DTN technology as enabler of cost-efficient
networking with wired and wireless integration- DTNRG in IETF76 Masato Tsuru *1,*2
tsuru@cse.kyutech.ac.jp
Shinya Yamamura *2, Akira Nagata *2{yamamura, nagata}@nict.go.jp*1: Network Design Research Center, Kyushu Institute of Technology (JAPAN)*2: Service Platform Architecture Research Center,
National Institute of Information and Communications Technology (JAPAN)

DTN-related Project Structure in NICT
NICT: National Inst. of Information & Comm. Technology
An incorporated administrative agency for R&D on Information Comm.
Technologies supported by MIC (Ministry of Internal Affairs and Comm.) as thecompetent authority (http://nict.go.jp/index.html)
promotion

1. Virtually Sustainable Access Networking Project (2006-2008)
Fundamental techniques: Epidemic routing, Network coding, Wifi rerouting, Multipath transport, etc.
Collaborated by Kyushu Inst. Tech., Osaka Univ. and Kwansei Gakuin Univ.
T. Matsuda, T. Takine: (p,q)-epidemic routing for sparsely populated mobile ad hoc
networks, IEEE J-SAC 26(5):783-793.
T. Matsuda, T. Noguchi, T. Takine: Broadcasting with Randomized Network Coding inDense Wireless Ad Hoc Networks, IEICE Trans. Comm. E91-B(10):3216-32252. Integrated Wired and Wireless Network Platform Project (2009-2010)
Under JGN2plus R&D on Platform Technologies for the New Generation Networkby NICT Service Platform Architecture Research Center
More architectural R&D towards Future Internet services
Copyright © 2009 National Institute of Information and Communications Technology (NICT) All Rights Reserved.

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DTN: Delay and Disruption Tolerant Networking
DTN technology is designed to overcome limitations in connectivity or
performance due toOpportunistic or scheduled intermittent links,
Huge error rate links (packet losses),
Huge or highly variable delay links,
Link bandwidth/loss/delay asymmetry,Internetworking among heterogeneous network architectures, .. etc

Originally targeting challenged environments such as Inter-Planetary Internet
But later... great generality and importance are known.
Low-earth orbit satellite

MarsCommunication outsideof the Internet

Aircraft
The Internet
Ｃｅｌｌｐｈｏｎｅ

VehicleSensor Network

Copyright © 2009 National Institute of Information and Communications Technology (NICT) All Rights Reserved.

Battlefield

3

DTN and Future Internet Research
A general framework for cost-efficient information exchangeover discontinuous space and time
As a basis for asynchronous (non-realtime) comm. acrossvery heterogeneous networks
DTN-related R&D proposals in NSF
NeTS FIND (Future Internet Design)
Postcards from the Edge: A Cache-and-Forward
Architecture for the Future Internet
Roy Yates, Dipankar Raychaudhuri, Sanjoy Paul, James
Kurose (Rutgers WINLAB; UMass)

The-Day-After Networks: A First-Response
Edge-Network Architecture for Disaster Relief
Haiyun Luo, Robin Kravets, Tarek Abdelzaher (UIUC)

Transient Network Architecture
Robert Kahn, Chaouki Abdallah, Henry Jerez, et al.
(CNRI)

Architectural Support for Selectively-Connected
End Systems: Enabling an Energy-Efficient FutureInternetMark Allman, Vern Paxson, Ken Christensen, Bruce
Nordman (ICSI, University of South Florida, LBNL)

4Our project
DTN-based R&D for future network services
For cost-efficient networking in rural and urban life rather than only for exotic
environments: Efficient use of limited wireless resources and/or Saving energy
Fully exploiting a combination of diverse network techniques for non-realtime
comm.: Integrated Wired and Wireless Network Platform
Universal identifier and Late binding
Store-(carry-)forward message delivery
A variety of Space and Time and Freq. (cognitive ratio) resource scheduling schemes
Bandw idthnarrow

ＳａｔｅｌlｉｔｅVOIPCellular phone

C HAT

WIFI

WIFIWIFI
S tore-carry-forward
scheme based
network infrastructure

E -Mai l

WIFI
WIFI

WIFI

W EB

Optica l /ADS LUP DATE

AUDI OS TREAM ING

DOW NL OAD

IP TV

broadPopulation

ruralurban

ruraldensity

5

Our project (cont.)
1. Integrated Multi-network Data Transfer Proxy Agent and its

Protocol– Large data transfer over multiple inferior networks between
intermediate nodes (proxy agents)– Integrating wide-area, stable but low-speed networks and narrowarea, high-speed but unstable, intermittent networks• WiFi, Cellar, Satellite, WiMAX,...

– Separating data transmission flows and control flows

2. Store-Carry-Forward Based Access Network Infrastructure– Virtual Segment (VS): a virtual access network along roads
supporting non-realtime large data exchange– Integrating short-range wireless comm and long-range
wired/wireless infrastructure based on store-carry-forward
scheme by vehicles (buses, cars, trains, ...)

