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WhitePaper

MeetEconomicandTechnologicalChallengesthroughIMSA next generation network that solves operational

difficulties facing todays telecommunications operators

By Lou Grilli, Syniverse Technology Manager

This white paper:

Discusses the business and technological challenges faced by today's

operators and explains how IMS can overcome those difficulties.

Provides an overview of IMS technology and how it developed.

Explains the economic benefits to be realized from the IMS framework.

Addresses industry concerns with pragmatic information about the realityof IMS today.

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TABLE OF CONTENTS

INTRODUCTION 1THEHIGH-LEVELDEFINITION 2THEMARCHTOWARDSTANDARDIZATION 2APROBLEM-SOLVINGSOLUTION 4THETECHNOLOGYBEHINDIMS 5ECONOMICIMPACTFOROPERATORS 9INDUSTRYCHATTERVS.REALITY 11CONCLUSION 14GLOSSARY 15

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INTRODUCTION

Telecommunications subscribers today are a technically savvy group with a long list

of wishes for their providers. Some of those wishes include:

Instantaneous communication.

Immediate access to new, enhanced services that increase productivity.

Ubiquity of services across network providers.

Access to advanced services that all work the same whether at home, at

work or on the road and whether utilizing wireline, wireless or cable systems

in either a home or roam network.

Access to voice, Internet, multimedia, productivity, education, entertainment

and other communication functions on a single device.

The ability to know if a family member, friend, co-worker or other buddy

list contact is available, where that person is and how that person wants to

be contacted.

Bundled services all on one bill.

Furthermore, todays subscribers can be fickle and are not averse to leaving one

operator to join an alternate provider that offers newer, faster or more advanced

services.

Additional challenges facing telecommunications service providers come from the

business side of the coin. Some of those challenges include:

Counteracting new or increased competition from other wireless, fixed and

cable operators with differentiated services. Offsetting brand erosion from mobile virtual network operators (MVNOs)

and resellers by providing more sticky services.

Countering the threat of declining average revenue per user (ARPU) by

quickly rolling out higher-value services.

Fortunately, the IP Multimedia Subsystem (IMS) provides an architectural framework

that gives all telecommunications operators wireline, wireless and cable the

means to cost-effectively manage the increasingly complex issues that must be

resolved to meet subscriber demands, preserve market share and increase revenue.

For consumers, IMS enables a consistent user experience in the look, feel and

behavior of applications as a consumer moves from home to road to office. This

user-centric paradigm brings together a consumers mobility domain (on the go),

enterprise domain (at work), residential domain (in the home) and wireless domain

(when remote).

For operators, IMS is a standards-based delivery infrastructure that will ease the

migration to fully converged communications and enable a multi-vendor

environment, provide for quicker roll-out of new services and applications, allow

interoperability between servers, and increase revenue.

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THE HIGH-LEVEL DEFINITION

What is IMS? Its easier to start with what IMS is not. IMS is not a new product, not a

new technology, not a new protocol. IMS is not something end users will be able to

see or even know about, although they will notice the new services enabled by IMS.

IMS is a framework architecture a definition of capabilities specified in a set of 3rd

Generation Partnership Project (3GPP) documents that defines components, services

and interfaces for next generation networks (NGN). It uses Voice over IP (VoIP)

implementation based on a 3GPP standardized implementation of session initiation

protocol (SIP), and it runs over the standard Internet protocol (IP). Connectivity with

existing phone systems both packet-switched and circuit-switched is supported

and, because IMS is access agnostic, it allows operators to use different underlying

network architectures. Furthermore, telecommunications operators are able to

provide both mobile and fixed multimedia services.

The primary driver behind IMS is the ongoing, cost-driven and, ultimately, inevitable

move away from circuit-switched services toward IP packet-based services. With IMS

there is no such thing as voice everything is data, whether that data is

exchanged via multimedia messages, conference or chat sessions, text messages, or

traditional conversations between two people. Granted, voice service can be billed

differently from other data sessions, and quality of service (QoS) for voice can be

dictated differently than other data services, but the bottom line is that all

exchanges are exchanges of IP data.

IMS is not entirely new; in fact, it incorporates many existing network concepts and

standards, such as VoIP, SIP signaling, IPv6, presence, call redirection and multimedia

services. What the new framework does is draw together call control and service

provisions into a horizontally integrated system that allows new services and

combinations of services (e.g., presence list, rich call group chat, Push-to-Talk,

multimedia advertising, instant messaging, multiparty gaming) to be developed and

deployed by mobile and fixed network operators in shorter time cycles and with

greater interoperability.

