IPv6 Neighbor Discovery over Syam Madanapalli Samsung ISO IETF 64 – Vancouver, Canada November 8 th 2005

IPv6 ND over – Issues Multicast Support Multicast Support is a connection oriented technology for the last mile is a connection oriented technology for the last mile Point-to-multipoint, No bidirectional native multicast support Point-to-multipoint, No bidirectional native multicast support Subnet Model Subnet Model Unclear Unclear May depend on Convergence Sub Layers (Ethernet CS, IP CS) May depend on Convergence Sub Layers (Ethernet CS, IP CS) Connection ID for IP Signaling Connection ID for IP Signaling CID for IP Signaling during the Network Entry CID for IP Signaling during the Network Entry Multiple connections may exist between MS and BS Multiple connections may exist between MS and BS Which connection to use? Which connection to use?

Convergence Sub-layer - Link Ethernet CS Ethernet CS IP Packet Terminates at AR IP Packet Terminates at AR There can be multiple ARs, so multiple Default Routers There can be multiple ARs, so multiple Default Routers Requires Router Discovery and Unreachability detection Requires Router Discovery and Unreachability detection BSARMS Link BSARMS Link? IP CS IP CS It is unknown whether the IP packet is terminated at BS or AR It is unknown whether the IP packet is terminated at BS or AR BS routes the packet to AR ? BS routes the packet to AR ? Tunnels the packet to AR? Tunnels the packet to AR?

Router Advertisements Supports multicast for the down link May need to define a default DL Multicast Connection (mCID) for RAs All MSs may need to join the mCID MS1 BSAR MS3 MS2 RA DLULmCIDn

NC, Next-Hop and NUD Who are the neighbors to an MS? Other MSs attached to the same BS? Depends on subnet model MS is always has to have an L2 connection to BS MS may not need the NC and NUD, if BS is the IP neighbor Type of Convergence Sublayer used may affect these MS1 BSAR2 MS3 MS2 AR3 AR1 Depending on how BS and ARs are connected may complicate these further.

Prefix Discovery Unique prefix to each MS Unique prefix to each MS Sharing same prefix with multiple MSs Sharing same prefix with multiple MSs MS tries to resolve the L2 address for the on-link prefixes MS tries to resolve the L2 address for the on-link prefixes Direct Communication between two MSs may not be possible Direct Communication between two MSs may not be possible May be the routers should advertise prefixes with L bit reset May be the routers should advertise prefixes with L bit reset

Address Autoconfiguration - Issues Whether other MSs are my neighbors (Subnet Model) Whether other MSs are my neighbors (Subnet Model) Whether the prefix is being shared with other MSs Whether the prefix is being shared with other MSs MS cannot multicast the DAD NS MS cannot multicast the DAD NS

Existing Solutions Applicability of RFC 2491 – IPv6 Over NBMA Applicability of RFC 2491 – IPv6 Over NBMA Frame Relay and ATM are end-2-end protocols Frame Relay and ATM are end-2-end protocols defines only the last mile defines only the last mile Can we still apply RFC 2491? Can we still apply RFC 2491? 3GPP like model 3GPP like model Assign unique prefix to each MS Assign unique prefix to each MS

A Possible New Solution A Down-link multicast connection A Down-link multicast connection E.g. for Router Advertisements E.g. for Router Advertisements All MSs may join this well-known multicast connection All MSs may join this well-known multicast connection Router advertise the prefixes with L-bit reset Router advertise the prefixes with L-bit reset No neighbors except the ARs No neighbors except the ARs Routers proxy for the end nodes (MSs) for Address Autoconfiguration Routers proxy for the end nodes (MSs) for Address Autoconfiguration Setup a default connection between MS and BS that can be used for IP Signaling Setup a default connection between MS and BS that can be used for IP Signaling Requires only the implementation change for Routers Requires only the implementation change for Routers No Protocol changes are required No Protocol changes are required MS IPv6 Stack can support multiple interfaces e.g , MS IPv6 Stack can support multiple interfaces e.g ,

Way Forward Understand WiMAX NWG needs Understand WiMAX NWG needs Understand the implications of Convergence Sub-layers Understand the implications of Convergence Sub-layers Understand the Network Models Understand the Network Models Develop Subnet Model Develop Subnet Model Develop Requirements Develop Requirements Make an I-D for recommendations to WiMAX NWG Make an I-D for recommendations to WiMAX NWG