Fat/Thin client for mobile applications
and the proposed way forward
MOHAMMAD REZA IZADI
KTH Information and
Communication Technology
Master of Science Thesis
Stockholm, Sweden 2012
TRITA-ICT-EX-2012:248
Fat / Thin client for mobile applications
and the proposed way forward
Mohammad Reza Izadi
[email protected]
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
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.
i
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.
iii
List of Abbreviations
3G
iLBC
ADSL
AMC
API
APSD
BSC
BTS
CGI
DCE
DLL
DSL
DTMF
FMC
FNO
FTP
GPRS
GSM
GUI
HTTP
IP
IVR
IM
LAN
LCR
MC
MLCR
MNO
OS
OSF
PBX
PC
PSTN
QoS
ROI
RPC
SEK
SIM
3rd Generation
Internet Low Bitrate Codec
Asymmetric Digital Subscriber Line
Aastra Mobile Client
Application Programming Interface
Automatic Power Save Delivery
Base Station controller
Base Transceiver Station
Common Gateway Interface
Distributed Computing Environment
Data Link Layer
Digital Subscriber Line
Dual Tone Multi Frequency
Fixed Mobile Convergence
Fixed Network Operator
File Transfer Protocol
General Packet Radio Service
Global System for Mobile Communications
Graphical User Interface
Hyper Text Transfer Protocol
Internet Protocol
Interactive Voice Response
Instant Messaging
Local Area Network
Least Cost Routing
Mobile Client
Mobile Least Cost Routing
Mobile Network Operator
Operating System
Open Software Foundation
Private Branch Exchange
Personal Computer
Public Switched telephone Network
Quality of Service
Return of Investment
Remote Procedure Call
Swedish Krona
Subscriber Identity Module
v
SIP
SMS
SQL
UMA
UMTS
UNC
UWN
VoIP
WiMax
Wi-Fi
WLAN
Session Initiation Protocol
Short Message System
Structured Query Language
Unlicensed Mobile Access
Universal Mobile Telecommunications System
UMA Network Controller
Unlicensed Wireless Network
Voice over IP
Worldwide Interoperability for Microwave Access
Wireless Fidelity
Wireless Local Area Network
vi
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
vii
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
viii
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 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 12.1. Normal calls - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 12.2. AMC Mobile LCR - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 12.3. AMC+PC Client - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ix
35
35
36
37
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
x
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
1
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!
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.
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
2
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.
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
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.
3
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]
to interact with PBX while running
different applications on the phone.

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.
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.
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]
2.1. 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:

2.2. Architectures to implement FMC
services
FMC services can be implemented in
four different architectures which are
known as:
PBX-Centric

In this model, PBX acts like an anchorpoint 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.

Carrier-Centric
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 dualmode cellular / Wi-Fi handsets.
Subscribers benefit from the fact that
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
4
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 dualmode 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.
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.
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.
5
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).
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.
-
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.

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.
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:
-
Usage of two different numbers
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.
Pure mobile service with mobile
number only
6
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]
7
3. IP-PBX
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.
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
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 IPPBX 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.
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.
An IP-PBX can be used with:


Existing phones along adaptors and
standard phones connecting to PC’s.
IP-Phones converting voice to IP
packets and vice versa.
Soft phones using with a handset
8
-
SIP (Session Initiation Protocol):
Another protocol like H.323, but
quite simpler.
and implemented, as well as avoiding long
distance changes between branches and
using one centralized directory that is
cheaper than many multiple directories.
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.
All in All, main advantages of an IPPBX compared to a conventional PBX are
as follows:






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

[6]
9
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
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.
Transfer Protocol (FTP) that uses Client /
Server interaction for sending and
transmitting files between servers. The
following sequence is executed in such a
system:
-
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.
-
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.
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
Figure (7): Traditional Fat Client / Server
10
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
speed
-
Most tools for 2-tier are very robust
-
2-tier architectures work properly
in homogeneous environments with
fairly static business rules

application
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.
development
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).
3-Tier Architecture
Developing 2-tier architecture to 3tier architecture requires placing a
11
Figure (9): 3-Tiered Application Architecture

N-tier Architecture
Advantages of 3-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.
- RPC calls provide greater overall
system flexibility than SQL calls in 2tier 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.
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.
- 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.
12
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:

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]
Upsizing the servers
13
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.
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.
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]

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.
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.
- Business Logic
5.1. Thin Client Architecture
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.
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:
- Data Access Logic
The lowest layer of the wireless solution
is a critical component which makes it too
complex to be created. [5]
14
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
15
installation might affect previously
installed programmes, which could be very
disturbing when it affects other vendors’
software.