THE MARCH TOWARD STANDARDIZATION

The first step in the development of IMS came about when the Universal Mobile

Telecommunications System (UMTS), as it moved toward an all-IP network, saw the

need to coordinate its efforts and standardize protocols and network elements.

3GGP, the standards body responsible for GSM standards, was chosen to provide

leadership in the development of the next generation of network standards.

The first effort to establish a formal definition of a wireless IP network was provided

in 3GPP Release 4, which separated the mobile network into circuit-switched and

packet-switched domains. This release specified basic IP connectivity between a

UMTS operator and external IP networks. Later, 3GPP Release 5 proposed the first

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version of IMS and allowed a UMTS operator to provide all services, end-to-end,

over IP. In a general way, Release 5 described IMS, SIP and the desirability of end-to-

end QoS as part of the all IP future. It also provided descriptions of VoIP services.

The current 3GPP Release 6 acknowledges and includes the requirements of fixed

and CDMA operators. It also defines mechanisms for providing services over

multiple bearer channels and defines interconnection to the public switched

telephone network (PSTN). Additionally, Release 6 formally adopts SIP and Diameter

definitions as its core, and defines the following four major IMS building blocks:

all-IP core network

all-IP radio access network (RAN)

multimedia call control based on SIP

QoS support for IP

3GPP Release 7 is now in committee and, in its present form, adds new functionality,defines fixed broadband access via IMS, deals with policy issues, specifies voice call

handover between cable and WLAN/IMS systems, and standardizes end-to-end QoS.

3GPP also has created a roadmap directing how to introduce IMS to a packet-

switched network and how to begin migrating away from circuit-switched services.

The effort to implement IMS as the definitive industry-wide standard for a converged

network is faced with the separate efforts of other telecommunication organizations

that are working on their own versions. The MultiMedia Domain (MMD), an effort by

the 3GPP2 organization for third generation CDMA2000 networks, is intended tomirror and be interoperable with IMS but with definite distinctions. The primary

differences are mainly in the implementation of the wireless packet network (a

1XRTT/EV-DO network versus a GPRS network centered on SGSN and GGSN), in the

RAN (CDMA versus GSM air interface differences) and in the use of IPv6 (required

for IMS but optional in MMD).

Fixed operators and cable operators also have embarked on standardization efforts.

In the United States, cable multiple systems operators (MSOs) have shown interest in

IMS by adopting a significant portion, but not all, of the IMS standard as part of the

CableLabs PacketCable 2.0 initiative. Meanwhile, fixed operators outside of NorthAmerica have turned to the European Telecommunications Standards Institutes

(ETSI) standardization committee, the Telecoms & Internet Converged Services &

Protocols for Advanced Networks (TISPAN), for a version of IMS. The result is a

TISPAN NGN definition heavily reliant on IMS specifications but geared toward

wireline operator implementation. North American fixed operators have gathered

together as the Alliance for Telecommunications Industry Solutions (ATIS) and

documented their own NGN definition, which borrows significantly from TISPAN but

has additional variations.

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Each of these versions of what generically are considered third generation or

next generation networks have remarkable similarities they are all based on the

same common thread of IP protocols (primarily SIP and Diameter) and they all

adhere to the same principals (converged networks, three-layer architecture, network

abstraction). On the other hand, they also all differ in some subtle and not-so-subtle

ways in the manner of interconnecting networks, in the way billing information is

exchanged and in numerous other network capabilities.

The bottom line is that while IMS and its cable, fixed and CDMA alternative versions

move all telecommunications service providers much closer toward the goal of

converged networks, there still is room for third-party vendors to provide

interoperability services to connect separate networks and resolve the differences

among the various standards.

A PROBLEM-SOLVING SOLUTIONThere are several problems inherent in todays networks that will benefit from a

move to the open-standard computing platform of IMS. Those problems include:

Highcostofdevelopingnewapplicationsandservicesforoperatorswhoaretryingtoremaincompetitive.Today, each newly developed application requires separate development of

functions that must be included in all new applications and services. Examples of

these common functions include billing, reporting, user interface and presence

management. Having to replicate the development of these functions for each and

every offering is a time-consuming and expensive process. Furthermore, new

services take longer to get to the revenue-generating end user. IMS solves this

problem by using standards-based functions that are reused rather than replicated

each time a new application or service is developed.

