2014-10-19 ~ Ilmu Tanpa Sempadan

Open Source, Delay Tolerant Network, Internet of Things

The Most Popular Traffic Exchange - Your Free Traffic Exchange - 1:1 Exchange Ratio, FREE Advertising!

Share Your Web Link Here

Saturday, October 25, 2014

1.4 The Proposed System

1.4  The Proposed System

An offline mail server in the rural area local area network (LAN) is where rural users can read, send and receive email locally in the LAN. Meanwhile the external email content to be sent online will be stored temporarily until it is transferred to infomediary device. The database synchronization system in the offline server computer will transfer and receive new database from the infomediary device as shown in Figure 1.2. Infomediary device working as a temporary storage and can be accessible via Wi-Fi or wireless local area network (WLAN). Then the database synchronization system in the online server computer will transfer and receive new email data from this infomediary device. Online mail server has all the features as offline mail server where the user in that area can use the offline email system locally through LAN. Online mail server is connected to the internet. This offline email system can be access from the internet through the online mail server. The external email content to be sent offline will be stored temporarily until it is being transferred to infomediary device and then to the offline mail server at rural area.

Figure 1.2: Offline email system components

Store and forward process between mail server and infomediary device provide the ability of connection between offline email system and online email system. This will enable the email content to flow through the offline environment to the internet environment and vice versa. It is critical to develop a suitable subsystem that can fulfill the need of this offline email system because there is a challenge in the email database synchronization. This synchronization system should have the ability to synchronize the database between the offline mail server and the infomediary device. It is also responsible to synchronize the database in the online mail server and database in the infomediary device. Infomediary device is a temporary storage for the email database operates wirelessly to collect the email data between the offline environment and the online environment. It should be portable, secured and has a long life battery. There are two different environments for this offline email system which is offline and online. Both sides consist of mail server and mail client for their respective environment. At the online side, the online mail system is connected to the internet using a personal home server. This mail server is running on Streamyx dynamic IP conjunction with Uniform Server. The Uniform Server is a Windows Apache, MySQL and PHP, Perl or Python (WAMP) package that allows the user to run a server on any Microsoft Windows Operating System based computer.

Confirm working Upgrade Ubuntu to latest Ubuntu 14.10

Do run all this command in order.


sudo apt-get clean


sudo apt-get autoclean

sudo apt-get -f install

sudo dpkg --configure -a

sudo apt-get -f install
If the output is:

0 upgraded, 0 newly installed, 0 to remove and 1 not upgraded.

That means it failed.

Next solution is to run:

sudo apt-get -u dist-upgrade

sudo apt-get -o Debug::pkgProblemResolver=yes dist-upgrade

All ok if output:
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.


sudo apt-get update && sudo apt-get dist-upgrade

sudo do-release-upgrade


Friday, October 24, 2014

1.3 Project Objective

1.3  Objective

The objective of this thesis is to provide an offline email system at rural area that has no internet connection. There are three research questions in this thesis as below:
1)      Implementation: How the user registration page should be implemented and how the store and forward process in delay tolerant network (DTN) supports the offline email system in terms of email connectivity from the offline environment network to online environment network?
2)      Functionality: Can the email data maintain in the mail server for a very long time delay until it synchronized with infomediary device? What is the limitation size of email data which include email content and file attachment? What are the types of data supported when uploading an attachment? Can the email data synchronization process avoid conflict when the email sent and replied from multiple sender and receiver or when the email sent and replied through multiple communications?

3)      Performance: What is the limitation movement speed of an infomediary device when moving through a mail server and performing a database synchronization?

Wednesday, October 22, 2014

1.2 Problem Statement

1.2  Problem Statement

TCP/IP does not fully support this offline email system because it requires immediate end-to-end path between sender and receiver. This means the connection must exist at the same time sender send the email because the email packets will travel through the transport layer and finally to the destination. The email client is disconnected from email server if there is no end-to-end path and the user cannot access their email account. However, if the Gmail offline application is used, the user has to bring their device to the connected area. In rural area, this seems not practical. Delay tolerant network (DTN) is designed to overcome this limitation by implementing store and forward message switching by overlaying a new protocol layer called the bundle layer. DTN use storage within the network to support the store and forward operation over networking paths. The problem arises when the emails have to be collected into another device before it is brought physically to the connected area. The store and forward process of DTN is integrated using the file synchronization method because it involves the third device and the third person to bring the emails to the connected area.

