Master of Science ThesisStockholm, Sweden 2012

TRITA-ICT-EX-2012:248

M O H A M M A D R E Z A I Z A D I

Fat/Thin client for mobile applicationsand the proposed way forward

K T H I n f o r m a t i o n a n d

C o m m u n i c a t i o n T e c h n o l o g y

Fat / Thin client for mobile applications

and the proposed way forward

Mohammad Reza Izadi mrib@kth.se

Master’s Thesis at Aastra Telecom AB / Sweden

KTH

Electrical Engineering

Wireless systems

Supervisour at Aastra Telecom AB / Sweden: Stefan Möller

Supervisor at KTH: Prof. Svante Signell

Examiner at KTH: Prof. S. Ben Slimane

i

Abstract

This project is aimed to highlight the

effectiveness of using clients on mobile

phones. The paper clarifies the need of

FMC by introducing new features in

business case that are going to be

executed in the near future to facilitate

the communication and interaction

among people and global networks. The

major subject discussed is to achieve a

goal in the telecommunications world

which is to lessen the call cost especially

when it comes to international calls by

implementing ‘GPRS Call Back’ using a

client installed on the mobile phone.

Moreover, two types of clients are

introduced namely ‘Thin’ & ‘Fat’ client.

Due to the fact that the user is able to use

one of the clients at one time, one of them

must be chosen as a preferred client to be

installed and used by the users. Owing to

the pros & cons related to each client,

comparison between two clients is

addressed based on some test cases

designed to experiment the usefulness of

both clients in several conditions.

iii

Acknowledgment

I would like to thank Professor

Svante Signell at KTH and Stefan

Möller at Aastra Telecom AB for their

advices and feedbacks while I was

doing this project.

I also thank my parents for all their

supports during my M.S. program.

v

List of Abbreviations

3G 3rd

Generation

iLBC Internet Low Bitrate Codec

ADSL Asymmetric Digital Subscriber Line

AMC Aastra Mobile Client

API Application Programming Interface

APSD Automatic Power Save Delivery

BSC Base Station controller

BTS Base Transceiver Station

CGI Common Gateway Interface

DCE Distributed Computing Environment

DLL Data Link Layer

DSL Digital Subscriber Line

DTMF Dual Tone Multi Frequency

FMC Fixed Mobile Convergence

FNO Fixed Network Operator

FTP File Transfer Protocol

GPRS General Packet Radio Service

GSM Global System for Mobile Communications

GUI Graphical User Interface

HTTP Hyper Text Transfer Protocol

IP Internet Protocol

IVR Interactive Voice Response

IM Instant Messaging

LAN Local Area Network

LCR Least Cost Routing

MC Mobile Client

MLCR Mobile Least Cost Routing

MNO Mobile Network Operator

OS Operating System

OSF Open Software Foundation

PBX Private Branch Exchange

PC Personal Computer

PSTN Public Switched telephone Network

QoS Quality of Service

ROI Return of Investment

RPC Remote Procedure Call

SEK Swedish Krona

SIM Subscriber Identity Module

vi

SIP Session Initiation Protocol

SMS Short Message System

SQL Structured Query Language

UMA Unlicensed Mobile Access

UMTS Universal Mobile Telecommunications System

UNC UMA Network Controller

UWN Unlicensed Wireless Network

VoIP Voice over IP

WiMax Worldwide Interoperability for Microwave Access

Wi-Fi Wireless Fidelity

WLAN Wireless Local Area Network

vii

List of Figures

1. Wireline Vs. Wireless Connection- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1

2. FMC Solution - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1

3. PBX links Fixed and wireless lines in an office - - - - - - - - - - - - - - - - - - - - - - - - - - 2

4. UMA Network Architecture - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 5

5. Femtocell usage at home - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 6

6. IP-PBX connects all devices via IP - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 8

7. Traditional Fat Client / Server - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 10

8. Thin Clint / Server - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 11

9. 3-Tiered Application Architecture - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 12

10. Web-Oriented N-Tiered Architecture - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 13

11. 4-Tiered Architecture with Server Load Balancing - - - - - - - - - - - - - - - - - - - - - - - - 13

12. Thin client’s layers - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 15

13. Fat client’s connections - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 15

14. ‘Aastra’ Client display on the phone - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 19

15. ‘Mobisma’ thin client display on the mobile - - - - - - - - - - - - - - - - - - - - - - - - - - - - 19

16. Out-of-call Functions - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 20

17. In-Call Functions - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 20

18. AMC Client Home Screen - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 22

19. Traditional way of making international calls - - - - - - - - - - - - - - - - - - - - - - - - - - - 32

20. Call back service via PBX - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 33

21. Call back service using PBX as an interface - - - - - - - - - - - - - - - - - - - - - - - - - - - - 34

22. Mobile roaming least cost routing business case - - - - - - - - - - - - - - - - - - - - - - - - - - 41

23. Return of investment - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 42

viii

List of Tables

1. First ten cases performed by fat client - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 29

2. DTMF Configuration on NOKIA E51 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 30

3. Roaming Calls - Traffic from ‘TeliaSonera’ operator for normal calls - - - - - - - - - 36

4. Data Traffic form ‘TeliaSonera’ operator for normal calls - - - - - - - - - - - - - - - - - - - - 36

5. Roaming Calls - Traffic from ‘TeliaSonera’ operator for GPRS Call Back - - - - - - - - - - 36

6. Data traffic for Call Back service using ‘AMC’ - - - - - - - - - - - - - - - - - - - - - - - - - - 37

7. Roaming Calls -Traffic by using ‘AMC’ + ‘PC Client’- - - - - - - - - - - - - - - - - - - - - - 37

8. Roaming Calls traffic for ‘Travel SIM’ + ‘MLCR’ - - - - - - - - - - - - - - - - - - - - - - - - 39

9. Data traffic for ‘Travel SIM’ + ‘MLCR’ - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 39

10. Data traffic for Call Back service using ‘Travel SIM’ + ‘MLCR’ - - - - - - - - - - - - - - - 39

11. Roaming calls traffic for ‘Travel SIM’ + ‘MLCR’ + ‘PC Client - - - - - - - - - - - - - 40

ix

Table of contents

1. Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1

2. Fixed Mobile Convergence - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 4

2.1. FMC Architecture - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 4

2.2.Architectures to implement FMC - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 4

3. IP-PBX - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 8

4. The Evolution of Client / Server Computing - - - - - - - - - - - - - - - - - - - - - - - - 10

5. Fat & Thin client - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 14

5.1. Thin Client Architecture - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 14

5.2. Fat Client Architecture - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 15

5.3. Thin Client Advantages - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 15

5.4. Thin Client Disadvantages - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 16

5.5. Thick Client Advantaged - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 17

5.6. Thick Client Disadvantages - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 17

6. Background - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 19

6.1. ‘Aastra’ Client - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 19

6.2. ‘Mobisma’ Client - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 19

6.3. Client’s Task - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 19

7. AMC Specifications - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 21

7.1. AMC features and advantages - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 21

7.2. Supported handsets - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 22

8. Study - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 25

9. Execution - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 26

9.1. Structure - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 26

9.2. Examples - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 28

9.3. Example of two test results - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 29

10. Describing the problem - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 32

11. Low cost international calls - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 33

12. Results - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 35

12.1. Normal calls - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 35

12.2. AMC Mobile LCR - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 36

12.3. AMC+PC Client - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 37

x

12.4. Travel SIM+PC Client - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 38

12.5. Travel SIM+MLCR+PC Client - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 40

12.6. Mobile roaming least cost routing business case - - - - - - - - - - - - - - - - - - - 41

12.7. Return of Investment - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 42

13. Thin & Fat client, comparison in functionality - - - - - - - - - - - - - - - - - - - - - - 43

14. Conclusion & Future works - - - - - - - - - - - - - - - - - - - - - - - -- - - - - - - - - - - - 46

15. References - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 47

16. Appendix - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 48

16.1. Example of a feature file - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 48

16.2. Roaming calls traffic from ‘TeliaSonera’, ‘Telenor’, and ‘Tre’ operators - - - 49

1

1. Introduction

Having wired line connection requires

us to have access to the wired system

(fixed line); therefore the user needs to be

inside the building where s/he can use the

system. Wireless connection solved the

problem, however due to barriers and

obstacles inside the buildings which lessen

the effectiveness of the propagation of

signals in the air, one needs to move

outside of the building to receive signal

and voice with good quality. Figure (1)

shows the problems arise by having only

one option of using wireline or wireless

connection.

Figure (1): Wireline Vs. Wireless Connection

FMC (Fixed Mobile Convergence)

brings the solutions by connecting wired

(fixed) line, and wireless (mobile) line.

The solution gives the opportunity of

answering either fixed line phone or

mobile phone. Obviously depending on the

situation that the user is standing on, desk

phone or cell phone can be used;

consequently no call or message gets lost

in the network. Figure (2) represents how

FMC solution eases communication by

increasing alternatives of replying calls.

Figure (2): FMC Solution

2

Having explained FMC, one is able to

answer either mobile phone or fixed line

phone when another party has made a call

to him, since both phones ring at the same

time. From the business point of view a

working person belongs to the enterprise,

regardless of the time and place. So even

when he makes a call from his mobile

phone to another party, his office phone

number (not his mobile number) is

displayed as his number.

Having explained FMC solution, next

equipment which comes as a handy device

to ease communication will be introduced.

A device that is basically used to do this is

called PBX (Private Branch Exchange).

PBX connects all internal fixed lines in a

factory / organization, and is also able to

link mobile phones (configured by

administrator) to the entire system. Figure

(3) simply shows the connection made by

PBX.

Figure (3): PBX links Fixed and wireless lines in an office

PBX makes easier dialling by

introducing extension number instead of

the whole number, e.g. 45678 instead of

0812345678, and also it integrates the

phones of one enterprise into a unified

system. Since phones are linked via

internal network, there is no cost for

making a call in this way!

Phone devices have been designed so

that they are able to perform many internal

office functions, but mobile phones still

lack a program to join them to the system.

What can be helpful in this case is called a

‘Client’. Invention of clients improved the

functionality of mobiles in the

communication systems. Client is a

program that is installed on the mobile

phone, giving the possibility of performing

all the applications accessible by PBX. As

a matter of fact a client works as an

interface between enterprise and operator.

