Heavy Reading

IMS & the Future of Softswitches in Next-Gen Networks

Softswitches are the heart of today's VOIP networks, but they have evolved since their introduction less than ten years ago and continue to evolve as carriers begin implementing IP Multimedia Subsystem (IMS) and next-generation network architectures. The original softswitches were modeled after the traditional TDM switches they were designed to replace, but over time carriers have been able to take advantage of the flexible nature of IP networks to implement distributed switching architectures. Along the way, the softswitch has morphed into a collection of components distributed across the network, or just a core call control element in the center of the network, depending on one's perspective.

With all the buzz today about IMS, Heavy Reading set out to determine whether the softswitch's days indeed are over, or at least numbered and if so, when they might end. Far from being over, we discovered that the softswitch has a lot of life left in it, as carriers continue to introduce and expand their VOIP networks. In fact, with the impending migration of many large TDM networks to VOIP, the growth in this sector may have only just begun.

One question is whether those networks will be VOIP networks or IMS networks. While some may predict the demise of the softswitch in favor of IMS, Heavy Reading's research shows that many carriers are not convinced that they need to implement IMS or replace their VOIP infrastructure with IMS, while others have not yet defined their IMS strategy. In fact, a strong case can be made that VOIP and IMS are not mutually exclusive at all.

Carriers have different drivers for migration to VOIP and IMS, including the type of carrier network (i.e., fixed, mobile, or both); their markets (i.e., developing or developed economy); their access infrastructure and broadband penetration; and the state of their existing switching infrastructure. Depending on the drivers for each particular carrier, different technology migration paths emerge: Incumbent operators in developed markets with fixed and wireless operations are most likely to migrate directly to IMS, while operators in developing markets are most likely to implement a migration path through softswitches. Some greenfield operators, such as voice-over-broadband (VOBB) service providers, may take an entirely different path that involves neither traditional softswitches nor IMS.

One of the greatest challenges in forecasting the future of softswitches is dealing with the ever-changing nature of the softswitch itself. Softswitches initially looked a lot like IP versions of traditional digital TDM switches, but over time they have morphed into a collection of elements spread throughout the network, from the access gateways to the core switching element or call control components. Some consider all the related elements as a part of the softswitch, and others consider only a few or just the central call agent as the softswitch. At the same time, the architecture of the softswitch is evolving and in many cases aligning with the IMS standards, blurring the distinction between the softswitch and IMS.

IMS & the Future of Softswitches in Next-Gen Networks investigates service provider expectations and plans regarding softswitches and evolution to IMS and how today's softswitches are changing to meet the needs of network operators in their next-generation networks. The report includes results of an exclusive worldwide survey of more than 150 service provider professionals, representing nearly 130 network operators worldwide, regarding their views on VOIP, IMS, and their network evolution plans.


Research for this report also included in-depth interviews with executives from 19 softswitch and related technology vendors, as well as five different types of service providers. Summaries of these interviews are presented in the 24 company profiles included in this report.

For a list of companies profiled and evaluated in this report, click here.

There is a fairly common consensus on how the functional elements contained within the softswitch will evolve to IMS. In most cases, the integrated softswitch evolves into the media gateway and Media Gateway Control Function (MGCF). The signaling gateway moves over to become a Signaling Gateway (SGW) in IMS. With some vendors, the call routing database becomes the Breakout Gateway Control Function (BGCF). The customer database must be migrated to the Home Subscriber Server (HSS), which most vendors have identified as a new element built or being built to IMS specifications. The call agent or call control elements of the integrated softswitch move to the Serving Call Session Control Function (S-CSCF) and Interrogating CSCF (I-CSCF), which vendors have also identified as new elements built or being built to IMS specifications. The Class 4/5 features of the softswitch move to the application layer and are contained in application servers. Often this is also accomplished as an evolution of the original softswitch, rather than creating a completely new product. Today session border controllers, which are not traditionally a part of the softswitch, provide the signaling security and gateway function between VOIP networks that evolves to the Proxy CSCF (P-CSCF) in IMS.

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The service provider survey conducted expressly for this report delivers deep insight not only into network operator plans for softswitch deployment, but also their long-term strategies for delivering IP-based services, including VOIP and IMS. Results provide quantitative information about network operator timetables and spending plans for IMS and softswitch-based VOIP services, as well as information about which companies are perceived by service provider buyers as the market leaders in these critical sectors.

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Report Scope and Structure

IMS & the Future of Softswitches in Next-Gen Networks is structured as follows:

Section I is an introduction to the report, with complete report key findings.

Section II offers an overview of softswitch technology and examines how it is evolving today in the context of next-generation networks.

Section III analyzes the major next-generation network architectures, as defined by the 3GPP, ETSI, PacketCable, and the MultiService Forum, with a consideration of how they are influencing the evolving definition and configuration of the softswitch.

Sections IV explores the evolution path from the existing softswitch to IMS and next-generation networks. It presents a common path outlined by softswitch vendors and also considers other trends, such as the elimination of switching classes, PSTN emulation and simulation, and feature servers.

Section V, based on Heavy Reading's exclusive survey, examines the service provider perspective on softswitching trends, summarizing their views on migrating to IMS, the factors they consider in selecting softswitches, and their reasons for migrating to IMS.

Section VI provides a synopsis of the overall direction of the industry and the various factors that will affect different operator strategies and plans.

Section VII includes detailed company profiles for each of the five service providers interviewed for this report, examining their VOIP infrastructure, their softswitch plans, and their expectations regarding IMS.

Section VIII comprises detailed company profiles for each of the 19 equipment vendors interviewed for this report, exploring their existing products, the features and components of those products, and their migration plans to IMS.

IMS & the Future of Softswitches in Next-Gen Networks is essential reading for a wide range of industry participants, including the following:

Softswitch vendors: How will the ongoing evolution of VOIP and IMS services affect operator and enterprise demand for your products? Where are the new opportunities for market growth? Are your products and marketing messages in line with customer plans and expectations? Are there significant gaps in your product line that need to be addressed to meet future demand for IMS-based VOIP technology?
Other VOIP and IMS technology suppliers: How will the convergence of IMS and VOIP affect demand for your products? Which technologies and platforms are emerging as the most likely winners in the new environment? Is your company in position to take advantage of those anticipated changes?
Service providers: How do your plans for VOIP and IMS compare with those of your competitors? Does your strategy deliver the best service-enablement and cost-control options for your network, or are there alternatives that will deliver greater efficiency? Which technology suppliers are in the best position to deliver the solutions you need?
Investors: Which technologies and platforms are emerging as the winning solutions in the softswitch sector, and which companies are the leading providers of those solutions? How will IMS affect profitability for softswitch vendors in the coming months and years?

IMS & the Future of Softswitches in Next-Gen Networks is published in PDF format.

PRICE: $3,795
Senior Analyst, Heavy Reading
Longo has had considerable experience with voice and IP services on the service provider side during his more than 20 years in the telecom industry...
Click here for full list of network operators and vendors included in this report.
85 pages of analysis covering current and projected deployment of softswitches and IMS-based VOIP services
Products and strategies detailed for 19 different softswitch technology providers
Complete evaluation of the likely impact IMS will have on the softswitch
Results and analysis of an exclusive worldwide survey of more than 150 service provider professionals (representing more than 130 different network operators) regarding current and projected softswitch and IMS deployment plans
PRICE: $3,795
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