906_Everything Over IP - Dynamics of the Strategic Changes in Voice and Data Networks

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A PROJECT REPORTON

Everything Over IP Dynamics of the StrategicChanges in Voice and Data Networks

TOWARDS PARTIAL FULFILLMENT OFTHE REQUIREMENTS FOR THE AWARD OFMASTER IN BUSINESS ADMINISTRATION IN TELECOM MANAGEMENT

SUBMITTED BY

CHIRANJIB DHAR

ANSHUMAN SENABHISHEK SINGHNEHA AGRAWALJITENDER SINGH

ROMI RAJE GUPTA

Symbiosis Institute of Telecom ManagementConstituent of Symbiosis International University

Pune 411 042

MBA - TM I Batch 2009-11


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CERTIFICATEThis is to certify that research project titled

Everything Over IP Dynamics of the StrategicChanges in Voice and Data Networks

Is a bonafide work carried out by

CHIRANJIB DHARANSHUMAN SENABHISHEK SINGH

NEHA AGRAWALJITENDER SINGHROMI RAJE GUPTA

Under the guidance of

Mr. Yatin Jog

Faculty IT, SITM

Towards the partial fulfillment of

Master of Business Administration in Telecom Management

(MBATM)

__________________ __________________

Research Project Guide Director


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Symbiosis Institute of Telecom ManagementResearch Project Report

Everything Over IP - Dynamics of the Strategic Changes in Voice and Data Networks | 3

ACKNOWLEDGEMENT

The Research Project on Everything over IP Dynamics of the Strategic Changes inVoice and Data offered us both a learning experience, as well as, a glimpse into theIP communication business. During the tenure of this project, we were fortunate tohave interacted with people, who in their own capacities have encouraged and guidedus.

For his unstinted and invaluable guidance, we wish to express our heartfelt gratitudeto my mentor Mr. Yatin Jog, without whom this project could not have been realized.

We are grateful to our Institute Director Mr. Sunil Patil, Deputy Director Mr. P.

Kulkarni and our Chairperson Placements, Prof. Sujata Joshi for their excellentcoordination with the industry for the Research project and thus giving us anopportunity to enhance our management & technical skills in the sense oforganizational activity.

We would also like to express our sincere thanks to the alumni in the industry for theirexpert guidance and constant cooperation. It was a privilege working with them andwe sincerely thank them for advising us whenever the road map seemed blocked,despite of their busy schedule.

Finally, we would like to express our deepest gratitude towards our institute

Symbiosis Institute of Telecom Management in which apart from the summer projectsyou get an opportunity to continuously work on the research projects and explore thetrends in the industry.


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Abstract

This project will review the viability of EoIP networks. The Internet, underscored by IP, has no

only affected every business, information systems department and software publisher, but it ha

changed world communications forever. The IP telephony, VoIP, IP Multimedia Subsystem, I

network, Internet, TCP/IP, dumb network, infranet etc are systems that are spearheading

dynamic change in the way we communicate. The IP protocol is not only the protocol of th

Internet, but it has become the default protocol for local networks in almost every enterprise

This project will study changes that are taking place in the telecommunications industry rangin

from a discussion about the companies installing massive global IP networks to the emergenc

of novel routing technologies, e.g. multi-protocol label switching (MPLS) and terabit route

technologies. The advantages of conversion to IP network like Reduced Transport cos

Abundant IP interfaces meeting requirements of different networks and evolution, Launchin

new services quickly, Saving maintenance and management cost, Fully complying wit

evolution to All IP network etc will also be discussed.

In a Nutshell

To study the technologies and protocols involved in all IP network To learn synchronization of legacy network with IP architecture To review the Indian regulatory concept of EoIP and policies adopted in other parts of th

world To study the compatibility issues of emerging/existing backhaul technologies Business analysis of EoIP


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Table of Contents

1. Executive Summary ........................................................................................................ 12

2. Introduction ..................................................................................................................... 13

3. A Basic Architecture for a EoIP Network ....................................................................... 14

3.1 INTRODUCTION ........................................................................................................ 14

3.2 IMS (IP Multimedia Subsystem)............................................................................... 16

3.2.1 A Layered Approach ............................................................................................. 18

3.2.1 Architecture ................................................................................................... 21

3.2.1 Architectural Elements ................................................................................. 25

3.2.1 IMS Benefits .................................................................................................. 30

3.3 NGN Services ........................................................................................................... 31

3.4 NGN Models .............................................................................................................. 33

3.4.1 Scenario 1: Network Consolidation .................................................................. 34

3.2.1 Scenario 2: Deployment of overlay packet based network ........................ 35

3.2.1 Scenario 3. Replacement of legacy TDM equipment .................................. 36

4. EoIP protocols .................................................................................................................... 38

4.1 Introduction ................................................................................................................... 38

4.2 SIP .................................................................................................................................. 40

4.2.1 Call Flow ........................................................................................................ 41

4.3 Migration from IPv4 to IPv6 ..................................................................................... 41

4.3.1 Problems faced by IPv4 ................................................................................ 41

4.3.2 Phases of IPv6 migration in NGN ................................................................. 42

5 Service aspects: Interoperability of services and networks in NGN ........................... 47

5.1 PSTN/ISDN evolution to NGN .................................................................................. 47

5.1.1 Aspects to consider when evolving to NGN ............................................... 47

5.1.2 Service requirements by national regulatory bodies.................................. 525.1.3 Emergency telecommunications in NGN..................................................... 52

5.1.4 Security aspects of evolution....................................................................... 53

5.1.5 Examples of network evolution scenarios .................................................. 53

5.2 PSTN/ISDN emulation and simulation .................................................................... 64

5.2.1 Interfaces ....................................................................................................... 66


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5.2.2 Adaptations ................................................................................................... 67

5.3 Call server-based PSTN/ISDN emulation ................................................................ 68

5.4 ENUM ........................................................................................................................ 68

5.4.1 Types of E-NUM .................................................................................................. 68

7. Services ........................................................................................................................... 74

7.1. Specific Services for next generation networks .................................................... 76

8 Generalized Mobility ....................................................................................................... 80

8.1 Introduction .............................................................................................................. 80

8.2 Considerations for mobility management in NGN ................................................. 80

8.2.1 Network environments.................................................................................. 80

8.2.2 General mobility management features ...................................................... 81

8.2.3 Considerations on user part......................................................................... 83

8.2.4 Mobility management functionalities ........................................................... 84

8.3 Classification of mobility management .................................................................. 85

8.3.1 Intra-CN MM ................................................................................................... 86

8.3.2 Intra-Network MM (Inter-CN MM) .................................................................. 87

8.4 Requirements for mobility management ................................................................ 87

8.4.1 General requirements ................................................................................... 888.4.2 Requirements for Inter-CNs MM ................................................................... 90

8.4.3 Requirements for Inter-ANs MM ................................................................... 91

8.5 Classification of mobility based on network topology .......................................... 93

9. Quality of Service Parameters for Next Generation Networks ..................................... 95

9.1 The role of voice in next generation networks ....................................................... 95

9.2 Quality of Service requirements for Voice over IP ................................................. 96

9.3 QoS solutions for VoIP .......................................................................................... 100

