JGN IPv6 Network
Kazumasa Kobayashi
Kurashiki University of Science and the Arts
Nishinoura 2640, Tsurajima-cho
Kurashiki-shi, Okayama, 712–8505 Japan
Kazuhiko Nakamura
TAO Tokyo Research & Operation Center
Otemachi 1-8-1 KDDI Otemachi Bldg.
Chiyoda-ku Tokyo, 100–8186 Japan

Satoshi Katsuno
TAO Tokyo Research & Operation Center
Otemachi 1-8-1 KDDI Otemachi Bldg.
Chiyoda-ku, Tokyo, 100–8186 Japan
Yukiji Mikamo
TAO Okayama Interoperability & Evaluation Lab
Ouchida 675, Teleport Okayama
Okayama-shi, Okayama, 701–0165 Japan

Hisayoshi Hayashi
Hitachi, Ltd., Enterprise Server DivisionHoriyamashita 1, Hadano-shi
Kanagawa, 259–1392 Japan
Yoshinori KitatsujiKDDI R&D Laboratories, Inc.
Ohara 2-1-15, Kamifukuoka-shi
Saitama, 356–8502 Japan

Abstract
To cope with the various problems arising from Internet
protocol such as scarcity of IP addresses in the Internet andincrease in the number of paths, research and development
has been conducted on IP version 6 (IPv6) as a next generation Internet technology. Telecommunications Advancement
Organization (TAO) has upgraded Japan’s nation-wide Gigabit Network (JGN: Japan Gigabit Network) to be compatible with IP version 6 (IPv6) as a wide-area network that
can accommodate next generation Internet technologies ofa world class. That is, access points capable of providing
IPv6 services are deployed in 47 locations across Japan including 28 router installation sites. With this deployment,
an IPv6 network has been developed enabling the execution of various verification and operation experiments, suchas early transition of the network from IPv4 to IPv6 and thedebagging of developed products in order to be compatible
with IPv6.
In addition, IPv6 interoperability evaluation laboratories have been set up in Okayama and at Makuhari (branchoffice) to execute the verification of interoperability between
systems for current IPv6-compatible router equipments, andan IPv6 research and operation center has been set up inTokyo (Otemachi) for developing operation and manage-

Akihiko Machizawa
Communications Research Laboratory
Nukui-Kitamachi 4-2-1, Koganei-shi
Tokyo, 184–8795 Japan
Hiroshi Esaki
The University of Tokyo
Hongo 7-3-1 Bunkyo-kuTokyo, 113-8656 Japan

ment technologies of the IPv6-compatible network equipment.
This paper describes the outline of the JGN IPv6 network from several aspects: a network topology, IPv6 routerequipment manufactured by multi vendors, setting up of thenetwork such as an address space and routing, and open
access points, and introduces research and development activities at the IPv6 interoperability and evaluation laboratories and the IPv6 system research and operation center thathave been newly set up in constructing this network.

1. Introduction
For the next generation very high-speed network,
the Telecommunications Advancement Organization (hereinafter referred to as TAO) has established a gigabit network
for research and development. JGN, Japan Gigabit Network, aims to contribute the research and development ofnetwork operation and management technologies, and advanced application technologies. JGN is an open researchand development network for various research organizations, e.g., governmental agencies, or enterprises, as wellas universities and research agencies [1].

To enable the JGN to accommodate various researchand development activities related to IPv6 (Internet Protocol Version 6) technology, which is a core network protocol
for the next generation Internet. Network equipments compatible with IPv6 has been installed and a test operation asa JGN IPv6 network has started on October 1, 2001.
It is said that IPv6 can provide ;application technologies. In order to join the JGN IPv6 network, the researcher proposes the research application, thatis reviewed and evaluated by TAO[4],2. Overview of JGN IPv6 network
2.1. Network Topology

Various functions, such as security, reliability, which
are required for emerging communication infrastructure

JGN networks uses ATM technology for datalink, andtherefore, the JGN IPv6 network is sitting on the JGN’s
ATM network. JGN IPv6 network has been constructedwith 57 operational sites, which are 28 router sites and 29bridge sites.
Among the router installation sites, we have four of coresites, i.e., the University of Tokyo, Teleport Okayama (inwhich the Okayama IPv6 Interoperability and Evaluation
Laboratory is also set up), Dojima and the Kyushu University. Four core sites are interconnected to configure thebackbone of the JGN IPv6 network. Other router sites areconnected to one of the four core sites, and the bridge sites
are connected to one of the router sites, respectively (Figure2.1).