Two different types of clients are

available: ‘Thin’ & ‘Fat’ Client. Fat client

is based on databases downloaded or

installed on the mobile phone, however

thin client basically is a server based client

which receives data from the server.

Clients have several applications which

will be discussing in this paper. Moreover

we are going to utilize the entire system to

achieve one of the main goals of the

telecommunication world which is

lowering call costs, especially when it

comes to international calls.

3

In this paper firstly FMC technology and

its architectures are described as well as

several ways of FMC implementation.

Next comes an introduction to IP-PBX to

give a simple concept of transmitting data

over IP where internet, phones, faxes, and

other devices can be connected and used

via PBX. Then evolution of Cleint / Server

is explained followed by Fat & Thin Client

description. What has been done for clients

is in the ‘Background’ part of the project

whereas in the ‘Study’ section it is argued

how to begin approaches for solutions. In

this trend, in the ‘Execution’ we explain

how a client is programmed by a feature

file to interact to the PBX, and outside

world; proceeding with the MLCR strategy

to reduce international call costs.

Second part of the paper relates to a

brief comparison between thin & fat client

is done, mostly based on the performed

tests on available clients. Each client has

its own advantages and disadvantages

which empowers it to be used in a specific

situation.

4

2. Fixed Mobile Convergence

What is intended to be fulfilled by FMC

is to provide a service which has both

fixed-line access provided by fixed

network operator (FNO), and mobile

access provided by mobile network

operator (MNO) in a single device. [2]

Several opportunities are driven by

advances in VoIP and cellular networking

technologies which improve productivity

in the industry and save telecommunication

expenses. By applying FMC, mobile

phones are able to connect to Wi-Fi

networks that provide lower call cost,

higher bandwidth, and having better indoor

coverage of Wi-Fi networks.

2.1. FMC Architectures

Several different architectures are

known within enterprise FMC, which are

distinguishable depending on how closely

mobile phones are linked to the enterprise

PBX. These architectures can be classified

as follows:

PBX-Centric

In this model, PBX acts like an anchor-

point for calls. When a user makes a call, it

is directed to the PBX, and PBX originates

a number to the second user so that the

recipient views the PBX number on his

caller-ID. If the phone is having the Wi-Fi

coverage, it gets connected directly to the

PBX via VoIP protocols, and all features

appear like a desk phone. If the phone is

outside the range of Wi-Fi, the phone acts

as a client of PBX.

PBX-Independent

Server is the anchor-point for managing

calls in this architecture, however relies on

the PBX for its telephony gateways. Server

works with different type of IP, and special

client needs to be installed on the handset

to interact with PBX while running

different applications on the phone.

Carrier-Centric

The strategy is based on a different

approach to FMC. In this architecture,

PBX has no role. The user installs a Wi-Fi

access point at home, and uses it whenever

the cellular coverage is poor. The cellular

network transports all calls to Wi-Fi

whenever the mobile phone is in the range

of access point.

The most famous carrier-centric FMC is

realized as UMA (Unlicensed Mobile

Access) which is a standard form of GSM

that is able to co-operate with many GSM

operators. [1]

2.2. Architectures to implement FMC

services

FMC services can be implemented in

four different architectures which are

known as:

Convergence within the handset

(Wi-Fi microcells at home)

The strategy works on the base of dual

mode (GSM-Wi-Fi or UMTS-Wi-Fi)

terminals which is also known as UMA

(Unlicensed Mobile Architecture).

Therefore the dual mode handset has

access to 2G/3G mobile services over

unlicensed spectrum technologies. [5]

UMA is a technology that allows mobile

services to be delivered by carriers over

Wi-Fi networks. Once UMA is

implemented, subscribers are then able to

automatically roam and switch between

Wi-Fi and cellular networks, having an

advantage of using UMA-enabled dual-

mode cellular / Wi-Fi handsets.

Subscribers benefit from the fact that

5

UMA has provided a service enabling

them to receive a high-performance, low

cost data as well as being capable of

connecting to a Wi-Fi network whenever

needed. [1]

Figure below illustrates how a dual-

mode handset works with both GSM and

Wi-Fi services:

Figure (4): UMA Network Architecture [10]

For the ‘indoor mode’ where the user is in

the coverage area of specific hot spots,

data is transmitted and received over IP,

and Wi-Fi technology is used. The call is

first routed through UWN (Unlicensed

Wireless Network), then to UNC (UMA

Network Controller), and finally to the

‘Mobile Network’ while normal fixed-like

tariffs are applied.

For the ‘outdoor mode’ the handset is

connected to the mobile network, and work

with GSM Service. Likewise the call is

first routed to BTS (Base Transceiver

Station), then to BSC (Base Station

Controller), and from there to the ‘Mobile

Network’, whereas tariffs are higher.

The mentioned strategy is for the

outgoing calls, and for the incoming calls

the reverse process is applied. The terminal

is able to switch automatically between

two services.

FemtoCells at home

A femtocell is a small cellular base

station installed at home providing wireless

access for indoor usage, however its

coverage and capacity is limited. Figure (5)

shows a deployed femtocell and its

connection to devices at home and outside

home.

6

Figure (5): Femtocell usage at home[11]

FemtoCells used at home increase the

indoor coverage for voice and high-speed

data mobile services. Connection to the

internet is carried on cable, DSL, or fiber.

If the user is located in the range of the

femtocell, the normal cellular network

covers its transmit ion signals; otherwise

the traffic is made by over the internet

connection (via broadband router).

Since a femtocell does not contain any

specific planning or manual configuration,

it can be easily installed and used by users

at home or enterprise environments. One

drawback to this technology is that a

femtocell is not capable of supporting

more than 5-8 users. On the other hand

femtocells provide customers with all the

benefits of a converged network including

mobile and fixed line connections. What a

user benefits the most is the ability to use

normal 3G handset which does not require

any modification or customization, which

is the only device he needs for having

access to the network anytime anywhere.

Offer a fixed like rate (Home-Zone)

This technology is fully based on the

mobile network. There are two existing

models applied for this type of

architecture:

- Pure mobile service with mobile

number only

No matter where the end-user is located

(inside or outside the ‘Home Zone’), the

number remains a mobile number. What a

customer gains is the fixed like rates for

outgoing calls made inside the ‘Home

Zone’. Incoming calls are charged

according to the tariffs defined by the

operator of the calling party.

- Usage of two different numbers

A fixed mobile number is used when

user is in the range of the ‘Home Zone’,

and a mobile number when he is outside

the ‘Home Zone’. The Mobile Network

checks if the user is inside the ‘Home

Zone’, and if so, it makes a connection

through the fixed number. In this case the

user benefits from the fixed rate prices for

outgoing calls. Some services such as

secretary services or short message service

enable the user to receive notification of

incoming calls when he is outside the

‘Home Zone’. The customer can also make

use of the fixed number to direct incoming

calls to his fixed number.

VoIP on mobile broadband

Since communication services are

becoming IP-based, VoIP gets more and

more popularity amongst other services.

VoIP has the potential to replace

traditional PSTN services as public

Electronic Communication services.

7

VoIP-based services are accessible via

ADSL, cable modem, Wi-Fi, WLAN, 3G

or other broadband IP connections through

VoIP terminals. Hence there are named

according to the underlying transport

technology such as: Voice over Broadband

(VoB), VoIP over mobile (VoWLAN,

Vo3G, VoWimax), etc. [2]

8

3. IP-PBX

For a normal PBX two separate

networks are needed: one network for

voice, and one for data.

Having utilized ’Voice over IP’ to send voice over data, removes the need for the

network used for voice transmission. As a

matter of fact an IP-PBX is comprised of

two different parts: a switch / router, and a

PBX which is in charge of voice

transmission over IP.

Figure (6): IP-PBX connects all devices via IP

In order to avoid QoS issues which are

the consequence of setting both computers

and telephones on a shared LAN,

computers are installed on a shared LAN

that is connected to the IP-PBX, while

telephones directly connected to the IP-

PBX as shown in the figure (6). Another

point worth to be considered is not

transmitting voice packets in a timely

manner to avoid poor telephone voice

quality.

An IP-PBX can be used with:

IP-Phones converting voice to IP

packets and vice versa. Soft phones using with a handset

Existing phones along adaptors and

standard phones connecting to PC’s.

Protocols used for packetizing VoIP

packets are:

- G.711: A standard for packetized voice

using 64 Kbs

- G.723: A standard for packetized voice

using 6.4 Kbs

Other standards used in IP-PBX

software are:

- H.323: A protocol for signalling and

telephone services used for

transmission of IP packets for voice,

video and data.

9

- SIP (Session Initiation Protocol):

Another protocol like H.323, but

quite simpler.

Some new technologies which were not

typically usable with the traditional

networks – such as using one central

directory across multiple locations and

unified messaging – are applicable by

implementing a single converged network

that has the advantage of carrying both

voice (pocket-sized) and data. Another

advantage is that a telephone can be moved

from one place to another since IP

addresses are defined to phones once they

are connected to the system.

As far as financial issues are concerned,

IP-PBX is a good candidate to be used in

new businesses since it needs only one

network instead of two, reducing cost

when a network is about to be designed

and implemented, as well as avoiding long

distance changes between branches and

using one centralized directory that is

cheaper than many multiple directories.

All in All, main advantages of an IP-

PBX compared to a conventional PBX are

as follows:

Handling both voice & data

Being cheaper by installing one

network instead of two

Reducing long distance changes

Being easier to provision

Allowing remote configuration

Supporting services such as unified

messaging

Being more flexible & scalable

[6]

10

4. The Evolution of Client / Server Computing

Back to many years ago computing

devices were only able to do processing at

the mainframe. Personal computers

replaced dumb terminals however

processing still used to be done on the

mainframe. As processing data became

more complicated, the need for sharing and

splitting data between mainframe and PC

arose. Hence the Client / Server technology

appeared to control huge amount of

computing processes and data storage.

Client / Server concept is recognised as

a system in which software components

interact so that multiple users are able to

communicate properly among each other.

In other words, this technology is a

computing architecture which makes an

integrated system among computers and

PCs on a network allowing distributed

computation, analysis, and presentation.

The client & server might exist on different

machines. Normally server is located at

one site in LAN, and client at the other

site.

Connectivity between Client / Server is

provided by networks using proper

protocols for communicating, or internet.

