JGN II (Japan Gigabit Network II)
A research and development system for advanced broadband networks

Ichiro Yamauchi
NTT Communications Corp.
NTT Hibiya Bldg., 1-1-6 Uchisaiwai-cho
Chiyoda-ku, Tokyo, 100-8019 Japan
Yukiji Mikamo
NICT Okayama Research Center
Ouchida 675, Teleport Okayama
Okayama-shi, Okayama, 701-0165 Japan

Takashi Miyake
Kurashiki University of Science and the Arts
Nishinoura 2640, Tsurajima-cho
Kurashiki-shi, Okayama, 712-8505 Japan
Junichi Shimada
National Institute of Information andCommunications Technology
Nukui-Kitamachi 4-2-1, koganei-shi
Tokyo, 184-8795 Japan

Kazumasa Kobayashi
Kurashiki University of Science and the Arts
Nishinoura 2640, Tsurajima-cho
Kurashiki-shi, Okayama, 712-8505 Japan
Abstract
JGN2, Japan Gigabit Network 2, has been established atthe end of March 2004. JGN2 is a successor of JGN1, which
has been established by Telecommunication Advancement
Organization (TAO) in 1999. JGN1 was desgined for thenation-wide R&D network for high speed network infrastructure.JGN2 has the same objective as JGN, howeveruses different layer 2 technologies. JGN1 have developpeda nation-wide IPv6 testbed, which was the largest scaleof multi-vendor IPv6 network. The network transition fromJGN1 IPv6 to JGN IPv6 has been smoothly achieved with
only total of 8 hour transition period. JGN2 IPv6 network
has the following features.
(1) Layer 2 testbed for Layer 3 research activities(2) Consideration of IP Multicast Research(3) Global IPv6 connectivity(4) Policy control to achieve appropriate AUP(5) Advanced layer 2 technologies; optical, GMPLS andlong-distanced-Ethernet

1. Introduction
Traffic measurement of data transmission in the professional networks shows a rapid increase of bandwidth requirement and transparent communications. Especially inHiroshi Esaki
The University of Tokyo
Hongo 7-3-1 Bunkyo-kuTokyo, 113-8656 Japanthese days, the applications that exchange large data volume over the networks with peer-to-peer fashion has been
increasing. One of the spectrum is a realtime multimedia
communication, such as (ultra) high-resolution digital image and video, or the three dimensional images. The otherspectrum is a peer-to-peer applications, such as Napstar orSKYPE. In order to accommodate these new applications
effectively and smoothly, we have to establish an advanced
networking technology. As frequently pointed out, the IPv6technology can provide the NAT-free IP infrastructure, so
as to provide transparent networking environment, and canbe the infrastructure to deliver the new applications, suchas ubiquitous computing or ubiquitous networking. Therfore, we need an IPv6 based R&D network, which allow towork on the exploration of new applications on top of ultra broadband network environment.
The Japan Gigabit Network[2], hereafter called ”JGN1”,
which was established by Telecommunications Advancement Organization (TAO), has been operating as a researchand development network testbed from 1999 to March
2004. Many researchers have achieved effective R&D activities using JGN1 through industry-academia-government
collaboration. A lot of prominent achievements has beendelivered in the areas of super-high-speed networking technologies and advanced application technologies. These
achievements include the develoyment of broadband IP networks throughout Japan and the development of IP version

hyogo-1
hyogo-2

tokyo-1

wakayama

tsukuba
tokyo-2

tochigi

nara

osaka

shiga

gunma

osaka-univ

saitamakyoto-univ

chiba

kyoto

tokyo-univ kanagawa

yamanashiniigatanagoya-2

nagoya-1

shizuokanagano-1

gifu
nagano-2

mietohoku-univ

kagawakochi-1

tokushimaiwate
aomorisendaiokayama-1

kanazawa-1

akita

ehime

tottorishimanekochi-2

yamaguchi

fukushimafukuoaka

yamagata

hiroshima-univ

toyama fukui kanazawa-2

okayama-2

hokkaido-1
hokkaido-2
kyushu-univsagakumamotooitanagasakimiyazakiokinawakagoshimakita-kyushu