MOOC - Extend your knowledge, Push your thinking further

Massive Open Online Course, I really love this phenomena nowadays. This is how technologies should be used. This is where knowledge know no limits. I often spend my night time before bed finishing some great and my favourite free course in various MOOC in the Internet. This is how I spend my quality time after playing with my son and daughter. This is some of my favourites:

This is where the Malaysian Universities (IPTA/IPTS) courses being offered.

Use your time wisely, don't waste it.


Tuesday, October 21, 2014



1.1  Overview

Email application has been commonly used as one of the communication tools which are cheap and easy to use as long as the person has internet connection. Email application is tolerant to delay and the email sender and recipient not required to be online at the same time. Email is suitable especially for those who not in urgency and delay in sending and receiving is acceptable. For those who live in the rural area without the Internet connection, even the application such as an email application is impossible. Rural area such as Bario has a telecentre which is built with the Internet facilities only offer the Internet connection in four kilometers diameter around the telecentre [1]. Therefore, the best approach to provide email services for users who has no internet connection at other areas is by introducing an offline email system. This offline email system using Transmission Control Protocol and Internet Protocol (TCP/IP) with the database synchronization application as a data mule where it works as a network bridge by bringing the pending emails from offline server computer to the online server computer.
TCP/IP has been used widely in the email application as well as in World Wide Web (WWW), File Transfer Protocol (FTP) and Voice-over-IP (VoIP). TCP/IP fundamental assumption is, there is always end-to-end communication between sender and receiver. End-to-end communication means that the network provides a reliable transport layer with immediate data transmission to the receiver and to provide data integrity, delivery guarantees, delivery acknowledgement, duplicate message suppression, per packet encryption and transaction management [2]. However, end-to-end communications cannot be applied in this offline email system because of the rural area is lack of continuous connection from sender to receiver. TCP/IP drops the packets if the next connection cannot be found immediately. Delay tolerant network (DTN) protocol is used in this thesis to solve this problem. DTN used store and forward operation and introduced a bundle protocol in between the application layer and the transport layer.
Delay tolerant network (DTN) is an approach to computer network to overcome the lack of end-to-end network connectivity. DTN tolerates delay and disruption with acceptable performance in high loss and delay error environments. DTN tries to solve some of the issues by relaxing some of the TCP/IP end-to-end communication assumptions by introducing bundle protocol. The bundle protocol defines a series of data blocks as a bundle. Bundles are routed in Store and Forward operation from source node to the destination node. Store and Forward operation is a DTN fundamentals where it is designed to use storage within the network and perform incremental progress before proceeding to another path.
This thesis focuses on an offline email system implementation in a rural area with some modification to the protocol because it is designed as such the email needs to be transferred to another different device before it can be transmitted. This offline email system is designed for rural users with no internet connection to allow them to access their email account and compose new messages or check the last reply as shown in Figure 1.1. Village A and Village B are located very far from the telecentre, from three kilometers to 40 kilometers. Rural villagers send their emails using their laptop or handphone and send it to the nearby offline mail server. From this offline mail server, the appointed person with infomediary device will collect all the emails from the offline mail server by positioning his infomediary device close to the offline mail server so that the transmission takes place wirelessly based on wireless local area network (WLAN) based on IEEE 802.11 standards. Conventionally, there is a need of a more internet hotspot datacenter at each village to stay connected which will require a higher cost.

Email application is asynchronous in nature and do not need end-to-end connectivity. Therefore, DTN store and forward fundamental is suitable for use to implement an offline email system in a rural area. In this thesis work, the store and forward process implemented by using file synchronization method. Store and forward process is a technique in which data is sent to an intermediate station and kept temporarily before sent to the final destination or to another intermediate station [3]. The file synchronization process is critical because the offline email on the offline mail server should capable to synchronize its database with the intermediate device and the online mail server. The intermediate device, known as an infomediary device is a temporary storage for the email database. This device collects the emails from the offline environment and brings them to the online environment.

Figure 1.1: Offline email system overview
This offline email system is working in two different environments which is an offline local area network (LAN) environment and online internet environment. Both offline and online mail server running on operating system Windows XP 32bit. Smartphone android 2.3.5 conjunction with Samba File sharing application working as an infomediary device to allow receiving and sending files between both mail servers. Only one online mail server is connected to regular Streamyx ISP (Dynamic IP) internet connection instead of the need of a more internet hotspot datacenter at each village.