Lackofinteroperabilityamongoperatorsofferingthesameservices.Normally, the first objective of operators is to roll out new services as quickly as

possible, both to keep subscribers interested and to increase revenue. Second and

third objectives are to provide subscribers the ability to use the service while

roaming and, sometimes much later in the process, the ability to use the new service

in conjunction with subscribers on another network.

For example, today many operators offer Push-to-Talk (PTT) service. Nextel was the

first to do so and set the standard for subscriber expectations regarding quick set up

and voice quality. Sprint (pre-Nextel) and Verizon then both rolled out Push-to-Talk

over Cellular (PoC) using their respective packet networks, and Alltel has PTT over its

circuit-switched network. However, Alltel subscribers cant PTT with Verizon or

Nextel, and Nextel cannot PTT with Verizon, and so on. This lack of interoperability

hampers the uptake of this valuable application much in the same way text

messaging didnt take off in the United States until operators used gateways to

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allow subscribers from one network to message with subscribers of another network.

Multimedia messaging is following the same slow course of acceptance and usage

because of the same interoperability issues.

However, the technology-agnostic framework proposed by IMS resolves, in advance,

these interoperability issues. In the case of PTT, subscribers on one network would

have the ability to immediately add a buddy list of PTT subscribers from another

network. The benefit for operators is increased income from faster acceptance and

increased use of newly rolled out services.

Inabilitytotakeadvantageofconvergednetworks.One of the promises of IMS is the concept of converged networks. At one time,

fixed voice access, fixed broadband access using DSL, Wi-Fi, mobile packet

networks and more were all isolated from each other and typically provided by

different service providers. IMS allows the subscriber to gain network access and use

the same applications, regardless of the media. This means an operator has the

potential for many additional roaming partners, including non-mobile partners.

THE TECHNOLOGY BEHIND IMS

There are several technological advantages when implementing an IMS service

model versus the current stovepipe service model. In the stovepipe model used

by most networks today and illustrated in Figure 1, applications stand alone and the

development of and access to each application is done independently of other

applications. There is no sharing of resources, even when the same sorts of

resources are required for each pipe. As a result, common service capabilities and

access technologies must be replicated for each application developed.

Each time an operator decides to develop a new service, such as mobile TV,

engineers working on the project also must develop the ancillary resources needed

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Figure 1: Current stovepipe application/services architecture.

X X

Mobile TV

Billing

QoS

Presence

MultiplayerInteractive

Gaming

Billing

QoS

Presence

PTT/

PoC

Billing

QoS

Presence

NETWORK

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to enable the new service. These essential resources or elements include items such

as billing, QoS, presence/availability and more. Then when the same operator rolls

out a different new service, such as a multi-player interactive game, the same

ancillary resources (i.e, billing, QoS, presence/availability) need to be developed

once again for the new game application. This time-consuming and expensive

development process must take place for each new application. One of the many

goals of IMS is to provide the necessary resources to all applications in a

standardized fashion through the application servers.

The IMS service model, as illustrated in Figure 2, can be viewed as a multi-

dimensional model with three layers, or planes the application plane, the control

plane and the transport plane. The way the elements of each plane are developed

using standards-based, technology-agnostic criteria addresses several difficulties

inherent in the traditional stovepipe model. The result is that IMS allows for the

integration of individual, standards-based components that can be mixed and

matched as needed or desired. In addition, the architecture separates support for aspecific device from the services available, allowing common functions to be

reutilized rather than replicated. The end result is significant time savings from

cutting implementation time in half, as some lab trials have shown. And if time

equals money, reducing time ultimately reduces cost.

IMS also allows for the convergence of wireline and wireless technologies. IMS is

access agnostic and offers the same framework for any kind of access (wireless,

wireline, cable) and for any type of data (VoIP, data, multimedia). Figure 3 on the

next page illustrates each layer and indicates how the architecture provides a level

of abstraction to the layer below it, simplifying implementation and connectivity.

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Figure 2: IMS application/services architecture. Capabilities the applications require, such as

billing, QoS and presence, are integrated into the overall IMS architecture, thus alleviating

the requirement to build them separately into each application.

