implementation and testing of delay tolerant … networking - implementation and -r.s.pdfthe...

International Journal of Computer Networking,

Wireless and Mobile Communications (IJCNWMC)

ISSN 2250-1568

Vol. 3, Issue 1, Mar 2013, 231-244

© TJPRC Pvt. Ltd.

IMPLEMENTATION AND TESTING OF DELAY TOLERANT NETWORK USING SELF-

CAPABLE AND ROUTING NODES: A CASE STUDY

R. S. MANGRULKAR1 & MOHAMMAD ATIQUE

2

1Research Scholar, Sant Gadge Baba Amravati University, Amravati, Maharashtra,India. Associate Professor, Computer

Engineering, department, B. D. College of Engineering, Sevagram .Wardha, India

2Professor, Post Graduate Department of Computer Science, Sant Gadge Baba Amravati University, Amravati,

Maharashtra, India

ABSTRACT

Routing is an issue of great interest for opportunistic network called Delay Tolerant Network. Most of routing

schemes that have been proposed till now are broadly classified as flooding and forwarding strategies. These routing

scheme are categorized based on the important characteristic of any routing protocol that is message transmission capacity.

In this paper, we summarize our work as case study in department of Computer Engineering, Bapurao Deshmukh College

of Engineering, Sevagram . We setup Delay Tolerant Network: A Self-Capable Network for routing message in

cooperation with intermediate node to the final destination. We design and developed a small device so called as a Node

sending message from source to destination. Nodes are routing original message by using flooding technique to deliver

finally to the targeted receiver of the original message. The hardware device here onwards termed as Node is created and

successfully demonstrated to study the working of delay tolerant network. Nodes are also capable of queuing and relaying

message, if they are not the target destination. The message transmission capacity of Delay tolerant Network even with

longer delay can’t be neglected. Ad hoc network may not deliver message from source to destination without having end-

to-end connectivity. This drawback is resolved in delay tolerant network. Our designed nodes are experimented and tested

to deliver the message up to 80-100 m distance with each node having storage capacity of 5 messages.

KEYWORDS: Routing, Delay Tolerant Network, Flooding, Sending

INTRODUCTION

Origin of most prominent and challenging network called Delay Tolerant Network (DTN) is Mobile Ad hoc

Network, MaNet. This type of network so called as challenged network because of no end-to-end connectivity between two

or more nodes[1]. On the other hand, the connectivity always ensured in conventional Mobile Ad hoc Network, MANET.

Manet is sparse and intermittently connected mobile ad hoc network where reliable communication is not sure for message

transmission. DTN uses “Store and Forward" approach of routing. Each node in DTN stores incoming message in the

storage section called “Buffer” if it is not target receiver of original message [2-4]. Intermediate receiver will cooperate

with source to deliver the message by taking part in selective flooding. Nodes, receiving the message, first check whether it

is wished destination. If not, it will again broadcast in the network. Finally delivered to destination. Intermediate node

copies incoming message and work as relay node in order to increase the probability of message delivery. DTN is called

opportunity network as the intermediate node always searches best opportunity to relay a message from source to

destination [5]. Probability of message transmission is more in DTN compared to MANET. MANET uses two-phase

approach to deliver data [6]. First phase is used for route setup from source to destination and second phase is used to send

message and argue route information till data transmission is over. This is not possible in case of DTN where nodes are

sparsely deployed in the region and the two or more nodes can exchange message when they come across transmission

232 R. S. Mangrulkar & Mohammad Atique

range of each other during the phase called "Contact" phase. Store and forward approach helps to increase message

delivery probability in DTN irrespective of time taken to deliver message over normal MaNet [7,8]. The nodes carry on

message transmission as they exist in the transmission range of each other. As soon as they move out of transmission range

of each other, communication link breaks. In conventional MaNet, a routing protocol has to establish end-to-end route

from source to destination using intermediate node. This connectivity should be preserved till message transmission gets

completed. This is not in case of DTN. In DTN, end-to-end path is rare and unstable in nature and opportunity to set up

complete route is negligible. DTN support those applications, whose time requirement is hours or even days or longer.

