第 17 部

Asian Internet Interconnection
Initiatives

485

第 1章Introduction
The Internet environment is now expanding rapidly in many countries and regions in
Asia. With this growth, many people starts using the Internet not only for research, training, and education, but also for several areas which are not limited to computer communication technologies, such as product promotion, advertisement or "Electronic Commerce"
type of use. For example, since 1995 the ASEAN countries has started using the Internet
for monitoring acid rain and air pollution in countries and regions in the south east Asia.
For the future of the Internet, the Internet community should encourage cooperative works
using the Internet in the broad area of culture, languages, infrastructures, technologies, art
works and other human activities.
In order to accelerate expansion of these kinds of cooperative works, it is important toshare expertise between engineers in the area of the Internet technologies and people who
are working for these activities. However, there are still some issues on infrastructures andtechnologies for information sharing in this region.
The major issue on the infrastructures is that the Asian countries do not share schemeand expertise on the Internet development, especially on the intra-Asia internetworking.
Many countries and regions in Asia have global Internet connectivity now. Almost all ofthem have links connected to gateways in the United States. In early phase of the Internet
development in Asia, this network topology was adequate and worked well, since almost
all of the trac was to/from sites in either the United States or European countries.
However, as growing demands of cooperative works among Asian countries, it becomes
popular to use the Internet as their ordinary communication channel. With this situation,
many people now complains about its large RTT and lack of bandwidth of the intra-Asia
Internet connectivity, because few Internet links were installed between the Asian countries.
The major portion of the intra-Asia trac is traveled via gateways in the United States;
in other words, the United States acts as a hub for intra-Asia Internet trac. It is obviousthat this situation should be improved. For promoting the intra-Asia Internet development,
we should make its good scenario, especially about its network design on its bandwidth,
topology and datalink technologies. Furthermore, the scenario should include the scheme to
487

488

1995 年度 WIDE 報告書

develop the Internet in the developing countries in Asia. Even in 1995, there are still somecountries which do not have any connectivity to the global Internet. For these countries,
the scenario should be a good guide to establish the rst link to the Internet and to promote
their local Internet development.
On technologies for information sharing in this region, we can use various kinds of applications including WWW, USENET news, and teleconferencing tools. As increasing usersof these applications, their consumption of bandwidth today has become major portion oftrac on the Internet. However, bandwidth upgrade of the international circuits is generally very hard because of its cost. Therefore, new technical requirements are arising forusing the Internet eciently in the sense of bandwidth consumption. There are several possible solutions such as national cache servers, datalinks with data compression functions,or alternative link installations. However, researches and experiments on these solutions
are required to evaluate if they are e ective for the Asian Internet environment.
For these issues, there are several possible solutions, but it is not clear which approach isthe best for its ecient development. The most practical way is to install testbed network,and to undertake collaborative researches and experiments on the network design and newtechnologies. In October 1995, the WIDE (Widely Integrated Distribute Environment)
project which is a research consortium in the Internet area of studies and the JSAT (Japan
Satellite Systems Inc.) which is a satellite communication company has started a testbed
construction and a series of research activities on the testbed. This activities is called "AI3
Project." Research topics of the AI3 project includes network design for the future AsiaPaci c Information Infrastructure (APII), new technologies which enables IP multicastingover satellite communication channels and advanced routing method to use the channels
eciently, and promotions of the Internet technologies for countries in Asia.

第 2章
AI3 Project Overview
The WIDE Project started the AI3 project in October 1995, in order to contribute, promote and encourage any related e orts toward achievement of the international information
infrastructure in the Asia-Paci c region. In this section, the overview of the AI3 project is
described.

2.1 Goals of the AI3
The AI3 project is primarily focused on technologies to provide an open Internet testbed
for research and academic community in Asia. With the testbed, we are aiming to promotesharing expertise and knowledge among researchers and engineers in the area of the Internet
technologies, to accelerate local Internet development, and to develop Internet technologies
for utilizing several types of datalinks as the Internet connection. Goals of the AI3 project
are as follows:
1. The AI3 project develops an information sharing infrastructure for accelerating morecooperative works among people in and around the Internet in the Asian countries.
For this goal, the AI3 project installs its testbed network using the VSAT satellite
communication channel. The details of the testbed is discussed in the later section.
2. The AI3 project develop an ecient Internet topology for the Asian countries. Furthermore, the AI3 project de nes recommendations and requirements for both international Internet connections among Asian countries and the future APII from bothtechnical and social viewpoints.
3. The AI3 project makes contribution for local development of the Internet in thisregion. There are still several countries where the Internet is not available. As apart of the testbed network, the AI3 project provides international circuits for thesecountries as their rst Internet connectivity.
489

490

1995 年度 WIDE 報告書

4. Using both existing Internet and the testbed network, the AI3 project makes e orts
to develop more ecient transmission technologies for multimedia applications andnew protocols, such as IP multicasting and IPv6. Moreover, we will try to develop
new operation scheme to achieve ecient use of international Internet connections,such as multiple backup link operation or application based routing.