9.3.1 Integrated Services (Intserv) .......................................................................100

9.3.2 Differentiated Services (Diffserv) ................................................................101

9.3.3 MPLS Traffic Engineering (MPLS-TE) .........................................................103

9.4 A solution framework for VoIP Quality of Service ............................................... 103

9.5 Interface descriptions ............................................................................................ 106

9.5.1 Interface IF-1 .................................................................................................106


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9.5.2 Interface IF-2 .................................................................................................106

9.5.3 Interface IF-3 .................................................................................................107

9.5.4 Interface IF-4 .................................................................................................107

9.5.5 Interface IF-5 .................................................................................................108

9.5.6 Interface IF-6 .................................................................................................109

9.6 Call setup for VoIP ................................................................................................. 109

9.7 Currently Defined Solutions for VoIP QoS ........................................................... 112

9.8 Quality Control Models for NGN............................................................................ 113

9.8.1 3GPP IMS ......................................................................................................113

9.8.2 ITU-T NGN-GSI .............................................................................................119

9.8.3 ETSI TISPAN .................................................................................................121

9.8.4 PCMM ............................................................................................................122

9.8.5 MSF ...............................................................................................................123

9.9 NGN Comparison ................................................................................................... 124

10. NGN security .............................................................................................................. 128

10.1 Objective of NGN security ..................................................................................... 128

10.1 Objectives for security across multiple network provider domains ................... 128

10.1 Threats to the NGN ................................................................................................ 12910.1 Areas of consideration and action for security policy as the five As ................ 133

10.1 Security Trust Models ............................................................................................ 135

10.5.1 Single network trust model .........................................................................135

10.5.2 Peering network trust model .......................................................................137

10.1 Standard Security policies .................................................................................... 138

10.1 Technical aspects concerning security ................................................................ 141

11. Business case ............................................................................................................ 143

11.1 Introduction ............................................................................................................ 143

11.2 Case Study: BT....................................................................................................... 144

BTs Objectives: .........................................................................................................144

NGN implementation: .................................................................................................145

Financial benefits: ......................................................................................................147

Advanced Services Offered: ......................................................................................148


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Laying the Foundation for the Digital Home ............................................................148

Launching Next-Generation IP Television ................................................................150

End-to-End Service Assurance .................................................................................150

Fusionthe worlds first seamless fixed-mobile phone service ............................151

Concerns ........................................................................................................................... 151

Conclusion ........................................................................................................................ 153

12. References ................................................................................................................. 154


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List of Figures

Figure 1 : Logical Representation of the network .................................................................. 15

Figure 2: Layered Architecture ............................................................................................. 18

Figure 3: NGN Architecture using Soft switch ....................................................................... 21

Figure 4: IMS and its Environment ....................................................................................... 23

Figure 5: : Relationship of session control entities to NGN Core networks ........................... 24

Figure 6: 3GPP IMS Architectural Overview ......................................................................... 25

Figure 7:Architectural Elements............................................................................................ 28

Figure 8: Multiservice access systems ................................................................................. 34

Figure 9: Scenario 2 ............................................................................................................. 35

Figure 10 Scenario 3 ............................................................................................................ 37Figure 11: : Protocol Stack for NGN ..................................................................................... 38

Figure 12: SIP Call flow ........................................................................................................ 40

Figure 13: Phase 0-Complete IPv4 based NGN ................................................................... 42

Figure 14:Phase 1-Connecting IPv6-based NGNs across IPv4-based NGN......................... 43

Figure 15: Phase 2-Connecting IPv6-based NGNs IPv4-based NGNs across dual-stack ..... 44

Figure 16: Phase 3-IPv4 Islands with IPv6-based NGN ........................................................ 45

Figure 17: Phase 4-Completed IPv6-based NGN ................................................................. 46

Figure 18: 1Preparation for evolution to NGN ....................................................................... 55

Figure 19:Realization of scenario 1 ...................................................................................... 56

Figure 20: Realization of scenario 2 ..................................................................................... 58

Figure 21:Realization of scenario 3 ...................................................................................... 59

Figure 22:IMS-based PSTN/ISDN evolution to NGN ............................................................ 60

Figure 23:Evolution of xDSL access to NGN ........................................................................ 62

Figure 24:Realization of signalling evolution scenario .......................................................... 63

Figure 25:Billing system evolution scenarios ........................................................................ 64

Figure 26:Emulation, simulation, interoperability and interworking with NGN ....................... 66

Figure 27:ENUM .................................................................................................................. 70

Figure 28:ENUM infra ........................................................................................................... 71

Figure 29:Example NGN Service Drivers ............................................................................. 77

Figure 30: Envisioned network environment of NGN ............................................................ 81

Figure 31: Mobility classifications according to service quality .............................................. 82Figure 32: User network configuration .................................................................................. 84

Figure 33:Classification of MM ............................................................................................. 86

Figure 34:Example of levels of mobility ................................................................................ 93

Figure 35: VoIP .................................................................................................................... 97

Figure 36:VoIP QoS Architecture ........................................................................................104

Figure 37: Interconnect via transit network ..........................................................................109

Figure 38:Call setup for VoIP ..............................................................................................111


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Figure 39:Positioning Of elements in Next Generation Networks.........................................115

Figure 40:Pull QoS Authorization flow (3GPP2 model) ........................................................118

Figure 41:NGN QoS Roles ..................................................................................................125Figure 42: Security ..............................................................................................................131

Figure 43: Five As ..............................................................................................................133

Figure 44:A single network trust model................................................................................135

Figure 45:A Peering network trust model .............................................................................138

Figure 46: BT ......................................................................................................................145

Figure 47:Single IP architecture ..........................................................................................146

Figure 48:PSTN Migration ...................................................................................................147


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Title of Project

Everything Over IP Dynamics of the Strategic Changes in

Voice and Data Networks and a Business Plan

Project Objectives

Comparative analysis of all the technologies and protocols with respect to variouparameters

New services offered and technical up gradation required

Best practices for efficient regulatory framework

Backhaul support analysis

A business case for EoIP services


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1. Executive Summary

"I think there is a world market for about five computers" Remark attributed to

Thomas J. Watson (Chairman of the Board of International Business Machines), 1943

to more than 350 million personal computers being sold in a year in USA alone and

over 150 million smart-phones being sold in a year worldwide.

People want to control their home appliances, security systems, know about the exact

location of their loved ones and much more while on the move. People want to

seamlessly move from one device to another. They want to be connected and

reachable on multiple devices through the same address. More and more people are

using devices to connect to their workstations or access their work folders stored ontheir work servers while on the move.

A feat which will require a network which will let all devices connect through the same

interface, a Ubiquitous network which will allow communication between machine

and machine and a man and machine. The requirement is for a network that will allow

any user to connect through any device to access any other device from any part of

the world. It can be a wired device or a wireless device.

The world is moving towards IP V6, a move that will accommodate all the devices. An

IP based network will allow every device to connect to each other. A migration to an

IP will also help in standardisation of interfaces.


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2. Introduction

Everything over Internet Protocol (EoIP) network is a packet-based network able to

provide services including telecommunications services and able to make use of

multiple broadband, Quality of Service (QoS) enabled transport technologies and in

which service-related functions are independent from underlying transport-related

technologies. It offers unfettered access by users to different service providers. It

supports generalized mobility which will allow consistent and ubiquitous provision of

services to users.