Therefore, it is necessary to delivered high priority message during "contact" phase. Problem and solutions of prioritize the

message is discussed in literature by many researchers.

In rest of the paper, Section II gives brief description of routing strategies in delay tolerant network. Section III

clearly gives idea of proposed delay tolerant network implemented and tested successfully. At last conclusion is given in

section IV.

ROUTING STRATEGIES IN DTN

Based on the strategies, routing in DTN is categorized in to two main categories, Flooding strategy and

Forwarding strategy [9]. Flooding strategy is based on the principal of replicating messages to enough nodes so destination

nodes must receive it. Forwarding strategy uses knowledge about network to select best path to the destination.

FLOODING STRATEGIES

In this strategy, the multiple copies of same message will be created and these copies will be delivered to the set

of nodes called relay nodes. Relay nodes stores the messages until they come in contact with destination node [10]. As

soon as the contact is made during "contact" phase, the messages are delivered by the relay nodes. Many of the strategies

are workout by the researchers before this DTN get popular. These strategies are studied in the context of mobile ad hoc

network where random mobility is good chance of bringing the source in contact with destination. Message replication is

then used to increase the probability the message is successfully delivered to the intended node. These protocols do not

want any prior global or local knowledge about network.

FORWARDING STRATEGIES

Forwarding Approach makes use of the network topology and local or global knowledge to find best route along

the path to destination [11]. This best route is used to deliver the message. The best route is selected depending on

parameters like probability of message delivery ratio, time required to deliver the message to destination. These parameters

are evaluated based on the earlier transmission. This approach does not replicate the message. Instead, A single path is

used which is estimated by evaluating some of the network parameters.

PROPOSED DELAY TOLERANT NETWORK SYSTEM ARCHITECTURE

In this section, we are summarizing case study about the work which we did at our campus for setting up message

transmission ability nodes for sending and receiving messages in the campus of Bapurao Deshmukh College of

Engineering, Sevagram, Wardha, Maharashtra, India. This work is carried as part of research project which is provisionally

shortlisted by All India Council for Technical Education (AICTE) Grand no. 8023/RIFD/RPS/166/(Pvt.)/2011-12. We

designed and developed a system consisting of hardware and software. The device so called Node is capable of sending,

receiving and storing messages. These Nodes are created with self broadcasting capability.

Implementation and Testing of Delay Tolerant Network Using Self-Capable and Routing Nodes: A Case Study 233

PROBLEM DEFINITION

Traditionally, mobile use mobile networks with an infrastructure network support, or mobile ad-hoc networks, to

set up communication sessions with other using underlying transport-layer in an end-to-end manner. Usually, TCP/IP is

used as a communication protocol, and routing protocols such as AODV or DSR are used. When a mobile loses the

connectivity, most applications requiring networking capacities (for example web browsers and email applications) will not

work anymore on the device.

Applying the DTN-based approach for these challenged mobile networks on the other hand relies heavily on

asynchronous communication, where the transport-level end-to-end connectivity is relaxed. The DTN-based approach

offers application-level end-to-end connections using the bundle protocol to deliver messages encapsulated as variable-

sized bundles in a hop-by-hop basis from the source to the destination.

It operates in a store-carry-forward manner forming an overlay layer and abstracting away the underlying

protocol stack, i.e., the bundle layer forms an asynchronous messaging platform. Consequently, an application running on

the mobile network that cannot maintain transport-level end-to-end connectivity can be made functional when the bundle

protocol has been taken in use in the communication protocol stack. Now, the application can communicate with the

remote application, if there is at least one path in time from the source node to the destination node (on the hop-by hop

basis).

OBJECTIVES

The main objective is to set up the delay tolerant network for sending and receiving messages. This task is

targeted with increase in message delivery probability and decrease in routing overhead and end-to-end latency. According

to the basic idea mentioned above, we have to connect our DTN nodes in Challenged Infrastructure-less ad-hoc network.