Address space, which is necessary and sufficient topreserve the end-to-end model.
IPv6 has also been designed to cope with various problems arising from Internet protocol version 4, such as theproblem of scarcity of IP addresses and increase in the number of routes in the Internet backbone.
(aboutFor example, IPv4 can accommodate only ) hosts to be connected to the Inter4,300 million: net, even if the whole of address space is assigned to host
addresses, On the other hand, IPv6 accomodates(about
340 undecillion:   ) hosts to be connected. Regarding the routing architecture, IPv6 is designed with theefficient routing aggregation.
Most of IPv6 standardization has been achieved part several years ago, to introduce the IP version 6 to the real production network (RFC2460)[2], ICMPv6 (RFC2463)[3]. In
these days, various kinds of functions for the configurationand operation of the IPv6 network has been standardized
and those functions have started to be implemented by various commercial router vendors.
The JGN IPv6 network has been established as a native
IPv6 network equipped only with IPv6-compatible equipments. And, JGN allows IPv4 traffic via IPv4/IPv6 dualstack operation, i.e., capable of accommodating both IPv4and IPv6. In order to contribute to the router vendors, JGN
IPv6 network is operated with a multi-vendor environmentthat includes two US vendors and three Japanese router vendors.
JGN IPv6 network contains the Okayama IPv6 Interoperability and Evaluation Laboratory and the Makuhari
branch office. In these laboratory, we evaluate each network equipments and application software. The evaluation
is functional compliancy of each equipment and interoperability among the network equipments. Also, the JGN
IPv6 network has the IPv6 Research and Operation Centerin Tokyo (Otemachi), in order to establish the operation andmanagement technologies of the IPv6-compatible networkequipments.
As described above, the JGN IPv6 network has been developed for research and development of the network operation and management technologies, as well as the advanced

2.2. Multi-vendor Environment
In order to establish the operational technologies and validate the interoperability among the routers manufactured
by various vendors, the JGN IPv6 network contains different types of routers from five router vendors (See Table 1). Every router is commercial router, that is compatible with IPv6 functionality, though the software runningin each router is sometime beta-code or alpha-code directly
provided by each vendor.
Each router vendor has their own interpretation for each
protocol specification to have different implementation.
Each router vendor has their implementation priority regarding the protocols and functions, that should be implemented as the IPv6 system. Therefore, it was sometime hardthat all routers in the JGN IPv6 network has the same functionality and has the interoperability. For example, regarding the IGP (Interier Gateway Protocol), US vendors have
implemented IS-IS first, however, Japanese vendors have
implemented OSPF first. With these diversity of functionaland protocol implementation for each router vendors, we
had to have serious consideration and cordination so as tooperate every function and every protocol.

2.3. Routing Configuration
The JGN IPv6 network has partially inherited topological characteristics of the underlying ATM network. However, using the ATM virtual path (PVC), the logical netework topology for layer 3 (IPv6) has been configured and2

Univ. of Tokushima

Kochi Traffic
Research Center

iKurashiki Univ. ofScience & Arts)

Iwamizawa city
Self-governing
Network CenterMedia Mix
SapporoNagano City
Fullnet Center

Ehime Univ.

Hiroshima Univ.

Tohoku Univ.

Okayama IEL

Iwate Pref. Univ.
(Tohoku Univ.
RIEC)

Tottori Univ.
Ishikawa Hi-tech
Exchange Center

Kitakyushu
Gigabit Lab
New Media
Plaza Yamaguchi

NTT Tenjin Bldg.

Hachinohe Inst.
of Technology

Niigata Univ.

Matsumoto Information
Creating Center
Teleport
Okayama

Hiroshima City Univ.