BILLING

QoS

PRESEN

CE

Mobile

TV

PTT/

PoC

Multiplayer/

Interactive

Gaming

ApplicationPlane

ControlPlane

Transport

Plane

}

}

}

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TheApplicationsPlaneThe applications plane in IMS has application servers (AS) but not actual

applications. An application developer creates the application, and the AS provides

the application-common functions, such as generation of billing information,

management of presence and subscriber availability, guaranteed voice-level QoS

and more, that are needed by all applications in the IMS environment. One of the

intents, and hence benefits, of IMS is that these common resources necessary to the

development of the applications are provided by the IMS network in a standardized

way. The basic premise is to build once, use many times by decoupling the shared

services from the infrastructure. Taking advantage of the shared, standards-based

resources saves time and development expenditures, allowing operators to make

new applications available quicker and at a reduced cost.

TheControlPlaneThe core of the IMS network is the control plane. What was called the switch in

older networks is called the call session control function (CSCF) in IMS. The CSCF isa softswitch that processes signaling using the SIP protocol. The application servers

in the application plane above the CSCF do all the communication work. The CSCF,

which is basically a SIP server and media controller, handles inbound and outbound

traffic and, as far as the application is concerned, takes care of any necessary circuit-

switched-to-IP conversions. From the CSCFs point of view, the specific media type

(RAN, Wi-Fi, DSL, etc.) is all an abstraction that is taken care of in the transport

plane.

The control plane also has another important difference from todays legacy network

architecture. The older home location register (HLR) has morphed into an all-IP

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GPRS, Edge,1xRTT, EV-DO

Cable Network Wi-FiDSL Network

WiMAX

TRANSPORT PLANE

CONTROL PLANE

APPLICATION PLANE

HSS

CSCF

SessionManagement

& Control

AS AS ASApplicationServers (AS)

(reutilize common

functions)

AccessAgnostic

GPRS, Edge,1xRTT, EV-DO

Cable Network Wi-FiDSL Network

WiMAX

TRANSPORT PLANE

CONTROL PLANE

APPLICATION PLANE

HSS

CSCF

SessionManagement

& Control

AS AS ASApplicationServers (AS)

(reutilize common

functions)

AccessAgnostic

Figure 3: The three IMS layers.

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database called the home subscriber server (HSS). The HSS database contains a lot

more information than the traditional HLR database. The HSS determines such

things as user location and availability, and it also performs authentication and

authorization functions. Furthermore, the HSS may be implemented using

commodity hardware rather than purpose-built network equipment, and it uses less

expensive off-the-shelf software. And the subscriber database contained in the

logical HSS can be distributed across multiple physical databases.

One of the most significant differences and biggest cost savings is that in the

IMS framework, switches and subscriber databases are all based on IP protocols,

specifically SIP. Network connections using IP rather than SS7 connections are much

less expensive.

TheTransportPlaneIn today's networks, the intelligence of the network, such as switches and the HLR, is

tied to the type of network. The result is that GSM HLRs only work with GSM

networks, CDMA authentication only works with CDMA networks, etc. One of the

visions of NGNs is that the intelligence of the network (i.e., switching and control

functions, subscriber database, authentication and authorization, etc.) looks and

behaves the same, regardless of the type of media used to access it. In IMS, the

transport plane provides this layer of abstraction for various access methods.

Both subscribers and operators will benefit as the industry moves a step closer to

the goal of one network anywhere, anytime, anyplace. This is because the network,

based on a common set of protocols (primarily SIP and Diameter), functions the

same using any underlying media type. The transport plane takes care of any specialneeds for the device, such as handing off a mobile subscriber from site to site. Thus,

an application appears and behaves the same to the subscriber, no matter what type

of device is being used at the time.

Taking advantage of all this, the subscriber would have access to her network and

associated applications and services, such as catching up on missed episodes of

"Lost" or checking scores for her fantasy football league, from her home network

whether she is on a train on her mobile phone, at home on a Wi-Fi access device or

at work on a fixed broadband connection. Additionally, this access-agnostic

architecture would allow this subscriber the ability to view her home digital videorecorder from her mobile phone, from her laptop on a Wi-Fi access point, from her

hotel Internet connection or, in the future, from her WiMAX or other broadband

connection.

The service provider who would benefit from this access-agnostic architecture will be

the one who offers multiple access avenues, such as a mobile operator who also

offers Wi-Fi and fixed broadband access, or the fixed operator with DSL lines who

may have cable properties and may also offer mobile service and Wi-Fi hotspots.