Interestingly the Client / Server computing

model is the base of many services and

systems used on the internet such as File

Transfer Protocol (FTP) that uses Client /

Server interaction for sending and

transmitting files between servers. The

following sequence is executed in such a

system:

- FTP Client requests a file existed

on another computer

- FTP server handles the client’s

request

- The server fetches the requested

file

- The file is sent to the client’s

system by the server

Several architectures of Client / Server

are discussed as below:

2-Tiered architecture

Client presents a GUI to the user and

calls for data from the server, whereas

database server is running on another

machine. A simple model of a Client /

Server application is comprised of a client,

and an application server. In other words

implementation of such a system is a Fat

Client-Thin Server where application logic

is placed in the thin client. Figure (7)

shows how a traditional fat Client / Server

works.

Figure (7): Traditional Fat Client / Server

11

Another alternative is using a Thin

Client-Fat Server model. In this pattern the

client manages the presentation part while

processing section is divided between

client & server, and database is stored in

the server. Due to the need for connecting

to the server for sketching data, allocated

bandwidth and number of users capable of

using the network effectively, is reduced.

Accordingly the network and transaction

speed are also slowed owing to heavy

interaction between client & server. Figure

(8) illustrates a brief performance of thin

client / server. Notice that the mentioned

architectures are not designed for mission

critical applications.

Figure (8): Thin Clint / Server

Advantages of 2-tier system are known

as:

- Good application development

speed

- Most tools for 2-tier are very robust

- 2-tier architectures work properly

in homogeneous environments with

fairly static business rules

3-Tier Architecture

Developing 2-tier architecture to 3-

tier architecture requires placing a

middle tier in between a client and

server. Three separated layers are

defined for this configuration:

presentation layer, functionality layer,

and data layer. The middle tier server is

typically coded, and is accessible by

several clients from separate

applications.

A standard protocol (DLL, API,

RPC) is responsible for handling the

connection of the client and the middle

tier as well as translating client calls to

database requests and vice versa.

Placement and connection between

Data Server, Application Server, and

Client is shown in figure (9).

12

Figure (9): 3-Tiered Application Architecture

Advantages of 3-tier architecture:

- RPC calls provide greater overall

system flexibility than SQL calls in 2-

tier architectures

- Understanding SQL is not a

requirement for 3-tier presentation;

subsequently firms will have access

to legacy data, and introduction of new

database technologies are simple.

- Provides for more flexible allocation

- Modularly designed middle-tier code

modules are reusable by several

applications.

- 3-tier systems such as Open Software

Foundation’s Distributed Computing

Environment (OSF/DCE) allows

additional features to support

distributed applications development.

N-tier Architecture

By increasing the number of middle

tiers to make connections to various

types of services, N-tier configuration

is created. These middle tiers act as an

integrator to link clients to servers, and

also to each other. Another way of

implementing an N-tier system is

partitioning the application logic

among hosts.

As illustrated in figure (10) the client

sends HTTP requests, and presents the

response received from the application

system. The web server that is used to

offload the network according to the

loads of data sent by the users’ requests

either returns or passes it to an

application server. Depending on what

the user (client) has requested, the

application server then run CGI scripts

for dynamic content, analyze database

requests, or set-up formatted responses

to client by having direct access to the

database (file) server.

13

Figure (10): Web-Oriented N-Tiered Architecture

As the system works, bottlenecks where

data is slowed can be identified and cleared

by adding the particular layer which causes

the bottleneck. Figure (11) simply shows

how multiple web servers tied to server

load-balancing can be used to provide

effective load-balancing between the

servers.

Figure (11): 4-Tiered Architecture with Server Load Balancing

The ability of servers to manage

end-to-end performance is of

importance since several users attempt

to access remotely for business-critical

functions. To achieve proper QoS in

case of ever-increasing load on servers

3 techniques are suggested:

Upsizing the servers

Deploying clustered servers

Partitioning server functions into a

‘tiered’ arrangement

In conclusion by deploying N-tier

architecture, application logic is split and

organized leading to faster

communications, greater reliability, and

better efficiency. [7]

14

5. Fat & Thin Client

Fat (Thick / Full) client is generally a

designed system which has software

loaded on the PC, mobile phone, etc. [3] In

this system, the client has a local copy of

the database on the device. [5] Therefore

the client is able to perform many

functions with no need for connection.

Thin client is basically a pure browser

based station. This indicates that there will

be no need for installed software on the

user’s PC, mobile phone, etc.; but a web

browser which allows the connection to the

server. [3] In fact devices are dependent on

servers for data storage and most services.

[4]

As far as this paper is concerned, two

mentioned clients are going to be discussed

in wireless applications. Thus from this

point on the focus will be on the roll of

clients on the mobile phone, and how

would be the effect of them on executing

several functions.

5.1. Thin Client Architecture

For having a better understanding about

the effectiveness of thin client on wireless

applications, first we have to study the

multi-layer thin client architecture to

recognize each component’s work. Two

Sides are known for wireless technology:

Client & Server. Layers defined according

to these sides are:

Client side

- Browser on device:

Browser is the only client layer of a

wireless system. The browser shows

information on the user’s device, which is

seen by the user. The information could be

written data, pictures, videos, etc.

Server side

- Presentation Logic:

This is the first and highest server-side

layer which specifies the device type and

must be able to mange the device’s

language by which information will be

shown to the user. This layer is very

critical since it should be compatible with

many devices to be usable in a wide range

of applications.

- Business Logic

This layer is responsible for business

rules for the application. Consequently this

layer must have a complete access to all

parts of the ‘Data Access Logic’ layer.

- Data Access Logic

The lowest layer of the wireless solution

is a critical component which makes it too

complex to be created. [5]

15

Figure (12): Thin client’s layers [5]

5.2. Fat Client Architecture

There are no layers defined for fat client.

The client has a local copy of database,

GUI (Graphical User Interface) on the

device. The connection between the device

and application server is either through

wired or wireless link.

Figure (13): Fat client’s connections [12]

5.3. Thin Client Advantages:

No download or installation:

The most important advantage of having

a thin client is the elimination of the need

for download a program, and installation of

different user interfaces to run the

program.

No installation conflicts, versioning

or environment issues

By executing the client user interface

from the browser, some problems

regarding installation will not occur.

Furthermore, some changes during

16

installation might affect previously

installed programmes, which could be very

disturbing when it affects other vendors’

software.

Available from any PC with

browser

Thin client can run on any platform that

supports the browser. This means that

neither configuration, nor file transition

between devices is needed for the client to

access information from any browser.

Instant updates and revisions

Having access to the server at anytime

anywhere makes it possible for the client to

get the very most updated and revised

information. [5]

Other advantages attributed to the thin

client are:

supports existing Web sites;

if the device is lost or stolen, it can

be disabled remotely;

no software deployment necessary

on client side;

updates take place over the air;

all processing and management

occurs at the server, so the mobile

device has fewer points of contact

with processing activity;

offers vendor-neutral, standard

integration with third- party Web

2.0 sites (e.g. Flickr, Facebook,

MySpace); and

data collected can be uploaded

immediately to Web 2.0

communities. [8]

5.4. Thin Client disadvantages:

Low level of interactivity

Since data transition requires connection

to the server, there is a lower level of

interaction between the user, and thin

client. For instance once some data is

shown on the screen, it would be difficult

to change screen entries based on the

previous entries.

May have to navigate multiple

browser screens to emulate current

client screens

Inasmuch as invoking data on the screen

involves a round trip to the server, this

process might also be slower comparing to

the thick client which has direct access to

the data source.

Must write to the lowest common

browser

The growing rate of browsers to the

market makes it more difficult for a thin

client to benefit form the newest browsers

with the latest features. The thin client user

interface must be written in a way to be

working with the lowest browsers which

may not have the advantage of newer

browser functionality.

Requirement of always on

connectivity

Obviously the thin client must always be

connected to the server, which is not

practically possible in some situations. [5]

Other disadvantages of thin client are

known as:

high-performance, scalable servers

required;

high bandwidth must be available

for multimedia applications;

additional thin clients place more

demands on the server;

if the network is down, the thin

client cannot access the server and

required processing power; and

Scaled screens and less robust

applications. [8]

17

5.5. Thick Client Advantages:

Rich screen functionality, high

level of interactivity

Since the client has the local copy of the

data base, applications appear to be more

interactive to the user which makes screen

applications seem faster.

Required client adds security,

persons w/o client cannot access

system

Security has a higher level since

outsiders cannot easily reach the installed

server side information.

No requirement of always on

connectivity

The thick client only needs to connect to

the server in order to sync the back end. As

a result the client is still capable of

working when a stable connectivity does

not exist. [5]

Some more advantages for fat client are

as follows:

offline and online use

reduced over the air (OTA)

network costs

wired and wireless modes

prolonged battery life due to offline

usage

a wide variety of applications

available

End-to-end security solutions

possible on client and server side.

[8]

5.6. Thick Client Disadvantages:

Updates, new features, and bug

fixes require users to download and

install client side software.

Once a user interface under thick client

is installed, other programs must be

somehow fixed to work with that. Arriving

new features and bug fixes require user

interface changes to be compatible with

those programs. This is the most important

disadvantage of thick clients because a

new interface must be built and installed to

be used for the case.

Server must account for multiple

versions of clients, increasing

complexity

Not all the users change to new client

software applications at once, and some

stay with the older versions; therefore

server must recognize different versions of

clients’ formats to service properly to all

terminals.

Cannot access system from “ad-

hoc” locations unless client is

installed

If software is not installed on the

system, in case of need to that software,

thick client is unable to request

spontaneously. Moreover the condition

becomes even worse when the user work in

different location, and cannot have access

to the whole installed soft wares. [5]

Other fat client related disadvantages:

purchasing and maintaining

applications on numerous devices

increases costs

some platforms have limited

application options

distribution of latest updates can be

difficult to coordinate

need to create back-end services to

support the use of access points

specific to a phone or network

Device and data security is

required, since the device stores

data. [8]

18

All in all making a decision on which

client to be chosen depends on the

requirements of application in each case.

As a matter of fact there is a trade-off

between the features of two types that

requires the necessity of considering

different working conditions to decide on

which client is more suitable.

