PE-based IPv6 multicast transition for mesh problem Yong Cui @ CERNET

Why we need multicast transition? From CERNET Existing multicast applications are in IPv4 Native IPv6 CERNET2 is expected to support IPv4 multicast applications IPv4 multicast traffic is low

What’s multicast transition problem How to setup a multicast tree in IPv6 backbone where edge of tree should be PE? ?

Auto-discovery members in mesh framework Auto-discovery of PEs (N PEs totally) Mesh framework or 4over6 based on MP-BGP

Potential solution Construct multicast tree in IPv6 backbone Dynamic mapped IPv6 tree (M trees) Dynamically mapping IPv4 mgroup to IPv6 mgroup Single static tree by PIM-SM IPv6 RP in IPv6 backbone PE-based static tree by PIM-SM (N trees totally) One tree rooted by each PE SPT rooted by each PE to all other PE

IPv4/v6 group mapping (S,G)v4 <->(S’,G’)v6 ,S’ is IPv6 address of the PE of S G’ is ff18:ssss:ssss:gggg:gggg::x s and g are the (S,G) P maintains M IPv6 group states if there are M IPv4 groups (S,G)v4 <->(S’,G’)v6 (S,G)v4 <->(S’,G’)v6

Construct a single tree in IPv6 backbone A single IPv6 group address is configure on RPv6 and PEs Egress PE initiates a single join procedure to RPv6 SPT rooted by RPv6, IPv6 tree optimization is a problem The number of IPv6 multicast groups is 1

Construct one tree rooted by each PE in IPv6 backbone Each ingress PE has its own IPv6 group address ingress PE sends its IPv6 group address to all other PEs by Softwire extensions Egress PE initiates a join procedure to each ingress PE (SPT rooted by each PE) The number of IPv6 multicast groups is N

IPv4 PIM-SM Sender/receiver Registration over IPv6 backbone Source S register S tree

Multicast Forwarding Source

Conclusion and future work Construct multicast tree in IPv6 backbone Dynamic mapped IPv6 tree (M trees) Dynamically mapping IPv4 mgroup to IPv6 mgroup Scalability problem in IPv6 core Single static tree rooted by IPv6 RP IPv6 tree optimization is a problem PE-based static tree by PIM-SM (N trees totally) One tree rooted by each PE SPT rooted by each PE to all other PE Scalability: Keep less states in the backbone Efficiency: PE may receive some packets they do not require Future work Comments & co-authors are welcome To be a WG document