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ECONOMIC IMPACT FOR OPERATORS

Beyond resolving a plethora of technical challenges inherent in todays stovepipe

architectures, IMSs biggest impact as the telecommunications industry moves

toward converged communications is the economic benefits. Todays market for

wireless services is becoming crowded. Several cable operators have joined togetherto offer mobile services bundled with broadband access branded under their own

names. Many MVNOs, including Disney, Virgin and ESPN, have started offering

targeted services. While all this traffic is still being delivered on the underlying

network operators physical network, the ARPU for this traffic is lower in some

cases, significantly lower than if these were the network operators own customers.

In addition, brand erosion is occurring as consumers are blurred to the distinction

between the real network provider and the brand owner from which the consumer

purchased the service. All this impacts an operator in the wallet.

Economic benefits of migrating to IMS will manifest themselves in several ways,including:

Additionalrevenuestreams.Already the trend is away from revenue produced by basic connectivity toward

revenue derived from next generation and high revenue-producing premium

services and applications made possible by IMSs ability to integrate voice, data and

content services. Also, the use of a flexible platform enables service providers to

build their own services or mix-and-match applications for a custom suite. End-user

opt-in to premium services will increase both ARPU and overall minutes of usage or,

more appropriately, megabytes of usage in the IMS world of data.

Costsavingsfromreducedoperatingandcapitalexpenses.The cost savings for mobile operators who move toward an all-IP IMS-standardized

network are considerable and come in a variety of forms, including:

A lower cost associated with implementing new technologies IMS provides

shared, standardized protocols and a decomposed architecture (build once,

use many times), so the time and expense needed to develop new

applications and services are greatly reduced.

Less expensive hardware platforms With IMS, operators have the capabilityto use less expensive, commercial hardware platforms (i.e., Unix box or

blade server) rather than purpose-built platforms for things such as a mobile

switching center or HLR.

Less expensive software development Instead of having to pay for

specially designed proprietary service control point application software

required for the complex workings of a switch, operators are able to

purchase and deploy less expensive, platform-independent Java

programming software.

Less expensive support Maintaining todays complex networks requires

complex monitoring and support tools. Likewise, the training to maintain the

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IMS PremiumServices

PresenceManagement:Know if and howpeople are avail-able to communi-cate acrossdevices.

Video Streaming:Share videostreaming fileswith others; viewvideo stream filesfrom the Web orother device.

Multi-partyGaming: Playinteractively withone or manypeople.

LocationServices: Abilityto retrieve locationspecific info.

Multimedia IM:Send/receive textmessages, graph-ics or prerecordedaudio/video clipsto/from other

users in near real-time.

VideoTelephony:Synchronize avideo and audiosession withanother user.

Rich Call GroupChat: Have avoice session withmultiple userssharing text,graphics and

pictures.

Mobile VideoConferencing:Conduct real-timevideo sessionbetween two ormore users ina mobileenvironment.

PersonalizedInfo Services:Get personalizedcontent deliverybased on user

profile.

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specialized skill sets required to support the networks can be costly and

time consuming. Moving to commodity networks and common protocols of

IMS will ease finding and maintaining the skill sets necessary for network

support.

Less staff for support and administration of this equipment By leveraging

common protocols and equipment, support staff can be more productive

and proactive to supporting the network. Efficiencies in support staff can

also be gained using commercial off-the-shelf hardware and software

platforms.

Lower maintenance costs Older equipment prevalent in todays network

typically carries hefty maintenance costs, despite being paid for and

depreciated. Additionally, some of the software in use today is no longer

supported by the original vendor, creating additional support issues. Newer

equipment and systems, even after taking into account initial purchase

costs, have a short-term payback period due to significantly lower support

costs. In many cases, maintenance costs for new hardware and softwarecomponents can be 10 to 40 percent less than existing equipment, which

puts the IMS network on a more favorable curve, as seen in Figure 4. Once

the legacy equipment is phased out, the operator can immediately start

recognizing lower maintenance costs.

Lowerriskprofile.Because new applications can be introduced with minimal deployment time, effort

and expense, the payback period is shorter and the risk of launching new services is

minimized.

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Ongoingcostofownership

Existing legacy network costs(fully depreciated)

Today Future

Estimated 10% to 40%

lower support costs

Initial investment of IMS network

Ongoingcostofownership

Existing legacy network costs(fully depreciated)

Today Future

Estimated 10% to 40%

lower support costs

Initial investment of IMS network

Figure 4: Estimated legacy vs. IMS network support cost savings.