2.2 The Project Organization
The WIDE Project made a kick-o of the AI3 project, however, it is obvious that thegoals of the project cannot be achieved only by the WIDE project. Therefore, the AI3 isorganized as a joint research program with other research entities called the AI3 partners.
The WIDE project and the AI3 partners make e orts and work cooperatively to 1) shareoperation of the AI3 testbed network, 2) develop new technologies for an information sharing infrastructure among Asian countries, and 3) make e orts to de ne recommendations
and requirements of the future APII.
From the view of the testbed installation, each AI3 partners is in charge of installationand operation of a gateway connected to the AI3 testbed. It includes procurement ofequipment for the gateway, installation fee, and e orts to obtain licenses from appropriate
local authorities to operate both the gateway ant the VSAT earth station. The Wide
Project and the JSAT are in charge of both the construction of the hub station in Japanand providing the VSAT bandwidth for this AI3 project.
Currently, the WIDE Project invited Institute of Technology Bandung (ITB) in Bandung, Indonesia, Asian Institute of Technology (AIT) in Bangkok, Thailand, and Hong
Kong University of Science and Technology (HKUST) in Hong Kong as the AI3 partners.
We are planning to add 4 more partners in Korea, Vietnam, Singapore, and Malaysia.

第 3章
The AI3 Testbed Network
Since October 1995, the AI3 project has been constructing its testbed network. On thistestbed, we will have a series of experiments In this section, technical aspects of our testbed
networks are discussed.

3.1 Topology of the AI3 Testbed Network
In the AI3 testbed network, we initially use the VSAT satellite links provided by JCSAT3 communication satellite. The JCSAT-3 launched in August 1995 provides the Asian Zone
Beam (Ku band) which covers several east and south east Asian countries and regions. The
coverage of the beam is shown in the Figure 3.1. This gure also depicts the requirementof the size of the antenna at the earth station which can provide 2Mbps link.
For the AI3 testbed network, we can install up to 8 earth stations. Its initial network
topology is shown in Figure 3.2. The AI3 testbed network is a star-shaped network; we will
install our hub site, which is connected to the Internet backbone, at WNOC-Nara locatedin Japan. From the hub site, 2Mbps satellite links are spanning to earth stations at the AI3
partners' site in several Asian countries. Currently, earth stations at the current partners'
location in Indonesia, Thailand, and Hong Kong are being installed. Other 4 earth stations
in Korea, Vietnam, Singapore, and Malaysia are still in planning phase. We are expectingthat all of the installation will be nished by the end of 1996.
Since the communication media of the AI3 testbed is VSAT satellite link, changing the
network topology is much easier than the case we use terrestrial links. For seeking an
optimal network topology of the testbed, the AI3 project makes statistical analysis of thelink utilization. Based on the statistical analysis, we will redesign its network topology
several times for more ecient use of the network.
491

492

1995 年度 WIDE 報告書

図 3.1: The minimum requirement on the size (diameter) of the VSAT antenna to get

2Mbps bandwidth using the JCSAT-3 Asian Zone Beam (Ku band)第 17 部

Asian Internet Interconnection Initiatives

493

under construction
planned

図 3.2: The initial topology of the AI3 testbed network. By the middle of 1996, AIT(Thailand), ITB (Indonesia), and HKUST (Hong Kong) are expected to join the AI3 testbed
network. More 4 stations in Korea, Vietnam, Singapore, and Malaysia are planned.

4941995 年度 WIDE 報告書

3.2 WISH Technology
Generally, the VSAT communication channel is modeled as a point-to-point link. But
the satellite communication is based on broadcast transmission mechanism. Considering
the large RTT of the satellite link, we want to handle VSAT link as a broadcast media,
especially for applications with IP multicasting (or MBone).
Since 1994, the WIDE project has been developing several datalink drivers, called "WISH
drivers," working with VSAT satellite channel in order to use the channel as an Internet
datalink. With these drivers, we can use the VSAT satellite channel as both a point-topoint link and a broadcast media simultaneously. Each earth station can handle the VSAT
satellite channel just as an Ethernet (but its bandwidth is limited to 2Mbps).
Currently, the WIDE Project operates a domestic satellite communication testbed network called "WISHbone" with these drivers. The WISHbone provides both 2Mbps pointto-point connections and a multicast channel from 1 to others among 7 earth stations
geographically distributed in Japan. Through the WISH experiments, we con rmed that
our WISH technology can improve the performance of both the Mbone type of multicast
communications and applications based on bulk data transfers. In order to isolate Mbone
trac from the terrestrial nationwide backbone, the WIDE project uses the WISHbone asa major Mbone transport since 1995.
In the AI3 testbed network, we introduce the WISH drivers as a major datalink management software. Just like the WISHbone, we add the IP multicasting capability to theAI3 testbed network. Thus, several real-time multimedia applications based on the IP
multicasting like VAT and NV can be used on the AI3 testbed network.

