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August 2007 | Volume 10 / Nuber 8
Feature Articles

Today's IMS Scene

By Richard Grigonis

IMS, the IP Multimedia Subsystem, is perhaps the most ambitious movement in telecom since the transition to digital signaling in the 1970s and 80s. Its goal is to overhaul the world's wireless and wireline networks, placing them atop a global, common service architecture that will allow service providers to quickly devise and deploy many new on-demand, IP multimedia and mobile services. Single platforms will be able to combine multiple services such as VoIP, IP Centrex, Fixed-Mobile, Hosted PBX and SMS.

The upcoming IMS Forum Plugfest III for Applications and Services will be held October 15-19, 2007, at the University of New Hampshire's InterOperability Lab (UNH-IOL) ( in Durham, New Hampshire, a huge 32,000-square-foot testing center founded in 1988. These interoperability and certification events as well as early deployments indicate that IMS, though slow to start, will be an inevitable single service architecture for network operators worldwide.

At the well-known telecom hardware and software vendor Dialogic (, Jim Machi, VP, Product Management and Planning, says, “Many people overuse the term IMS. IMS is more than just the original 3GPP wireless spec and all that. To me, the industry looks at IMS as an IP infrastructure framework in the public network area, although some people are now starting to talk about how IMS could affect the enterprise. The movement to an IP network is happening. Whether you call that IMS or 'NGN plus' doesn't matter. What does matter is that a change is occurring. Customers ask us about it and we see it in the products we're selling. Therefore, we do 'believe in' IMS. It will probably follow what I call a typical 'telephony adoption curve', which will be years in length. We're starting to make our products IMS capable today so that people can migrate to IMS at their own pace. You can place our components in an IMS network today - although there are few such networks at the moment - or you can place them in an IP network and have an IP media server connected to the network.

Dialogic's Director of Marketing, Bill Byant, says, “I just think IMS is on a traditional deployment curve, the same kind that you saw with VoIP itself. Like VoIP, IMS will take some time, longer than most of us might prefer, but it will eventually be ubiquitous.”

Security in an IMS Environment

Amusingly, many people have been so concerned over IMS testing and adoption rates, they've ignored more potentially serious matters such as security.

For example, at Apertio (, Bill Bondy, CTO Americas, says that the ability to consolidate information into a single database helps security in an IMS network, particularly when one is figuring out ways to federate or share information among a particular set of organizations.

“Apertio was formed about five years ago,” says Bondy, “based on some technology created in the U.K. to consolidate subscriber data. Our whole heritage is built on building what we call a single logical database for any telecom core network, such as wireless, cable, fixed-line, you name it. The whole idea is to simplify core networks that currently are saddled with many different database silos and systems implementing subscriber data, services and, in a parallel line of activity, unify different security implementations to protect that data and those services. We take these networks and greatly simplify them by consolidating data into a single logical database which can scale without any bounds and can grow as big as a customer needs in terms of storage and number of transactions supported. You no longer have to worry about various data locations and all of the intricacies and security surrounding that. On top of that database, we offer a number of applications, either produced by Apertio, such as an HSS [Home Subscriber Server], or partner apps from the likes of BEA, Motorola and Siemens.”

Bondy continues: “We see from our customers, including a large U.S. CDMA operator who unfortunately I can't name at the moment, that they're looking to consolidate much of their core network data, as well as making this data work for IMS. This particular vendor is doing a lot of work with the cable companies and others on an IMS front. Specifically in terms of security for IMS, one of the issues they have is how to create a synergistic security model around not only their independent groups within the company, but with the partners that will be sharing this IMS data to provide services that are fixed-mobile convergent in nature or multiple network-spanning types of services. One of the big areas with which they're concerned is 'identity federation' as well as 'data federation', and all of the security aspects of those.”

“We see that there's a lot of work going on in the standards groups to identify ways of securing this data,” says Bondy, “and allowing it to be reused among different partners and network components - you see it in the Liberty Alliance as well as the people involved with the Security Assertion Markup Language [SAML], an XML-based framework for communicating user authentication, entitlement, and attribute information developed by the Security Services Technical Committee of the Organization for the Advancement of Structured Information Standards [OASIS].

“Our U.S. CDMA customer wants to be able to share IMS subscriber profile data so that they can enable fixed-mobile convergence [FMC],” says Bondy. “You may ask how they go about doing that. They could use SAML or independent provider security mechanisms on these data systems to allow the sharing of security and identity credentials. One reason they chose our system is that they were swamped with having 50 or even 100 or 200 different databases in the networks that had to be coordinated using SAML or the Liberty Alliance and interoperate with these protocols to provide identity federation and data sharing. Instead of doing something 100 times they just want to do it once in each core network. That's where our solution comes into the picture.”

Charge It Up!

As with security, billing, bookkeeping and policy-type functions also take on a more exacting character in an IMS environment. At Openet (, Vice President of Global Marketing Mike Manzo says, “IMS to us represents an evolution, not a revolution. Part of the reason we believe IMS is real is that we see the first adoption of infrastructure occurring in the space in which we operate, and that is around the charging applications. Openet builds an array of event processing and transaction management software-based solutions for operators. We have positioned ourselves as a provider of transactional intelligent solutions, meaning that we build capabilities that help operators gather or extract increased value from the activity on their network. IMS is a key trend for us, because, whereas it is not the 'cause' it is perhaps the 'end game' relating to the volume and complexity of transactions on service provider networks resulting from the deployment of new services.”