100Mbps
1Gbps
1Gbpsx2
10GbpsHitachi
GS4000AlliedTelesis
9812T

Figure 1. Layer2 network topology
6 technologies to the Internet.
In April 2004, in response to the announcement of ”eJapan Strategy2” by the Japanese government’s IT Strategy Headquarters in July 2003, the National Institute of Information and Communications Technology (NICT)[3] hasstarted the operation JGN2. JGN2, which is the successionof JGN1, is aming to accelerate and lead the R&D activities
on the advancement of information and communications
technology. JGN2 is a new advanced network testbed forresearch and development that builds upon and further development of the technologies developped by JGN1. Also,
NICT has started the operation of an international broadband testbed between Japan and U.S. from August 2004.
This international connection is designed to promote the international joint research activities between domestic andoverseas researchers for the next generation internet technologies. JGN2 will also contribute to human resource development. Regional activities and practical research activities over JGN1 infrastructure has stimulated through the useof JGN1 network.
This paper describes the outline of JGN2, focusing on
the introduction to layer2/3 networking which is called as”JGN2 IPv6”, using Ethernet technology.

・ Layer2/3 Testbed Network・ GMPLS1 Testbed Network・ Optical Testbed Network

2.1. Layer2/3 Testbed NetworkJGN2 has access points capable of providing layer2/3
services throughout Japan, in 47 prefectures and city governments (total of 63 places) like JGN1. The network’s entire core-node link is connected with 10GBase-X. The details such as bandwidth of every link and topology etc., isshown in Figure 1.
Layer2/3 Testbed Network service provides the following:• Ethernet connection (Layer2) service
1. Point-to-Point connection service
This service connects 2 points by L2 connection
based on VLAN.
2. Multi-point connection service
This service connects multiple points by L2 connection based on the same VLAN.
• IP connection (Layer3) service
This service connects JGN2 users among each other,

2. Overview of JGN2 network
JGN2 is composed of the following 3 functions of network.

1

Generalized Multi-Protocol Label Switching

GMPLS Network 1(AS 1)

Tokyo<relay station>

Tsukuba

DCF

DCF
DCF

50Km

150Km

DCE
DCF

1 DCF

DCE

DCF
1=Optical Spectrum Analyzer

E-NNIFigure 3. Optical Testbed Network ”A”

Osaka

Nara

Kyoto

OFA

AWG

OFA
OFAGMPLS Network 2(AS 2)
NTT OXCNTT GMPLS-Router

KDDI OXCKDDI GMPLS-Router

Figure 2. GMPLS Testbed Networkor to other research networks and other users, at the IP
level (a service with an IPv4/IPv6 dual stack).
• Useful interfaces for users
10/100/1000base-T (for all users)
1000base-X (for all users)
10Gbase-X (not for all users)

OSW

AWG

OFA

OFA

OFA

48Km

AWG

AWG

16Km

AWG
OSW

AWG

Figure 4. Optical Testbed Network ”B”
This testbed enables users to use ”wavelength” as wellas ”band” as they please. Also, multiple users can divide the testbed resource and use it simultaneously.
Optical Testbed Network service provides the following:Experiments on optical transmission between specificpoints.

2.2. GMPLS Testbed Network

3. Feature of Layer2/3 network

The GMPLS testbed of JGN2 is composed of OXCs2 andvarious router models that carries out two different GMPLS
Autonomous System (GMPLS-AS), and validates the interoperability by External-Network-Network-Interface (ENNI) between two different GMPLS-AS.
This GMPLS testbed establishes not only the onlyrouter-connected network but the OXC-router-connected
network with high quality interoperability of GMPLS-AS.
It is shown in Figure2.
GMPLS Testbed Network services provides the following: Connectivity at the optical wavelength level, at where
OXC is installed. Two types of interfaces are used: 1Gbps
and 10Gbps.

This chapter describes the characteristics and transitionof JGN2 network.