FEATURES:

Packet-based transfer

Separation of control functions among bearer capabilities, call/session, and

application/ service

Decoupling of service provision from transport, and provision of open

interfaces

Support for a wide range of services, applications and mechanisms based

on service building blocks (including real time/ streaming/ non-real time

services and multi-media)

Broadband capabilities with end-to-end QoS (Quality of Service). Interworking with legacy networks via open interfaces

Generalized mobility

Unfettered access by users to different service providers

A variety of identification schemes

Unified service characteristics for the same service as perceived by the

user

Converged services between Fixed/Mobile

Independence of service-related functions from underlying transport

technologies

Support of multiple last mile technologies

Compliant with all Regulatory requirements, for example concerningemergency communications, security, privacy etc.


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3. A Basic Architecture for a EoIP Network

3.1 INTRODUCTION

A EoIP network is a packet-based network which can provide services including

Telecommunication Services and able to make use of multiple broadband, Quality of

Service-enabled transport technologies and in which service-related functions are

independent from underlying transport-related technologies.

The EoIP functional architecture shall incorporate the following principles.

1. Support for multiple access technologies: The NGN functional architecture

shall offer the configuration flexibility needed to support multiple accesstechnologies.

2. Distributed control: This will enable adaptation to the distributed processingnature of IP networks and support location transparency for distributedcomputing.

3. Open control: The network control interface should be open to support servicecreation, service updating, and incorporation of service logic provision by thirdparties.

4. Independent service provisioning: The service provision process should beseparated from network operation by using the above-mentioned distributed,open control mechanism. This is intended to promote a competitiveenvironment for NGN development in order to speed up the provision ofdiversified value-added services.

5. Support for services in a converged network: This is needed to generateflexible, easy-to-use multimedia services, by tapping the technical potential ofthe converged, fixed-mobile functional architecture of the NGN.

6. Enhanced security and protection: This is the basic principle of an openarchitecture. It is imperative to protect the network infrastructure by providingmechanisms for security and survivability in the relevant layers.

7. Functional entity characteristics: Functional entities should incorporate thefollowing principles: Functional entities may not be distributed over multip le physical units but may

have multiple instances.
http://en.wikipedia.org/wiki/Computer_networkhttp://en.wikipedia.org/wiki/Broadbandhttp://en.wikipedia.org/wiki/Quality_of_Servicehttp://en.wikipedia.org/wiki/Quality_of_Servicehttp://en.wikipedia.org/wiki/Quality_of_Servicehttp://en.wikipedia.org/wiki/Quality_of_Servicehttp://en.wikipedia.org/wiki/Quality_of_Servicehttp://en.wikipedia.org/wiki/Broadbandhttp://en.wikipedia.org/wiki/Computer_network


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Functional entities have no direct relationship with the layered architecture.

However, similar entities may be located in different logical layers. It offers

unrestricted access by users to different service providers. It supportsgeneralized mobility which will allow consistent and ubiquitous provision of

services to users.

Figure 1 : Logical Representation of the network

EoIP or also known as NGN involves three main architectural changes that need to

be looked at separately:

In the core network, NGN implies a consolidation of several (dedicated oroverlay) transport networks each historically built for a different service intoone core transport network (often based on IP and Ethernet).

It implies amongst others the migration of voice from a circuit-switchedarchitecture (PSTN) to VoIP, and also migration of legacy services such asX.25, Frame Relay (either commercial migration of the customer to a newservice like IP VPN, or technical emigration by emulation of the "legacyservice" on the NGN).

In the wired access network, NGN implies the migration from the dual systemof legacy voice next to xDSL setup in local exchanges to a converged setup inwhich the DSLAMs integrate voice ports or VoIP, making it possible to removethe voice switching infrastructure from the exchange.

In the cable access network, NGN convergence implies migration of constantbit rate voice to CableLabs PacketCable standards that provide VoIP and SIPservices. Both services ride over DOCSIS as the cable data layer standard.

Next Generation Networks are based on Internet technologies includingInternet Protocol (IP) and Multiprotocol Label Switching (MPLS). At the
http://en.wikipedia.org/wiki/PSTNhttp://en.wikipedia.org/wiki/VoIPhttp://en.wikipedia.org/wiki/X.25http://en.wikipedia.org/wiki/Frame_Relayhttp://en.wikipedia.org/wiki/Access_networkhttp://en.wikipedia.org/wiki/DSLAMhttp://en.wikipedia.org/wiki/PacketCablehttp://en.wikipedia.org/wiki/Session_Initiation_Protocolhttp://en.wikipedia.org/wiki/Session_Initiation_Protocolhttp://en.wikipedia.org/wiki/PacketCablehttp://en.wikipedia.org/wiki/DSLAMhttp://en.wikipedia.org/wiki/Access_networkhttp://en.wikipedia.org/wiki/Frame_Relayhttp://en.wikipedia.org/wiki/X.25http://en.wikipedia.org/wiki/VoIPhttp://en.wikipedia.org/wiki/PSTN


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application level, Session Initiation Protocol (SIP) seems to be taking over fromITU-T H.323.

For voice applications one of the most important devices in NGN is aSoftswitch - a programmable device that controls Voice over IP (VoIP) calls. Itenables correct integration of different protocols within NGN. The mostimportant function of the Soft switch is creating the interface to the existingtelephone network, PSTN, through Signaling Gateways and Media Gateways.Hotheyver, the Soft switch as a term may be defined differently by the differentequipment manufacturers and have somewhat different functions.

The NGN is characterized by the following fundamental aspects:

Packet-based transfer

Separation of control functions among bearer capabilities, call/session, andapplication/service

Decoupling of service provision from transport, and provision of openinterfaces

Support for a wide range of services, applications and mechanisms basedon service building blocks (including real time/streaming/non-real timeservices and multi-media)

Broadband capabilities with end-to-end QoS and transparency Interworking with legacy networks via open interfacesGeneralized mobilityUnfettered access by users to different service providers

A variety of identification schemes which can be resolved to IP addressesfor the purposes of routing in IP networks

Unified service characteristics for the same service as perceived by the userConverged services between Fixed and Mobile networks Independence of service-related functions from underlying transport

technologiesSupport of multiple last mile technologiesCompliant with all Regulatory requirements, for example concerning

emergency communications and security/privacy, etc.

3.2 IMS (IP Multimedia Subsystem)

The IP Multimedia Subsystem (IMS) is an architectural framework for delivering

internet protocol (IP) multimedia to mobile users. It was originally designed by the

wireless standards body 3rd Generation Partnership Project (3GPP), and is part of

the vision for evolving mobile networks beyond GSM. Its original formulation (3GPP

R5) represented an approach to delivering "Internet services" over GPRS. This vision
http://en.wikipedia.org/wiki/Softswitchhttp://en.wikipedia.org/wiki/VoIPhttp://en.wikipedia.org/wiki/PSTNhttp://en.wikipedia.org/wiki/Signalling_Gatewayshttp://en.wikipedia.org/wiki/Media_Gatewayshttp://en.wikipedia.org/wiki/Media_Gatewayshttp://en.wikipedia.org/wiki/Signalling_Gatewayshttp://en.wikipedia.org/wiki/PSTNhttp://en.wikipedia.org/wiki/VoIPhttp://en.wikipedia.org/wiki/Softswitch


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was later updated by 3GPP, 3GPP2 and TISPAN by requiring support of networks

other than GPRS, such as Wireless LAN, CDMA2000 and fixed line.