Available
browser
from
any
PC
client. For instance once some data is
shown on the screen, it would be difficult
to change screen entries based on the
previous entries.

with
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.

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.
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]





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]

Requirement
connectivity
of
always
on
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:




5.4. Thin Client disadvantages:

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.
Other advantages attributed to the thin
client are:


May have to navigate multiple
browser screens to emulate current
client screens
Low level of interactivity

Since data transition requires connection
to the server, there is a lower level of
interaction between the user, and thin

16
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]
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.
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
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.
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]




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]
Other fat client related disadvantages:




5.6. Thick Client Disadvantages:

Cannot access system from “adhoc” 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]
Some more advantages for fat client are
as follows:


Server must account for multiple
versions of clients, increasing
complexity

Updates, new features, and bug
fixes require users to download and
install client side software.
17
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]
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.
18
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 (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 standby mode (out-of-call features), and during
the talk on the phone (in call features).
Figure (14): Aastra Client
display on the phone
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.
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.
19
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 (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.
Figure (17): In-Call Functions
20
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.



Having said the AMC Client key
features, some of its main advantages are
described as follows:

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.

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 upto-date versions or applications are
available on the websites for download,
which all it takes for installation is a single
click.
 Unified User Experience
Key product features (taken from
‘Comdasys’ enterprise):

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’.
7.1. AMC features & advantages



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
Easy-to-Use and very intuitive GUI
Multi-Language support
Excellent voice quality over
WLAN
Seamless In-Call handover with
voice call continuity
21
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.

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.
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
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:
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
E51, N95 8GB, N95, 6120 classic, E61i,
E65, E90, E70, E60, N80
Samsung & LG smart phones are
supported on a Project Specific basis.
There are some more devices which are
supported as they are compatible with the
above ones:
22
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).

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.

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.


Direct Media Connect for
optimized Voice Call Routing
via WLAN
major
In addition to that, testing has been and
is being conducted with products from
major professional WLAN infrastructure
Providers, among them:
Supports
Over-the-Air
deployment via ‘Comdasys’
FMC appliance and / or
external tools
Multiple SIM card support with
Follow-Me functionality
all
The AMC Client has been tested with all
major Access Points such as AVM, Belkin,
DLink, Linksys, Netgear, and others.
Instant Messaging and Presence
Support

Compatible with
WLAN solutions
- 3Com
- Aruba Networks
- Bluesocket Networks
- Cisco Aironet
- Colubris Networks
- Meru Networks
- Siemens Hipath Wireless
23
Supported voice supplementary services:
- 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
- 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)
1
. Some parts have been taken directly from
www.comdasys.com (2009) due to being so
specific.
24
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.
arriving information necessitate
being up-to-date according to the
recent findings.

Two different schools of thought are to
be taken into the consideration:

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.
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
25
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.

A general view of a ‘Feature File’ is
shown:
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:


All lines must be separated by a
comma, and it is not allowed to
have empty line(s) between the
lines.
#DTMFLIST
feature-line 1,
feature-line 2,
.
.
.
feature-line n,
# DTMFLIST
‘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
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],…,
do with that; otherwise it takes the
same number as ‘Command ID’.
1. Display text: Defines the command
which is going to be run
4. Activated: To activate a feature this
number is set to 1, to deactivate,
that must be 0.
2. Command ID: A number which has
to be unique, and is defined by the
designer such that interacts with the
client.
5. Feature
type:
Represents
a
hexadecimal
number
which
configures the dynamic display of a
feature:
3. Parent ID: A number which is
related to the ‘Command ID’ of the
previous line if it has something to
F
Digit8
F
Digit7
FF
Digit6/5
FF
Digit4/3
FF
Digit2/1
Digit 2/1: Is set to 1 if a feature
handles In-Call feature, and for Out-ofCall feature it is 0.
executed; for example for having a
conferance is only applicable while
having 2 users on the line.
Digit 4/3 : Shows the number of
active calls needed for a feature to be
Digit 6/5 : Defines the number of
parked / held calls.
26
Digit 7 : Defines the type of
comparison between active calls, and it
takes 3 numbers:



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.
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 .
VOICEMAILNUMBER:
The
voicemail number which is defined in
the settings will be used. No user
interaction is required.
1: If the number of active
calls is equal to or greater
than the number of active
calls defined in Digit 3/4 .
TAKENUMBER: Take number
specified in settings will be used for the
feature.
2: If the number of active
calls is exactly equal to the
number of active calls
defined in Digit 3/4 .
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)
Digit 8: The same procedeur for Digit 7
is used here but for parked / held calls as
defined
in digit 6/5.
Value 2: Same as for value 1, but a
checksum will not be added!
9. DTMF Sequence(s)
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.
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.
7. PBX Index: Specifies the ‘Aastra’
PBX ID for which the feature is
activated.
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.
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:
27
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)
Automatic call termination is not activated.
The PBX-Index for which the feature is
activated is 0.
Sequence type is 2, so

The type of comparison is not specified,
so comparison is based on <=

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 submenu. It is an “out-of-call” feature; hence a
call will be initiated.
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]
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.
1
. A full view of a ’Feature File’ is shown in the
‘Appendix 16.1’.
28
9.3. Example of two test results
‘NOKIA E51’, and highlights the very
first ten test cases by a fat client.
1. The following table illustrates a
simple test result executed on the
Table 1: First ten cases performed by fat client
Nr.
Test cases
Result
1
Making an outgoing external call
OK
2
3
4
5
6
7
8
9
10
Comment
00 must be added in front of the original Nr. (e.g 0712345678
==> 000712345678)
Making a call to internal short
extension
Calling the voice mail number
Calling emergency number (112)
Making a video call
Send a message (SMS/MMS)
Incoming external call
Incoming internal extension call
Receiving 2 internal calls, joining
them; making an outgoing
external call, joining them.
OK
Tested
OK
Fail
OK
OK
OK
Not tested
Not tested
The client does not support video calls.
Tested
Tested
Tested
OK
Tested
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:
29
Table 2: DTMF Configuration on NOKIA E51
DTMF Configuration
Feature Test
Case
Enquiry
DTMF Sequence
Enquiry,101,101,1,FF0101,0,0,2,*,NUMBER,
Pendling
Pendling,102,102,1,010001,0,0,0,*,
End call / Unhold
End call / Unhold,104,104,1,10010101,0,0,0,***1,
Application
Result
Making a new call during the
current one(s)
Working
Properly
Max 8 calls
Moving between existing calls
Working
Properly
Changing the name
from 'Brokering' to
'Pendling' does not
work on the display
Ignored
Having more than 2 calls at the same
time while each user is able to hear
and talk to others
Working
Properly
Asking a busy user to make a call
back
Working
Properly
Making it possible for a busy user (to
whom call made) to receive a call
during his current call
Working
Properly
Conference
Conference,103,103,1,FF0101,0,0,0,3,
Call Back
Call Back,125,125,1,FF0101,1,0,0,5,
Call waitng
Call Waiting,105,105,1,FF0101,0,0,0,4,
Hold
Hold,106,106,1,FF0101,0,0,0,***,
Ignored
Park
Park,107,107,1,FF0101,1,0,0,****76,
Ignored
Giving the possibility of
answering either the
mobile phone or another phone while
both are ringing at the same time
Working
Properly
Take
Take,108,108,1,0,0,0,2,*,TAKENUMBER,
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,#,
User
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#,
Ignored
Forwarding on No Reply,114,109,1,0,0,0,2,,,
Ignored
Ignored
Forwarding off
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
Forwarding if Busy,118,109,1,0,0,0,2,,,
Ignored
User
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#,
Ignored
Personal Call Routing,126,126,1,0,0,0,2,,,
Ignored
Voice mail
Forwarding off
Forwarding on no
reply
User
Voice Mail
Voice Mail
Forwarding off
Personal Call
Routing
Call Routing
Comment
Diverting the number to another one
Working
Properly
Ignored
Ignored
Ignored
Ignored
Ignored
Ignored
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
30
Max 8 calls
Configuration
(initialiazation &
cancelation)
is performed via MX1
Programmer, not
the mobile device
Cancelation is
performed via MX1
programmer, not the
mobile device
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.
31
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.
The solution suggested by AMC is
back strategy feasible by executing
back strategy using a client. First
explain how the system would work,