3.3 The Con guration of the AI3 Earth Station
The AI3 earth station is a gateway system for providing connectivity to the AI3 testbed
network. Figure 3.3 shows the basic con guration of the AI3 earth station. Each earth
station is con gured with a router, a VSAT IDU, and a VSAT ODU. The VSAT IDU works
as a modem to the VSAT channel, thus the interface of the IDU is V.35 or RS449. If we
use the VSAT channel as a point- to-point Internet connection, we can use several types ofgateway systems which can handle high speed serial link such as CISCO routers or UNIX
workstation gateways with serial interfaces.
In order to use the AI3 testbed network with the IP multicasting capability, the routershould be platforms which the WISH drivers can be installed. Currently, the WISH drivers
can work on either the Sun workstations with SunOS 4.1.4 or IBM-PC compatibles with
RISCOM serial line interfaces running under BSD/OS 2.0.1.

第 17 部

Asian Internet Interconnection Initiatives

495

V.35/RS449
Serial I/F

Local Internet
Gateway

VSAT IDUVSAT ODUThe AI 3 Earth Station
IDU:
ODU:

In-Door Unit
OutDoor Unit

図 3.3: The basic con guration of the AI3 earth station.

3.4 License
The hardest part of the beginning of the AI3 project is "obtaining a license." In countries in this region, governments have many kinds of regulations to restrict internationalcommercial communication services. Furthermore, the licensing process normally takes
several months. For example, the JSAT who is an owner of the JCSAT-3 satellite mustobtain a license for its commercial operation of the satellite from the Ministry of Posts andTelecommunications of the Japanese government. This licensing process normally takes
about 5 months. Thus, we expect that the AI3 partners have to spare much time in 1996
to obtain licenses from the appropriate local authorities.

3.5 AUPThe acceptable use of the AI3 testbed network is limited to activities for achievement of
the AI3 goals. In other words, the AI3 testbed is not AUP free. We de ne this AUP because
the AI3 project is not willing to make any con icts with local ISP development. The AI3
testbed accepts either trac for the AI3 researches or support for the AI3 activities.

第 4章
Research Plan on our Testbed
On our AI3 testbed network, a series of research activities is planned. In this section,
several research topics we are planning are introduced.

4.1 Link Backup Coordination
One of the major issues in the AI3 testbed network is to design and develop the international mutual connectivity backup method. Because of the rapid growth of the Internet
users, availability and stable operation of the Internet connectivity has become more signi cant. Almost all of the countries in the Asia have direct connections to the Internet
gateway sites, such as MAE-West or NAPs in the United States. However, there are few
connections among the Asian countries. Hence, in the case that the link to the UnitedStates is down, these countries will lose their Internet connectivity. Even with links among
the Asian countries, there is no coordination to use them as their backup connectivity to
the Internet. This situation should be improved.
Throughout the AI3 project, we will provide the AI3 testbed for connectivity backup
operation. However, strategies and requirements on the connectivity backup operation
are still not clear. Thus, we try to de ne the strategies, then develop technologies toimplement the strategies on the operational mutual connectivity backup method for theInternet in Asia. For this objective, the AI3 project plans several experiments using its
testbed network. Especially, our experiments are focused on the topology and routing
design of the AI3 testbed network, routing servers, and the policy routing implementation
techniques.

4.2 Application Based Routing
Another technical issue is the application based routing technology. It is the major
characteristics of the VSAT satellite link fhat its RTT is about 500ms. This large RTT
makes signi cant impact on the operation of several applications. In general, this feature496

第 17 部

Asian Internet Interconnection Initiatives

497

Data

Internet

ClientInternet(terrestrial link)

ServerRequest Commands

図 4.1: The concept of the Application Based Routing. The data ow from the server tothe client is detoured to the satellite link.