These nodes must send and receive message from source to their destination with store and forward inbuilt capacity.

HARDWARE REQUIREMENT

Hardware Requirement

• ASK Super Regenerative Receiver : ST-RX02-ASK

• ASK Transmitter Module : ST-TX01-ASK

• Microcontroller : P89V51RD2

• Encoder : HOLTEK’s HT640 encoder

• Decoder : HOLTEK’s HT658/S decoder

• MAX223 Driver IC : Multichannel RS-232 Drivers/Receivers

• RS-232 Port : Serial Port

• Computer System : With Windows XP

GENERAL DESCRIPTION OF ST-TX01-ASK TRANSMITTER

The ST-TX01-ASK is an ASK Hybrid transmitter module. ST-TX01-ASK is designed by the Saw Resonator,

with an effective low cost, small size, and simple-to-use for designing. Frequency Range: 315 / 433.92 MHZ. Supply

Voltage: 3~12V. Output Power: 4~16dBm Circuit Shape: Saw


Figure 1: St-Tx01-Ask Transmitter

Figure 2: Pin Description of ST-TX01-ASK Transmitter

GENERAL DESCRIPTION OF ST-RXX02-ASK REGENERATIVE RECEIVER

The ST-RX02-ASK is an ASK Hybrid receiver module. A effective low cost solution for using at 315/433.92

MHZ. The circuit shape of ST-RX02-ASK is L/C. Receiver Frequency: 315 / 433.92 MHZ. Typical sensitivity: -105dBm .

Supply current: 3.5mA . IF Frequency:1MHz

Figure 3: ST-RXX02-Ask Regenerative Receiver

Figure 4: Pin Description of ST-RXX02-ASK Regenerative Receiver


MICROCONTROLLER P89V51RD2

The P89V51RD2 is an 80C51 microcontroller with 64 KB Flash and 1024 bytes of data RAM. A key feature of

the P89V51RD2 is its X2 mode option. The design engineer can choose to run the application with the conventional 80C51

clock rate (12 clocks per machine cycle) or select the X2 mode (6 clocks per machine cycle) to achieve twice the

throughput at the same clock frequency. Another way to benefit from this feature is to keep the same performance by

reducing the clock frequency by half, thus dramatically reducing the EMI. The Flash program memory supports both

parallel programming and in serial In-System Programming (ISP). Parallel programming mode offers gang-programming

at high speed, reducing programming costs and time to market. ISP allows a device to be reprogrammed in the end product

under software control. The capability to field/update the application firmware makes a wide range of applications

possible. The P89V51RD2 is also In-Application Programmable (IAP), allowing the Flash program memory to be

reconfigured even while the application is running.

Figure 5: Pin Description of P89V51RD2FA

HT640/S ENCODER

The HT640/S encoder is a CMOS LSI for remote control applications. It is paired with the HT658/S decoder. The

HT640 encoder is encoding 18 bits of information, which consists of 10 address bits and 8 data bits. The programmable

address / data is sent together with the header bits by means of an RF or an infrared transmission medium on receiving a

trigger signal on the TE line.

Figure 6: HT640/S Encoder


HT640/S DECODER

The HT658/S decoder is a CMOS LSI for remote control applications. It is paired with the HT640/S encoder. The

HT658 decoder receives serial address and data from the encoder that are sent by a carrier using an RF or an IR

transmission medium. It then compares the serial data twice continuously with its local address. If no errors or unmatched

codes are met, the input data codes are decoded and then transferred to the output pins. The VT pin also goes high to point

out a valid transmission. The decoder is decoding 18 bits of information that consists of 10 bits of address and 8 bits of

data.

