BAck exchange between the MN and the HA
IPv6 Home Address bootstrapped through IKEv2
DS-MIPv6 IPv4 HoA bootstrapped through BU/Back exchange
NEMO Mobile Network Prefixes are bootstrapped through BU/BAck exchange
MONAMI6 Flow filters are exchanged using BU/BAck
A RFC 3775-compliant MN does not have to initiate an IKEv2 exchange or send a BU when it discovers it is attached to the home link
The IKEv2 exchange is typically done when the BU is about to be sent
The MN does not send BU until it discovers it is on the visited link

4. Home Link detection
Home link detection in RFC 3775 is based on receiving router advertisements from the home agent
Neighbor discovery is not possible on certain p2p links
IPsec tunnels
Even in the generic case RFC 3775, if the MN is not aware of its home prefix, router advertisements cannot tell the MN it is at home
Home link detection may require at the minimum an IKEv2 exchange with the home agent even when the mobile node is on the home link

5. Forwarding at the Home Agent
When a packet for the MN’s HoA arrives at the home agent, it needs to forward the packet to the corresponding point-to-point link
It is not clear how this state – MN IP address to corresponding p2p link – is created on the HA
Might vary with each type of point-to-point link
Neighbor discovery is typically not run over these point-to-point links for the HA to create the forwarding state
Forwarding entries at the home agent for NEMO mobile network prefixes not created until a binding update from mobile router is received

6. Home Address management on the MN
When attached to p2p links, the mobile node configures addresses using the link specific mechanisms
The addresses are assigned to the interface that correspond to the p2p link on the mobile node
When the mobile node moves away from the home link,
It needs to treat those addresses as home addresses (IPv4 and IPv6)
Move the addresses to the Mobile IPv6 virtual interface

7. Service Selection Option
The Service Selection option may be used by the MN to indicate to the HA which service it wants in the BU
RFC 5149
Without the BU sent on the home link, the MN cannot indicate the service it wants
The Service selection option may be included in the lower layer messages (that are used to set up the p2p links)
But the service selection option may not be the same, could be for just getting “access”

8. Possible Solution #1
Describe how the mobile node boots up over the home link works with existing mechanisms
IKEv2 exchange from home link to detect home link attachment
MIP6_HOME_PREFIX attribute (RFC 5026) must be implemented
Configure DS-MIPv6 IPv4 HoA using IKEv2 or DHCP over p2p links
Configure NEMO mobile network prefixes using DHCPv6 prefix delegation
Specify additional behavior for the home agent and MN to associate addresses configured using p2p link-specific mechanisms as home address(es)
Setup up routing for mobile network prefixes even though DHCPv6 prefix delegation is used
HA must be a DHCPv6 relay agent
Service selection included in the p2p link setup messages or the IKEv2 exchange with the home agent
Leave out flow filter exchange when the mobile node boots up on the home link

9. Possible Solution #2
The MN sends a binding update when it attaches to the home link over the point-to-point link
A new flag in the BU to indicate that the BU is being sent from the home link
The HA confirms this in the Binding Ack
Mobile IP tunnel is not created
State created on the HA mapping the home address to the appropriate p2p tunnel
Packets for the home address would then be routed over the p2p link
Any other configuration information like the DS-MIPv6 IPv4 home address, NEMO MNP is obtained in this BU/BAck exchange
Service selection option and flow filters are conveyed in the BU
No modifications to RFC 3775
This would be an optional extension to be used only by those mobile nodes which attach to home link via p2p links
Configurable on the mobile node

10. Next Steps Should MEXT address this?
Do we develop a new solution (BU with special flag) or describe how it is supposed to be done with existing protocols and bootstrapping mechanisms?
Do we want the same bootstrapping mechanisms used irrespective of whether the mobile node boots up on the home or the visited link?