NGN Is Upon Us

The NGN Is Upon Us

In recent years, the telecommunication market has undergone significant change in terms of technology and business climate. We have entered an age were broadband access comes in so many different flavors, including cable, DSL, Wi-Fi, WiMAX, fiber and customer access to various services available over the Internet are unparalleled.

One of the most explosive new areas is Voice over IP (VoIP). This technology is exciting in so many ways, because for the first time in history, customers really do have a choice in the service provider they use for their local and long-distant phone calls. In addition, VoIP does not simply mean "voice". While the marketing term has become well-entrenched, VoIP technology also enables video telephony and data collaboration: services that were either non-existent or expensive to use with older access technologies.

This web site was developed by Packetizer, which has long-been a supporter of VoIP technology. The purpose for this site is to provide information to end-users about the new service provider choices now available to them through IP-based networks.

You should beware that NGN is an overloaded term. The basic ideas are simple enough, but service providers and equipment manufacturers are trying to take the opportunity to "re-invent" the Internet and call it the NGN and define a very complex architecture with questionable return on investment.

What is the NGN? The Next Generation Network (NGN) is a popular phrase used to describe the network that will replace the current PSTN network around the world today used to carry voice, fax, modem signals, etc. By definition, the NGN is essentially a managed IP-based (i.e., packet-switched) network that enables a wide variety of services. Among those services are VoIP, videoconferencing, Instant Messaging, e-mail, and all other kinds of pakcet-switched communication services. The ITU defined the term NGN in Recommendation Y.2001 as follows: Next Generation Network (NGN): a packet-based network able to provide telecommunication services and able to make use of multiple broadband, QoS-enabled transport technologies and in which service-related functions are independent from underlying transport-related technologies. It offers unrestricted access by users to different service providers. It supports generalized mobility which will allow consistent and ubiquitous provision of services to users. One of the most important aspects of NGN is the deliberate separation of the access provider from the "service" provider (see the highlighted text above). For those that do not understand what this means, it means that the access provider (the service provider that provides you, the customer, with access to the NGN) may be different than the service provider that provides you with various services, such as voice and video communication, e-mail, stock quotes, or other services. We say "may", because the access provider and service provider might be the same company. For example, as a subscriber to cable services, you may elect to purchase voice (telephone) services from your cable company. In that case, your access provider and your voice service provider is one in the same. However, the NGN removes this restriction from you—you have a choice. If you prefer to purchase voice services from another company (e.g., Vonage or Lingo), you have that option, too. Never before have consumers had so many options. Of course, not everybody is happy with the ability for consumers to have a choice. Why? Because the NGN represents a real threat to the current business model of incumbent service providers. The old-world carriers would prefer to control both the access and the services, blocking competitors from being able to come into the market and offer competitive services. However, times change and consumers have the right to choose the service providers that provide them services. We have just entered a new era where customers with broadband Internet access can now select their voice service provider of choice—perhaps one that physically exists in an entirely different country! As the incumbent carriers start exploring the possibilities the NGN will bring, they will soon realize an unbounded opportunity for new sources of revenue through a multiplicity of new kinds of services. As we move forward deploying the Next Generation Network, users may have one or many access providers providing access in a variety of ways, including cable, DSL, Wi-Fi, WiMAX, fiber, etc. into the NGN. Once connected, the options for service providers for voice, video, and data services will be virtually unlimited. We live in exciting times and are just on the verge of a revolution. NGN Functional Architecture The NGN architecture as defined by the ITU and ETSI borrows heavily from the work done by 3GPP. The diagram below shows the architecture that has been defined for the NGN in ITU-T Rec. Y.2012.

According to Y.2012, the NGN architecture supports the delivery of multimedia services and content delivery services, including video streaming and broadcasting. An aim of the NGN is to serve as an PSTN and ISDN replacement.

The NGN architecture defines a Network-Network Interface (NNI), User-Network Interface (UNI), and an Application Network Interface (ANI). The Transport stratum provides IP connectivity services to NGN users under the control of Transport control functions, including the Network Attachment Control Functions (NACF) and Resource and Admission Control Functions (RACF).

The NACF and RACF are two components of the NGN. A more detailed component view of the NGN is shown in the following figure:

Terminals that talk to the NGN will authenticate with the Network Attachment Control Functions (NACF), receive an IP address, get configuration information, etc. Once attached to the network, terminals will communicate directly or indirectly with the Resource and Admission Control Functions (RACF) in order to get desired QoS for communication, get permission to access certain resources, etc.

There are a number of components within this architecture which would suggest a "freedom of services" to users. Users would potentially have access to RTSP-based streaming services, PSTN access, IMS access, and access to "other multimedia components". In this author's opinion, the very fact that these components are listed as the components of the NGN suggests that the service providers behind this effort wish to have too much control.

Note that "legacy" terminals (user devices) must pass through a gateway device. Perhaps this makes sense for legacy PSTN equipment, but what about newer IP devices? Are all IP devices, by default, NGN devices? They are not, according to those trying to define the NGN. So, what are IP devices we use today? Are they exclused from the NGN or locked into tight control with limited access? It would seem so, suggesting that the NGN is at odds with the Internet and a threat to the Internet as we know it.

The IMS layer, while certainly suitable for wireless networks, is very much a restrictive component within any kind of "next generation" fixed network. Below is a diagram that shows the functional architecture of the NGN with interfaces to the various functional elements.

The primary purpose of IMS is to provide control over telephone calls. In a "next generation" network, why would it be that the access provider would, in any way, try to specify how the phone system internals should function? According to ITU-T Rec. Y.2001, access and service should be separated and IMS really has no business being a core part of the NGN. You can look at IMS as nothing more than a means of maintaining the current legacy telephone company business model of counting minutes and charging for minutes of use. That kind of business model is dated and needs to be replaced with something more forward-looking. The only interesting aspect of the NGN architecture as proposed by the ITU and ETSI is the "other multimedia" components. Through these components, it might be possible to truly deliver a new kind of network that users may find useful. The NASS and RACS layers are quite reasonable, as access to the network must necessarily be controlled. However, once network access is granted, the kinds and types of services accessible to the user should be virtually unlimited (though that does not equate to "free", understand). Through the "other multimedia" components, it might be possible for terminal equipment manufacturers to provide equipment that might deliver the services that users expect today, as well as new kinds of services that users might want. In fact, the ITU has initiated work on a new multimedia system called H.325, which promises to deliver on the promises of the NGN. Specifically, H.325 will allow a user to use multiple devices togther with multiple applications in order to communicate with another person. As the system is envisaged, any application developer could create an application that simply "plug in" to the H.325 terminal. The user could, for example, use a mobile phone to talk on a phone, see a video feed on an LCD screen, collaborate on a document through a PC ("screen sharing" or "application sharing"), and receive a file to a mobile handheld device, all within the context of a call to another person. The possibilities are amazing. A very important distinction between the work on H.325 and IMS is that H.325 is designed to work on the Internet as it is today. Look at H.325 as a big step forward in terms of communication capabilities, without all of the complexity of the NGN architecture.