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Host 4over6

Host 4over6 . For IPv6 host connecting IPv4 Internet. Yong Cui, Jianping Wu Tsinghua Univ. (CERNET). Contact: cuiyong@tsinghua.edu.cn. Outline. Introduction Elements in host 4over6 Stateless approach Combination with Dual-Stack Lite Stateful approach Next steps. Introduction.

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Host 4over6

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  1. Host 4over6 For IPv6 host connecting IPv4 Internet Yong Cui, Jianping Wu Tsinghua Univ. (CERNET) • Contact: cuiyong@tsinghua.edu.cn

  2. Outline • Introduction • Elements in host 4over6 • Stateless approach • Combination with Dual-Stack Lite • Statefulapproach • Next steps

  3. Introduction • Pure IPv6 network • With the coming IPv4 address exhaustion, pure & native IPv6 network comes to reality • IPv4 access is still required for hosts in IPv6 network • SW IPv4-over-IPv6 Hub & Spoke • Some hosts need to provide IPv4 service to the IPv4 Internet • Operators (CERNET) need to support all apps & avoid xlate (NAT44 or NAT64) • Use case study • high-end client (host): Hope to have global IPv4 addrto support various apps even dynamically • Servers (host): Move IPv4 servers to IPv6 networks without loss of IPv4 clients • Having global IPv4 addr will be a Value-Added Service NO NAT44 NO NAT64 IPv4 Service IPv4 Internet IPv6 Edge Network

  4. General Idea of Host 4over6 • Leverage some global IPv4 addresses • Operators hope to leverage their existing resource of IPv4 blocks • Assign global IPv4 addr dynamically to host or CPE • Bidirectional 4over6 tunnel • Use bidirectional tunnel for traversing IPv4 traffic over IPv6 networks NO 44 NAT NO 46 NAT IPv4 Service IPv4 Internet IPv6 Edge Network Leverage IPv4 global address bidirectional 4over6 tunnel

  5. Elements in Host 4over6 • Tunnel Initiator(TI) • Host or CPE in IPv6 edge networks • Request global IPv4 addr when needed • Establish 4over6 tunnel toward Tunnel Concentrator • Tunnel Concentrator(TC) • IPv4/IPv6 dual stack router as the 4over6 tunnel endpoint • Perform encap/decap • DHCPv6 server • Allocate both IPv6 address and tunnel concentrator address to tunnel initiator • Dynamically allocate host 4over6 address to tunnel initiator TI : host IPv4 Internet IPv6 Edge Network IPv4 home network TC TI: CPE DHCPv6 Server host

  6. Stateless: DHCPv6 Extension • Allocate tunnel concentrator IPv6 address • draft-ietf-softwire-ds-lite-tunnel-option-03 • Host 4over6 address (IPv4-Embedded IPv6 address) • NSP + global IPv4 addr + suffix • draft-ietf-behave-address-format-09 • New DHCPv6 option (OPTION_HOST_4OVER6_ADDR) to allocate this address: • Implicitly allocate IPv4 addr by DHCPv6 OPTION_HOST_4OVER6_ADDR option-len: 16 octets IPv4-Embedded IPv6 address

  7. Stateless approach • 4over6 Host • Request 4over6 addr from DHCPv6 server • Abstract embedded IPv4 addr and config IPv4 stack • Tunnel initiator Encap/Decap • TC: NO stateful mapping • Need to inject a few IPv4 prefix into IPv6 RT • Only in one IPv6 edge network (NSP-based) payload payload IPv4 network Global v4 Src Global v4 Src v4 Dst v4 Dst IPv4 Internet v6 Src v6 Dest payload IPv6 Edge Network Global v4 Src CPE v4 Dst v6 Src Request host 4over6 addr v6 Dest payload TC payload host Global v4 Src Global v4 Src v4 Dst v4 Dst v6 Src Global IPv4 NSP IPv4 Suffix Concentrator Addr v6 Dest DHCPv6 Server Concentrator Addr NSP IPv4 Suffix

  8. Stateless approach (CPE scenario) • CPE function • DHCP46: request host 4over6 address from DHCPv6 server when host launch global DHCPv4 request to CPE • Tunnel Initiator: Encapsulation/decapsulation • IPv4 host • No any change in CPE mode payload • IPv4 network Global v4 Src payload v4 Dst DHCP46 Request global ipv4 Global v4 Src v4 Dst IPv4 Internet v6 Src v6 Dest IPv6 Edge Network CPE reply global IPv4 addr CPE Request host 4over6 addr TC Reply host 4over6 address host DHCPv6 Server

  9. Combination with Dual-Stack Lite:Host scenario • DHCPv6 server • Use the same DHCPv6 option to get the concentrator IPv6 address (draft-ietf-softwire-ds-lite-tunnel-option-03) • Add an option for 4over6(OPTION_HOST_4OVER6_ADDR) • Tunnel concentrator • Outbound, differentiate by Srcaddr • Public – host 4over6; Private – DS-lite • Inbound Differentiate by Dstaddr • In CGN address pool – DS-lite; otherwise: host 4over6 IPv6 Edge Network IPv4 Internet DHCPv6 with option HOST_4OVER6 Host4over6 SERVER Launch a host 4ovr6 process TC DHCPv6 Server DS-lite CLIENT Launch a DS lite process Inform the TC IPv6 addr

  10. What Host 4over6 achieves? • Support bidirectional communication • Leverage existing global IPv4 address • Support both IPv4 clients and IPv4 servers • Avoid NAT44 to support all apps • Avoid per flow state maintenance • Can easily combine with DS-Lite • Encourage IPv4 servers move to IPv6 without loss of IPv4 users • Ensure high-priority host to have full access to IPv4 without NAT • Provide value-added service

  11. Stateful approach of Host 4over6 • Tunnel concentrator maintains global IPv4 addr pool • Initiator uses both DHCPv6 & DHCPv4 • Request TC’s IPv6 addr from DHCPv6 server with DS-Lite tunnel option • Request IPv4 addr from DHCPv4 server (TC) with DHCPv4 over IPv6 tunnel • Concentrator maintains the state of address mapping • Host global IPv4 address: Host IPv6 address Mapping (not per flow): Global IPv4 addr – IPv6 addr IPv4 Internet IPv6 Edge Network 4over6 Host TC DHCPv4 over IPv6 tunnel DHCPv6 TC IPv6 addr DHCPv6 Server

  12. Next step • Set up a design team… • cuiyong@tsinghua.edu.cn • jianping@cernet.edu.cn • Implementation on host/CPE/TC • Ask for accepting as WG document • Valuable comments • Alain Durand, Yiu Lee, Olivier Vautrin, Chris Metz, Rajeev Koodli, Eric Nordmark, Cathy Zhou, MingweiXu, Xing Li, … Welcome to join…

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