19

6. Background

Several vendors have released mobile

clients for mobile phones. These clients are

installed on the phones, and are tested to

verify that they are working properly.

Two clients are available in this project:

6.1. ‘Aastra’ client which is a fat client

designed by a German company called

‘Comdasys’. Since it is a new client, it has

to be tested for different features, and the

problems happening during the test need to

be removed. Figure (14) shows the display

of this client.

Figure (14): Aastra Client display on the phone

The client contains almost all functions

that are available in the normal (without

client) mode as well as having new

features letting the user to utilize them

according to his need.

6.2. ‘Mobisma’ client which is a thin

client designed by a Swedish company

called ‘Mobisma’. Like the previous one

this client should also be tested for

verification of its features. Figure (15)

represents the display of this client on the

mobile phone.

Figure (15): Mobisma thin client

display on the mobile phone

Although the display differs a bit from

the normal mode, it is ready for testing.

The display can be improved in the next

versions.

6.3. Client’s task

The client is designed so that the normal

functions such as dialling, answering, etc.

are like the normal mode (without client),

as well as having new features in the stand-

by mode (out-of-call features), and during

the talk on the phone (in call features).

Out-of-call features are features that one

is able to active before receiving a call. As

an example in case of being busy due to

having lunch, meeting, vacation, etc. one

adjusts his phone so that he is not

reachable. If a second party tries to follow

the mobile phone holder, depending on the

adjustment, he would follow another phone

or end up in other options. Figure (16)

shows several possibilities that one is able

to select according to his position. In case

one is not available, the client is

responsible for dropping the call or

diverting it to another number.

20

Figure (16): Out-of-Call Functions

In call (during call) features are

applicable either while both parties are

talking on the phone, or when the second

party is busy. Obviously the second party

is always affected by applying in-call

features. We consider both possible

scenarios with some examples:

1. Both parties are talking:

The user decides to initiate another call,

but he wants to keep the current call as

well. The feature is called ‘Enquiry’ that

allows the user to perform the task.

Moreover, the user can move between the

calls, do conference call, etc.

2. The second party is busy:

In case of urgent need to talk to the

second party when he is busy, the user

makes a call waiting after hearing the busy

tone, and the second party is alerted by an

extra beep during his talk. The user is also

able to activate call-waiting, that makes a

call to himself from the second party when

he gets free. Figure (17) illustrates some of

functions available to perform during the

call.

Figure (17): In-Call Functions

21

7. AMC Specifications

Inasmuch as this project is mostly based

on AMC Client, we intend to describe

more about its applications as well as

considering main attributed specifications

according to the information that

‘Comdasys’ -the designer enterprise- has

obtained:

The AMC Client is an FMC mobile

application which is able to be run on dual

mode handsets. The client works in

conjunction with the ‘Comdasys FMC

controller systems.’ Regardless of where

the user is standing and whatever network

(Cellular or WLAN) he is using, the AMC

Client provides users with Unified

Communication services. It has been

designed and optimised in a user-friendly

manner so that no matter what kind of

baseband and the chosen communication

mechanism is, the client provides a

seamless user experience.

Once AMC is implemented and

installed, users are capable of experiencing

truly unified communication on their

mobile phones as well as having access to

their corporate IP-PBX or Soft switch

telephony features both via GSM &

WLAN networks. Furthermore the service

has been implemented so that In-Call

handovers between WLAN and cellular

networks is doable; therefore user

continues talking while travelling from

WLAN network installed in the office to

the outside GSM network and vice versa.

7.1. AMC features & advantages

Key product features (taken from

‘Comdasys’ enterprise):

Easy-to-Use and very intuitive GUI

Multi-Language support

Excellent voice quality over

WLAN

Seamless In-Call handover with

voice call continuity

Instant Messaging & SMS over

WLAN

Visual missed calls, missed IM /

SMS and new voice mail

notifications

Native contact list in integration

Detailed call history logs

Support speakerphone & headsets

both in Cellular & WLAN

Automatic and manual WLAN

network selection with WLAN

networks prioritization settings

802.11 e APSD support increasing

battery life (WLAN & FMC mode)

G711 and iLBC native codec

support

Having said the AMC Client key

features, some of its main advantages are

described as follows:

Truly Mobile Communication

The AMC Client deployed with the

‘Comdasys’ FMC solutions enabling users

with true Enterprise Mobility without

common limitations. Wherever the user is,

all PBX features are accessible from the

mobile phone. Users set their mind free of

costs owing to the selection of optimal

baseband by the system while not losing

quality features. ‘It is like having your

fully featured office desk phone in the

palm of your hand’.

Simple and easy to deploy

AMC Client is easy to install on the

mobile phone. The mobile applications can

be downloadable from an e-mail

attachment or a website. Moreover new up-

to-date versions or applications are

available on the websites for download,

which all it takes for installation is a single

click.

Unified User Experience

22

AMC not only provides users with

simple-to-use features to ease

communication, but also reduces the

number of devices that a user needs to be

reachable anytime anywhere. One number,

one device, one mail box makes it simpler

and more profitable to interact between

existing networks.

Improve Work Efficiency

The more reachability and

responsiveness of users, the more

productivity and efficiency of workforce is

guaranteed. Giving one contact number

and one mailbox means that everyone

knows how to get hold of each other

making sure that no data get lost in the

Voice Mail Junk.

Cost Control

AMC has got the ability to select the

most cost-efficient baseband to

communicate, obtaining gain control over

the enterprise communication.

Figure (18) illustrates some of AMC

Client features available on the screen:

Figure (18): AMC Client Home Screen

7.2. Supported Handset

The AMC Client has been designed for

the most popular OS on the smart phones

which is S60 3rd

Edition platform. The

following Nokia devices have been tested

and worked successfully:

E51, N95 8GB, N95, 6120 classic, E61i,

E65, E90, E70, E60, N80

There are some more devices which are

supported as they are compatible with the

above ones:

6124 classic, 6120 Navigator, N96, 6220

classic, N78, N82, N95-3NAM, N81, N81

8GB, 6121 classic, 5700 XpressMusic,

N77, 6110 Navigator, N93i, N76, 6290,

N75, N91 8GB, E62, E50, 5500, N93i,

N73, N71, N92, 3250, N91

Samsung & LG smart phones are

supported on a Project Specific basis.

23

Supported features:

Hotspot / Home Office Support:

Contrary to most other

Enterprise FMC Solutions, you

can use the MC Client across the

Internet and from your Home

Office without Feature

Limitations.

Different Modes of Operation

from full Dual Mode (WLAN /

GSM) to Single Mode

(GSM/GPRS) to pure GSM. The

full Usability is maintained in

Single Mode Operation by using

the cellular network as a

simultaneous data channel (e.g.

GPRS).

Guided Feature Invocation

(user can only select what is

possible in the current state)

with support for Handovers

(Feature display will be

dynamically updated as soon as

a data channel such as WLAN /

GPRS) are available. This

includes calls that have been

initiated in pure GSM.

Instant Messaging and Presence

Support

Supports Over-the-Air

deployment via ‘Comdasys’

FMC appliance and / or

external tools

Multiple SIM card support with

Follow-Me functionality

Direct Media Connect for

optimized Voice Call Routing

via WLAN

Support for Loudspeaker,

Headset, Mute as well as

Bluetooth Hands free / Headset,

Adjustable Volume for both

GSM and WLAN calls

Client main screen mimics S60

Home Screen for best usability

including such things as Active

Profile and Clock Display

Automatic activation of

application on phone startup

Very Simple 3-Parameter

Configuration (or automatic

configuration generated from

FMC Controller)

WLAN Infrastructure Support

with Configurable Thresholds

for improved Access Point to

Access Point Roaming. No

additional Software required.

Compatible with all major

WLAN solutions

The AMC Client has been tested with all

major Access Points such as AVM, Belkin,

DLink, Linksys, Netgear, and others.

In addition to that, testing has been and

is being conducted with products from

major professional WLAN infrastructure

Providers, among them:

- 3Com

- Aruba Networks

- Bluesocket Networks

- Cisco Aironet

- Colubris Networks

- Meru Networks

- Siemens Hipath Wireless

24

Supported voice supplementary services:

- Hold / Resume, Consultation, Toggle

- Conferencing (3 party)

- Blind Transfer, Attended Transfer

- Call Waiting

- Call Pickup

- Direct Call Pickup

- Boss Secretary

- Call Forwarding (On No Reply, On

Busy, Always)

- Call Parking / Retrieve

- Call Back Busy / Call Back No Reply

(Call Completion)

- Calling Party Name Display (name

sent from PBX, or name in Cell

Phone’s Contact List)

- Call Back to Client (for Saving

Charges on International GSM

calls)1

1 . Some parts have been taken directly from

www.comdasys.com (2009) due to being so

specific.

25

8. Study

One major part of the project was

gathering information regarding

functionality of the PBX systems and

Clients’ work. Nowadays PBX systems are

vastly used in many offices and companies.

The advantage of using PBX is that each

user gets an extension number. Staff do not

have to call the complete number, when

they want to connect each other in the

office. Since the issue is a more focused on

mercenary aspects of the business, most of

my references refer to commercial

websites and pre-existed documents of

‘Aastra Telecom’ related to the subject.

Two different schools of thought are to

be taken into the consideration:

Data form the previous works

which are already available. I

started by reading those references

such as instructions describing how

the PBX, Clients, etc. are working

together in the system. This part of

the study covers all the information

I need to know before starting the

practical work. Due to the fresh

new essence of the clients, this part

of project took me almost two first

months; however new daily

arriving information necessitate

being up-to-date according to the

recent findings.

Practical aspect of a project is

meant to face some problems that

were not thought over in the theory.

Should any unexpected problem

arise, I needed to review what I had

read, and tried to find new stuff

corresponding to the case. In some

situations the only treatment left

was to perform try and error work,

and find out the best approach to

continue the process.

Finally what is at hand in my project is

utilizing past information as well as

executing those data in the real world, to

get a good result out of experiments, and

make us closer to an important aim of

telecommunication which is lowering the

call cost making the world of

communication and interaction more

usable and beneficial. Furthermore

choosing a thin / fat client is discussed to

give a good perspective on how each client

acts in several circumstances, and which

one is more efficient to be selected by a

user.

