� Deploying, Hardening, and Benefiting from Next-Generation NetworksMichael J. Burns

Finally, there is the question of how one benefits

from the NGN and IMS. How does the service provider

benefit, and how does the end user benefit? One key

for the service provider will be the ability to design,

develop, and test new services that are dependent on

IMS. There is a growing consensus that speed in mov-

ing from service concept to service reality will be a key

differentiator for service providers in the IMS-enabled

world. The service delivery environment, as well as

“right-sized” tools and processes to support it, becomes

critically important. From the end user’s standpoint,

there will be exciting new services enabled by next-

generation networks and IMS. Ensuring that these

services meet the users’ needs and that they provide

the quality of service demanded by end users are other

challenges addressed in this issue.

How to Deploy NGN?When considering issues around NGN and IMS de-

ployment, it is important to frame the questions intel-

ligently. “Toward a Unified Service Delivery Process for

Next-Generation Services” provides a new framework

and vocabulary for communicating about the variety of

actors, objects, and methods needed for next-generation

service delivery. The service-oriented solution frame-

work (SOSF) that is proposed in this paper can serve as

a foundation when thinking about the practical impli-

cations of later papers in this section.

As service providers start to deploy IMS, they are

faced with the question of how best to locate the var-

ious functional components that constitute an IMS-

based network. “An Analysis of Capital Expenses and

Performance Trade-Offs Among IMS CSCF Deploy-

ment Options” examines this issue. In particular, this

paper investigates the question of whether control

functions such as the call session control function

IntroductionLike previous General Papers issues of the Bell

Labs Technical Journal, this General Papers issue pres-

ents a smorgasbord of research papers that should

give the reader a reasonably good feel for some of the

most important current areas of innovation and crit-

ical thinking within Alcatel-Lucent. Not surprisingly,

next-generation networks (NGN), particularly those

based on the IP Multimedia Subsystem (IMS), are the

focus of much attention.

The papers in this issue investigate, in one way or

another, aspects of three questions that are funda-

mental to the success of NGN. First, how should serv-

ice providers deploy next-generation networks? For

example, there are open questions about how best to

distribute components throughout an IMS-based net-

work. Network configuration and capacity planning

are not new problems, but they do have some new

wrinkles to consider when one is thinking about IMS.

In addition, for the near term, there are still some in-

teresting questions around how best to provide

IMS-to-public switched telephone network (PSTN)

interconnection.

The second question that papers in this issue ad-

dress is the question of hardening NGN reliability.

Certainly, reliability is a topic that is important to tra-

ditional telecommunications networks as well as to

next-generation networks. As some of the papers in

this issue point out, though, there are some special

considerations of next-generation networks that

should be taken into account when designing for re-

liability. Further, because telecommunications net-

works are so central to the global economy and daily

life in the new “flattened world” [1] reliability fail-

ures have the potential to lead to severe problems,

not just mere annoyances.

Bell Labs Technical Journal 12(4), 1–4 (2008) © 2008 Alcatel-Lucent. Published by Wiley Periodicals, Inc. Publishedonline in Wiley InterScience (www.interscience.wiley.com) • DOI: 10.1002/bltj.20262

2 Bell Labs Technical Journal DOI: 10.1002/bltj

(CSCF) should be centralized in the network or

decentralized. This paper looks at two important fac-

tors in making such a decision—capital expense costs

and network latency.

“IMS Network Signaling Peering: Challenges and

Proposal” points out some of the considerations

around IMS-to-PSTN interconnection. It analyzes IMS

peering challenges from the perspective of Session

Initiation Protocol (SIP) signaling peering. It also pres-

ents a high level IMS signaling routing process that

identifies key peering decision points. It further de-

scribes how the implementation of such a process

should accelerate the deployment of IMS networks

and reduce the reliance on the existing PSTN network

for inter-carrier communications among IP endpoints.

“Advanced IMS Client Supporting Secure

Signaling” takes a different approach to the IMS-to-

PSTN interconnection issue. This paper describes an

IMS client that serves as a Voice over Internet Protocol

(VoIP) client to set up calls between IP devices and

inter-works with circuit-switched networks to deliver

calls to PSTN phones. It also details how a number of

supplementary services are supported by the client,

as well as how various secure protocols are supported.

The final two papers in this section propose new

approaches to network planning and network con-

figuration. While the specific example networks ad-

dressed in these papers are not IMS-based networks,

the concepts discussed in the papers would certainly

apply to IMS-based networks. “An Approach for

Just-in-Time Radio Access Network Capacity Planning

in CDMA Networks” investigates the complex prob-

lem of how a radio access network (RAN) should be

optimally equipped to accommodate fluctuations in

traffic patterns over time, while fulfilling the service

provider’s quality of service (QoS) requirements.

Current network configuration models have some

shortcomings, such as requiring a large amount of

manual effort and not being particularly flexible.

“Automating Network Configuration Tasks Using

Multi-Level Modeling” describes a prototype auto-

mated configuration tool using multi-level modeling

for Universal Mobile Telecommunications System

(UMTS) terrestrial radio access network (UTRAN)

networks that mitigates these problems.

How to Harden NGN Reliability?“Reliability Concerns for Next-Generation

Networks” is a letter that provides an introduction to

the reliability section of this Bell Labs Technical Journal.