Figure 7: HT640/S Decoder

MAX RS 232 DRIVER/RECEIVER

The MAX232 is a dual driver/receiver that includes a capacitive voltage generator to supply EIA-232 voltage

levels from a single 5-V supply. Each receiver converts EIA-232 inputs to 5-V TTL/CMOS levels. These receivers have a

typical threshold of 1.3 V and a typical hysteresis of 0.5 V, and can accept 30-V inputs. Each driver converts TTL/CMOS

input levels into EIA-232 levels

Figure 8: Max RS 232 Driver/Receiver

SOFTWARE REQUIREMENT

• Keil Software Development Tool with µVision2 and the C51 Microcontroller Development

• Philips Flash Magic

• EAGLE 5.11.0 Light software


KEIL SOFTWARE DEVELOPMENT TOOL

The Keil Software 8051 [12] development tools are the programs use to compile C code, assemble the assembler

source files, link program, create HEX files, and debug target program. µVision2 for Windows™ Integrated Development

Environment: combines Project Management, Source Code Editing, and Program Debugging in one powerful environment.

C51 ANSI Optimizing C Cross Compiler: creates relocatable object modules from C source code, A51 Macro Assembler:

creates relocatable object modules from 8051 assembler source code, BL51 Linker/Locator: combines relocatable object

modules created by the compiler and assembler into the final object module. LIB51 Library Manager: combines object

modules into a library which may be used by the linker. OH51 Object-HEX Converter: creates Intel HEX files from

absolute object modules.

HYPERTERMINAL

Hyper Terminal, a Windows XP application, can be used to receive or send serial data through RS232. To open

HyperTerminal, go to Start Menu, select all programs, go to Accessories, click on Communications and select

HyperTerminal. To start a new connection, go to File menu and click on new connection. The connection window opens.

Give a name to your connection and select 1st icon and click on OK. Connection property window opens here. Select Bit

rate as 9600bps, Data bits 8, Parity as none, Stop bit 1, Flow control none and click OK. Now the serial data can be read on

hyper terminal. In program, Timer1 is used with auto reload setting. The baud rate is fixed to 9600bps by loading TH1 to

0xFD. The value 0x50 is loaded in the SCON register. This will initialize the serial port in Mode1. The program

continuously receives a character (say ‘a’) from the serial port of the computer and sends it back.

IMPLEMENTATION AND WORKING

We tried to implement simple hardware model “A massage transmission in Delay Tolerant Network”. We

designed three hardware devices called Nodes. These nodes are capable of performing following functions:

• Working of these Nodes are based on RF transmitter and receiver

• These Devices are controlled by 8051 microcontroller through our software developed in C language embedded

on microcontroller.

• These devices are connected to computer.

• Messages are sent from one device to other device written on computer HyperTerminal.

First we mount the three transmitters, receiver and Microcontroller on the three separate printed circuit board.

Then we mount various small components like capacitor, resistor, switches, LED etc. To transmit and receive message for

the RF transmitter and receiver, we also mount Encoder and Decoder. Using Keil Software Development tools we develop

C code for 8051 Microcontroller. This C code converted into Hex format using Keil Software. After this we use Philips

Flash Magic for burning or dumping this C code Hex file on Microcontroller. Then we connected these three hardware

devices with computer together called nodes.

These nodes are named as A, B and C. To prove working node A will send message on computer HyperTerminal

to C even when C is not in coverage (range) area of A or vice -versa. This is possible by using node A as source and node

B as intermediate node. Finally node C will receive it as soon as contact is set up between intermediate node B and target

node C. This is the way of imposing store and forward policy which is the main philosophy of Delay Tolerant Network.

The detailed hardware design of device showing interfacing of all hardware components like RF Transmitter-

Receiver and Microcontroller is shown in Fig. 8. This circuit diagram is designed using EAGLE software.