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Lesschurn.Customer loyalty increases when one operator can deliver lifestyle voice and data

services and when the customer has access to new applications and services with no

delay and no interoperability concerns. Because IMS enables rapid service creation

via simple modular elements, the result is faster time to market and satisfaction of

consumer demand.

Preservedroamingrevenue.With todays networks, operators risk losing roaming revenue to VoIP providers,

especially when connecting through Wi-Fi access points. The emergence of mobile

devices like handsets and smartphones that take advantage of Wi-Fi will drive

subscribers to use Wi-Fi when sitting in one place, such as at home, in a coffee shop

or at a convention. Wi-Fi service also will be offered by third-party, non-operator

vendors. Mobile service providers can preempt this movement by forming

agreements with Wi-Fi providers and allowing subscribers to access the Wi-Fiservice, with billing and security provided by the mobile operator. This will enable

subscribers to continue to access applications from their mobile phones or

smartphones the same, whether on their cellular network or in a local access point.

INDUSTRY CHATTER VS. REALITY

Chatter: Most deployed IMS services are just trials. Furthermore, commercialapplications are centered on a single application or a small group of applications,

such as PTT and video.

Reality: It is true there is no full IMS commercial production network today, and trialsare limited or are only implementations of single applications. However, since a new

network is a significant investment, operators are especially careful before rolling out

anything widespread to ensure the viability of these new capabilities, user

acceptance, QoS and operational issues. Actually, IMS acceptance will really be no

different than it was for the roll-out of digital networks when there was only analog.

Eventually all voice and multimedia communications, both mobile and fixed, will

move to flexible, IP-based technologies and replace current circuit-switched

technologies. IMS is the evolution path for softswitch architecture.

Chatter: IMS is an all or nothing architecture.Reality:This is not true. Fortunately, the migration to IMS can occur in a piecemealfashion and be easily phased in by integrating circuit-based technologies, preserving

existing billing systems, etc. Operators can pick and choose which elements to

implement, so the migration to IMS can be gradual and deliberate with a focus on

the elements that make the most technological and fiscal sense. Furthermore, there

is no definition of mandatory versus optional functions. This means a network can

evolve from todays intelligent network (IN)-based, circuit-switched paradigm to the

IMS model over time and with minimal pain.

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Chatter: The return on investment for moving to the IMS architecture is just not highenough to justify the changeover.

Reality: The cost for a complete replacement of an existing and, in most cases,depreciated network with a brand new from-the-ground-up IP-based network

certainly cannot be cost-justified by the incremental revenue derived from additional

services or from the cost savings in maintenance and support. As just discussed in

the previous point, IMS should not be looked at as a wholesale replacement of an

existing network. Instead, the move to IMS is best made in small increments (e.g.,

adding IP capability in the form of a softswitch alongside the existing mobile

switching center or adding VoIP and multimedia alongside existing voice circuits),

and each upgrade can then be justified independently. From a high level, IMS works

as a set of standards to guide these incremental upgrades so that as operators

evolve their networks, they do so in a manner that facilitates interoperability with

other operators.

Chatter:There are 1.8 billion mobile phones in the world today, almost all controlledby IN-based circuit switches. Even new 3G-324M mobile video telephony services

are run over 64 kbps circuit-switched data service. There is no economic justification

for replacing this circuit-switching equipment.

Reality:It is true there is limited availability of IMS user equipment, specifically SIPclients on mobile devices. This will change, though. Remember that at one point

when operators started discussing countering fraud using authentication, no phones

were authentication-capable. However, driven by the operators, a complete change-

out of handsets occurred in a matter of a few years. The same process will take place

for IMS-enabled devices.

Chatter:Despite the goal of IMS to enable many competitors, it is the incumbentswho are typically winning IMS deals.

Reality: It does seem that a handful of vendors, the same vendors who have alwaysled the industry, are making headlines with big contracts. However, a number of

start-up companies, many never seen in the telecommunications industry, have

stepped up to fill niches in the IMS playing field. While some of these new entrants

will settle out over time or be merged into larger players, it has given operators the

opportunity to be introduced to new technologies from many new players.

Chatter: 3GPP R5 introduced many of the basic concepts which make up an IMS-compliant network; however, R5 is still not deployed in most 3G networks.Furthermore, IMS has been/is being further refined in several revisions, none of

which are fully baked at this point, and additional revisions will emerge over the

next decade. Also, much work remains in standards committees. ETSI and the

International Telecommunication Union (ITU) are looking at PSTN simulation versus

emulation, and some vendors are pushing to require SIP instead of H.248 as the

media server interface while other vendors continue to oppose this change. Its

unlikely that any standards will ever be agreed upon.