then introduce different strategies
achieve the goal.
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.
call
call
we
and
to
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.
2. ‘B’ party receives
the call via operator.
B
SW EDEN
Op e a to r B
GSM / POTS
Roaming network
----------------------------------USA
A
Operator A
GSM / Voice
1. ‘A’ party establishes a
call from abroad to ‘B’
party
Figure (19): Traditional way of making international calls
32
11. Low cost international calls
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.
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
B
Voice / GSM / POTS
Data / GPRS
PBX
A
Voice / GSM
Figure (20): Call back service via PBX
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.
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.
33
B
VOICE / GSM / POTS
2. Operator
routes the
connection
to the PBX.
Operator
ISDN / T runk
IP
3
Internal line
2
SW EDEN
IP / GPRS
Main office
PBX
3. PBX connects two
parties simultaneously
via operator.
1
VOICE / GSM
-----------------------------------
1.‘A’ party establishes
a call from abroad to
‘B’ party.
Operator
A
USA
Figure (21): Call back service using PBX as an interface
34
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.
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’.
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
1
. All tables containing entire data from three
mentioned operators are available in the ‘Appendix
16.2’.
35
Table 3: Roaming Calls - Traffic from ‘TeliaSonera’ operator for normal calls
% of total # Minutes SEK/Minute # Minutes
Call from US
Call received in US
Call from China
Call received in China
54,7%
45,3%
54,7%
45,3%
138 939
138 939
97 672
97 672
15,00
4,61
22,00
4,99
75 998,75
62 940,74
53 425,56
44 246,05
Total for
period
1 139 981,25
290 156,80
1 175 362,42
220 787,78
depicts ‘Data Traffic’ provided by
‘TeliaSonera’, and the corresponding price
for the two mentioned countries.
Another noticeable cost issue is the
‘Data Traffic’ charged by operators. Many
operators charge on 50 Kb. Table below
Table 4: Data Traffic form ‘TeliaSonera’ operator for normal calls
SEK/setup
% of total # MB
(50kb)
Data communication with
10,7%
1 586
4,80
Server per 50 Kb - US
Data communication with
7,6%
1 115
5,80
Server per 50 Kb - China
# of Call
setups
Total for
period
46 313
7 612,05
32 557
6 465,93
whereas ‘Total Roaming Traffic’ which is
the sum of two mentioned values is 12 660
875,30 SEK.
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,
12.2. AMC Mobile LCR
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.
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
Table 5: Roaming Calls - Traffic from ‘TeliaSonera’ operator for GPRS Call Back
% of total
Call from US
Call received in US
Call from China
Call received in China
0%
100%
0%
100%
# Minutes SEK/Minute
138 939
138 939
97 672
97 672
36
15,00
4,61
22,00
4,99
Total for
period
0,00
0,00
138 939,49 640 511,03
0,00
0,00
97 671,61 487 381,35
# Minutes
As seen from the table all calls are made
to be received calls. Hence, there will be
no charge for making a call.
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.
The data traffic is the same as before
like what is shown in ‘Table 4’. AMC
Mobile LCR requires making a call over
Table 6: Data traffic for Call Back service using ‘AMC’
Number of
calls per 50Kb
Data communication with Server per 50
50
Kb - US
Data communication with Server per 50
50
Kb - China
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.
Number of
50Kb steps
Data cost for
call back
926
4446
651
3777
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.
Comparing the result for normal
roaming calls and GPRS Call back
indicates that using AMC LCR Mobile
results in cost saving:
12.3. AMC + PC Client
Total Roaming Traffic (direct call): 12
660 875,31 SEK
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:
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
Table 7: Roaming Calls -Traffic by using ‘AMC’ + ‘PC Client’; (30 % of users using ‘PC Client’)
Total for
% of total # Minutes SEK/Minute
# Minutes
period
0,0%
138 939
15,00
0,00
0,00
Call from US
70,0%
138
939
4,61
97
257,64
448
357,72
Call received in US
0,0%
97 672
22,00
0,00
0,00
Call from China
70,0%
97 672
4,99
68 370,13
341 166,94
Call received in China
37
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’.
price down to 0.05 & 0.06 SEK per
minute.
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).
38
Table 8: Roaming Calls traffic for ‘Travel SIM’ + ‘MLCR’
Call from US
Call received in US
Call from China
Call received in China
% of total
# Minutes
SEK/Minute
# Minutes
0%
100%
0%
100%
138 939
138 939
97 672
97 672
0,00
0,05
0,00
0,06
0,00
138 939,49
0,00
97 671,61
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.
Total for
period
0,00
6 946,97
