Transcript ppt - Apnic
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. JANOG = Japan Network Operators’ Group http://www.janog.gr.jp/ IPv6-OPS has “Routing Sub-Group”. This 2002/03/05 group focuses “ISP Backbone Routing Issues”. APNIC SIG-IPv6 2 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. 2002/03/05 APNIC SIG-IPv6 3 Agenda Multi-homing EGP IGP 2002/03/05 APNIC SIG-IPv6 4 Multi-Homing Overview There are some techniques to do multihoming 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. 2002/03/05 APNIC SIG-IPv6 5 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. 2002/03/05 APNIC SIG-IPv6 6 Category of Multi-Homing BGP based (A organization has AS number and PA address) Announcing PI address Currently, Registries do not allocate IPv6 PI address. punching hole Anything will not change. 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. 2002/03/05 APNIC SIG-IPv6 7 RFC3178 Model ISP A PA(A) PA(B) PA(A) ISP B PA(B) RouterA RouterB PA(A) + PA(B) 2002/03/05 APNIC SIG-IPv6 8 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. 2002/03/05 APNIC SIG-IPv6 9 punching hole The Internet B A P(A) A P(A) ISP A ISP B B P(A) 2002/03/05 User X APNIC SIG-IPv6 10 Problems of punching hole Increasing number of routes Increasing route convergence time Needs more powerful routers It makes more cost to provide ISP services 2002/03/05 APNIC SIG-IPv6 11 Multi prefix ISP A ISP B A B P(A) P(B) P(A) P(B) host 2002/03/05 host APNIC SIG-IPv6 12 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. 2002/03/05 APNIC SIG-IPv6 13 Agenda Multihoming EGP IGP 2002/03/05 APNIC SIG-IPv6 14 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. 2002/03/05 APNIC SIG-IPv6 15 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. 2002/03/05 APNIC SIG-IPv6 16 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 2002/03/05 of full routes increase tremendously. APNIC SIG-IPv6 17 Agenda Multi-Homing EGP IGP 2002/03/05 APNIC SIG-IPv6 18 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. 2002/03/05 It depends on network design APNIC SIG-IPv6 19 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. 2002/03/05 APNIC SIG-IPv6 20 Conclusion Much Much bigger address spaces Potential number of external routes in future Multi-homing Aggregation No PI(Provider Independent) address for enterprises Punching hole allowed? Any criteria? /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. 2002/03/05 APNIC SIG-IPv6 21 Acknowledgements discussion member(1/2) Akihiro Inomata Masaru Mukai Kuniaki Kondo Tomohiko Kurahashi Rie Shimada Toshihiro Araki Yasushi Endo Tomohide Nagashima Tsuyoshi Tomochika Hiroyuki Tanahashi Yasuhiro Shirasaki Akira Nagakawa Ryuuichi Takashima Teruo Watanabe Toshio Tachibana 2002/03/05 Fujitsu PowerdCom IIJ IIJ Panasonic Japan Telecom Japan Telecom Japan Telecom NTT Communications NTT Communications NTT Communications PowerdCom PowerdCom PowerdCom Ani&Company APNIC SIG-IPv6 Chair Co-Chair 23 discussion member(2/2) Tomohiro Fujisaki Takashi Arano Kazuhiko Nakahara Koichiro Fujimoto Hiroki Ishihara Ikuo Nakagawa Tomohiko Kusuda Kenichi Nagami Masahito Omote Masamichi Miyaji Satoshi Kobayasi Shiro Niinobe Hirotaka Asai Yoshiyuki Ezura Akinori Maemura 2002/03/05 NTT Communications Asia Global Crossing NEC/BIGLOBE NEC Corporation NEC Corporation Intec Web & Genome Informatics Intec Web & Genome Informatics Toshiba Sapporo Medical University Sapporo Medical University Nextec NTT West NTT West IRI Equant APNIC SIG-IPv6 24 Questions?