Effectively, IMS provides a unified architecture that supports a wide range of IP-based

services over both packet- and circuit-switched networks, employing a range of

different wireless and fixed access technologies. A user could, for example, pay for

and download a video clip to a chosen mobile or fixed device and subsequently use

some of this material to create a multimedia message for delivery to friends on many

different networks. A single IMS presence-and-availability engine could track a user's

presence and availability across mobile, fixed, and broadband networks, or a user

could maintain a single integrated contact list for all types of communications.

IMS History

IMS was originally defined by an industry forum called 3G.IP, formed in 1999.

3G.IP developed the initial IMS architecture, which was brought to the 3rd

Generation Partnership Project (3GPP), as part of their standardization work for

3G mobile phone systems in UMTS networks. It first appeared in release 5

(evolution from 2G to 3G networks), when SIP-based multimedia was added.

Support for the olderGSM and GPRS networks was also provided.

3GPP2 (a different organization) based their CDMA2000 Multimedia Domain(MMD) on 3GPP IMS, adding support forCDMA2000.

3GPP release 6 added interworking with WLAN. 3GPP release 7 added support for fixed networks, by working together with

TISPAN release R1.1. The Telecoms & Internet converged Services & Protocols for Advanced

Networks (TISPAN) is a standardization body of ETSI, specializing in fixednetworks and Internet convergence. It was formed in 2003 from theamalgamation of the ETSI bodies Telecommunications and Internet Protocol

Harmonization Over Networks (TIPHON) and Services and Protocols forAdvanced Networks (SPAN).
http://en.wikipedia.org/w/index.php?title=3G.IP&action=edithttp://en.wikipedia.org/wiki/3GPPhttp://en.wikipedia.org/wiki/3Ghttp://en.wikipedia.org/wiki/Mobile_phonehttp://en.wikipedia.org/wiki/Universal_Mobile_Telecommunications_Systemhttp://en.wikipedia.org/wiki/Evolution_to_3Ghttp://en.wikipedia.org/wiki/Evolution_to_3Ghttp://en.wikipedia.org/wiki/GSMhttp://en.wikipedia.org/wiki/GPRShttp://en.wikipedia.org/wiki/3rd_Generation_Partnership_Project_2http://en.wikipedia.org/wiki/CDMA2000http://en.wikipedia.org/wiki/Wireless_LANhttp://en.wikipedia.org/wiki/Fixed_phonehttp://en.wikipedia.org/wiki/TISPANhttp://en.wikipedia.org/wiki/Standardizationhttp://en.wikipedia.org/wiki/ETSIhttp://en.wikipedia.org/wiki/Internethttp://en.wikipedia.org/wiki/Internethttp://en.wikipedia.org/wiki/ETSIhttp://en.wikipedia.org/wiki/Standardizationhttp://en.wikipedia.org/wiki/TISPANhttp://en.wikipedia.org/wiki/Fixed_phonehttp://en.wikipedia.org/wiki/Wireless_LANhttp://en.wikipedia.org/wiki/CDMA2000http://en.wikipedia.org/wiki/3rd_Generation_Partnership_Project_2http://en.wikipedia.org/wiki/GPRShttp://en.wikipedia.org/wiki/GSMhttp://en.wikipedia.org/wiki/Evolution_to_3Ghttp://en.wikipedia.org/wiki/Universal_Mobile_Telecommunications_Systemhttp://en.wikipedia.org/wiki/Mobile_phonehttp://en.wikipedia.org/wiki/3Ghttp://en.wikipedia.org/wiki/3GPPhttp://en.wikipedia.org/w/index.php?title=3G.IP&action=edit


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3.2.1 A Layered Approach

IP Multimedia Subsystem is standardized reference architecture. IMS consists ofsession control, connection control and an applications services framework along

with subscriber and services data. It enables new converged voice and data

services, while allowing for the interoperability of these converged services

between internet and cellular subscribers. IMS uses open standard IP protocols.

So users will be able to execute all their services when roaming as well as from

their home networks. So, a multimedia session between two IMS users, between

an IMS user and a user on the Internet, and between two users on the Internet is

established using exactly the same protocol.

The 3GPP architecture is split into three main planes or layers, each of which is

described by a number of equivalent names: Service or Application Plane,

Control or Signaling Plane, and User or Transport Plane.

Figure 2: Layered Architecture


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Application Plane

The application plane provides an infrastructure for the provision andmanagement of services, and defines standard interfaces to common

functionality including

configuration storage, identity management, user status (such as presence and

location), which is held by the Home Subscriber Server (HSS)

billing services, provided by a Charging Gateway Function (CGF)

control of voice and video calls and messaging, provided by the control plane.

Control Plane

The control plane sits between the application and transport planes. It routes the

call signaling, tells the transport plane what traffic to allow, and generates billing

information for the use of the network.

At the core of this plane is the Call Session Control Function (CSCF), which

comprises the following functions.

The Proxy-CSCF (P-CSCF) is the first point of contact for users with the IMS. TheP-CSCF is responsible for security of the messages between the network and the

user and allocating resources for the media flows.

The Interrogating-CSCF (I-CSCF) is the first point of contact from peered

networks. The I-CSCF is responsible for querying the HSS to determine the S-

CSCF for a user and may also hide the operator's topology from peer networks

(Topology Hiding Inter-network Gateway, or THIG).

The Serving-CSCF (S-CSCF) is the central brain. The S-CSCF is responsible for

processing registrations to record the location of each user, user authentication,

and call processing (including routing of calls to applications). The operation of

the S-CSCF is controlled by policy stored in the HSS.

This distributed architecture provides an extremely flexible and scalable solution.

For example, any of the CSCF functions can generate billing information for each

operation.


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The Control Plane also controls User Plane traffic through the Resource and

Admission Control Subsystem (RACS). This consists of the Policy Decision

Function (PDF), which implements local policy on resource usage, for example to

prevent overload of particular access links, and Access-RAC Function (A-RACF),

which controls QoS within the access network.

User Plane

The User plane provides a core QoS-enabled IPv6 network with access from

User Equipment (UE) over mobile, WiFi and broadband networks. This

infrastructure is designed to provide a wide range of IP multimedia server-based

and P2P services.

Access into the core network is through Border Gateways (GGSN/PDG/BAS).

These enforce policy provided by the IMS core, controlling traffic flows between

the access and core networks.

Within the User Plane

the Interconnect Border Control Function (I-BCF) controls transport level security

and tells the RACS what resources are required for a call

the I-BGF, A-BGF Border Gateway Functions provide media relay for hiding

endpoint addresses with managed pinholes to prevent bandwidth theft, and

implement NAPT and NAT/Firewall traversal for media flows.


