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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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IPv6 Routing Considerations
Masaru Mukai / POWERDCOM
Kuniaki Kondo / IIJ
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”.
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.
APNIC SIG-IPv6 42002/03/05
Agenda
Multi-homing EGP IGP
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.
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.
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.
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)
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.
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)
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
APNIC SIG-IPv6 122002/03/05
Multi prefix
P(A) P(B)
ISP A ISP B
P(A)P(B)
A B
host host
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.
APNIC SIG-IPv6 142002/03/05
Agenda
Multihoming EGP IGP
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.
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.
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.
APNIC SIG-IPv6 182002/03/05
Agenda
Multi-Homing EGP IGP
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
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.
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.
Acknowledgements
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
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
Questions?