26

9. Execution

The execution part of the project

requires firstly installing the client, then

configuring the client according to a

‘feature file’ installed simultaneously with

the client, and finally examining it while

changing the ‘feature file’ to get the

acceptable result out of experiments.

The client is designed such that it works

as the ‘feature file’ is written. ‘Feature file’

is like a code or program for the client.

Some general information about the

‘feature file’ name as follow:

‘Feature file’ is a text file, and its

name has to be like: feature.txt

All lines have to be encapsulated in

a block starting & ending with: #

DTMFLIST

All lines must be separated by a

comma, and it is not allowed to

have empty line(s) between the

lines.

A general view of a ‘Feature File’ is

shown:

#DTMFLIST

feature-line 1,

feature-line 2,

.

.

.

feature-line n,

# DTMFLIST

9.1. Structure

Each line is comprised of a command

which consists:

[displaytext],[CommandID],[ParentID],[Activated],[FeatureType],[Terminate], [PBXIndex],[SequenceType],[DTMF Sequence],[DTMF Sequence],[DTMFSequence],…,

1. Display text: Defines the command

which is going to be run

2. Command ID: A number which has

to be unique, and is defined by the

designer such that interacts with the

client.

3. Parent ID: A number which is

related to the ‘Command ID’ of the

previous line if it has something to

do with that; otherwise it takes the

same number as ‘Command ID’.

4. Activated: To activate a feature this

number is set to 1, to deactivate,

that must be 0.

5. Feature type: Represents a

hexadecimal number which

configures the dynamic display of a

feature:

F F FF FF FF Digit8 Digit7 Digit6/5 Digit4/3 Digit2/1

Digit 2/1: Is set to 1 if a feature

handles In-Call feature, and for Out-of-

Call feature it is 0.

Digit 4/3 : Shows the number of

active calls needed for a feature to be

executed; for example for having a

conferance is only applicable while

having 2 users on the line.

Digit 6/5 : Defines the number of

parked / held calls.

27

Digit 7 : Defines the type of

comparison between active calls, and it

takes 3 numbers:

Unespecified or 0: If the

number of active calls is

equal to or less than the

number of active calls

defined in Digit 3/4 .

1: If the number of active

calls is equal to or greater

than the number of active

calls defined in Digit 3/4 .

2: If the number of active

calls is exactly equal to the

number of active calls

defined in Digit 3/4 .

Digit 8: The same procedeur for Digit 7

is used here but for parked / held calls as

defined

in digit 6/5.

6. Terminate: Sometimes it is

necessary to terminate a call after

processing a feature. If the number

is set to a value more than 0, the

call would be terminated after 10

seconds.

7. PBX Index: Specifies the ‘Aastra’

PBX ID for which the feature is

activated.

8. Sequence Type: This item specifies

how to handle DTMF sequences.

Value 0: Single, i.e. all DTMF

sequences defined for the feature are

concatenated and sent as DTMFs

without any further action, no number

is required

Value 1: Number Feature. For this

feature, 4 numbers are supported which

can be specified:

NUMBER: User interaction is

required since the user needs to define

a phone number to process this feature.

ALARMNUMBER: If specified via

Configuration SMS, this number will

be used. No user interaction is

required.

VOICEMAILNUMBER: The

voicemail number which is defined in

the settings will be used. No user

interaction is required.

TAKENUMBER: Take number

specified in settings will be used for the

feature.

A checksum can be added by the client

upon processing this feature to enable the

server to verify the correct transmission

(see also Value=2)

Value 2: Same as for value 1, but a

checksum will not be added!

9. DTMF Sequence(s)

This setting defines the transmitted

DTMF sequence. The number of

configured DTMF sequences (separated by

comma) is not fixed, merely limited to 255

characters as already mentioned. All

specified sequences will be concatenated to

one sequence ordered as defined in the file.

If DTMF sequences are defined for a

feature type of 1 or 2, one sequence has to

be defined as ″NUMBER″

(″ALARMNUMBER″,

″VOICEMAILNUMBER″,

″TAKENUMBER″ respectively). This

signals the position of the phone number

within the compound sequence. It is not

allowed to have more than one

″NUMBER″ or ″ALARMNUMBER″ or

″VOICEMAILNUMBER″ or

″TAKENUMBER″ per sequence.

28

9.2. Examples

Single Feature Example

Enquiry,101,101,1,FF0101,0,0,2,***,NUMBER

Default display text: Enquiry

CommandID = 101

No parent because ParentID =

CommandID

Feature is activate

In-call-feature (FF0101)

Will be displayed as long as number of

active calls is not greater than one

(FF0101), and number of parked calls is

less than or equal to 255 (FF0101)

The type of comparison is not specified,

so comparison is based on <=

Automatic call termination is not activated.

The PBX-Index for which the feature is

activated is 0.

Sequence type is 2, so

a number is required. In this case

“NUMBER” indicates that the user

has to select the number and no

predefined number has to be used.

no checksum will be appended.

Parent Feature

Call Forwarding,110,110,1,0,0,0,2,,, User,111,110,1,0,1,0,2,*21,NUMBER,#, Voice Mail,112,110,1,0,1,0,2,*21,VOICEMAILNUMBER,#,

Call Forwarding is the top-level-feature.

It will not be processed, because it has the

child features ″User″ and ″Voice Mail″.

The Sequence Type must be 2 in those

cases. Children will be displayed in a sub-

menu. It is an “out-of-call” feature; hence a

call will be initiated.

The child ″User″ is a feature which

requires a number to be selected by the

user. The call will be terminated

automatically after 10 seconds. The child

″Voice Mail″ is configured in the same

way as child “User”, but the voice mail

number will be used to process this feature.

After recognising how to work with

‘feature file’1 and the client, we are to look

at the assignment for making less costly

calls which is discussed in the next step.

[9]

1 . A full view of a ’Feature File’ is shown in the

‘Appendix 16.1’.

29

9.3. Example of two test results

1. The following table illustrates a

simple test result executed on the

‘NOKIA E51’, and highlights the very

first ten test cases by a fat client.

Table 1: First ten cases performed by fat client

Nr. Test cases Result Comment

1 Making an outgoing external call OK 00 must be added in front of the original Nr. (e.g 0712345678

==> 000712345678)

2 Making a call to internal short extension

OK Tested

3 Calling the voice mail number Not tested

4 Calling emergency number (112) OK Not tested

5 Making a video call Fail The client does not support video calls.

6 Send a message (SMS/MMS) OK Tested

7 Incoming external call OK Tested

8 Incoming internal extension call OK Tested

9 Receiving 2 internal calls, joining them; making an outgoing external call, joining them.

OK Tested

10 Using the PBX command 'Lunch', entering time when you are back from lunch

OK The feature works from the client point of view.

Having looked at the result clarifies that

‘Voice mail, and ‘Emergency call’ were

not executed due to some difficulties or

lack of facilities in the service which must

be removed to prepare the conditions for

testing those features. Furthermore, ‘Video

call’ is not supported by the client that is

left on the list to be improved in the next

version of the client.

2. The previous test was pretty

straight forward, and in the next

step we are going to make it a little

more complicated. In this case

DTMF Configuration is considered

which is related to experimenting

In-Call features on NOKIA E51.

The table below represents the test

cases and the results:

30

Table 2: DTMF Configuration on NOKIA E51

DTMF Configuration

Feature Test Case

DTMF Sequence Application Result Comment

Enquiry Enquiry,101,101,1,FF0101,0,0,2,*,NUMBER, Making a new call during the current one(s)

Working Properly

Max 8 calls

Pendling Pendling,102,102,1,010001,0,0,0,*, Moving between existing calls Working Properly

Changing the name from 'Brokering' to 'Pendling' does not

work on the display

End call / Unhold End call / Unhold,104,104,1,10010101,0,0,0,***1, Ignored

Conference Conference,103,103,1,FF0101,0,0,0,3,

Having more than 2 calls at the same

time while each user is able to hear

and talk to others

Working

Properly

Call Back Call Back,125,125,1,FF0101,1,0,0,5, Asking a busy user to make a call

back

Working

Properly Max 8 calls

Call waitng Call Waiting,105,105,1,FF0101,0,0,0,4,

Making it possible for a busy user (to

whom call made) to receive a call

during his current call

Working

Properly

Hold Hold,106,106,1,FF0101,0,0,0,***, Ignored

Park Park,107,107,1,FF0101,1,0,0,****76, Ignored

Take Take,108,108,1,0,0,0,2,*,TAKENUMBER,

Giving the possibility of

answering either the

mobile phone or another phone while

both are ringing at the same time

Working

Properly

Configuration

(initialiazation &

cancelation)

is performed via MX1

Programmer, not

the mobile device

Voice Mail Voice Mail,122,122,1,0,0,0,2,VOICEMAILNUMBER, Ignored

Forwarding Forwarding,109,109,1,0,0,0,2,,, Ignored

Call Forwarding Call forwarding,110,109,1,0,0,0,2,*21,NUMBER,#, Diverting the number to another one Working

Properly

Cancelation is

performed via MX1

programmer, not the

mobile device

User User,111,110,1,0,1,0,2,*21,NUMBER,#, Ignored

Voice mail Voice

Mail,112,110,1,0,1,0,2,*21,VOICEMAILNUMBER,#, Ignored

Forwarding off Forwarding off,113,110,1,0,1,0,0,#21#, Ignored

Forwarding on no

reply Forwarding on No Reply,114,109,1,0,0,0,2,,, Ignored

User User,115,114,1,0,1,0,2,*61,NUMBER,#, Ignored

Voice Mail Voice

Mail,116,114,1,0,1,0,2,*61,VOICEMAILNUMBER,#, Ignored

Forwarding off Forwarding off,117,114,1,0,1,0,0,#61#, Ignored

Forwarding if busy Forwarding if Busy,118,109,1,0,0,0,2,,, Ignored

User User,119,118,1,0,1,0,2,*67,NUMBER,#, Ignored

Voice Mail Voice

Mail,120,118,1,0,1,0,2,*67,VOICEMAILNUMBER,#, Ignored

Forwarding off Forwarding off,121,118,1,0,1,0,0,#67#, Ignored

Personal Call

Routing Personal Call Routing,126,126,1,0,0,0,2,,, Ignored

Call Routing Call Routing 0,129,126,1,0,1,0,0,*450#, Ignored

Call Routing Call Routing 1,130,126,1,0,1,0,0,*451#, Ignored

Call Routing Call Routing 2,131,126,1,0,1,0,0,*452#, Ignored

Call Routing Call Routing 3,132,126,1,0,1,0,0,*453#, Ignored

Call Routing Call Routing 4,133,126,1,0,1,0,0,*454#, Ignored

Call Routing Call Routing 5,134,126,1,0,1,0,0,*455#, Ignored

Take Back Take back,123,123,1,0,0,0,0,#76#, Ignored

Redkey Redkey,124,124,1,0,1,0,2,*73,ALARMNUMBER,#, Ignored

31

The table contains almost all In-call

features used by AMC. DTMF Sequence

represents the code lines of feature file.