is not suitable for applications with interactive operations such as TELNET. However,
several techniques to improve the performance in the application level is available. Someof the WWW clients establish several HTTP sessions in parallel with the WWW servers
so that the large RTT is expected to be less signi cant. Therefore, applications with thiskind of parallel data fetch capability can be used comfortably even on the satellite links.
Of course, applications with bulk data transfers such as FTP can be used e ectively on thesatellite link if high throughput is guaranteed over the satellite link.
From the observation of many applications based on the server/client model, trac froma server to its client is much larger than one from the client to the server. In many case,the client sends short request commands to the server, then server returns large amount ofdata for the client. We may use this unbalanced trac pattern to improve the applicationlevel performance. For example, a method that carries the command from the client tothe server via terrestrial links with short delay and returns the data from the server tothe client via satellite links with large bandwidth may provide good performance for usersof the application (see Figure 4.1). Especially, in the situation where the ratio of theunbalanced trac is high, e.g., the Video-on- Demand service on the Internet, this method
can be applied and provides better performance.
In order to accommodate this method to the Internet, the AI3 will develop and evaluate
a new gateway system on which the application based routing mechanism is introduced.

4.3 Weather Monitoring and Link Bit Rate Control
As described in the last section, the AI3 testbed network is constructed with the JCSAT3 Asian Zone beam (Ku-band). The beams in the Ku-band have less interference but more

498

1995 年度 WIDE 報告書

rain attenuation rather than beams in the C-band. The VSAT link may be down in thecase that it is heavy rain around the AI3 earth station. In the current design of the AI3
earth station, the rain margin is set 3dB, therefore, the 2Mbps VSAT link may be downwith 20mm/hour rain. Since the rain over 20mm/hour is observed several times in therainy season in the south east Asia, this kind of link down will occur many times in thesecountries.
With the satellite link characteristics, we can still use the link if we decrease the link bit
rate from 2Mbps to slower rate (e.g., 256Kbps), even with heavy rain. The link bit rate
where the link can be survived in the heavy rain depends on the rain. The heavier the rain
is, the slower link bit rate we can use. Moreover, since the link is basically point-to-point,
both end station of the link have to decrease the link bit rate synchronously. In the casethat only the AI3 satellite link provides an Internet connectivity to a country, this kind ofrobust link operation is important in order to avoid connectivity loss.
In the AI3 experiences, we will develop an automatic link bit rate controller for raindegradation. Figure 4.2 shows the con guration of the link bit rate controller. In order tomeasure the beam power at the earth station, we can use a spectrum analyzer which has
GPIB control port. The VSAT IDU we use has a control interface (RS232c) with which
we can control the link bit rate by a computer. Based on the beam power monitoring,the controller changes the link bit rate automatically in order to avoid link down by rain.
Furthermore, we add the weather monitoring box to the controller. The weather data canbe used as hints for the control strategy implemented in the controller.

4.4 Global Testbed
We are going to use the AI3 testbed network as a part of several global testbed such as
MBone and SixBone.
As described in the section 2.3, we introduce the WISH drivers as our data link management software. With the drivers, we can use the AI3 testbed network as an IP multicastingtransport. We can expand the MBone testbed over the AI3 testbed network so that experiments using MBone can be conducted on the AI3 testbed network.
For the IPv6 developments, the global testbed network called "SixBone" is now underconstruction. The AI3 project will contribute for its expansion to the Asian countries using
our testbed network.

第 17 部

Asian Internet Interconnection Initiatives

VSAT ODU

Gateway

VSAT IDU

Weather Monitor
Link Bit Rate Control
Commands(via RS232c)
Received Beam
(GPIB)

Link Bit Rate Controller

Spectrum Analyzer(measure the beam power)(RS232c)

図 4.2: The Link Bit Rate Controller at the AI3 earth station.

499

第 5章
Summary and its Current Status
The AI3 project started in 1995 is aiming at testbed construction and a series of research
activities to accelerate cooperative works in and around the Internet in the Asian countries
and regions. In this article, we introduce an overview of the project, technical aspects ofthe testbed, and several research activities in the project.
The AI3 project is still concentrating on construction of its earth stations at both partners' site and at our hub site in Japan. Currently, the VSAT earth stations in Indonesia,
Thailand, and Hong Kong are under construction. We are expecting that the rst link in
our testbed network will be in operation by August 1996.
The AI3 project will report its activities mainly at APNG meeting1 . For sharing information, the AI3 project provides its WWW service2 . In the WWW service, we are providing
several technical reports on our experiments.

1 Several documents about APNG (Asia Paci c Networking Group) are available at its WWW serverat the URL <http://www.apng.org/>.
2 The service can be reachable through our WIDE project home page at the URL<http://www.wide.ad.jp/>.
Alternatively, you can directly access to the WWW page at<http://shika.aist-nara.ac.jp/research/ai3>.

500