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3.2.1 Architecture

The IMS architecture which is deployed using a softswitch can be divided intolayers as follows:

Figure 3: NGN Architecture using Soft switch

A softswitch is a central device in a telecommunications network which

connects telephone calls from one phone line to another, entirely by means of

software running on a computer system. This work was formerly carried out by

hardware, with physical switchboards to route the calls.
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A softswitch is typically used to control connections at the junction point between

circuit and packet networks. A single device containing both the switching logic

and the switching fabric can be used for this purpose; however, moderntechnology has led to a preference for decomposing this device into a Call Agent

and a Media Gateway.

The Call Agent takes care of functions including billing, call routing, signalling,

call services and so on and is the 'brains' of the outfit. A Call Agent may control

several different Media Gateways in geographically dispersed areas over a

TCP/IP link.

The Media Gateway connects different types of digital media stream together to

create an end-to-end path for the media (voice and data) in the call. It may have

interfaces to connect to traditional PSTN networks like DS1 orDS3 ports (E1 or

STM1 in the case of non-US networks), it may have interfaces to connect to ATM

and IP networks and in the modern system will have Ethernet interfaces to

connect VoIP calls. The call agent will instruct the media gateway to connect

media streams between these interfaces to connect the call - all transparently to

the end-users.
http://en.wikipedia.org/wiki/Circuit_switchinghttp://en.wikipedia.org/wiki/Packet_networkhttp://en.wikipedia.org/wiki/Call_Agenthttp://en.wikipedia.org/wiki/TCP/IPhttp://en.wikipedia.org/wiki/Media_Gatewayhttp://en.wikipedia.org/wiki/Public_Switched_Telephone_Networkhttp://en.wikipedia.org/wiki/Digital_Signal_1http://en.wikipedia.org/wiki/DS3http://en.wikipedia.org/wiki/E-carrierhttp://en.wikipedia.org/wiki/STM-1http://en.wikipedia.org/wiki/Asynchronous_Transfer_Modehttp://en.wikipedia.org/wiki/Internet_Protocolhttp://en.wikipedia.org/wiki/Ethernethttp://en.wikipedia.org/wiki/VoIPhttp://en.wikipedia.org/wiki/VoIPhttp://en.wikipedia.org/wiki/Ethernethttp://en.wikipedia.org/wiki/Internet_Protocolhttp://en.wikipedia.org/wiki/Asynchronous_Transfer_Modehttp://en.wikipedia.org/wiki/STM-1http://en.wikipedia.org/wiki/E-carrierhttp://en.wikipedia.org/wiki/DS3http://en.wikipedia.org/wiki/Digital_Signal_1http://en.wikipedia.org/wiki/Public_Switched_Telephone_Networkhttp://en.wikipedia.org/wiki/Media_Gatewayhttp://en.wikipedia.org/wiki/TCP/IPhttp://en.wikipedia.org/wiki/Call_Agenthttp://en.wikipedia.org/wiki/Packet_networkhttp://en.wikipedia.org/wiki/Circuit_switching


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Figure 4: IMS and its Environment

The softswitch generally resides in a building owned by the telephone company

called a central office. The central office will have telephone trunks to carry callsto other offices owned by the telecommunication company and to other

telecommunication companies (aka the Public Switched Telephone Network or

PSTN).

Looking towards the end users from the switch, the Media Gateway may be

connected to several access devices. These access devices can range from

small Analog Telephone Adaptors (ATA) which provide just one RJ11 telephone

jack to an Integrated Access Device (IAD) or PBX which may provide several

hundred telephone connections.

Typically the larger access devices will be located in a building owned by the

telecommunication company near to the customers they serve. Each end user

can be connected to the IAD by a simple pair of copper wires.
http://en.wikipedia.org/wiki/Telephone_companyhttp://en.wikipedia.org/wiki/Central_officehttp://en.wikipedia.org/wiki/PSTNhttp://en.wikipedia.org/wiki/RJ11,_RJ14,_RJ25http://en.wikipedia.org/wiki/Integrated_access_devicehttp://en.wikipedia.org/wiki/Private_branch_exchangehttp://en.wikipedia.org/wiki/Private_branch_exchangehttp://en.wikipedia.org/wiki/Integrated_access_devicehttp://en.wikipedia.org/wiki/RJ11,_RJ14,_RJ25http://en.wikipedia.org/wiki/PSTNhttp://en.wikipedia.org/wiki/Central_officehttp://en.wikipedia.org/wiki/Telephone_company


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The medium sized devices and PBXs will typically be used in a business

premises and the single line devices would probably be found in residential

premises.

At the turn of the 21st century with IP Multimedia Subsystem or IMS), the

Softswitch element is represented by the Media Gateway Controller (MGC)

element, and the term "Softswitch" is rarely used in the IMS context, rather it is

called AGCF (Access Gateway Control Function).

Figure 5: : Relationship of session control entities to NGN Core networks
http://en.wikipedia.org/wiki/IP_Multimedia_Subsystemhttp://en.wikipedia.org/wiki/Media_Gateway_Controllerhttp://en.wikipedia.org/wiki/Media_Gateway_Controllerhttp://en.wikipedia.org/wiki/IP_Multimedia_Subsystem


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Figure 6: 3GPP IMS Architectural Overview

3.2.1 Architectural Elements


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a) Access Gateway Control Function (AGCF)

This functional entity is the first point of contact for residential and access media

gateways. This entity is specific to the IMS based PSTN/ISDN emulation

component. It performs the following functions:

Act as an MGC for controlling media gateways functions located in resident ial

and access gateways.

Interact with the resource and admission control function (RACF).

Interact with the network attachment Control Function (NACF) to retrieve line

profile information.

Perform signaling inter-working between SIP (including any ISUP information

that may be encapsulated) and analog signaling (through H.248 signals and

events).

Manage SIP registration procedures on behalf of legacy terminals connected

behind the media gateways.

Moreover, the AGCF shall provide basic feature logic for

placing, holding and transferring of calls;

determining end of dialling;

reporting the state of a terminal (e.g. parking, out of order, on service, off-hook, on-session, etc.) via SIP.

supporting the collection and reporting of events to AS via SIP for example

basic call events, service activation, service deactivation, service interrogation

and mid-call events.

From the service points of view they are transparent to AGCF.

delivering several dial tone patterns selected by the application server;

The AGCF does not hold any user profile but shall be made aware if user

equipment can handle several simultaneous calls.

b) Multimedia Resource Function Controller (MRFC)The behavior of the MRFC is identical in the IMS based PSTN/ISDN Emulation

service component and in the IMS.

c) Media Gateway Control Function (MGCF)


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The role of the MGCF is identical in the IMS based PSTN/ISDN Emulation

service component and in the IMS. Signaling procedures for inter-working with

ISUP signaling are slightly different due to the presence of encapsulated ISUPinformation inside the IMS-PES and the need to ensure full ISDN transparency

in case of ISDN calls transiting through the IMS-PES.

d) Call Session Control Protocol (CSCF)

Several roles of Session Initiation Protocol (SIP) servers or proxies, collectively

called Call Session Control Function (CSCF), are used to process SIP

signaling packets in the IMS.

i) Proxy Call Session Control Function (P-CSCF)The behavior of the P-CSCF is identical in the IMS based PSTN/ISDN

Emulation service component and in the IMS. However, the P-CSCF is not

used in configurations where an AGCF is required to control residential or

access media gateways, using H.248.

ii) Service Call Session Control Function (S-CSCF)

The behavior of the S-CSCF is identical in the IMS based PSTN/ISDN

Emulation service component and in the IMS, except that, as an option, thepresence of encapsulated ISUP information may be used as a potential

Service Point Trigger (SPT) in SIP signaling.

iii) Interrogating Call Session Control Function (I-CSCF)

The behavior of the I-CSCF is identical in the IMS based PSTN/ISDN

Emulation service component and in the IMS.

e) Application servers

Application servers host and execute services and interface with the S-CSCF

using Session Initiation Protocol (SIP). An Application Server Function (ASF)

offers value added services and resides either in the user's home network or in

a third party location. The third party could be a network or simply a stand-

alone AS. Application Server Functions may provide standalone services or

value added services on top of a basic session. For resource control purposes,

the first


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category of Application Server Functions (ASF Type 1) may interact with the

RACS, while the second category (ASF Type 2) relies on the control

subsystemthat provide the basic session over which the valued added service is built.