Monday, October 20, 2014




A thesis submitted
In fulfillment of the requirements for the Master of Advanced Information Technology

Faculty of Computer Science and Information Technology


This thesis focuses on extending offline email system in a local area network environment to the internet connected email system in online environment based on delay tolerant network. This offline email system will allow the rural users to have an access to the internet connected email system. It allows the user to read, write and send email in an offline local network environment. This offline email system will be able to connect to online email system via infomediary device based on delay tolerant network concept. Even though in an offline environment, user also able to read, write and send email as if he or she is in an online environment. This offline email system will allow the email flow through the offline environment to the online environment and vice versa. The most important part of this offline email system is an implementation of email database synchronization between offline mail server and infomediary device and between online mail server and infomediary device. Another part is an implementation of offline and online email system consist of mail server and mail client for both sides. This offline email system will be using operating system Windows XP 32bit, wireless local area network, and internet connection 1MB/s TMnet Streamyx Dynamic IP with the conjunction of Uniform Server for personal home server. This offline email system consists of offline mail client, offline mail server, database synchronization at offline server, infomediary device, online mail client, online mail server and database synchronization at online server.

Informediary Device - Data Mule

Data Mule is an evocative term for a vehicle that physically carries a computer with storage between remote locations to effectively create a data communication link. A data mule is a special case of Sneakernet, where the data is automatically loaded and unloaded when the data mule arrives at its terminal locations. Disruption Tolerant Networking (DTN) can use data mules to exchange data among computers that do not have access to the TCP/IP-based Internet.
Data mules have been used to offer internet connectivity to remote villages. Computers with a disk and wifi link are attached to buses on a bus route between villages. As a bus stops at the village to pick up passengers and cargo, the DTN router on the bus communicates with a DTN router in the bus station over Wi-Fi. Email is down-loaded to the village and up-loaded for transport to the Internet or to other villages along the bus route.
Data mules are a cost-effective mechanism for rural connectivity because they use inexpensive commodity hardware, can be quickly installed, and can be piggy backed on existing transportation infrastructure.
Despite potentially long delays for receiving data, surprisingly large bandwidths can be achieved. For example, delivering a 1TB disk once per day has an effective bandwidth of 100Mbit/s.
The term data mule was originally coined as the acronym Data MULE. (Mobile Ubiquitous LAN Extension)


^ Alex (Sandy) Pentland, Richard Fletcher, Amir Hasson, "DakNet: Rethinking Connectivity in Developing Nations," IEEE Computer, vol. 37, no. 1, pp. 78-83, Jan. 2004 [1]
^ Eric Brewer, et. al. "The Case for Technology in Developing Regions," IEEE Computer, vol. 38, no. 6, pp. 25-38, June 2005, [2]
^ Rahul C. Shah, Rahul C. Shah, Rahul C. Shah, Waylon Brunette, "Data MULEs: Modeling a Three-tier Architecture for Sparse Sensor Networks" Intel Research Tech Report IRS-TR-03-001 January, 2003.[3]

Sunday, October 19, 2014

Project Sketch: Draft of Plan

Feasibility Study of DTN
Email System Architecture Study
-Mail Server
-Informediary Device
-Info Station Laptop
-Mail Client
Server Setup
-Mail Server = hMailserver
-Mail Client = SquirrelMail
-File Synchronization = FreeFileSync
Hardware Setup
-WiFi/LAN Router
-2 Network PCs(Mail Server/Mail Client)
Installation & Testing

1) Project Outline
 This application introduces new technique for email, blogs and bulletin  bulletin boards
 to be kept in the memory box temporarily before the data will be sent to
 another temporary hard disk and finally to the mobile server. For MAIT 6
 months studies, the scope will be smaller - Maybe on one of these -
 addressing /application/ performance. Start with comparison offline and
 online, outline the features needed in offline, requirements, design and
 simple results with justification.

2) Collection of Data
Emails,Blogs,Bulletin Boards ->memory box->temporary hard disk->mobile server

3) Analysis of Data

Comparison Offline & Online System

Features needed in Offline System

4) Chapter (s) Completed and Progress





5) Problem (s) Faced

6) References