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IPv6 Routing Considerations

IPv6 Routing Considerations. Masaru Mukai / POWERDCOM Kuniaki Kondo / IIJ. Background. This talk shows the result of “IPv6 Operation Study Group(IPv6-OPS)” discussion in Japan IPv6-OPS was held twice over night meeting and BoF in JANOG8 Meeting last year.

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IPv6 Routing Considerations

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  1. IPv6 Routing Considerations Masaru Mukai / POWERDCOM Kuniaki Kondo / IIJ

  2. Background • This talk shows the result of “IPv6 Operation Study Group(IPv6-OPS)” discussion in Japan • IPv6-OPS was held twice over night meeting and BoF in JANOG8 Meeting last year. • JANOG = Japan Network Operators’ Group • http://www.janog.gr.jp/ • IPv6-OPS has “Routing Sub-Group”. • This group focuses “ISP Backbone Routing Issues”. APNIC SIG-IPv6

  3. IPv6-OPS Routing Sub-Group • Motivation • Address architecture will change in IPv6. • Address Length is 128 bit • Address allocation scheme will change • We would like to know what is difference between IPv6 and IPv4. • Goal • This group survey how IPv6 address architecture influences IPv6 routing? • If possible, this group hopes to make typical IPv6 network models. APNIC SIG-IPv6

  4. Agenda • Multi-homing • EGP • IGP APNIC SIG-IPv6

  5. Multi-Homing • Overview • There are some techniques to do multi-homing such as using BGP, using NAT, etc.. • In IPv4, some ISPs use to connect inter-ISP or between ISP and customer for redundant. • Customer want to have redundant line and to do load-balancing same as IPv4 network, when IPv6 come. APNIC SIG-IPv6

  6. IPv4 Multi-Homing • One AS announces a part of address block which was allocated for other AS by registry. It makes to increase number of full routes. • One AS customer want to do multi-homing, but their network scale does not so large as getting AS number. • ISPs probably allow this configuration based on customer requires. • To increase number of full routes makes some problems. • For example, if number of full routes increase continuously, then BGP convergence time also increase. APNIC SIG-IPv6

  7. Category of Multi-Homing • BGP based (A organization has AS number and PA address) • Anything will not change. • Announcing PI address • Currently, Registries do not allocate IPv6 PI address. • punching hole • The number of IPv6 punching holed routes are unknown. • Multi prefix • Some prefixes are assigned by each upstreams. • Source address selection can be used • This behavior is different each implementation. • RFC3178 model • This is possible solution, but it needs more costs such as operation cost, line cost, etc. APNIC SIG-IPv6

  8. RFC3178 Model PA(A) ISP A PA(B) ISP B PA(A) PA(B) RouterA RouterB PA(A) + PA(B) APNIC SIG-IPv6

  9. Problems of RFC3178 Model • Problems of using tunnel • To separate responsible area is difficult. • Responsible area can not separate clearly. • There is security problem why traffic might through unwilled ISPs. • There are no-method to limit bandwidth of tunnel lines. • If this model does not use tunnel, then it needs more leased lines. It means that it needs more line costs. APNIC SIG-IPv6

  10. punching hole The Internet B A P(A) P(A) ISP A ISP B A B P(A) User X APNIC SIG-IPv6

  11. Problems of punching hole • Increasing number of routes • Increasing route convergence time • Needs more powerful routers • It makes more cost to provide ISP services APNIC SIG-IPv6

  12. Multi prefix ISP A ISP B A B P(A) P(B) P(A) P(B) host host APNIC SIG-IPv6

  13. Problems of Multi Prefix • There are some implementations, but behavior is different each implementations. • Every host must be cared which prefix is better for sending packets. • Every host must select source address. • Both of backup and load-balance are defective in multi-prefix situation. • A router which can do policy routing must be more generic. APNIC SIG-IPv6

  14. Agenda • Multihoming • EGP • IGP APNIC SIG-IPv6

  15. EGP • Overview • People needs a solution for IPv6 traffic control • Announced prefix will decrease. It makes that traffic will be concentrated to some of routers in ISP. APNIC SIG-IPv6

  16. Problems of Traffic Control • In IPv6 network, ISPs can not control traffic using separated prefixes. • If ISPs announce more specific routes, then number of full routes increase tremendously. • In some cases, inter-AS traffic might concentrate specific border routers. APNIC SIG-IPv6

  17. Traffic Control Solutions for IPv6 • Upstream ISPs control traffic • prepend, community • New Method • To use MPLS • To propose BGP-5 • ISPs announce more specific routes. • Number of full routes increase tremendously. APNIC SIG-IPv6

  18. Agenda • Multi-Homing • EGP • IGP APNIC SIG-IPv6

  19. IGP • Our discussion summary • Networks might have more number of internal routes than number of external routes. • We would like to consider new network design for IPv6 which is considered aggregation of IP blocks. • If we design network same as IPv4, then IPv6 networks probably have more number of internal routes than IPv4 network. • It depends on network design APNIC SIG-IPv6

  20. Problems of IGP • Aggregating prefixes is necessary for decreasing number of internal routes. • One of possible way is that prefixes aggregate for each POPs. • Address blocks are assigned to POPs according to number of lines or forecast of number of customers. APNIC SIG-IPv6

  21. Conclusion • Much Much bigger address spaces • Potential number of external routes in future • Multi-homing • No PI(Provider Independent) address for enterprises • Punching hole allowed? Any criteria? • Aggregation • /48 static assignment per a customer needs special design consideration about aggregation in ISP internal networks. • How can address policy supports this? • Traffic engineering • Less external routes to be announced make TE harder. APNIC SIG-IPv6

  22. Acknowledgements

  23. discussion member(1/2) • Akihiro Inomata Fujitsu Chair • Masaru Mukai PowerdCom Co-Chair • Kuniaki Kondo IIJ • Tomohiko Kurahashi IIJ • Rie Shimada Panasonic • Toshihiro Araki Japan Telecom • Yasushi Endo Japan Telecom • Tomohide Nagashima Japan Telecom • Tsuyoshi Tomochika NTT Communications • Hiroyuki Tanahashi NTT Communications • Yasuhiro Shirasaki NTT Communications • Akira Nagakawa PowerdCom • Ryuuichi Takashima PowerdCom • Teruo Watanabe PowerdCom • Toshio Tachibana Ani&Company APNIC SIG-IPv6

  24. discussion member(2/2) • Tomohiro Fujisaki NTT Communications • Takashi Arano Asia Global Crossing • Kazuhiko Nakahara NEC/BIGLOBE • Koichiro Fujimoto NEC Corporation • Hiroki Ishihara NEC Corporation • Ikuo Nakagawa Intec Web & Genome Informatics • Tomohiko Kusuda Intec Web & Genome Informatics • Kenichi Nagami Toshiba • Masahito Omote Sapporo Medical University • Masamichi Miyaji Sapporo Medical University • Satoshi Kobayasi Nextec • Shiro Niinobe NTT West • Hirotaka Asai NTT West • Yoshiyuki Ezura IRI • Akinori Maemura Equant APNIC SIG-IPv6

  25. Questions?

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