Examples of Application Server Functions are SIP Application Servers and

OSA

Application Servers.

f) Breakout Gateway Control Function (BGCF)The behavior of the BGCF is identical in the IMS based PSTN/ISDN Emulation

service component and in the IMS. A BGCF (Breakout Gateway ControlFunction) is a SIP server that includes routing functionality based on telephonenumbers. It is only used when calling from the IMS to a phone in a circuit

switched network, such as the Public Switched Telephone Network (PSTN) or

the Public land mobile network (PLMN).

Figure 7:Architectural Elements

g) User Profile Server Function (UPSF)


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The User Profile Server Function (UPSF) is responsible for holding the

following user related information:

Service-level user identification, numbering and addressing information.Service-level user security information, access control information for

authentication and authorization.

Service-level user location information at inter-system level, the UPSF

supports the user registration, and stores inter-system location information,

etc.

Service-level user profile information.

The UPSF may store user profile information related to one or more service

control subsystems and applications. The UPSF does not contain profile

information related to IP connectivity subscriptions. Such information is hold in

the Network Attachment Subsystem (NASS). However, where it makes sense in

the context of a particular business model, the UPSF may be co-located with the

data base function of the NASS. (The subset of the UPSF hosting IMS-related

data is equivalent to the subset of the HSS entity defined in 3GPP TS 123 002 for

cellular systems, excluding the HLR/AUC functionality.)

h) Subscription Locator Function

The Subscription Locator Function (SLF) is a functional entity that can be

accessed by service control subsystems and Application Server Functions to

retrieve the identity of the UPSF containing the service-level user profile of aparticular subscriber.

i) Charging and Data Collection FunctionsCharging and Data Collection functions include data collection functions and

mediation functions to the billing systems (for supporting both on-line and offline

charging) or other management applications that may use the same data.

The specification of a generic architecture of the charging and data collection

functions is outside the scope of TISPAN NGN Release 1.

j) Interworking Function (IWF)The Interworking Function (IWF) performs the interworking between protocols

used within TISPAN NGN service control subsystems and other IP-based

protocols (e.g. between the SIP profile used in the IMS and other SIP profiles

or IP-based protocols such as the H.323 protocol).

k) The Interconnection Border Control Function (IBCF)


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The Interconnection Border Control Function (IBCF) controls the boundary

between two operators' domains. The functionality of the IBCF encompasses:

interaction with transport resources, through the resource and admission control subsystem, including NAPT (Network Address and Protocol

Translation) and firewall functions;

insertion of the IWF in the signalling route when appropriate;

screening of signalling information based on source/destination, beyond

what is already performed inside each of the subsystems (e.g. by the

THIG functionality of the I-CSCF for the IMS core subsystem)

l) PSTN Gateways

A PSTN/CS gateway interfaces with PSTN circuit switched (CS) networks. Forsignaling, CS networks use ISDN User Part (ISUP) (or BICC) over Message

Transfer Part (MTP), while IMS uses Session Initiation Protocol (SIP) over IP.

For media, CS networks use Pulse-code modulation (PCM), while IMS uses

Real-time Transport Protocol (RTP).

A Signaling Gateway (SGW) interfaces with the signaling plane of the CS. It

transforms lower layer protocols as Stream Control Transmission Protocol

(SCTP, an Internet Protocol (IP) protocol) into Message Transfer Part (MTP, an

Signaling System 7 (SS7) protocol), to pass ISDN User Part (ISUP) from the

MGCF to the CS network.

3.2.1 IMS Benefits

Benefits to the user:

Single sign on Application bundling in realtime (e.g. simultaneous usage of voice and data

applications) Realtime messaging without store & foreward Multiparty communication services (e.g. chatting, conferencing) Enrichment and personalization (e.g. realtime multimedia, buddy lists,

presence, push services, subscriber self administration) Anywhere service access from various access networks

Benefits for the operator:


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Fast and flexible service creation (1 SIP client) Innovative realtime multimedia service offers

Full control of services by operator Service differentiation by flexible bandwidth allocation and guaranteed QoS Fixed / mobile convergence Common service control infrastructure for PS domain for cost optimization and

easy service introduction Longterm CS migration by shifting voice traffic towards PS domain

3.3 NGN Services

Most traditional services relate to basic access/transport/routing/switching services,

basic connectivity/resource and session control services, and various value-added

services. NGNs will likely enable a much broader array of service types, including:

Specialized resource services (e.g., provision and management of transcoders,

multimedia multipoint conferencing bridges, media conversion units, voice recognition

units, etc.)

Processing and storage services (e.g., provision and management of information

storage units for messaging, file servers, terminal servers, OS platforms, etc.)

Middleware services (e.g., naming, brokering, security, licensing, transactions, etc.)

Application-specific services(e.g., business applications, e-Commerce

applications, Supply-chain management applications, interactive video games, etc.)

Content provision services that provide or broker information content (e.g.,

electronic training, information push services, etc.)

Interworking services for interactions with other types of applications, services,

networks, protocols, or formats (e.g., EDI translation)

Management services to maintain, operate, and manage communicationscomputing networks and services.

Voice Telephony NGNs will likely need to support various existing voice telephony

services (e.g., Call Waiting, Call Forwarding, 3-Way Calling, various AIN features,

various Centrex features, and various CLASS features). Note, however, that NGNs

are not trying to duplicate each and every traditional voice telephony service currently


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offered. Rather, they will likely attempt to support only a small percentage of these

traditional services, with an initial focus on the most marketable voice telephony

features and the features required from a regulatory perspective.

Data (Connectivity) Services Allows for the real-time establishment of connectivity

between endpoints, along with various value-added features (e.g., bandwidth-on-

demand, connection reliability/resilient Switched Virtual Connections [SVCs], and

bandwidth management/call admission control).

Multimedia Services Allows multiple parties to interact using voice, video, and/or

data. This allows customers to converse with each other while displaying visual

information. It also allows for collaborative computing and groupware.

Virtual Private Networks (VPNs) Voice VPNs improve the interlocation networking

capabilities of businesses by allowing large, geographically dispersed organizations

to combine their existing private networks with portions of the PSTN, thus providing

subscribers with uniform dialing capabilities. Data VPNs provide added security and

networking features that allow customers to use a shared IP network as a VPN.

