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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 .
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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