Reality:Tackling such a daunting task as defining a completely IP-based framework,starting with large and general descriptions covering every aspect of the network,

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inevitably requires on-going work, refinement, change requests and addendum. It

also is inevitable that mistakes and omissions have or will be found and need

correction. Simply put, the various releases are just steps in the migration toward full

implementation of NGNs. Remember, any new protocol, technology, standard or

architecture goes through changes as it is refined and implemented. For example,

the original protocol specifications for GSM MAP signaling looked very different

than they do now, the ANSI-41 protocol for many years was considered an interim

standard (hence the notation IS-41 Rev A/Rev B/Rev C) and we are in the midst of

witnessing the evolution of Wi-Fi (the 802.11a/b/g/n series). Furthermore, friction is

undeniable between the TISPAN and 3GPP efforts to define one efficient network

that will meet very divergent business models. And neither ITU nor 3GPP have a

reputation for rapid standards development. Even if everyone agrees to some

selected subset of IMS to pursue, the telecommunications industry has a history of

forking on technical advancements as innovation keeps outrunning the standards

process. However, everyone is used to multiple variations and, most importantly, the

goals of all the groups involved are in harmony to create an operator-friendlyenvironment for real-time, packet-based calls and services that not only will preserve

traditional carrier controls over user signaling and usage-based billing but also will

generate new revenue at reduced implementation costs.

Chatter: Everyone is getting all hyped up about IMS and it isnt even here yet. Also,there are plenty of technological alternatives to IMS.

Reality:Despite industry enthusiasm about and anticipation of IMS, especially itstechnological convergence aspect, IMS in its present form is not a given. And it is

true that IMS implementation is not a necessity for todays applications. Cable

operators do not need to operate an IMS-compliant network to offer voice over theircable networks; likewise, fixed network operators do not need IMS to offer video.

Mobile operators are providing video calls to subscribers using 64K time division

multiplexing (TDM) connections, a technology that transmits multiple signals

simultaneously over a single transmission path. And PTT, which emerged as one of

the biggest reasons to move to IMS, is done today in the proprietary-integrated

digital enhanced network (iDEN), a wireless communications technology that

provides support for voice, data, short messages (SMS) and dispatch (two-way) radio

in one phone with excellent results. However, operators will need new applications

with new revenue streams applications that will not be easy to develop without

IMS. Additionally, not accepting IMS or its eventual evolution will mean acontinuation of the lack of interoperability. So although IMS is not a full-fledged

architecture as of today, the desire for interoperability and the quest for increased

revenue will continue the push to make IMS a working reality within the next two to

four years.

Chatter:Significant differences exist among NGN versions developed by 3GPP,3GPP2, CableLabs and TISPAN. Therefore, a fully converged network is nearly

impossible.

Reality: Although underlying similarities exist among the different NGN versions, thedifferences are still considerable. So, yes, the dream of a fully converged network

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across the board is something that remains elusive for the time being. However,

these differences are not a reason to summarily dismiss a migration to an IMS

architecture. IMS, as an NGN, is coming, and operators will find ways to bridge

interoperability issues among networks just as they do now. Fortunately,

companies already are working on services that will connect all networks and resolve

the differences among the various standards.

CONCLUSION

There is no doubt IMS is the coming standards-based NGN architecture of choice in

both the technological and economical arenas for todays wireless, wireline and

broadband operators. The primary driver behind IMS is a move away from circuit-

switched services toward IP packet-based services. However, IMS will support both

systems. And because the framework is access agnostic, IMS allows operators to

continue to use different underlying network architectures.

As expected, IMS responds to and solves many of the industrys biggest

technological challenges, including the lack of interoperability among operators who

offer the same services and the inability of operators to take advantage of

converged networks.

More importantly, IMS creates definite economic rewards, including:

Additional revenue streams.

Cost savings from reduced operating and capital expenses.

Lower development costs for new applications and services. Lower risk profile for deploying new applications.

Less churn.

Preserved roaming revenue.

Although the migration to IP and packet networks is well underway, that journey is

taking place in several different ways by different standards committees. The result is

that the differences between IMS versions are significant enough so that

interoperability issues will likely continue to be problematic, and operators will need

to find ways to overcome these issues. Fortunately, as has been the case in the past,

operators will be able to find solutions from third parties that will help solve theinteroperability challenges.