Public Network Computing (PNC) Provides public network-based computing

services for businesses and consumers. For example, the public network provider

could provide generic processing and storage capabilities (e.g., to host a web page,store/maintain/backup data files, or run a computing application). The public network

provider would charge users for the raw processing and storage used, but would have

no knowledge of the specific content/application. Alternatively, the public network

provider could provide specific business applications (e.g., Enterprise Resource

Planning [ERP], time reporting, vouchers, etc.) or consumer applications (e.g.,

TaxCut, kitchen remodeling program, etc.), with all or part of the processing/storage

happening in the network. The public network provider could charge based on an

hourly, daily, weekly, etc. licensing fee for the service (e.g., rent-an-app).

Unified Messaging Supports the delivery of voice mail, email, fax mail, and pagesthrough common interfaces. Through such interfaces, users will access, as well as be

notified of, various message types (voice mail, email, fax mail, etc.), independent of

the means of access (i.e., wireline or mobile phone, computer, or wireless data

device).

Information Brokering Involves advertising, finding, and providing information to


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match consumers with providers. For example, consumers could receive information

based on pre-specified criteria or based on personal preferences and behavior

patterns.

E-Commerce Allows consumers to purchase goods and services electronically

over the network. This could include processing the transactions, verifying payment

information, providing security, and possibly trading (i.e., matching buyers and sellers

who negotiate trades forgoods or services). Home banking and home shopping fall

into this category of services. This also includes business-to-business applications

(e.g., supply-chain management and knowledge management applications).

Call Center Services A subscriber could place a call to a call center agent by

clicking on a Web page. The call could be routed to an appropriate agent, who could

be located anywhere, even at home (i.e., virtual call centers). Voice calls and e-mail

messages could be queued uniformly for the agents. Agents would have electronic

access to customer, catalog, stock, and ordering information, which could be

transmitted back and forth between the customer and the agent.

Interactive gaming Offers consumers a way to meet online and establish

interactive gaming sessions (e.g., video games).

Distributed Virtual Reality Refers to technologically generated representations ofreal world events, people, places, experiences, etc., in which the participants in and

providers of the virtual experience are physically distributed. These services require

sophisticated coordination of multiple, diverse resources.

Home Manager With the advent of in-home networking and intelligent appliances,

these services could monitor and control home security systems, energy systems,

home entertainment systems, and other home appliances. Imagine youre watching

television and the doorbell rings no problemyou just use the TVs remote to get a

view of your front entrance to see whos there. Or imagine monitoring your house

while youre away on a trip, or your in-house nanny watching your children while

youre at work.

3.4 NGN Models


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Scenario 1. Network consolidation Scenario 2. Deployment of overlay packet based network Scenario 3. Technology replacement

3.4.1 Scenario 1: Network Consolidation

a) Maximum utilisation of the installed capacities in the TDM switches:

optimal utilisation of the already installed DLEs expansion of their service area replacement of analogue exchanges with subscriber capacities, served by

DLEs optimisation of the connectivity on regional level, reducing the number of

nodal service areas

b) Limited deployment of multiservice access systems

provision of POTS, ISDN BA, ISDN PA, digital LL (n x 64 k), xDSL (ADSL,HDSL), served by MSANs and xDSLs by DSLAMs

splitting the dial up Internet traffic from the PSTN and routing it to the datanetwork

Figure 8: Multiservice access systems

Major Advantages


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Optimal utilisation of the existing TDM equipment, thus reducing theanalogue part of the network, network infrastructure optimisation.

Significant CAPEX and OPEX reducement, due to the expansion of existingDLEs, decreasing the number of analogue exchanges in operation.

Major Disadvantages

IP Network development delay Limited number of services to be offered Possible PSTN overload, due to the prevailing dial up Internet access and

limited deployment of MSANs and DSLAMs

3.2.1 Scenario 2: Deployment of overlay packet based network

Ongoing network consolidation (as for scenario 1 - optimal utilisation of thealready installed TDM equipment)

Deployment of IP-based overlay network Deployment of Multiservice access systems and DSLAMs for broadband

services provision Initial (limited) deployment of VoIP services for enterprise and business

customers

Figure 9: Scenario 2

Major Advantages


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Optimal utilisation and Capitalisation on the existing TDM equipment

The IP overlay network, combined with the Multiservice access systems -initial step towards the future common packet based network

Better services portfolio, especially for business and enterprise customers Reduced OPEX in the TDM part of the network Future save investments

Major Disadvantages

Increased Opex Increased Capex

3.2.1 Scenario 3. Replacement of legacy TDM equipment

Starting point of:

Replacement of the existing PSTN equipment with packet based one Building up a common packet based network for voice, data and video Accelerated deployment of multiservice access systems Offering voice

services via softswitch with local exchange functionality


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Figure 10 Scenario 3

Major advantages

Deployment of an unified packet based network for voice, data and video Investments are in a prospective technology Rich services portfolio, including multimedia services

Major disadvantages

Part of the NGN equipment is still under research and development, IP based equipment is deployed mainly in enterprise networks major concerns about QoS CPEs require significant investments, if mass deployed


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4. EoIP protocols

4.1 Introduction

NGN is considered as converged network aggregating different functionalities of

existing network with common IP/MPLS backbone. NGN network offers

interoperability using multiple protocols. The main feature of NGN architecture is

separation of service, transport and control layers, which are interconnected by open

interfaces and use standards protocols as below:

Figure 11: : Protocol Stack for NGN


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MEGACO/H.248

It is protocol which is sponsored from IETF and ITU. It is used inside one MGC(media gateway controller) for controlling media gateways (MG-s). This protocol

allows the GC to tell to the MG-s when to send and receive information towards/from

different addresses. This protocol also is useful for sending all information to the MGC

from MG-s regarding with detected events such is: on hook, off hook etc. The

equivalent protocol of MEGACO according to ITU is H248.

SIP

Session Initiation protocol is protocol that resides into application layer and is

signaling protocol. SIP plays a very important role for session creation for audio/video

conferences, interactive games and for call orientation towards IP network. SIP is

IETF standard which supports traditional telephony services within IP domain such

are: routing, identification, call establishment and other services.

H.323 protocol

This protocol is for multimedia conferences, including here: voice, video and data in

packet switched networks. H323 standard can be applied in networks that which

offers different services: IP telephony, networks for offering voice and data, video and

data etc. The main components of H323 protocol are: terminals, Multipoint ControlUnits

(MCUs), Gateways, Gatekeeper, Border Elements / Peer Elements.

Real time protocol

This protocol offers end-to-end voice transmission in real time. Whereas H323 is used

for data transmission in IP based networks, the RTP protocol is used for data

transmission in User Datagram Protocol (UDP). RTP together with UDP offers

functionality to the transport protocol. The RTP protocol identifies the type of load,

enumerates sequences, measures time etc.

Real Time Control protocol (RTCP)

It is a copy of RTP which offers control services. The main function of RTCP is

identification of transport level for one RTP source


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4.2 SIP

The Session Initiation Protocol (SIP) is a signaling protocol for initiating, managingand terminating voice and video sessions across packet networks. SIP sessions

involve one or more participants and can use unicast or multicast communication.