Toyama Pref.
Integrated
Information Center

Univ. of Aizu
Sendai City
Informaiton & Industry
Plaza Net U

Saga Shinbun
TsukubaGigabit Lab.

Univ. of Electro-Communications(Univ. of Tokyo)

Kyushu Univ.

Inst. of Advanced
Biosciences, Tsuruoka

Nagasaki Univ.

(Univ. of Tokyo)
Univ. of Tokyo, IML

Kumamoto
Pref. Office

La Merse

Kagoshima Univ.

Oita 2nd Sofia
Plaza Bldg.
Miyazaki Univ.

(NTT Dojima Bldg.)

Tokyo ROC

Nagoya Univ.

(Keio Univ. Yagami)

Hyogo Ion Beam
Medical Center

Mie Pref. Collegeof Nursing
Shiga Univ. of Medical
Science Hospital

Wakayama Univ.
Asia-Pacific HubCenter of TAO(Keio Univ. SFC)

Utsunomiya Univ.

Makuhari Gigabit Lab

Connection
to 6bone
Yokosuka Research Park
Access Points

Osaka Univ.

Nara Inst. ofSci. & Tech.

Nago City
Multimedia Bldg.
Osaka Univ.

Softopia
Japan Center
Kyoto Univ.
Kei-han-na R&D Support
Center for Telecommunications

Hitachi
CiscoCisco
GR2000 GSR12406 7206VXRJuniper
M20

NECIX5010

Fujitsu
NECGS-R940 MegaAccessResearch Centers, etc.

Hitachi
Juniper
CiscoCisco
GR2000 GSR12406 7206VXR
M20

JGN(OC-12)
JGN(OC-3)
OthersFigure 1. JGN IPv6 network topology(Otemachi, Tokyo), and is also connected to 6Bone, which
is a global IPv6 experimental network. Regarding connection with other IPv6 networks, connection with local IXs,
such as NSPIXP-3 (Dojima, Osaka) and OKIX (Okayama),
is also being considered. The current JGN IPv6 network (asof October 18, 2002) has the following 11 peerings ;Table 1. Routers in JGN IPv6 network
Vendor nameProduct nameNum. of routers
Cisco Systems
GSR12406
37200VXR
6Juniper Networks M20
8Hitachi Ltd.
GR2000-6H
13Fujitsu Ltd.
GeoStream R-940
3NEC Corporation IX5010
3

WIDE Project (AS 2500)
KDDI (AS 2516)
Netsurf (AS 4675)

sometime re-configured. The current layer 3 network topology has been designed to establish the JGN IPv6 network
easily for starting the stable initial operation. So that, thecurrent layer 3 network topology is basically hub-and-spokewith four hubs (i.e., four core site with hierarchical topology). Router sites and bridge sites, excepting the core sites,
are single-homing to each of their upstream site. According to the testing and evaluating items, the layer 3 network
topology will be modified, when we need.
Regarding the external connectivity, JGN IPv6 network
uses BGP4+ for peering with other IPv6 neteworks. TheJGN IPv6 network is connected to the WIDE NSPIXP-6[5]FINE (AS 4678)
MIND (AS 4680)
PoweredCom (AS 4716)
APAN Tokyo-XP (AS 7660)
KDDI Laboratories (AS 7667)
IPv6 Promotion Council Network (AS 17935)
APII (AS 18083)
3

that TAO has developed so far. By engaging in the daily operation of the network, the user is afforded the opportunity
to learn network operation technologies of IPv6 different
from those of IPv4.
In the Internet, an operation form not assumed by a developer is often adopted. It is expected that with direct
feedback from plural network administrators in the JGN
IPv6 network, potential problems can be found at earlystages. Tools and instrumentation systems for evaluating
the compatibility and performance of IPv6 are also lacking and continue to do so. The WIDE Project has addressed the research and development of IPv6 from theearly days. There have been many projects conducted: theworld-famous KAME project[7] in which a program is being developed for providing an IPv6 stack for PC-UNIXs
such as FreeBSD and NetBSD, the USAGI project[8] targeting Linux, the TAHI project[9] aiming at the exact implementation verification of IPv6, etc. In the JGN IPv6, itis necessary for as much cooperative work to be conductedwith these projects as possible and for the technologies tobe shared so that IPv6 is popularized early. For that purpose, it is very important to store and share not only direct
research achievements, but also information with respect tothe processes in which these are obtained.