Some applications are not available or

ready to test (Ignored). What is of

importance in this test case is that by

dialling short number and extended

number we realize that making a call using

the client, a short number i.e. 5 digits

number takes approximately 11 seconds to

be received, while dialling the extended

number i.e. 12 digits number takes

approximately 15 sec; which means that

each extra digit takes approximately up to

half a second.

32

10. Describing the problem

Clients have been designed to facilitate

the communicational works. There are

many new applications that make it easier

to get connected, and interaction becomes

more innovative.

Cost of the call has always been the

centre of attention before making a call,

and becomes more important when it

comes to international calls. It may happen

to anyone being abroad in case of making a

roaming call. The first idea springing to

mind is how to reduce the cost which is

rather high for international roaming calls.

The solution suggested by AMC is call

back strategy feasible by executing call

back strategy using a client. First we

explain how the system would work, and

then introduce different strategies to

achieve the goal.

In order to make an international call,

traditionally user ‘A’ used to call user ‘B’,

and get connected via operator. Figure (19)

shows such a system. The mentioned way

is too much costly, and is not reasonable to

be used. Both parties connection is done

via the roaming mobile network.

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Figure (19): Traditional way of making international calls

2. ‘B’ party receives

the call via operator.

1. ‘A’ party establishes a

call from abroad to ‘B’

party

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BB

AA

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33

11. Low cost international calls

As explained previously, PBX is vastly

used in many offices, and work places. The

advantage of using PBX is to avoid

dialling full numbers, and also lowering

call costs. Instead of calling directly, one is

able to benefit from ‘Call Back Service’

provided that he is subscribed to PBX

service.

Figure (20) shows a rough picture of

what is happening when making a call

applying call back service. Firstly, ‘A’

party initiates a call to ‘B’ party via PBX;

the connection is established based on data

over GPRS. Then PBX receives the signal

and makes a call to ‘B’ party, and

simultaneously to the ‘A’ party. ‘Call

Back’ comes from the fact that ‘A’ party

receives a call form PBX after making a

call; and in the next stage two parties start

talking.

Figure (20): Call back service via PBX

Figure (21) illustrates more clearly how

two parties (one from abroad) are

connected each other via operator, and

PBX system. Since the user ‘A’ is

subscribed to the service its connection to

the operator, and PBX is performed over

IP. PBX works as an interface, making a

link between ‘A’ party and ‘B’ party via

operator.

The first connection between the ‘A’ party

and operator is done via IP. Consequently

the cost reduces, and the only charge price

must be paid for the call back service

which has been made from the PBX to the

‘A’ Party.

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BB

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VVooiiccee // GGSSMM

VVooiiccee // GGSSMM // PPOOTTSS

34

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Figure (21): Call back service using PBX as an interface

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11

22 33

1.‘A’ party establishes

a call from abroad to

‘B’ party.

2. Operator

routes the

connection

to the PBX.

3. PBX connects two

parties simultaneously

via operator.

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PBX

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35

12. Results

Once the AMC installed on the mobile

phone, now it is time to test it and calculate

how we can benefit by using it. In order to

perform that, business case tool for

‘Mobile Least Cost Routing’ calculations

is defined. This business case tool

calculates the benefits of using the Aastra

Mobile Client (AMC) with call back

service-AMC 1.5 Mobile LCR (MLCR)-

and benefits of using the MLCR and PC

client / Dual Mode together while

travelling. The business case also shows

the ROI (Return of investment) for users

using Multiple Local SIM cards (“Travel

SIM”). The tool calculates the cost saving

for one site travelling abroad.

In most countries it is cheaper to receive

a roaming call than making it while

travelling. The GPRS call back functions

are making all calls to receiving calls. The

PC / Dual mode client will make a VoIP

call over internet which is in most cases for

free.

To have a good perspective on how the

system works and how much we can gain

by using that, we need to experiment, and

compare the statistics taken from different

conditions. The experiment is based on

making and receiving calls from several

countries. There are some input data as

follows:

Number of employers (Mobile Users):

15611

Number of users travelling abroad

during the experiment period: 3747 which

is the 24% of the total number of users.

Three supporting operators are

‘TeliaSonera’ which supports 70% of the

network, ‘Telenor’ & ‘Tre’ 15% each.

First ten countries are experimented

covering 70% of the total in the world:

EU (taken as a country), USA, China,

Japan, India, Malaysia, Australia, South

Africa, Singapore, Indonesia. According to

the statistics in each of these countries

45.3% of the calls are receiving calls, and

54.7% are making calls. The price for

making and receiving calls varies for

different countries.

12.1. Normal calls

For example making a call through

‘TeliaSonera’ operator from the USA costs

15 SEK per minute, while a call from

China costs 22 SEK per minute; receiving

a call in those countries costs 4.61 & 4.99

SEK per minute respectively.

Table below1 shows some values for

making and receiving calls to and from the

USA & China through ‘TeliaSonera’.

1 . All tables containing entire data from three

mentioned operators are available in the ‘Appendix

16.2’.

36

Table 3: Roaming Calls - Traffic from ‘TeliaSonera’ operator for normal calls

% of total # Minutes SEK/Minute # Minutes Total for period

Call from US 54,7% 138 939 15,00 75 998,75 1 139 981,25

Call received in US 45,3% 138 939 4,61 62 940,74 290 156,80

Call from China 54,7% 97 672 22,00 53 425,56 1 175 362,42

Call received in China 45,3% 97 672 4,99 44 246,05 220 787,78

Another noticeable cost issue is the

‘Data Traffic’ charged by operators. Many

operators charge on 50 Kb. Table below

depicts ‘Data Traffic’ provided by

‘TeliaSonera’, and the corresponding price

for the two mentioned countries.

Table 4: Data Traffic form ‘TeliaSonera’ operator for normal calls

Considering all ten countries and three

operators, the ‘Total Roaming Calls’ is

12603807,94 SEK, and ‘Total Data Traffic

International Travelling’ is 57 067,36 SEK,

whereas ‘Total Roaming Traffic’ which is

the sum of two mentioned values is 12 660

875,30 SEK.

12.2. AMC Mobile LCR

If the call back strategy is involved

using AMC Mobile LCR, then all calls will

be converted to received calls since

receiving a call is cheaper than making a

call for international calls. As a matter of

fact the user ‘A’ establishes a call which is

routed over IP to the PBX. Next the PBX

first makes a call to the user ‘B’, and then

to the user ‘A’; therefore user ‘A’ receives

a call over voice as a call back, which

lowers the call cost to some considerable

extent. The following table illustrates how

the GPRS Call Back service affects the

price of calls.

Table 5: Roaming Calls - Traffic from ‘TeliaSonera’ operator for GPRS Call Back

% of total # Minutes SEK/Minute # Minutes

Total for period

Call from US 0% 138 939 15,00 0,00 0,00

Call received in US 100% 138 939 4,61 138 939,49 640 511,03

Call from China 0% 97 672 22,00 0,00 0,00

Call received in China 100% 97 672 4,99 97 671,61 487 381,35

% of total # MB

SEK/setup (50kb)

# of Call setups

Total for period

Data communication with Server per 50 Kb - US

10,7% 1 586 4,80 46 313 7 612,05

Data communication with Server per 50 Kb - China

7,6% 1 115 5,80 32 557 6 465,93

37

As seen from the table all calls are made

to be received calls. Hence, there will be

no charge for making a call.

The data traffic is the same as before

like what is shown in ‘Table 4’. AMC

Mobile LCR requires making a call over

IP; so the user has to pay the price for data

traffic run over IP. In other words the user

is charged for normal data traffic as well as

data traffic offered by the operator for call

back service. Statistics for two countries

related to data traffic for call back is

gathered in table 6.

Table 6: Data traffic for Call Back service using ‘AMC’

Number of calls per 50Kb

Number of 50Kb steps

Data cost for call back

Data communication with Server per 50 Kb - US

50 926 4446

Data communication with Server per 50 Kb - China

50 651 3777

Having noticed all the data from 3

operators and 10 countries indicates that

the ‘Total Roaming Calls’ is 7 020 613

SEK, normal ‘Total Data Traffic

International Travelling’ (without call back

request) is 57 067 SEK, ‘Data Traffic Call

Back Request’ is 50 533 SEK; so ‘Total

Roaming Traffic’ is 7 128 213 SEK.

Comparing the result for normal

roaming calls and GPRS Call back

indicates that using AMC LCR Mobile

results in cost saving:

Total Roaming Traffic (direct call): 12

660 875,31 SEK

Total Roaming Traffic (GPRS call

back): 7 128 213 SEK

In fact what we gain from call back

strategy is 44% saving in the cost which is

equal to the amount of 5 532 662 SEK for

three months turning to 21 130 650 SEK

for a year.

Another factor which is worth to be

mentioned is ROI. Taken the fact that a full

system with MLCR Client costs 1100 SEK

for a user (average price), and cost saving

per user is 44% (492 SEK), then ROI

would be 2.2 months.

12.3. AMC + PC Client

Inasmuch as our goal is to reduce the

price for international calls, there exist

some more ways to fulfil the fact. ‘PC

Client’ can be of help in our case. Having

the privilege of using PC Client makes it

possible to make calls via PC Client while

travelling. Assuming that 30% of users do

as such, following results form

‘TeliaSonera’ for roaming calls are

obtained:

Table 7: Roaming Calls -Traffic by using ‘AMC’ + ‘PC Client’; (30 % of users using ‘PC Client’)

% of total # Minutes SEK/Minute # Minutes

Total for period

Call from US 0,0% 138 939 15,00 0,00 0,00

Call received in US 70,0% 138 939 4,61 97 257,64 448 357,72

Call from China 0,0% 97 672 22,00 0,00 0,00

Call received in China 70,0% 97 672 4,99 68 370,13 341 166,94

38

Comparing the results with ‘Table 5’,

number of minutes is multiplied by 70% in

each case, indicating 30% saving in the

cost. Data traffic is having the same values

as ‘Table 4’, and data traffic for call back

service is like ‘Table 6’.