Borrowing from ubiquitous Internet protocols, such as HTTP and SMTP, SIP is text-

encoded and highly extensible. SIP may be extended to accommodate features and

services such as call control services, mobility, interoperability with existing telephony

systems, and more.

SIP is being developed by the SIP Working Group, within the Internet Engineering

Task Force (IETF). The protocol is published as IETF RFC 2543 and currently has

the status of a proposed standard.

Figure 12: SIP Call flow


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4.2.1 Call Flow

Session Establishment:

1. The calling User Agent Client sends an INVITE message to Bobs SIP address:

sip:[email protected]. This message also contains an SDP packet describing the

media capabilities of the calling terminal.

2. The UAS receives the request and immediately responds with a 100-Trying

response message.

3. The UAS starts ringing to inform Bob of the new call. Simultaneously a 180

(Ringing) message is sent to the UAC.

4. The UAS sends a 182 (Queued) call status message to report that the call is

behind two other calls in the queue.5. The UAS sends a 182 (Queued) call status message to report that the call is

behind one other call in the queue.

6. Bob picks up the call and the UAS sends a 200 (OK) message to the calling UA.

This message also contains an SDP packet describing the media capabilities of Bobs

terminal.

7. The calling UAC sends an ACK request to confirm the 200 (OK) response was

received.

Session TerminationThe session termination call flow proceeds as follows:

1. The caller decides to end the call and hangs-up. This results in a BYE request

being sent to Bobs UAS at SIP address sip:[email protected]

2. Bobs UAS responds with 200 (OK) message and notifies Bob that the

conversation has ended.

4.3 Migration from IPv4 to IPv6

4.3.1 Problems faced by IPv4 Non equal geographical distribution (>50% USA) Exhaustive use not achievable New technologies and features (mobile computing, multicast,

security, QoS, Real-Time Services, etc.) Too complicated (e.g. Routing) Virtually impossible to reach 100% network utilization efficiency


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4.3.2 Phases of IPv6 migration in NGN

The subsistent NGN are based on IPv4. Also, all subsistent user accessrequirements are based on IPv4. In the near future these networks would be

replaced by IPv6-based NGN.

However, giving the enormous scale of the current Internet, the migration period

from the legacy IPv4-based NGN to all IPv6-based NGN is expected to be long.

Hence, a prudent approach is to deploy IPv6 incrementally while keeping IPv4

access available.

During the transition period, IPv6 migration would start from relevant small areas

first, then, stretch into the core of the Internet; and at the same time, IPv4

network will become smaller and smaller, till vanish at the end.

In this clause, migration period is divided into three phases. In each phase, NGN

operators would structure their networks differently from IPv4/IPv6 point of view.

This document also provides recommendations on how NGN operators should

strategize their IPv6 migration in different phases.

Phase 0: NGN with IPv6

The subsistent NGN is IPv4-based. IPv4 plays an essential role. There has no

IPv6 networks deployed. In this phase, there is no IPv6 services provided at all.Correspondently, operator networks do not adopt any IPv6 functions.

Figure 13: Phase 0-Complete IPv4 based NGN


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In this phase, IPv6 may be deployed in some customer networks locally. IPv6-based

NGN islands may also be linked to each other through IPv6-over-IPv4 tunneling or

protocol translation technologies. However, since operators networks do not provideIPv6 connectivity services, these IPv6 islands are totally isolated from NGN

operators' perspectives. The NGN is still completely IPv4-based.

Phase 1: Connecting IPv6-based NGNs across IPv4-based NGN

At the early stages of IPv6 co-exists with native IPv4 environment, there would be

only a few and isolated IPv6-based NGN, like islands, floating around IPv4-based

ocean, as shown in Figure.

The initial focus of this phase is on the migration and transition techniques, rather

than dealing with traffic volume.

In this phase, the most important IPv6 functional requirement for operators networks

is to support IPv6 tunnels in IPv4 network. There may be limited number of IPv6-only

hosts, but they should be able to communicate with legacy IPv4-only hosts, and also

with each other through IPv4-based NGN, e.g., with 6PE support across IPv4-MPLS

backbone.

Figure 14:Phase 1-Connecting IPv6-based NGNs across IPv4-based NGN


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Phase 2: Connecting IPv6-based NGNs and IPv4-based NGNs across dual-

stack NGN

With increased IPv6 adoption, backbone routers would be upgraded to dual stack

routers and form IPv4 and IPv6 logical dual-plane, where there exists a separate

operation for IPv4 and IPv6, respectively, in data plane, control plane and

management plane, and IPv4 and IPv6 run in the same physical network.

In this phase, as shown in Figure, IPv4 and IPv6 logical planes are isolated from each

other mutually. However, the same NGN devices may be used for both IPv4 and

IPv6 logical planes.

According to traffic situation, resources may be dynamically adjusted between IPv4

and IPv6 logical planes.

Figure 15: Phase 2-Connecting IPv6-based NGNs and IPv4-based NGNs across dual-stack


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Phase 3: Connecting IPv4-based NGNs with IPv6-based NGN

The IPv4 address exhaustion will eventually result large scale adoption of IPv6 andthus IPv6-only NGN, as shown in Figure. In this phase, vast majority of business

applications have moved to IPv6 network. Core backbone only supports IPv6.

Sporadic small-size IPv4-based NGN may distribute around the large IPv6-based

NGN. IPv4-over-IPv6 tunnels are required to support IPv4/IPv4 communication

through IPv6-based NGN. Protocol translation would still be needed to allow IPv4

hosts access to IPv6 services.

Figure 16: Phase 3-IPv4 Islands with IPv6-based NGN

Phase 4: Completed IPv6-based NGN

Finally, as shown in Figure , IPv6 will replace IPv4 totally. NGN will become pure

IPv6-based.


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Figure 17: Phase 4-Completed IPv6-based NGN

In this phase, there is no IPv4 connectivity service provided by NGN operators.

Correspondently, operator networks do not adopt any IPv4 functions.

In this phase, IPv4 may still exist in some customer network locally. IPv4-based NGN

may also be linked to each other through IPv4-over-IPv6 tunnels or protocol

translation mechanisms. However, since operators networks do not provide IPv4connectivity service, these IPv4 islands are totally isolated from the NGN operators

perspective. The NGN is completely IPv6-based.


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5 Service aspects: Interoperability of services and networks in

NGN

5.1 PSTN/ISDN evolution to NGN

A public switched telephone network or integrated services digital network

(PSTN/ISDN) being one of the networks in telecommunication is considered to be a

prime candidate for evolution to the next generation network. Because of the

widespread deployment and the use of PSTN/ISDN, evolution to NGN should be

considered as a step-wise approach.

In PSTN/ISDN, most of the functionalities are located in a single exchange and may

use proprietary protocols. However, in the NGN, functionalities may be distributed

amongst several elements. The following clauses provide detailed steps for evolution

of PSTN/ISDN to NGN.

5.1.1 Aspects to consider when evolving to NGN

TransportTransport is an important part of any network. It encompasses functions related to:

User premises equipments (e.g., terminals, PBXs, routers); The access network equipments (e.g., line termi

Documents

906_Everything Over IP - Dynamics of the Strategic Changes in Voice and Data Networks