It points out a number of factors that can influence

the reliability of next-generation networks, and de-

scribes how the reliability of next-generation net-

works is even more important than the reliability of

traditional telecommunications networks.

Given the complexity of NGN reliability, as de-

scribed in the paper above, the common current ap-

proach of doing initial network design and economic

optimization before doing reliability assessment and

design can lead to inefficiencies or worse. “Reliability

of Next-Generation Networks With a Focus on IMS

Architecture” introduces two new concepts to help

with NGN reliability design. These include the service

matrix as a tool to systematically represent the call

paths of the NGN and the multiple services it sup-

ports, and significant point of failure (SgPoF) analysis,

which encourages and enables design-for-service re-

liability early in the overall network design process.

Panel 1. Abbreviations, Acronyms, and Terms

CDMA—Code division multiple accessCSCF—Call session control functionIMS—IP Multimedia SubsystemIP—Internet ProtocolIPTV—IP televisionNGN—Next-generation networkQoS—Quality of servicePCA—Portable call agentPSM—Partial session mobility

PSTN—Public switched telephone networkRAN—Radio access networkSgPoF—Significant point of failureSIP—Session Initiation ProtocolSOSF—Service-oriented solution frameworkUMTS—Universal Mobile Telecommunications

SystemUTRAN—UMTS terrestrial radio access networkVoIP—Voice over Internet Protocol

DOI: 10.1002/bltj Bell Labs Technical Journal 3

Dependable power sources are essential to the re-

liable operation of any telecommunications network.

“Optimal Deployment of Power Reserves Across

Telecom Critical Infrastructures” shows some ways in

which the considerations around the placement of

backup power generators in an NGN differ from the

factors that determine such placement in the PSTN. It

also presents an optimization model for determining

how to deploy backup generator power within next-

generation networks.

How to Benefit From the NGN?The first two papers in this section describe tools

that have been used to help develop new products and

services, tools that can be applied to the development of

NGN services as well as traditional telecommunications

services. “Effective Requirements Traceability: Models,

Tools, and Practices” presents a generic framework for

designing a requirements traceability strategy. It also

describes TraceabilityWeb, a tool that integrates multi-

ple artifact repositories, test management systems, and

feature repositories. TraceabilityWeb automatically gen-

erates artifact mappings, computes and maintains a

multi-relational matrix, and generates personalized,

role-based views and reports (e.g., vertical traceability,

horizontal traceability, and verification gap reports).

“Portable Call Agent: A Model for Rapid

Development and Emulation of Network Services”

describes a tool that enables the rapid development

and emulation of network services. The portable call

agent (PCA) has been used in a variety of applica-

tions; services developed in it are dynamically exten-

sible and reconfigurable. The paper presents a formal

model that details the theoretical underpinnings of

call flow graphs used in PCA.

The two papers above describe tools that help

telecommunications companies, such as Alcatel-

Lucent, develop new products and services. Following

these papers, “Generic Service Provisioning and

Invocation in IMS” is a Bell Labs Technical Journal letter

that proposes a new mechanism to allow end users to

provision and invoke new services that they them-

selves create in IMS-based networks. This concept takes

the idea of efficient service delivery to the extreme by

putting the tools for new service delivery in the end

users’ hands. As an example, the paper describes an

automatic multilingual translation telephony service

and shows the IMS-based network components that

would be involved in the service logic execution.

Presence and location awareness will become

common in next-generation networks. “Spanning a

Multimedia Session Across Multiple Devices” describes

an innovative service that takes advantage of those

capabilities to allow a multimedia session to be dis-

tributed over multiple devices that are in close physi-

cal proximity to a user. This paper surveys existing

methods to provide partial session mobility (PSM), de-

scribes a proposed network-initiated method to sup-

port PSM, shows how to combine the proposed method

with terminal-initiated PSM, and describes how such

a service could be supported via IMS.

Another service that holds much promise is

Internet Protocol television (IPTV). Measuring IPTV

service quality, however, is non-trivial because of the

system complexity as well as the subjective nature of

video quality assessment. “Analysis and Realization

of IPTV Service Quality” presents an investigation of

IP video service quality metrics with a focus on cor-

relating viewer perception with network performance

and operation. It describes a set of techniques for

measuring video quality with respect to network per-

formance indicators, network configuration, digital

video attributes, and video content.

References[1] T. L. Friedman, The World Is Flat: A Brief History

of the Twenty-First Century, Farrar, Straus &Giroux, New York, NY, 2005.

(Manuscript approved August 2007)

MICHAEL J. BURNS is a technical manager in theSoftware Models and InfrastructureResearch Department at Alcatel-Lucent BellLabs in Murray Hill, New Jersey. He currentlyleads a team that develops software toolsand services for use by Alcatel-Lucent’s

business divisions. During his career he has performedsystems engineering, user experience design, andsoftware development for a wide range of operationssupport systems and multimedia- and Web-basedapplications and services. He is a member of theAssociation for Computing Machinery (ACM). Dr. Burnsearned a B.A. in psychology from Washington and LeeUniversity in Lexington, Virginia, and an M.A. and Ph.D.in cognitive psychology from the University ofCalifornia, Los Angeles (UCLA). �