To compute the total savings, data from

all operators are gathered and compared to

the previous results. Total Roaming Call is

4,914,429 SEK, Data Traffic International

Travelling (without call back request) is

57 067, Data Traffic for Call Back request

is 35 3731 SEK, and Total Roaming Traffic

utilizing PC Client as well as AMC is

equal to 5 006 869 SEK.

Total Roaming Traffic (direct call): 12

660 875,31 SEK

Total Roaming Traffic (AMC + PC

Client): 5 006 869 SEK

60% saving in cost is obtained applying

both PC Client & AMC meaning

7 654 006 SEK saving for 3 months, and

29 616 025 SEK for one year.

If purchasing a full system containing

MLCR Client and PC Client costs 1600

SEK for a user, knowing that cost saving

for a user per month is 681 SEK, then ROI

would be 2.3 months.

12.4. Travel SIM + MLCR

Next scenario would be introducing

‘Travel SIM’ which reduces the call cost to

some significant extent; for example

making and receiving call from the USA &

China costs 4.61 & 4.99 SEK per minute

respectively, while ‘Travel SIM’ brings the

1 . The value is obtained by taking 70% of the Data

Traffic for Call Back request in the previous stage

(12.2).

price down to 0.05 & 0.06 SEK per

minute.

39

Table 8: Roaming Calls traffic for ‘Travel SIM’ + ‘MLCR’

According to what table is showing the

call cost is brought down with the help of

‘Travel SIM’, and there is no made call in

the system as a result of having ‘AMC

Client’, making all made calls to received

calls by executing call back strategy.

Another difference is related to the data

traffic calculation. The difference is visible

where calculation of data traffic is based

on number of calls per 10 Kb. In fact data

traffic without call back request is 1.95

SEK per 10 Kb for all countries. Therefore

data traffic cost becomes less expensive

than the previous cases (Table below).

Table 9: Data traffic for ‘Travel SIM’ + ‘MLCR’

% of total # MB

SEK/setup (10kb)

# of Call setups

Total for period

Data communication with Server per 10 Kb - US

10,74% 1 586 1,95 46 313 3 092,39

Data communication with Server per 10 Kb - China

7,55% 1 115 1,95 32 557 2 173,89

Comparing the results of ‘Table 9’ and

‘Table 4’, it is obvious that the total cost

for period has been decreased. The total

price is 41 205 SEK without using ‘Travel

SIM’, and 20173 with that, which has

almost been halved. On the other hand

when it comes to computing ‘Data Traffic’

for call back request, the price goes up

since in this case number of calls- which is

equal to the previous amount- is divided by

10; thus the cost is higher than before

(Table 10).

Table 10: Data traffic for Call Back service using ‘Travel SIM’ + ‘MLCR’

Number of

calls per 10Kb Number of 10Kb steps

Data cost for call back

Data communication with Server per 10 Kb - US

10 4631 9031

Data communication with Server per 10 Kb - China

10 3256 6349

Again comparing ‘Table 10’ to ‘Table 6’

highlights the fact that the data cost for call

back has been increased. Number of call

setups which is similar in all cases is

divided by 10 instead of 50. Although the

price per setup is less than the amount for

% of total # Minutes SEK/Minute # Minutes

Total for period

Call from US 0% 138 939 0,00 0,00 0,00

Call received in US 100% 138 939 0,05 138 939,49 6 946,97

Call from China 0% 97 672 0,00 0,00 0,00

Call received in China 100% 97 672 0,06 97 671,61 5 469,61

40

previous cases, each value is multiplied by

5, hence the data traffic cost goes up. Total

data cost for call back -from TeliaSonera

operator- is 58 912 SEK, whereas in the

previous case it was 24 067 SEK.

Once all countries and operators are

taken into consideration ‘Total Roaming

Call’ is calculated as 794 621 SEK, ‘Data

Traffic International Travelling’ without

call back request is 28 818 SEK, Data

Traffic Call Back Request is 130 448 SEK,

and the some of mentioned values which is

the ‘Total Roaming Traffic’ is 953 887

SEK.

Having analyzed the results now it is

time to see how much saving we get by

applying ‘Travel SIM’ together with AMC:

Total Roaming Traffic (direct call): 12

660 875,31 SEK

Total Roaming Traffic (AMC + Travel

SIM): 953 887 SEK

92% saving -compared to normal direct

call- by using call back solution while

having ‘Travel SIM’ means 11 706 988

SEK saving for 3 months, and 45 827 954

SEK saving in a year.

Cost saving per user is 1042 SEK per

month. If each user is charged for 1100

SEK for having AMC, then the ROI would

be 1.1 month.

12.5. Travel SIM + MLCR + PC Client

The last but not the least scenario would

be applying ‘Travel SIM’, ‘AMC’, and

‘PC Client’ altogether so as to have the

better performance and less costly

international calls. To explain the rule of

each component it suffices to point out that

‘AMC’ makes all made calls to received

calls, ‘PC Client’ removes the need for

making all calls via Mobile phone, and

‘Travel SIM’ reduces the call cost per

minute.

What is shown in ‘Table 11’ is the result

gathered by ‘TeliaSonera’ while having the

combination of three mentioned

components. It is assumed that 30% of

users use ‘PC Client’ for making calls.

Table 11: Roaming calls traffic for ‘Travel SIM’ + ‘MLCR’ + ‘PC Client’

% of total # Minutes SEK/Minute # Minutes

Total for period

Call from US 0% 138 939 0,00 0,00 0,00

Call received in US 70% 138 939 0,05 97 257,64 4 862,88

Call from China 0% 97 672 0,00 0,00 0,00

Call received in China 70% 97 672 0,06 68 370,13 3 828,73

Data traffic for both cases with and

without call back request is the same as the

last results. All in all having observed the

information from three operators in 10

counties shows that ‘Total Roaming Call’

is 556 234 SEK, ‘Data traffic’ without call

back request is 28 818 SEK, ‘Data Traffic

Call Back Request’ is 91 3141 SEK, and

sum of all costs comes to 676 366 SEK

which relates to the ‘Total Roaming

Traffic’.

1 . The value is obtained by taking 70% of the Data

Traffic for Call Back request in the previous stage

(12.4)

41

The saving cost is calculated as below:

Total Roaming Traffic (direct call): 12

660 875,31 SEK

Total Roaming Traffic (AMC + Travel

SIM): 676 366 SEK

The saving in cost is estimated as 95%,

which is 11 984 509 SEK for three month,

and for one year is 46 938 037 SEK.

Providing that ‘PC Client’ & ‘AMC’ costs

1600 SEK for a user, since cost saving per

user is 1066 SEK per month, ROI becomes

1.5 month.

12.6. Mobile roaming least cost routing

business case

As far as the business case is concerned,

a chart comparison gives the best

perspective of how much we gain from

each service, and how much intuitive

difference exists between using different

technologies. Figure (22) depicts the

comparison between the cost/year by

applying different services. The most

visible change occurs due to using ‘AMC’

where the cost goes down by

approximately half as before. ‘Travel SIM’

also has a big effect where by utilizing

both ‘AMC’ & ‘Travel SIM’ the cost is

reduced to less than a tenth of its first

value.

Figure (22): Mobile roaming least cost routing business case

Having Bought the necessary equipment

or program does not necessarily guarantee

the use of services since in some

circumstances it might not work (e.g. not

all countries have supporting operator for

Travel SIM use). Thus according to the

Mobile roaming least cost routing business case

0 kr

10 000 000 kr

20 000 000 kr

30 000 000 kr

40 000 000 kr

50 000 000 kr

60 000 000 kr

Current yearly Mobile roaming cost

Estimated yearly Mobile roaming

cost after installing mobile client

Estimated yearly Mobile roaming

cost after installing mobile client &

PC client

Estimated yearly Mobile roaming

cost after installing mobile client +

Travel SIM

Estimated yearly Mobile roaming

cost after installing mobile client +

PC client + Travel SIM

42

chart, each user can figure out what kind of

service is more useful for his case, and

selects the best choice.

12.7. Return of Investment

Return of investment (ROI) is calculated

as a period of time that the paid money for

buying equipments or services is back;

considering the fact that call costs has been

reduced. Next figure illustrates the ‘Return

of Investment’ per month:

Figure (23): Return of investment

The important mentionable point is that

in all cases after 3 month at the most, the

price that the user has paid in order to use

the privilege of the service is returned.

Consequently it is really worthwhile to get

the service, especially when long time use

is the intention.

Retrurn Of Investments

0,0

0,5

1,0

1,5

2,0

2,5

System with Mobile

LCR client

System with Mobile

LCR client & PC client

System with Mobile

LCR client & Travel

SIM

System with Mobile

LCR client + PC client

+ Travel sim

Mo

nth

Months

43

13. Thin & Fat client, comparison in functionality

Functionality of clients depends on

several parameters. Each client must be

installed and tested on different phones to

verify its efficiency. There are some

factors which are essential to be tested

and verified. Since in some cases available

clients are not absolutely designed to be

examined, this part of project is rather

based on the research and information

about the clients, though in some parts

comparison is on the ground of

experiments.

In-call / Out-of-call features:

As defined before, these features are

responsible to handle some options related

to the calls. The more flexibility a client

shows on these features, the more it allows

the user to play with options in different

situations.

Since the two available clients (namely

‘Aastra’ & ‘Mobisma’, where the former

one is a fat client and the latter one is a thin

type), has not been designed to be working

in the same way, and this features need to

be tested practically, it is not possible to

easily determine which client shows better

performance. In fact ‘Aastra Client’ works

properly in all cases, but not all features

are completely implemented on the

‘Mobisma Client’; consequently there is

not enough resources at hand to judge for

such a case.

User-friendly design:

Mobile phones have become an integral

part of human’s life. Even small kids have

one in their pocket. Since everyone is not

so much educated as a businessman, or an

engineer, applications must be designed so

that everyone can use them.