“Certain services that operators want to deploy will be best served by deploying them with an IMS architecture,” says Manzo. “Openet's play in that space is to provide both offline and online charging solutions as well as policy enforcement and policy decision solutions. Essentially, with these services being deployed, there is a certain volume of transactions that need to get processed in session, whether it's a balance reservation, authentication, or content filtering rule. There's a myriad of different decision that need to be made and enforced by the network's device that's enabling the service. Post-service, there are events produced on the network that need to be aggregated, filtered, enriched and served to downstream business systems so that business objectives can be achieved. That can be anything from billing to complying with lawful intercept regulations to detecting revenue leakage. So, we're providing a suite of IMS-compliant solutions that will enable operators to do all of these things.”

“Openet has an IMS deployment today for offline charging and we continue to see requests emanate from tier-1 operators as they gather information or are looking for specific bids for online charging applications,” says Manzo. “It's clear that they won't immediately move all of their existing services to an IMS architecture. Instead, they want to launch one or two discrete services on an IMS architecture, get those to market, and then slowly evolve the rest of their network over time.”

Joe Hogan, Openet's Founder and CTO, says, “Operators are looking at two things: They've got their strategic IMS core build-out for which they're selecting online and offline charging systems. Interfaces to the IMS core equipment for charging are mandatory, therefore to build an IMS network that supports service delivery you need a charging system in place. It won't work without one. Therefore, this is part of the First Phase package that they purchase. Secondly, operators know that, between now and the time they will have a full IMS network - which is many years from now - they're looking for a charging system having the architectural longevity to bring them to IMS and be useful when IMS arrives, as well as deal with the challenges of today and several quarters from now, all while they slowly increase the number of services delivered over IMS from a small proportion to ultimately the majority of their services.”

“As part of that infrastructural revival, operators are using the IMS standards set as a good place to capture the latest thinking on what charging systems should look like and what architectures they should have,” says Hogan. “This is not only good for IMS but also serves the challenges of today and tomorrow. The operator RFPs are quite interesting. They specify IMS compliance, but there's a lot of general charging features that are also required. The tier-1 operators say they need an IMS-compliant state-of-the-art charging system to deal with services they're rolling out over the next few years. If the first couple of services they roll out are successful and there's no loss of faith in IMS, then they'll continue with the rollout of more services on IMS. As those rollouts gain pace, the operators won't have to change their charging platforms, since they will already be IMS-compliant systems.”

Fulfillment, IMS Style

Joe Frost, Vice President of Marketing at JacobsRimell (, says, “We see that many operators and vendors are still engaged in lab trials, verifying the IMS-based interoperability of their products. Most of these guys have recognized that there's a key factor involved in getting this stuff to work. It really hinges on being able to get a handle on better control and better visibility of the operational data.”

“Our claim to fame is that we're a software company that delivers OSS solutions to tier-1 operators,” says Frost. “We do it differently from everyone else in that the traditional way of doing OSS is by what we call a network-centric point of view. One normally looks from the network inventory upwards and then does the provisioning and activation from there. But we've always approached this from the opposite end, from the subscriber user identity point of view. Our platform centers on an information model where we model the identity, the context, etc., of the user and then we apply products and services to that individual identity. This allows the operators to build a subscriber information model allowing them better personalization and increased efficiency of their operations because they are working essentially on a live data model of the operational data sitting in the network and BSS/OSS systems.”

Frost elaborates: “When you look at the value proposition of IMS - whether you're a telco or wireless operator or an MSO cable operator - at the highest level it's really all about adding intelligence to the network so that you can deliver a wider range of products and services to an equally wide range of user devices, across a wide range of access technologies. What we're talking about here, of course, is real convergence, convergence the way it should have been done in the first place.”

David Jacobs, CTO and Co-Founder of JacobsRimell, says, “We're coming out of the other side of all of the interoperability trials, and more people are beginning to realize that these IMS elements really do work and can now start to be applied. But having gone through those standards body type of interoperability workshops, people also recognize that the full operationalization of IMS and capabilities is a bit off. That's where we come into play.”

“For example, you're perhaps aware that the Home Subscriber Server [HSS], the thing that holds data dealing with entitling any particular device to use the network and gain access to specific applications, also holds data about the individual that's using that device and whether or not they can reach an application and make use of it. People who are trying to create new applications that can be delivered to end users now realize that an HSS has its limitations. An HSS doesn't necessarily have the 'richness of data' that's needed, and it doesn't necessarily have the right performance in terms of being able to access large lists of information quickly, such as if you were attempting to implement a group-type service and you wanted to be able to pull back a whole set of information from the HSS. The current HSS interfaces just don't support that kind of scenario; they force you to retrieve just one record at a time. If you try to pull up 100 records of a group list at one time, it doesn't work. People are already trying to think through how to get around these limitations.”

“Our whole approach to fulfillment starts with examining the key information and we then devise appropriate processes and capabilities,” says Jacobs. “Some of that information may be an abstraction from the real underlying data of the service-delivering application. But fundamentally, it's about having those processes that work on that data and then being able to perform various other processes that synchronize that data with the network or with the service-delivering applications. What that in turn allows you to do is to insert all of the good practices around abstraction, such that you can create reusable processes; that in turn allows you to be able to separate the changes in the network from the processes or portals used by end users. It gives you a 'layer of indirection' that makes everything far more operable.”

“The other real benefit this approach gives you is that it allows you to work with 'rich' data such that if you've got an information set that's quite rich you can choose which subset of that information to push down to different network elements, such as an HSS or whatever, and suddenly the whole system becomes a lot more usable,” says Jacobs.

IMS may be on a bumpy road, but in the great telecom road rally, it's still on course. Companies such as those mentioned in this article will help “fill in the gaps” and help the world's network operators and service providers adopt IMS and make it a success. IT

Richard Grigonis is Executive Editor of TMC's IP Communications Group.

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