Figure 9: Interfacing of Transmitter and Decoder

Figure 10: Circuit Diagram of Hardware Device

Figure 11: Complete Hardware Device(Node)Designed for Our Study


We develop the algorithm for node to node message transfer with store and forward capacity. For this, we

assigned device names as A, B and C. In coding we take the facility to enter the device name as destination that is which

device on which we have to send the message and also to check that if this device is within the coverage area of source

device. Doing this if source node found that destination is not in his coverage area, it broadcast the message to its

neighboring nodes. This can be done using the coverage signal pin present on the microcontroller. Flowchart given in

Fig.12 shows the working of node to node message transfer with store and forward policy. We develop printed circuit

board (PCB) by etching circuit diagram on developing board and made three such PCB. We implement our three devices

using three separate Transmitter and receiver IC with all devices has microcontroller IC (8051) and RS 232 driver IC, with

this our three node able to transfer and receive data. In the next stage we mount RF transmitter, receiver ,decoder ,encoder,

Microcontroller, RS 232 driver IC and all the small components like resister ,capacitor, crystal oscillator ,switches ,reset

button of transmitter ,sockets etc. We used the evaluation version of the Keil IDE for MCS-51 family (also known as C51

evaluation software) [13] Integrated development environment popularly known as IDE is a suite of software tools that

facilitates microcontroller programming. The Keil IDE enables to develop the program in C and assembly as well. We used

C for programming. We used Philips Flash Magic [14] to Programming the Flash memory of microcontroller.

Figure 12: Flow Chart for Our Approach

Figure 13: Screen Shot of Keil Software


Following Steps are Carried Out for Implementing this Work.

• Developed the code in C

• Simulate the code

• Converting the code into HEX format

• Dumped the code in microcontroller

• Prototyped and debugged using in-circuit testing

• Emulate the code in project.

Following Algorithm for Microcontroller Coding is Used.

[1] START

[2] initialize int z,m,k;

char ch1,mess3[z],mainmess[15],mess4[],mess5[],mess7[];

[3] initialize TMOD=0x20,TH1=0xF0,SCON=0x50,TR1=1,Inbit=1,P1=0xFF;

[4] while Inbit = 1

do

serialsend data

if serialreceive equals ‘a’

then

m=’a’

else m=’b’

[5] switch case

case m=’a’

serialsend data to mess7[];

serialreceive data to mainmess[];

serialreceive data to mess5[];

do

DELAY [500];

break;

[6] case m=’b’


serialreceive data to mainmess[];

serialreceive data to mess7[];

do


DELAY [500];

break;

[7] default case


If Inbit = 1;

ch1 = P1;

serialsend ch1;

DELAY [500];

[8] END

These devices are connected to computer system using RS 323 Serial cable and connect these devices to computer

Serial port. Using RS 232 these Devices are able to connect with computer HyperTerminal also able to send and receive

message type on HyperTerminal. At first we connect three Devices to computer system and then reset the Devices by

pressing reset button. Then open the HyperTerminal and set parameter on it as follows.

• Connect Using - Port x ( where x from 2 to 6 )

• Baud Rate - 9600

• Hardware - None

Then enter the Device name to which we have to send message (A, B or C) and then type message after pressing

enter key message successfully transmit from source Device to destination Device with store and forward policy.

In which if destination Device is not in the coverage area of source Device in such a case first message receive by

middle Device or neighboring Device from source he can store message on it and as soon as destination come in its

coverage area he transmit store message to destination Device.

CONCLUSIONS

In this paper, we first introduced Delay Tolerant Network. Later, detail implementation of the system is given.

This system is implemented and tested in the department of Computer Engineering, B. D. College of Engineering,

Sevagram, Wardha, Maharashtra, India. The motive behind this work is to give brief idea about implementation of delay

tolerant network and its practical study for message transmission. Device so called as Node, designed and developed are

capable of sending and receiving message up to 80-100 m. These nodes are capable of storing 5 messages. The messages

are stored in EPROM. Store and forward approach practically implemented. Thus the conclusion is that the delay tolerant

network plays important role in message transmission even in infrastructural less architecture.

The message transmission capability of Delay tolerant Network even with longer delay can’t be neglected. Adhoc

network is not able to deliver message from source to destination without having end-to-end connectivity. This end to end

connectivity never ensured in delay tolerant nodes. Therefore the delay cannot predict for message. The practical

implementation of delay tolerant network is required to precisely explain the concept of this type of network. The research

on the delay tolerant network is still going on and the work is refined continuously to cope up with the problem of large

delays as well as precise timely delivery of messages. In future we will rectify this work for increasing transmission and


storing capability of these nodes and will try to correlate with the applications which involve message transmission in

absent of Ad hoc infrastructure.

