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Softwire Mesh Multicast draft-xu-softwire-mesh-multicast-00. Mingwei Xu, Yong Cui, Shu Yang Tsinghua University Chris Metz, Greg Shephard Cisco IETF79 Meeting, Beijing Nov 2010. Outline. Background Mesh multicast framework Scenarios IPv4-over-IPv6 scenario IPv6-over-IPv4 scenario
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Softwire Mesh Multicast draft-xu-softwire-mesh-multicast-00 Mingwei Xu, Yong Cui, Shu Yang Tsinghua University Chris Metz, Greg Shephard Cisco IETF79 Meeting, Beijing Nov 2010
Outline • Background • Mesh multicast framework • Scenarios • IPv4-over-IPv6 scenario • IPv6-over-IPv4 scenario • Summary
Background • Softwires Charter and RFC4925 state multicast is a requirement • Operators have expressed requirements for multicast solution • Softwire Mesh Unicast methods have been defined. Where is the Multicast? • Is section 11 of RFC5565 sufficient? • MVPN-like schemes can achieve “many-to-one” mapping • “One-to-one” mapping (Internet-style multicast) is needed
Mesh multicast framework E-IP E-IP S AFBR AFBR I-IP Transit Core AFBR AFBR E-IP E-IP R R I-IP Tree E-IP Tree
Scenario • IPv4-over-IPv6 scenario • IPv6-over-IPv4 scenario • Remember that IPv6 address is longer than IPv4 address, thus additional effort will be required
IPv4-over-IPv6 (S,G) (p::S,p::G) RPF (S,G) RFC 5496
Group address mapping • FFXY must be in accordance with the IPv6 multicast address format of [RFC2373] • The next 10 octets are assigned by ISP 0 16 96 127
Actions performed by AFBR • Process E-IPv4 PIM messages • Perform E-IPv4 PIM to I-IP PIMv6 message conversion • Transmit and receive I-IP PIMv6 messages
IPv6-over-IPv4 - Difficulty • Because of larger space of IPv6 address • Hard to map without collision • I-IP IPv4 multicast address limitations: Not all IPv4 multicast addresses are available
Possible Solutions • Limit IPv6 address space • Pick up a portion of IPv6 addresses • Approximate “one-to-one” • Select a good hashing function to make collision happen occasionally • Inter-AFBR signaling • Signal each AFBR about mapping information
Limit IPv6 address space IPv6 space Limited v6 space IPv4 space Mapping
Approximate “one-to-one” IPv6 address IPv4 address
Inter-AFBR signaling G G’ (S,G) ? (S’,G’) (S,G)
Summary • Only need changes on AFBR • Reduce redundant traffic compared to MVPN-like schemes • More details will be added