Authors:
Jiann-Liang Chenz, Szu-Lin Wuy,Yang-Fang Li, Pei-Jia Yang,Yanuarius Teofilus Larosa
2011 7th International Wireless Communications and Mobile
Computing Conference (IWCMC),
On page(s): 1463 - 1468, July. 2011
報告:陳昶安 MA1G0107

Introduction

Background Knowledge

Proposed IMS cloud QOS mechanism

System design and performance analysis

Conclusion
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
The IP Multimedia Subsystem (IMS) supports
heterogeneous networking and provides
Quality of Service (QoS) policy.

For mobile computing, an open platform is
required to access multimedia services.

All of the above issues must be addressed
when developing next-generation wireless
communications technologies and applications.
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
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Figure 1 illustrates a IMS cloud architecture in a heterogeneous network.

The IMS architecture which is based on the 3GPP
(3rd Generation Partnership Project) system,
defined QoS policy module, which consists of
Policy and Charging Rules Function (PCRF),
Policy and Charging Enforcement Function
(PCEF).

The cloud computing architecture is divided into
three layers, Software as a Service (SaaS),
Platform as a Service (PaaS), and Infrastructure
as a Service (IaaS).
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Heterogeneous Networks
•
The heterogeneous network is a next-generation
communication network that provides wireless links
via 3G, WLAN or WiMAX in overlapping networks.
•
A 3G supports multimedia communication and is
expected to evolve into All-IP technologies.
•
The WiMAX wireless broadband technology provides
long-distance last-mile access to high bandwidth.
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
The IEEE 802.11x protocols for wireless local
area network (WLAN) use the same basic
protocol
for
over-the-air
modulation
techniques.

In heterogeneous networks, 3G can support a
high-mobility environment.

The WiMAX supports mobile terminals
moving at speeds up to 120Km/h.
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Cloud Computing
•
The cloud computing architecture is divided into
three layers.
•
The bottom layer is Infrastructure as a Service
(IaaS), which has a service-oriented architecture.
•
The middle layer is Platform as a Service (PaaS),
a service platform that developer can use to
deploy their own applications.
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
The top layer of the Software as a Service (SaaS)
provides services so that each user can access
services according to their requirements.

Hadoop is a software platform for a java-based
development environment that has high
scalability, high efficiency, and high reliability.

The two components of Hadoop are Hadoop
Distributed File System (HDFS) and MapReduce.
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IP Multimedia Subsystem (IMS)
•
The purpose of IMS is to provide services in a 3G
network infrastructure and to enable QoS
exchange in different networks.
•
The 3GPP-defined IMS core component is Call
Session Control Function (CSCF).
•
The components are divided into P-CSCF
(Proxy-CSCF), I-CSCF (Interrogating-CSCF) and
SCSCF modules (Serving-CSCF).
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
The P-CSCF is the first contact point in IMS.

The P-CSCF is responsible for authentication
requests, which is forwarded to the specific target.

The ICSCF is the contact point between network
operators and UEs (User Equipment).

The S-CSCF is the core component of IMS,
which is located in attributed network for UE
session control and registration services.
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
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Figure 2 illustrates the proposed IMS Cloud QoS system architecture.

The lower layer model, IaaS is the development
platform used for building the IMS system.

The PaaS provides a platform for system
administrators to develop the Hadoop framework
needed for distributed file system and
MapReduce technology.

The upper layer model is SaaS, which enables
users to obtain information and services via cloud
computing systems.
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
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Figure 3 illustrates the proposed system module, which includes IaaS,
PaaS and SaaS.
Infrastructure as a Service (IaaS)
•
In IaaS, a service is accessed through different
networks in an IMS environment.
•
The IMS is implemented through an open and standard
architecture to provide multimedia applications.
•
The IMS framework includes the Policy and Charging
Rules Function (PCRF) and Policy and Charging
EnForcement point (PCEF) components needed for
QoS policy implementation.
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
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Figure 4 illustrates a complete IMS QoS framework architecture, in which the
policy repository by the open source of XDMS server is used to store definitions of
QoS policy files.
Platform as a Service (PaaS)
•
The high fault tolerance of HDFS enables it to
deploy on low-cost hardware devices.
•
The HDFS is suitable for massive data and
provides high throughput.
•
MapReduce is a parallel programming model for
data processing and is used by Google for largescale data processing in distributed computing
environments.
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Software as a Service (SaaS)
•
This layer is implemented by using the Hadoop
SaaS system for extracting the user wants to
access information and applications to achieve
the service function.
•
For instance, users can access applications
through Web Services such as multimedia (video
streaming),
management
(user
process
management) and social network applications.
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
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Figure 5 shows the cloud computing service
architecture.

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Figure 6 illustrates the test scenario, which included 3G, WiMAX and
WiFi access technologies.
System Implementation
1) Hadoop system design and operation:
•
One mainly machine, called hdp-1, is the
Master, and another two machines, hdp-2 and
hdp-3, are the Slaves.
•
This study utilizes the Representational State
Transfer(REST) Web Services to get Hadoop
services.
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•
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The user interface is shown in Figure 7.

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Figure 8 shows the installed system.
2)
•
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IMS core design and operation:
Figure 9 illustrates the established IMS environment.

This study sets up IMS components in the
master machine (hdp-1).

Clients then communicate by using SIP
protocol to access the IMS network.

The system defines all domain policies rule.
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
26
The four CSCFs modules are started as shown in Fig. 10.

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Figure 11 shows the Policy Control Management.

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Figure 12 shows how an Android phone is used to access the cloud
computing portal site by QR code and how services can be accessed
through the cloud computing interface.
Performance Analysis
• Figure 13 compares the results with and without cloud computing system
when a client request is set to retrieve 128MB.
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
30
Figure 14 shows the system throughput for VoIP, video streaming and Web
browser.
•
The proposed IMS Cloud QoS mechanism has
the following three layers:
Infrastructure as a Service (IaaS) layer
Platform as a Service (PaaS) layer
Software as a Service (SaaS) layer
•
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The IaaS layer mainly accesses heterogeneous
networks such as UMTS, WLAN and WiMAX
through the IP Multimedia Subsystem.

The PaaS layer manages the cloud computing system
in the Hadoop Distributed File System and the
MapReduce mechanism for analyzing user preferences.

The SaaS layer allows users to access desired
applications such as the Web, social networks and
management services.

The system implementation shows that throughput
capacity with cloud computing is higher than without
cloud computing when numerous users request services.
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