NTT DoCoMo (AS 18262)
As for the IGP (Interier Gateway Protocol), we have to
use RIPng rather than OSPF or IS-IS. This is simply because not all routers installed in the JGN IPv6 network support OSPF nor IS-IS.
Finally, at this moment of time, JGN IPv6 netework has
not applied the multicast routing protocol. We are going tointroduce the PIM-SM with IPv6, whenever all routers installed in the JGN IPv6 network support it. Some routers
have already implemented the PIM-SM to make sure the interoperability among them, however some routers have not
implemented yet.
Whenever all routers are ready to enable OSPF (i.e.,OSPFv3) or PIM-SM with IPv6, we will start to run theserouting protocol on the JGN IPv6 network.
An IPv6 address block employed in the JGN IPv6 network uses the NLA addresses (3ffe:516::/32) in a pTLA address block allocated by the WIDE Project[6]. A method for
assigning addresses to each of the router site and the bridge
site is recognized as one of the experiments associated with
IPv6 operation. Although we use the WIDE NLA address
space, JGN IPv6 network obtains own AS (AutonomousSystem) number (i.e., AS 17394), so that we can run experiments on exchange of the BGP routing information withother IPv6 networks.

3. Verification and Evaluation of Interoperability

2.4. Installation of Network Equipments
Among the 57 operation sites, 47 operation sites excluding some sites for research facilities are publicly opened as
the access points (POP) Each access point provides IPv6
connectivity via Ethernet (10/100 Mbps) to the JGN IPv6
network user.
At each access point of the router sites, router, that has
been compatible to IPv6, and an Ethernet switch accommodating the users are installed. Any user, who want to use theaccess point at the router site requests to interconnect to theJGN IPv6 netework via Ethernet switch (10-/100BASE-T).
At each router site, an address space of /48 is allocated fora segment for user accommodation.
The bridge site provides an environment in which IPv6
can be used by extending the IPv6 segment (datalink). Inorder to bridge between the router site and bridge site, weuse the ATM-Ethernet bridge.

The current IPv6-compatible router equipments do nothave full interoperability performance among those equipments manufactured by various vendors. Frankly saying,
the capability of interoperability among IPv6 equipments
would be similar to the status of IPv4 in ten years ago.
The JGN IPv6 project executes the verification and evaluation of interoperability among the IPv6-compatible routerequipments. For this research purpose, we have established
the Okayama IPv6 Interoperability and Evaluation Laboratory.
All pieces of the router equipments, that have been introduced in the JGN IPv6 network, are installed in the laboratory so as to be executed verification and evaluation. Afterthe varification and evaluatoin at the laboratory, only theequipments working correctly and having the interoperability with other equipments are introduced into the JGN IPv6network.
The following items would be verification and evaluation
items:

2.5. Network operation policy
In the JGN IPv6 network, the actual network operation
and a monitoring work of the network itself deserve experimental approaches. Therefore, in the JGN IPv6 network,router installation sites have been newly set up at several locations that differ from the JGN IPv4 network access points

Verification of accuracy and compliancy of IPv6 functions
Performance evaluation
45. Conclusions

Verification of interoperability between equipments
supplied by various vendors

In order that as large as possible number of researchgroups and organizations can participate in research and development related to IPv6 technology, the 47 access points
in the JGN IPv6 network have been established in order toenable JGN to accommodate IPv6 traffic. The JGN IPv6
network is expected to establish how to introduce the IPv6technology to the commercial network or to the multi vendor IPv6 networking environment.
Considering the transition of the Internet from IPv4 toIPv6 (or we should say the introduction of IPv6 to the pure
IPv4 network environment), it seems to be mandatory for
the IPv6 network to be enable what has been enabled in
the existing IPv4-based Internet. In addition, the following points are essential technical points, that we have to resolved ;Verification of availability and compatibility amongequipments
Verification of stability, failure tolerance, and etc.
Verification of functions when being in a redundantnetwork topology.
The IPv6-compatible router from each manufacturer experiences fairly frequent version up. This is because eachmanufacturer wants to implement a new function of IPv6 asmuch as and as fast as possible. They are fixing the technical problems for the software implementation at the router
software with a short turn-around periods.

