Home North AmericaNorth America 2007 Making next-generation networks work

Making next-generation networks work

by david.nunes
Roger WardIssue:North America 2007
Article no.:6
Topic:Making next-generation networks work
Author:Roger Ward
Title:President of the Multiservice Forum, MSF, and Head of Network Evolution Strategy for BTís Chief Technology Office
Organisation:MSF and Network Evolution Strategy for BTís Chief Technology Office
PDF size:380KB

About author

Roger Ward is the President of the Multiservice Forum (MSF) and Head of Network Evolution Strategy for BTís Chief Technology Office. Mr Ward heads up BTís involvement in industry fora and has been heavily involved in the MultiService Forum since its foundation. As MSFís President he has done much to help the Forumís focus on multi-vendor interoperability and the GMI global interoperability programmes, in particular GMI2006 that has done so much to justify the claim to ëmaking NGNs workí. Mr Ward is a Chartered Engineer and a Member of the IEE holding a BS with honours in electrical engineering from Cambridge University, an MS in telecommunications systems from Essex University, and an MBA from Warwick University.

Article abstract

The Internet has created demand for raw bandwidth as well as for more and better services. Carriers can be more than bandwidth pushers by combining services that match the flexibility of the Internet with the quality, availability and location information of the telephone system. The combination of next-generation networks, NGN, and IMS, IP Multimedia Subsystems, gives them the tools to deliver what users want, but implementing this is tricky without the implementation agreements and certification that the MultiService Forum, MSF, provides.

