IMS: How Telecoms is Becoming More Like the Internet

Next Generation Network (NGN) technology is a term that refers to the transition from the traditional technical organisation of telecoms services to one that is based on IP, the Internet Protocol. The TSSG who are based in the Waterford Institute of Technology in Ireland have been researching and prototyping the technology that is going towards building the telecoms architecture of the immediate future. This new type of telecoms structure is referred to as IMS, the IP Multimedia System.

The older system, Signaling System 7, (SS7) was a well standardized, elaborate, complex set of protocols for building telephony functions such as carrier pre-select services, computer-telephony integration and pre-pay. But the application and service model had some big weaknesses.

As can be seen in the main picture, it was vertically integrated so a developer or innovator was limited to building a specific application on top of a specific subscriber data layer with specific media functions and a specific network interface. As a consequence, there were lots of different protocol variants for each kind of application.

Shane Dempsey is an NGN architect at the TSSG and he explains further, “ It meant that the only people who could run a telecommunication service were network operators working with system integrators.

“It was a massive system integrations exercise because you had to know, for example, lots of different variants for the protocol for a particular equipment vendor for this network operator who has a speciality for this equipment and so on. The question becomes, “How do I make this work?” This led to really expensive development life-cycles.

“IMS is not child’s play but it is a lot less hassle. Because it’s a lot less hassle there are API layers being built on top of it.”

IMS has a horizontal model for its architecture as opposed to a vertical one. This allows for a common database for subscriber data and common media function capabilities. Telecoms architecture starts to look a lot more like internet architecture.

One of the many reasons for shifting to this new telecoms structure was a realization that the success of web based applications, particularly those based on social networks, on the internet implied that there were similar opportunities to be exploited in the area of mobile technology.

Shane points out that, “Previously, telecoms vendors didn’t believe that they needed additional ways of storing information like the contacts that you have, your directory of friends, the presence that you have or your dynamic information like your location. It didn’t really occur to them that you needed that.”

However, creating that functionality in SS7 was difficult because of the inherent complexities. However, the move to IMS is not necessarily straightforward.

When you move to a mobile internet it becomes necessary to move to a packet based network. Once you are doing that you might as well have IP switching in the core.

Shane goes on to say, “IP in the core network isn’t a huge deal because the internet is IP at the core. But pushing IP out out into the network is a big deal because previously it was based on time slot technologies. If you are making calls, voice is time slot orientated. [By means of Time Division Multiplexing — TDM.] So moving to IP is a major effort in terms of standardization.

“Packet switching is a kind of a colloquialism that internet scientists use. The packets aren’t of a fixed size but the data can be divided up into packets and you don’t necessarily get the same throughput at every second. So you can get a voice traffic coming through plus internet traffic where people are sharing all sorts of files, documents, audio, video, etc., which are being sent over the same connection.”

By having foundation layers that are common to all parts of the system a great many applications of which some are in some form of existence today become easier to build and easier to deploy.

For businesses, for example, it will be easier to have:

  • Corporate Directory: You can have your own business contacts on your mobile phone but it is now possible to access your companies own directory if it is active.
  • CRM: Applications will be easier to build. It will be much easier to be able to see who is on or off the grid and where they are.
  • Communication Log: For corporate audit services.

For more general use the Rich Communication Suite offers functions on our mobile handsets that we are familiar with from the internet such as:

  • Calls enriched with multimedia sharing.
  • Video call and conferencing.
  • Hi Definition quality voice calls.
  • Enhanced messaging.
  • Mobile and desktop convergence: All the operators are making web service APIs available for the IMS platforms. This will allow third party developers so build applications that can set up conference calls, pull presence information and pull location information and so on.

As Shane states, “We’ll effectively be using internet communications everywhere.”

Shane has a slideset that you may view for further information.

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