Methodology for assigning IPv4 and IPv6 addresses

4. Management Technology of IPv6 network

Methodology for upgrading and/or deploying hosts
and routers

Since SNMPv3[10], which is a network management
protocol compatible with IPv6, is in the process of being
standardized at the IETF, it would be hard that the router
products provided by the manufacturers are equipped withan IPv6-based network management capability. Similarly,
almost all products of network management applications do
not have an acceptable compatibility with IPv6. At least,
the JGN IPv6 network should have the following functions;

Methodology for deploying IPv6-compatible DNSs
A transition senario in the individual sites toward theIPv6-compatible sites
A transition senario in the whole Internet toward theIPv6-based Internet
In the JGN IPv6 network, solutions for these issues has
been investigated and examined through the operation of
the live network. An introduction and evaluation of IPv6technologies into the live experimental network (JGN IPv6network) is essential to realize the following issues, e.g., operation control, security, load distribution, stream communication. The JGN IPv6 network is a wide-area next generation experimental network that could resolve such marketneeds.
From now on, interconnection of this network with otherIPv6 networks including oversea networks (e.g., Abeline inthe USA) will be progressed. At the same time, the technical verification and evaluation of network equipments will
be carried out.
Finally, the JGN IPv6 network is expected to serve as afield of acquisition and establishment of the IPv6 technology. The operators at the JGN IPv6 access points across thecountry (Japan) are convinced that useful experiences canbe shared among the JGN IPv6 network users through theactual and live network operation.

Cability to collect traffic information of an interface
with an IPv6 address
Cability to perform correct address notation corresponding to 128 bits,
The IPv6 Research and Operation Center in Otemachi(Tokyo) is in charge of the development of software required for operation and management for the actual operation of the JGN IPv6 network. The Reseach and Operation
Center performs the following tasks as operation management works for the JGN IPv6 network.
Management of IPv6 addresses and assignment
Management of network topology and monitoring ofrouting information
Management of IPv6 servers, e.g., name servers andWEB servers.

Acknowledgement

Interconnection with other IPv6 networks
The center is also developing the network management
tools and a traffic collecting and monitoring system.

We sincerely thank the persons who related with this particular project in TAO. Also, we thanks to the Ministry of5

Public Management, Home Affairs, Posts and Telecommunications, who gave us the opportunity to be involved inthe construction of the JGN IPv6 network. The JGN IPv6network is operated by a considerably large number of engineers including the network engineers. We would also liketo take this opportunity to thank the network engineers who
took part in the operation of the JGN IPv6 network for theircooperation.

References[1] TAO
HomePage,
http://www.jgn.tao.go.jp/.

“JapanGigabitNetwork,”[2] S. Deering and R. Hinden, “Internet Protocol Version 6(IPv6)
Specification,” IETF RFC2460, Dec. 1998.
[3] A. Conta and S. Deering, “Internet Control Message Protocol(ICMPv6),” IETF RFC2463, Dec. 1998.
[4] TAO Home Page, “About the start of test operationof IPv6 service in the Giga-bit Network for Research,”
http://www.jgn.tao.go.jp/org tec/ipv6 start.html.
[5] NSPIXP-6, IPv6-based Internet Exchange in Tokyo,
http://www.wide.ad.jp/nspixp6/.
[6] WIDE Project Home Page, http://www.wide.ad.jp/.
[7] KAME Project Home Page, http://www.kame.net/.
[8] USAGI Project Home Page, http://www.linux-ipv6.org/.
[9] TAHI Project Home Page, http://www.tahi.org/.
[10] J. Case, R. Mundy, D. Partain and B. Stewart, “Introductionto Version 3 of the Internet-standard Network Management
Framework,” IETF RFC2570, Apr. 1999.

6