ipv6 routing considerations

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IPv6 Routing Considerations Masaru Mukai / POWERDCO M Kuniaki Kondo / IIJ

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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. - PowerPoint PPT Presentation

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Page 1: IPv6 Routing Considerations

IPv6 Routing Considerations

Masaru Mukai / POWERDCOM

Kuniaki Kondo / IIJ

Page 2: IPv6 Routing Considerations

APNIC SIG-IPv6 22002/03/05

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”.

Page 3: IPv6 Routing Considerations

APNIC SIG-IPv6 32002/03/05

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.

Page 4: IPv6 Routing Considerations

APNIC SIG-IPv6 42002/03/05

Agenda

Multi-homing EGP IGP

Page 5: IPv6 Routing Considerations

APNIC SIG-IPv6 52002/03/05

Multi-Homing

OverviewThere 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.

Page 6: IPv6 Routing Considerations

APNIC SIG-IPv6 62002/03/05

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.

Page 7: IPv6 Routing Considerations

APNIC SIG-IPv6 72002/03/05

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.

Page 8: IPv6 Routing Considerations

APNIC SIG-IPv6 82002/03/05

RFC3178 Model

ISP A ISP B

PA(A) + PA(B)

RouterBRouterA

PA(A) PA(B)

PA(B)PA(A)

Page 9: IPv6 Routing Considerations

APNIC SIG-IPv6 92002/03/05

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.

Page 10: IPv6 Routing Considerations

APNIC SIG-IPv6 102002/03/05

punching hole

ISP A ISP B

User X

A

The Internet

P(A)

B

AB

P(A)P(A)

Page 11: IPv6 Routing Considerations

APNIC SIG-IPv6 112002/03/05

Problems of punching hole

Increasing number of routes Increasing route convergence timeNeeds more powerful routers It makes more cost to provide ISP services

Page 12: IPv6 Routing Considerations

APNIC SIG-IPv6 122002/03/05

Multi prefix

P(A) P(B)

ISP A ISP B

P(A)P(B)

A B

host host

Page 13: IPv6 Routing Considerations

APNIC SIG-IPv6 132002/03/05

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.

Page 14: IPv6 Routing Considerations

APNIC SIG-IPv6 142002/03/05

Agenda

Multihoming EGP IGP

Page 15: IPv6 Routing Considerations

APNIC SIG-IPv6 152002/03/05

EGP

OverviewPeople needs a solution for IPv6 traffic controlAnnounced prefix will decrease. It makes that

traffic will be concentrated to some of routers in ISP.

Page 16: IPv6 Routing Considerations

APNIC SIG-IPv6 162002/03/05

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.

Page 17: IPv6 Routing Considerations

APNIC SIG-IPv6 172002/03/05

Traffic Control Solutions for IPv6

Upstream ISPs control trafficprepend, community

New MethodTo use MPLSTo propose BGP-5

ISPs announce more specific routes.Number of full routes increase tremendously.

Page 18: IPv6 Routing Considerations

APNIC SIG-IPv6 182002/03/05

Agenda

Multi-Homing EGP IGP

Page 19: IPv6 Routing Considerations

APNIC SIG-IPv6 192002/03/05

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

Page 20: IPv6 Routing Considerations

APNIC SIG-IPv6 202002/03/05

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 accordi

ng to number of lines or forecast of number of customers.

Page 21: IPv6 Routing Considerations

APNIC SIG-IPv6 212002/03/05

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 consi

deration about aggregation in ISP internal networks. How can address policy supports this?

Traffic engineering Less external routes to be announced make TE harder.

Page 22: IPv6 Routing Considerations

Acknowledgements

Page 23: IPv6 Routing Considerations

APNIC SIG-IPv6 232002/03/05

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

Page 24: IPv6 Routing Considerations

APNIC SIG-IPv6 242002/03/05

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

Page 25: IPv6 Routing Considerations

Questions?