Presentation by Masataka Mawatari at APRICOT 2017 on Thursday, 2 March 2017.

1. Japan Internet Exchange Co., Ltd.
Masataka MAWATARI <mawatari[at]jpix.ad.jp>
The trend stats of routing table
at JPIX route servers
APRICOT 2017 @ HCMC, Vietnam
Lightning Talk

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Osaka
Nagoya
Meieki
Metropolitan TOKYO
Otemachi
Nihonbashi
Toyosu
Tennozu
Otemachi 2nd
JPIX switchs are deployed at 3 areas in Japan

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Osaka
Nagoya
Meieki
Otemachi
Nihonbashi
Toyosu
Tennozu
Otemachi 2nd
JPIX operates 2 IX segments in Japan
JPIX TOKYO Segment
JPIX OSAKA Segment
Nagoya Meieki site can offer Tokyo
vlan and Osaka vlan as well.
*1
*1

4. The route server operated at JPIX
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IX switch
Route
Server
Routes announced from AS64500
Routes announced from AS64501
Routes announced from AS64502
RS client 1
(AS64500)
RS client 2
(AS64501)
RS client 3
(AS64502)
JPIX route server transparently announces all routes received from
all RS clients, JPIX members peering with the route server, for
every RS clients. That’s a service policy for JPIX route server.
announcing all routes received
from all route clients
announcing all routes received
from all route clients
announcing all routes
received from
all route clients

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Increasing the number of routes

6. The number of IPv4 routes (Tokyo RS)
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members
routes
a new member
started peering
and announced
many routes
an existing
member started
announcing
many routes
[members][routes]
All peers moved
to the new RS
from old one
a new member
started peering
and announced
many routes
2013/01/16
JPIX renewed
route server
2013/07/31
JPIX removed
old route server

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members
routes
[members][routes]
The number of IPv6 routes (Tokyo RS)
an existing
member started
announcing
many routes
2013/01/16
JPIX renewed
route server
2013/07/31
JPIX removed
old route server

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The number of IPv4 routes (Osaka RS)
[members][routes]
members
routes
an existing
member started
announcing
many routes
2015/01
JPIX started
Osaka RS service

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The number of IPv6 routes (Osaka RS)
[members][routes]
an existing
member started
announcing
many routes
members
routes
2015/01
JPIX started
Osaka RS service

10. Findings from research
about the number of routes
• About IPv4 routes at Tokyo RS, there were some
period of decreasing routes, but it was temporary.
Growing the routing table approx. 4,000 routes per
year.
• About IPv6 routes at Tokyo RS, there is a strong
possibility to happen big changes depending on the
changing BGP policy by members using RS.
• About both IPv4 and IPv6 routes at Osaka, the
number of members is fewer than Tokyo now. But
it will be similar trend of Tokyo with increasing the
number of members.
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11. Reference: BGP max-prefix-limit
• Cisco IOS/IOS-XE
– (config-router)
neighbor <IP address> maximum-prefix <the number of routes> <threshold>
• Cisco IOS-XR
– (config-bgp-nbr-af)
neighbor <IP address> maximum-prefix <the number of routes> <threshold>
• Juniper JUNOS
– [edit protocols bgp group <group name>]
set neighbor <IP address> family inet unicast prefix-limit maximum <the number of
routes>
set neighbor <IP address> family inet unicast prefix-limit teardown <threshold>
• Brocade Ironware
– (config-bgp)
neighbor <IP address> maximum-prefix <the number of routes> <threshold> [teardown]
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* please see the configuration guide by network gear venders.

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The distribution of prefix size

13. The distribution of IPv4 prefix size (Tokyo RS)
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[Prefix size]
[Routes]
some routes
greater than /24 exist
（as of Sep. 2016）

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（as of Sep. 2016）
The distribution of IPv6 prefix size (Tokyo RS)
[Routes]
[Prefix size]
some routes
greater than /48
exists
the number of /32 (minimum allocation size) routes
is fewer than /48 (minimum assignment size)

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The distribution of IPv4 prefix size (Osaka RS)
[Routes]
[Prefix size]
（as of Sep. 2016）

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The distribution of IPv6 prefix size (Osaka RS)
[Routes]
[Prefix size]
（as of Sep. 2016）

17. • About Tokyo, some prefixes greater than minimum
assignment size (IPv4: /24, IPv6: /48) exist.
• There is little relationship between the number of
members peering with RS and the distribution of the
prefix size. /24 (IPv4) and /48 (IPv6) is the highest in
both Tokyo and Osaka.
• The trend of prefix size distribution will be changed by
IPv4 address transfer and IPv6 usage.
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Findings from research
about the distribution of the prefix size

18. Conclusion
• The routing table trend at JPIX route server
has the almost same aspect as the global
internet routing table.
• Please inform your peers, and let IXes (as
operators of RS you do peering) know in
advance, when the number of advertised
routes will be changed much.
• Please keep your prefixes data in PeeringDB
up-to-date. 
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