Full Article

Broadband is the issue. The stakes have been raised from ëtelephone access for allí to ëbroadband Internet connection for allí, and those already connected want even more as the Internet develops new services demanding ever more bandwidth. From the end usersí viewpoint the key question is, ìcan the carriers give me enough bandwidth for all the services I want?î Nevertheless, it isnít just about raw bandwidth. Congestion can occur even with very high bandwidth, and when it does you will not get the performance that you need and expect for your critical services. That is why the carriers want to become more than simple bandwidth providers. They believe they can offer much more – services that match the flexibility of the Internet, but incorporate the quality, availability and location information of the telephone system to provide an even better offering. This is not easy to achieve. It requires a radical restructuring of the telephony network into a next-generation network, NGN, and a new technology to drive it. The most promising technology for NGNs is IMS, IP Multimedia Subsystems, and the MultiService Forum, MSF, is a global association of service providers and system suppliers committed to making NGNs work. About IMS IMS began as part of the set of standards for 3G mobile telephones designed to improve data services on the 3G phone network. It was not designed to enable any particular new application, but rather to make it easier to add new applications quickly and efficiently – i.e. to be an applications enabler. In the past, new telephony applications were rare and were added almost from scratch. Developing the new applications was an expensive, time-consuming process, and even installing the service was often difficult. If a phone subscriber wants to add a new telephony service – a new line, fax or ADSL, say – it takes time and generally requires a visit by a technician. Compare that with the ease of downloading and installing an application such as Skype or Acrobat Reader. Internet Protocol, IP, offers such flexibility that the Internet has spawned a host of new applications and the possibility of endless future ones – video, voice, printed word in many forms and permutations. If the carriers were to compete, what was needed was a new telecoms network flexible enough to allow any number of future applications to be added in a similar way without needing adjustments to the carrier network each time. So IMS was designed around Internet Protocol, IP, and set out to define a ëcontrol layerí distinct from the ëapplicationí or ëservice layerí into which all future applications could be simply plugged in without needing any changes to the control layer. Although IMS was originally conceived for the 3G network, its creators had the wisdom to define a control layer that was not only independent of the service layer but also of the ëtransport layerí, so that it would work not just for 3G networks but on any fixed or mobile network with packet switching functions. So, in an IMS world, I might initiate a call to a colleague from my highly functioned laptop, and during the call, without any re-dialling or break in the conversation, I could send a video stream and download some text files and a slide presentation to the colleague. If they happened to receive my initial call on a traditional home telephone, then they would need to pick up a video phone, a fax or switch on a computer to receive everything I sent – but that limitation lies in his handset, rather than the phone system. Similarly, during the call I might say: ìWe havenít finished this discussion, but itís time to walk the dog. Iím continuing this conversation on my mobile phone, so keep your amended draft until Iím back at my desk.î You could argue that this is not so much a revolution as simply the way communications should be. The reason these services are fragmented lies in the history of the telephone infrastructure. Despite constant improvements over the decades, telephony always aimed at linking two or more phones together to deliver the spoken word. IMS is not aimed at any one service, but instead defines a flexible control structure that can be applied to any media or service. It applies just as much to the existing services and users, as it does to the new services that will emerge over the next decade. Because full IMS conversion is such a major investment, there are those who argue that it is not justified. Why take that trouble to build a system to deliver services many of which are available on the Internet? Internet real-time services do not have the same reliability or quality as the phone system, but with enough bandwidth they might be close enough. They argue that although IMS promises more than the Internet, it might not be enough to justify the investment. Faced with such arguments, and the pressures of increasing competition, the industry needed to accelerate the process – at best to make these next-generation networks a reality in the shortest possible time, or at least to decide clearly whether they are a viable way forward. That is where the MultiService Forum has a role to play. The MultiService Forum, MSF The role of the MSF is to bridge the gap between what is theoretically possible in next-generation networking and what is real – hence our motto ëmaking NGNs workí. We have nearly 50 members, including many of the industryís major carriers and vendors across Europe, North America and the Far East – including BT, Vodafone, Verizon, Korea Telecom and NTT. Together we have developed an agenda and a methodology that adds real value for our members and to the industry. Over the past five or six years, we have focused upon an 18-month/two-year cycle addressing very specific deliverables and building up to an event called GMI held every two years. At the beginning of the cycle, the members come together and make their best judgment on the most likely architecture being defined by major industry standards bodies such as ETSI, 3GPP and the ITU-T. The members also define practical physical scenarios that would be encountered in real-life deployments. That is a key distinction – practical deployments require physical networks, not functional architectures. The MSF makes the bridge from functional to physical by selecting and profiling suitable protocols, specifying options, and filling gaps to produce implementation agreements that provide the basis for products. Meanwhile, work goes on setting up a massive network to put the agreements to the test – see Figure 1. The last GMI, completed in October 2006, included 12 days of intensive testing of some 200 devices. To give some idea of the scale of this operation, five of the worldís top carriers – BT, KT, NTT, Verizon and Vodafone and a world-class test facility UNH-IOL – collaborated to provide five host sites; preparing each host site for this project typically requires three or more months. During the event, engineers at each site usually worked 14 hours a day. The result was world-class networked test facilities spanning three continents and bringing together dozens of carriers and vendors in a massive ërealí network trial to validate MSF Release 3 Implementation Agreements covering a wide range of topics, including roaming across multiple network types (including cellular and WiFi), QoS issues (including session border control and bandwidth management), and interoperability with 3GPP release 4. We recognize that a pure IMS infrastructure will not exist in isolation. For the foreseeable future, carriers will have to deal with IMS networks, pre-IMS VoIP networks and existing legacy infrastructure. Figure 2 shows the sort of end-to-end interconnects we focused on. Service providers A and C have MSF R3 architecture, which is our interim hybrid of existing legacy fixed-line networks with added IMS components for converged network solutions. Service provider B might be a smaller start-up able to go straight to a pure IMS network, while service provider D may be a packet cable or some other network provider who is completely non-IMS. So what we were testing in the final scenario was IMSís ability to justify the investment, as it is being installed piece by piece into the global infrastructure, by delivering value-added services to users roaming across these networks. The tests verified not just ëwill it work?í, but also looked at the quality of service, inter-working between carriers and different IP versions, security interoperability, third-party applications and service brokering. The way ahead The MSF began GMI 2006 with an open mind, hoping to see what problems would arise. There was an expectation that IMS equipment might be well short of what the standards defined, but in reality standards compliance proved significantly better than we thought it might be. Much of the equipment interworked straight away, almost out of the box. It was clearly time to take the next step by initiating an industry-wide certification programme, focused on key interfaces. In addition, we concluded that GMI 2008 would be too long a wait for additional testing, as the pace of development accelerates. We therefore also decided to establish a permanent interoperability facility for vendors to test their products for compliance to MSF IAs. By proving that NGNs can work, and accelerating their development and acceptance worldwide, the MSF is taking the world ëbeyond broadbandí. We are putting the focus back onto service rather than simple capacity. The Internet has created a hunger for bandwidth, but it has also created a hunger for innovative services. Nevertheless, there is still an expectation from the PSTN that services will be there when you want them. With NGNs the carriers can provide both the reliability of the PSTN, and the service innovation of the Internet. Itís a better way to do business.

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