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A Concept of Integrated Multi-network Data Transfer
Integrating wide-area, stable but low-speed networks and narrow-area, highspeed but unstable, intermittent networks (WiFi, Cellar, Satellite, WiMAX,..)As a new transport protocol between Proxy Agents, especially by separating
data transmission flows and control flows
serverrelay function

control flow
data flow

e.g. satellite link

upload to server
retransmission
or rate control,
address notificationinterworking withwireless gateway nodeInternetdetectionof reachable I/F
file to betransferredavailable bit rate

leaky or heavily varying bit rate

mobile sender(e.g. in a rural area)

download from server

e.g.
WiFi service
inside a cartime
frequent disconnection

timereceiver(e.g. in a high-speed moving vehicle)7

An application-level Experiment (Plan)
Emergency networking in Disaster– by Wifi AP at balloons and satellite comm.
Integrated Multi-network
Data Transfer Proxy Agent
Town Office

WiFi

WiFi

antenna on car
BGAN EXPLORER

Integrated Multi-network
Data Transfer Proxy Agent

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A Concept of Virtual Segments
Divide the communication area to some virtual segments （VSs)
In a VS, messages are transferred in a SCF manner by vehicles
Take a shortcut between VSs via connected links

sea

land
Virtual Segment 2

Virtual Segment 1
ＢＮ

SMN: Segment Management Node

ＢＮ
ＢＮ

SMN

roadSMN

ＢＮ

SMN

ＢＮ

SMN
ＢＮＢＮ
ＢＮ

SMN
ＢＮ

ＢＮ

ＢＮ

islandＢＮ

Virtual Segment 3

Virtual Segment 4

Copyright © 2009 National Institute of Information and Communications Technology (NICT) All Rights Reserved.

9Schematic description of VS
Correspondent Node (CN)Each stationary or mobile
Core Network comm. user.

Virtual Segment
ＣＮＲＮ

ＢＮ

ＢＮ

Virtual Segment
Geographical region surrounded
and delimited by one or more BNs
along the roads.
Copyright © 2009 National Institute of Information and Communications Technology (NICT) All Rights Reserved.

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Message exchange between VS and Internet
1.
2.
3.
4.

User N1 wants to send a request message (REQ) to Internet
Car R1 crossing BaseNode BN1 acts as a relay in this VS
When R1 approaches N1, REQ is passed to N1
When R1 approaches BaseNode BN2, REQ is passed to BN2
Internet
Wired/Wireless
PersistentConnection

Core Network

Virtual Segment

App. ServerREQ

Ｎ１
Ｒ１

ＢＮ１

REQ

ＢＮ２

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Message exchange between VS and Internet (cont.)
5.
6.
7.
8.

BaseNode BN2 sends REQ to the destination (the applicationserver) on the Internet though a core network
A reply message (REP) is sent to both BN1 and BN2
When R2 approaches BN1, REP is passed to R2
When R2 approaches N1, REP is passed to N1, the origin
Internet
Wired/Wireless
PersistentConnection

App. ServerCore NetworkVSＮ１
Ｒ２REP

ＢＮ１

REQREP

ＢＮ２

12

An image of deployment of Virtual Segment

100m

A field trial is being planned on December 2009 at Iizuka city.
Copyright © 2009 National Institute of Information and Communications Technology (NICT) All Rights Reserved.

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An application-level Experiment (Plan)
Traffic congestion information advertisement(traffic information, accident information )Field trial is planning in December 2009Internet
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２．Forward info. to each
BN inner segment or outersegment via core network.

BN2

BN1
RN/CN

RN/CN

3. Each RN/CN receives info.
from nearest BN or other RNs.

CNcaraccident

RN/CN

1.Send traffic congestion
information to crossing RNs
or nearest BN.

Copyright © 2009 National Institute of Information and Communications Technology (NICT) All Rights Reserved.

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An image of pre-experiments
Pre Field Trial on 25th August 2009 at Fukuoka city.

Relay Node ( A man riding on a bus with portable pc
equipped with wireless comm. device)

Correspondent Node is put on the side of the road
Copyright © 2009 National Institute of Information and Communications Technology (NICT) All Rights Reserved.

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Can Store-carry-forward be practical?
File Transmission Time comparison
500
Assumed VS parameters
Relay speed = 36km/hour
Traffic= 10 unit/hour
Communication range = 200m
Data transmission speed = 10Mbps

Avelage Delay Time (minutes)

400

300

Cell phone(PDC/line）

Cell phone(PDC/packet）

phone（analogue）
cdmaone

2M
10M
100M

PHS

200phone（ＩＳＤＮ）

100

VS(1km)ＡＤＳＬ

W-CDMA

VS(10km)VS(5km)

FTTH

0123456789101112

VS can provide throughput performance comparable to the narrowband media

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Can Store-carry-forward be practical? (cont.)

Amazon Web Services (AWS) Import/Export– In uploading huge data to the centers, the time required
to prepare and ship a USB to a near AWS site is shorter
than that by using a limited Internet connection• http://aws.amazon.com/importexport/Pigeon Networking☺
– South Africa pigeon 'faster than broadband (ADSL)‘ for4GB data transfer across country• http://news.bbc.co.uk/2/hi/africa/8248056.stm– Homing pigeons get down to business,
ferrying rafting company photos• http://www.denverpost.com/news/ci_6209735
17Concluding Remarks
In Japan, DTN-related research (in NICT) arose in2006 and have much attention recently
NICT is leading
In corporation with universities (Osaka-u, U-Tokyo,Kyutech, Kuwansei Gakuin-U, etc.)
Commercial Interest slowly increasing...

The current NICT project (2009-2010) aims at
Integrated Wired and Wireless Network Platform
as cost-efficient networking platform for non-realtime, asynchronous, and large-sized data comm.
In the next project circle from 2011, DTN, otherwireless-related research including cognitive radio,and Future Internet research may be (hopefully)
more collaborated in both NICT and Japan.
Copyright © 2009 National Institute of Information and Communications Technology (NICT) All Rights Reserved.

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