Finally, IMS implementation should be viewed as a strategy of migration rather than

replacement of an entire network. Operators can pick and choose which elements to

implement, so the migration to IMS can be gradual and deliberate with a focus first

on the elements that make the most technological and fiscal sense. In essence, IMS

can be viewed as a roadmap for operators to use to guide them through an

evolution to fully converged communications a process that is already underway.

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GLOSSARY

3GPP(3rdGenerationPartnershipProject):Group set up to produce globallyapplicable technical specifications and technical reports for a 3rd Generation Mobile

System based on evolved GSM-core networks. It produced the standards for W-

CDMA (UMTS). The scope of the 3GPP was later widened to include themaintenance and development of GSM technical specifications and reports.

3GPP2(3rdGenerationPartnershipProject2): Counterpart of 3GPP, withresponsibility for standardizing the CDMA2000-based members of the IMT-2000

family. 3GPP2 is spearheaded by ANSI.

AS(ApplicationServer): IMS-compliant, SIP-based multimedia application servershost and execute value-added multimedia services, such as network games, video

content, PTT, instant messaging, presence, etc.

CSCF(CallSessionControlFunction): SIP proxy server that provides call controlsimilar to a VoIP softswitch, although a CSCF uses 3GPP-specific SIP extensions.

There are three different types of CSCFs: A proxy CSCFis a SIP proxy that provides

subscriber access to network-based voice and multimedia services; it front-ends the

serving CSCF. A serving CSCFis the primary call controller for the operator network.

The interrogating CSCFis another SIP proxy optionally used by the operator to hide

internal configurations.

Diameter: The AAA (authentication, authorization and accounting) protocol forapplications such as network access or IP mobility. The basic concept is to provide a

base protocol that can be extended in order to provide AAA services to new access

technologies. Diameter is intended to work in both local and roaming AAA

situations. The name is a pun on the RADIUS protocol, which is its predecessor (a

diameter is twice the radius). Diameter is not directly backwards compatible but

provides an upgrade path for RADIUS.

FMC(Fixed-MobileConvergence): The delivery of communications services basedon a combination of fixed and wireless technologies. FMCs intent is to make

available a wide range of services through a single telecommunications network

foundation.

HSS(HomeSubscriberServer): In IMS, the HSS replaces the legacy networks homelocation register (HLR). The HSS stores subscriber and service-related information,

including user identities, registration data, access parameters and service activation

information. It keeps track of which subscribers belong to the network and their

service capabilities. The CSCF consults with the HSS before initiating SIP

connections (calls).

IMS(IPMultimediaSubsystem): Next generation network for operators from the3GPP who use the IP protocol as their foundation.

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About the Author

Lou Grilli, a technology manager for Syniverse Technologies, has been involved with

wireless data since 1985, with responsibilities ranging from writing software for a

wireless packet network to managing operations for ANSI-41 applications to

directing wireless clearing house operations. He has been on the carrier and vendorside of the business equation, working business cases for telematics opportunities

and industry mandates for wireless number portability, wireless intelligent network,

and SMS services and products. He also has published numerous articles on number

portability, roaming and fraud.

About Syniverse Technologies

Syniverse Technologies (NYSE: SVR) is a leading provider of mission-critical

technology services to wireless telecommunications companies worldwide. Syniverse

solutions simplify technology complexities by integrating disparate carriers systemsand networks in order to provide seamless global voice and data communications to

wireless subscribers. Carriers depend on Syniverses integrated suite of services to

solve their most complex technology challenges and to facilitate the rapid

deployment of next generation wireless services.

Syniverse provides services to over 350 telecommunications carriers in more than 50

countries, including the ten largest U.S. wireless carriers and six of the ten largest

international wireless carriers. Headquartered in Tampa, Florida., U.S.A., Syniverse

has offices in major cities throughout North America, The Netherlands, China, and

the United Kingdom, and a global sales force in Brazil, France, India, Italy, Japan,

Luxembourg, Norway, Singapore and Slovakia.

Syniverse is ISO 9001:2000 certified and TL 9000 approved adhering to the principles

of customer focus and quality improvement practices.

Syniverseprovidessolutionsthatassisttheglobalcommunicationsindustrysolvechallengesitfacesbefore,duringandaftermigrationstoanIP-coreenvironment.Visitusatwww.syniverse.comformoreinformation.

2006 Syniverse Technologies, Inc. All rights reserved under U.S. and international copyright

laws. Rev. 6-06