2.3. Optical Testbed Network
JGN2 has two different optical testbed capable of researching various optical properties shown in Figure 3 andFigure 4.
2Optical Cross Connect

3.1. Design policy of JGN2 Layer2 network
JGN2 L2 network is constructed based on the following
design policy.
• The point-to-point connection service that depends on
Ethernet-VLAN (Layer2 based path) can be provided.
• All Layer2-switches have IPv6 MLD-snooping (Multicast Listener Discovery snooping)[1] function, that
does not exert influence on the other (non listener)
ports.
At first, it was mainly designed to provide L2 based service, though this design policy differ substantially from numerous ISP’s and the research and development testbeds offoreign countries (most of them usually offer L3 based services). However, there was a definite reason for the design
policy to allow users researching on several issues on IPlayer to offer the path of subordinate position layer (L2).
The users say that they are able to use the network freely

without considering about AS and domain of the IP address
service organization (e.g. NICT).
Next, it is predicted that the demand of multicast contents delivery on the IPv6 network will increase from now
on, so the selected devices (Layer2 switches) need to equip
the function that can avoid IPv6 MLD-snooping which
avoids multicast packet flooding from non-multicast listeners. At present, the interoperability ”IPv6 MLD-snooping”
function among layer2 switches of various vendors are tackling to commercialization.

JGN1v6 Network(ATM)ATM SW

ATM SW

NODE1NODE2
IPv6 RoutertransitionLAN

Ethernet SW

IPv6 RouterLAN

Ethernet SW

JGN2v6 Network(Ether)

3.2. Transition from “JGN1v6” to “JGN2v6”
The transition of JGN1 IPv6 network which that sat
on the JGN1’s ATM network (hereafter called JGN1v6) toJGN2 IPv6 network which sits on the JGN2’s Ether network (hereafter called JGN2v6) was successful in a shortperiod of time.
It was carried out by emulating JGN1’s ATM virtual paths (PVC) with JGN2’s Ethernet paths (VLAN)
and therefore the downtime of the JGNv6 was minimized successfully. The method is as follows (Figure5).
• Make JGN2’s Ethernet VLAN-Identification with
JGN1’s ATM PVC-Identity Operate on both JGN1v6
network and JGN2v6 network throughout the transition period, until the normal operation of JGN2v6
network is confirmed.
The transition of JGN network was done under the following preconditions, scheduling, technical issue that werestrictly set. The challenges of this transition were:• The difference of technology specification of ATM(JGN1) and Ethernet (JGN2), and the physical topology of JGN1 and JGN2, had to be accurately defined,
and the optimum design and scheduling of the networktransition had to be followed.
• The transition and launch had to be finished within 14days; all 23 circuits related with JGN2v6 network, and63 circuits of JGN2, had to be connected smoothly, andall the circuit examinations had to be completed.
• The migration of network had to be done in the condition without using remote maintenance tools, because
all of the network elements (mainly, the circuits) thatcompose JGN2 network were not assembled at thesame time.
• Regardless of the construction progress of JGN2v6
network, all the equipment that compose JGN1v6 network had to be removed before a certain completionterm.
On the above condition, this transition was completed
perfectly in total of 8 hours (4 hours for two days) without any problem.

Figure 5. Transition of JGNv6
To face these challenge, intensive coordination of all theJGN2 and JGN2v6 operators was necessary, in order to succeed in this network transition.

4. Conclusions
As a result of many promotions of JGN2 including thesuccessful transition of JGN1v6, utilization rate of JGN2network in September 2004 was several times more thanthat of JGN1. As of September 2004, after 6 months fromthe launch of JGN2 on April 1, 2004, the concrete number of general and/or testbed research is 52, and the number of network event usage is 16. Still, many results associated to rapid application expansion of JGN2 network is expected more than ever.
Hereafter, the collaborative accomplishment of an integration of the latest research themes such as ”IPv6 over
GMPLS” is also likely to be expected.

5. Acknowledgements
We sincerely thank the people who have greatly contributed to this particular project in NICT. Also, we thankto The Ministry of Internal Affairs and Communications,who gave us the opportunity to be involved in the construction of the JGN2 network. The JGN2 network is operated
by a considerably large number of engineers including network engineers. We would also like to take this opportunity to share our appreciation to the network engineers whotakes part in the operation of the JGN2 network.

References[1] B. Haberman. Source Address Selection for the Multicast
Listener Discovery (MLD) Protocol. RFC 3590, 2003.
[2] N. I. of Information and C. Technology. Japan Gigabit Network.
http://www.jgn.nict.go.jp, 2004.
[3] N. I. of Information and C. Technology. NICT - National Institute of Information and Communications Technology.
http://www.nict.go.jp, 2004.