Since both clients are supposed to be

equipped with the same functions, it does

not seem that this function differs for the

clients. From what the experiment shows,

making a call via the available thin client

(Mobisma), requires pressing ‘Yes’, or

‘No’ indicating on the display after

pressing the dial key, where by pressing

‘Yes’, the call is established via a server.

This stage is not required in the Fat client.

Although this looks like performing one

more step in the thin client, this function

can be removed for the next versions of

thin client, since it is obvious that when a

person dials a call, he is aimed to talk, and

no more questions is needed to connect to

the server.

How fast is each client?

It takes a while for the client to react to

each function. The faster reaction specifies

the more reliable client in urgent situations,

and better design quality.

Due to having all the programmes

installed on the fat client, it reacts faster

than thin client, considering the fact that

thin client has to firstly connect to the

server.

Two scenarios are to be considered

while making a call using the fat client:

- Dialling a short number i.e. 5 digits

number takes approximately 11 seconds to

be received.

- Dialling the extended number i.e. 12

digits number takes approximately 15 sec;

which means that each extra digit takes

almost up to half a second.

Establishing a call via thin client as

mentioned before needs one more step,

therefore it takes some more time; however

the conditions of comparing is not fair in

this case.

All in all what can be concluded is that

available working clients show faster

44

reaction for fat client, but when too much

data is saved on the memory of a phone,

where it might make some ciaos and messy

condition, thin client can be a substitute;

while upgrading the server would help the

system to have a network as fast as

possible.

Versatility (being able to work)

on different mobile phones:

Clients are not compatible with all of the

mobile phone’s OS. Some operating

systems do not allow the client to be run or

working properly on them. The client

which has the possibility to work on more

mobiles attracts more interest, and market

share.

A document prepared by the ‘Aastra’

client designer shows that the client works

on two models of LG cell phones namely,

KS10 & KT610; most of NOKIA mobile

phones, however it is noted that in some

models such as E61 & E62 load speaker is

not supported; and when it comes to

SAMSUNG call phones, the problem of

supporting load speaker exist for some

models.

As far as ‘Mobisma’ client is concerned,

it is not as old as ‘Aastra’ client, and it is

not tested on too many cell phones for all

features; consequently there is no good

reason to compare thin & fat client

regarding the working clients at hand.

Moreover, ideally thin client is created to

be working with almost all cell phones,

since less compatibility between the client

and mobile OS is necessary due to having

many functions working on the server

which is separated from the mobile phone.

Cost efficiency and financial

issues:

Perhaps the most important criterion for

a customer is the price. The money that

one spends to purchase a product plays an

important role in his selection. Actually the

price of making a call and following

services are also important.

Obviously fat client requires having a

smart phone which is costly. Thin client is

meant to be running on all cell phones, and

eliminates the need for buying smart

phones; hence thin client is a more cost-

effective choice if it is designed so that it

works on all phones as expected from its

goal.

Reliability in terms of working

properly in different conditions:

Being dependent on a server or vendor’s

conditions, makes it impossible that a

client reacts to all the function all the time.

For instance being far away from the

server may be problematic if the client is

fully dependent on server. Consequently a

client should be experimented in different

conditions to measure its working quality.

Having full coverage of the server is

nothing guaranteed everywhere; therefore

thin client is exposed not to be working in

some places. A client which is a

combination of thin & fat client can be

helpful in this case, where it opens a new

horizon for designers and future works.

What has each type of client got

to improve?

Nothing is perfect; nor is a client. New

versions of clients are released day by day

to remove previous flaws and make them

more usable. Being capable of matching

with the new technology of mobile phones

is a privilege for a client, and the more a

client accepts new changes, the more it

brings attraction to itself.

Fat client is a client tested in many

phones and network systems, so the

problems have been recognised and solved

45

to some extent, and it is almost ready to be

released to the market. Thin client on the

other hand is newer, consequently its

problems are to be extracted and known to

be solved later. Revising what has

mentioned for thin & fat client reveals that

features like ‘In-call’, ‘Out-of-Call’

features must be examined and performed

by thin client to benefit perfectly from this

type of client.

46

14. Conclusion & Future Work

In conclusion, as results show for the

strategy of ‘GPRS’ call back, using AMC

brings 44% cost saving, AMC + PC client

gives 60%, Travel SIM + MLCR makes

92%, and using those three tools altogether

results in 95% cost saving which is pretty

high amount of money when it comes to a

long time usage. Thus taking advantage of

AMC is really beneficial in call costs,

especially when it can be used together

with other equipments mentioned. Future

prospect in this case can be improving thin

client such that the whole process is

practically done without a need for more

memory so as to install fat client, and also

no need for buying expensive smart

phones. Further debates would be

beneficial after releasing the clients in the

market to be used in extended

environment.

To sum up, it seems that regarding pros

and cons of each client, there is a trade-off

for choosing each one. As a matter of fact,

considering accessible clients, ‘Aastra’

client has more feasibility to be used,

however ‘Mobisma’ client needs to be

upgraded for new features and applications

to be tested and verified for its potential

usage. As far as financial aspects are

concerned, it can be deducted that thin

client is able to take the place of fat client

in the future, though it requires having

powerful and supporting servers. Fat client

is also capable of working until it will be

replaced by thin client, however evidently

it has its own advantages and can be used

specifically in particular circumstances

where thin client is not properly applicable.

47

15. References:

[1] http://www.arubanetworks.com/pdf/technology/whitepapers/wp_FMC_UMA.pdf

[2]http://www.erg.eu.int/doc/publications/2009/erg_09_06_report_on_fixed_mobile_convergenc

e.pdf

[3]http://www.hendrickhondasc.com/images/weekendspecials/Thick-vs-Thin.pdf

[4]http://dell.symantec.com/files/3/wp_altiris_thinclients_090506.pdf

[5]http://www.technologycrafters.com/technologycrafters/documents/Thick%20Vs%20Thin%20

Client.pdf

[6] http://www.silicon-press.com/briefs/brief.ippbx/brief.pdf

[7] http://cis.cuyamaca.net/draney/214/web_server/client.htm

[8] http://www.comnews.com/features/2008_September/0908_pros_web.aspx

[9] Some ’Aastra Telecom’ documents related to the subject

Pics’ references:

[10] http://www.convergedigest.com/images/bp/BBW/newstep-fig1.gif

[11] http://mobiledevdesign.com/tutorials/MDD-femtocell-ap-basestations-Figure01-1117.jpg

[12]http://www.technologycrafters.com/technologycrafters/documents/Thick%20Vs%20Thin%2

0Client.pdf

48

16. Appendix

16.1. Example of a feature file

# DTMFLIST

Enquiry,101,101,1,FF0101,0,0,2,*,NUMBER,

Pendling,102,102,1,010001,0,0,0,*,

End call / Unhold,104,104,1,10010101,0,0,0,***1,

Conference,103,103,1,FF0101,0,0,0,3,

Call Back,125,125,1,FF0101,1,0,0,5,

Call Waiting,105,105,1,FF0101,0,0,0,4,

Hold,106,106,1,FF0101,0,0,0,***,

Park,107,107,1,FF0101,1,0,0,****76,

Take,108,108,1,0,0,0,2,*,TAKENUMBER,

Voice Mail,122,122,1,0,0,0,2,VOICEMAILNUMBER,

Forwarding,109,109,1,0,0,0,2,,,

Call forwarding,110,109,1,0,0,0,2,,,

User,111,110,1,0,1,0,2,*21*,NUMBER,#,

Voice Mail,112,110,1,0,1,0,2,*21,VOICEMAILNUMBER,#,

Forwarding off,113,110,1,0,1,0,0,#21#,

Forwarding on No Reply,114,109,1,0,0,0,2,,,

User,115,114,1,0,1,0,2,*61,NUMBER,#,

Voice Mail,116,114,1,0,1,0,2,*61,VOICEMAILNUMBER,#,

Forwarding off,117,114,1,0,1,0,0,#61#,

Forwarding if Busy,118,109,1,0,0,0,2,,,

User,119,118,1,0,1,0,2,*67,NUMBER,#,

Voice Mail,120,118,1,0,1,0,2,*67,VOICEMAILNUMBER,#,

Forwarding off,121,118,1,0,1,0,0,#67#,

Personal Call Routing,126,126,1,0,0,0,2,,,

Call Routing 0,129,126,1,0,1,0,0,*450#,

Call Routing 1,130,126,1,0,1,0,0,*451#,

Call Routing 2,131,126,1,0,1,0,0,*452#,

Call Routing 3,132,126,1,0,1,0,0,*453#,

Call Routing 4,133,126,1,0,1,0,0,*454#,

Call Routing 5,134,126,1,0,1,0,0,*455#,

Take back,123,123,1,0,0,0,0,#76#,

Redkey,124,124,1,0,1,0,2,*73,ALARMNUMBER,#,

# DTMFLIST

49

16.2. Roaming calls traffic from ‘TeliaSonera’, ‘Telenor’, and ‘Tre’ operators

- Roaming Calls – Voice & Data Traffic from ‘TeliaSonera’, ‘Telenor’, and ‘Tre’ operators

for normal calls

50

51

- Roaming Calls – Voice & Data Traffic from ‘TeliaSonera’, ‘Telenor’, and ‘Tre’ operators

for ‘GPRS Call Back’ as well as Data Traffic for ‘Call Back’ service

52

53

- Roaming Calls – Voice & Data Traffic from ‘TeliaSonera’, ‘Telenor’, and ‘Tre’ operators

for ‘AMC’ + ‘PC Client’ as well as Data Traffic for ‘Call Back’ service

Notice: It is estimated that 30% of calls are initiated by ‘PC Client’ while travelling.

54

55

- Roaming Calls – Voice & Data Traffic from ‘TeliaSonera’, ‘Telenor’, and ‘Tre’ operators

for ‘Travel SIM’ + ‘MLCR’ as well as Data Traffic for ‘Call Back’ service

56

57

- Roaming Calls – Voice & Data Traffic from ‘TeliaSonera’, ‘Telenor’, and ‘Tre’ operators

for ‘AMC’ + 'MLCR + PC Client as well as Data Traffic for ‘Call Back’ service.

Notice: It is estimated that 30% of calls are initiated by ‘PC Client’ while travelling.

58

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TRITA-ICT-EX-2012:248