REFERENCES

1. Akadet Mathurapoj, Chotipat Pornavalai, (Ed). 2007. “Fuzz-Spray: Efficient Routing in Delay Tolerant Ad hoc

network based on Fuzzy,” in Proceeding of FUZZ-IEEE International Conference 2009, (pp. 104-109).

2. Jian Shen, Sangman Moh and Ilyong Chung, “Routing Protocols in Delay Tolerant Networks: A Comparative

Survey,” in Proceeding of 23rd

International Technical Conference on Circuits /systems, Computer and

communications (ITC-CSCC 2008), pp. 1577-1580,2008.

3. Vassilis Tsaoussidis, http://www.spice-center.org/dtn-agent-issues

4. Giorgos Papastergiou, Nikolaos Bezirgiannidis, Vassilis Tsaoussidis, “On the Performance of Erasure Coding

over Space DTNs”, in Proceedings of the WWIC'12, 10th international conference on Wired/Wireless Internet

Communication, pp.269-281,2012.

5. J. D’souza, Johny Jose, “Routing approaches in Delay Tolerant Networks: A Survey,” International Journal of

Computer Applications, Vol. 17, pp. 9-15, 2010.

6. Efthymios Koutsogiannis , Lefteris Mamatas , and Ioannis Psaras , “Storage-Enabled Access Points for Improved

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7. K. Fall, “A Delay –Tolerant Network Architecture for challenged internets,” Journal of Communications, A

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8. Tournoux, P., Lochin, E., Leguay, J., Lacan, J., “Robust streaming in delay tolerant networks,” in in Proceeding

of IEEE ICC, Cape Town, South Africa, pp. 1-5, June 2010.

9. Eyuphan Bulat, Sahin Cem Geyik, Boleslaw K. Szymanski, “Conditional Shortest Path Routing in Delay Tolerant

Networks,” in Proceeding of 2010 IEEE International Symposium, World of Wireless Mobile and Multimedia

Networks (WoWMoM), pp. 1-6, June 2010.

10. G. Wang, B. Wang, Y. Gao, “ Dynamic Spray and Wait Routing Algorithm with Quality of Node in Delay

Tolerant Network,” in Proceeding of International Conference on Communications and Mobile Computing ,

published by IEEE Computer Society, pp. 452-456, 2010.

11. Lei Yin, Hui-mei Lu and Y. Cao, “A Novel Single Copy Replication Routing Strategy for Delay Tolerant

Networks, ” in Proceeding of 5th

IEEE International Conference, Wireless Communications, Networking and

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and Cluster Control,” in Proceeding of International Conference on Computational Intelligence and Security,

IEEE Computer Society, pp.397-401, 2009.


AUTHOR’S DETAILS

Prof. R.S.Mangrulkar1 is working as Associate Professor and head department of Computer Engineering, Bapurao

Deshmukh College of Engineering, sevagram, Maharashtra, India. Currently he is persuing PhD from SGBAU Amravati.

He has total 12 years of teaching and research experience. His area of interest is delay tolerant network, ad hoc network,

cryptography. He has published many research papers in national and international journal. He has delivered many guest

lectures on Latex and its importance in research writing and also conducted workshop on NS2. He is also serving as reviver

of many International Journal.

Dr. Mohammad Atique2 is working as Associate Professor in Post Graduate department of Computer Science,

SGBAU Amravati. He has total 22 years of teaching experience. His work gets recognized by many National and

International journals. He is also reviver of reputed National and International journal. He is recognized as PhD supervisor

for RTM Nagpur and SGBAU Amravati university. Currently 12 students are perusing PhD under him. His area of interest

is Soft computing, Operating System, Ad hoc Network, Delay tolerant network, data mining etc. He has chaired many

sessions and also delivered keynote in National and International conference, STTPs in India. He also begs grant for his

research work from various funding agency in India.

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