0,00
5 469,61
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
Data communication with
Server per 10 Kb - US
Data communication with
Server per 10 Kb - China
SEK/setup
(10kb)
# of Call
setups
Total for
period
10,74%
1 586
1,95
46 313
3 092,39
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
Number of
calls per 10Kb
10Kb steps
Data communication with Server per 10
10
4631
Kb - US
Data communication with Server per 10
10
3256
Kb - China
Again comparing ‘Table 10’ to ‘Table 6’
highlights the fact that the data cost for call
back has been increased. Number of call
Data cost for
call back
9031
6349
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
39
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.
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.
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.
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.
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
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’
Call from US
Call received in US
Call from China
Call received in China
% of total
# Minutes
SEK/Minute
# Minutes
0%
70%
0%
70%
138 939
138 939
97 672
97 672
0,00
0,05
0,00
0,06
0,00
97 257,64
0,00
68 370,13
Total for
period
0,00
4 862,88
0,00
3 828,73
Call Back Request’ is 91 3141 SEK, and
sum of all costs comes to 676 366 SEK
which relates to the ‘Total Roaming
Traffic’.
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
1
. The value is obtained by taking 70% of the Data
Traffic for Call Back request in the previous stage
(12.4)
40
The saving cost is calculated as below:
12.6. Mobile roaming least cost routing
business case
Total Roaming Traffic (direct call): 12
660 875,31 SEK
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.
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.
Mobile roaming least cost routing business case
60 000 000 kr
50 000 000 kr
Current yearly Mobile roaming cost
40 000 000 kr
Estimated yearly Mobile roaming
cost after installing mobile client
Estimated yearly Mobile roaming
cost after installing mobile client &
PC client
30 000 000 kr
Estimated yearly Mobile roaming
cost after installing mobile client +
Travel SIM
20 000 000 kr
Estimated yearly Mobile roaming
cost after installing mobile client +
PC client + Travel SIM
10 000 000 kr
0 kr
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
41
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:
Retrurn Of Investments
2,5
Month
2,0
1,5
Months
1,0
0,5
0,0
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
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.
42
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.

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.
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.
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.
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.

How fast is each client?
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.
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.
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.
Since both clients are supposed to be
equipped with the same functions, it does
not seem that this function differs for the
All in all what can be concluded is that
available working clients show faster
43
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.

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 costeffective choice if it is designed so that it
works on all phones as expected from its
goal.
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.

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.
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.
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.
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.

Reliability in terms of working
properly in different conditions:

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.
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
Fat client is a client tested in many
phones and network systems, so the
problems have been recognised and solved
44
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.
45
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.
46
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
47
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
48
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
49
50
- Roaming Calls – Voice & Data Traffic from ‘TeliaSonera’, ‘Telenor’, and ‘Tre’ operators
for ‘GPRS Call Back’ as well as Data Traffic for ‘Call Back’ service
51
52
- 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.
53
54
- Roaming Calls – Voice & Data Traffic from ‘TeliaSonera’, ‘Telenor’, and ‘Tre’ operators
for ‘Travel SIM’ + ‘MLCR’ as well as Data Traffic for ‘Call Back’ service
55
56
- 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.
57
58
TRITA-ICT-EX-2012:248
www.kth.se