This article originally appeared in the May 2011 issue of NGN.

As telecom service providers we are concerned how new applications will perform over the next generation networks to attract subscribers and enhance the user experience. Users have embraced new applications such as games, social media and content delivery and have periodically experienced lack of quality of service with the performance of such services.

 NGN IP convergence is once again breaking out everywhere. We now have convergence of applications, content and services. Applications are downloaded onto user devices or service models are deployed where the user device only requires a browser. These processes place huge burdens on networks as many of us have seen with the introduction of the iPhone.

LTE (News - Alert) may alleviate the problem but it is a long-term evolution, and the growth of smart devices is rapid. There is a need to know what performance is being delivered by networks and what extra capacity needs to be installed to provide a satisfactory user experience. We need to test and benchmark the performance and quality of experience of a vast array of applications over the new networks, so we can see where we are today and what remains to be done to ensure continued consumer enthusiasm for these exciting apps.

The NGN Forum Plugfest 9 – www.NGNForum.org/plugfest – (midyear 2011) is the event to test and verify interoperability today.

Convergence (News - Alert) moves the network infrastructure toward commodity equipment and lower cost network provisioning. IP is the way to converge wireless as well as wireline networks. IP multimedia subsystem networks are playing a part in ensuring security and quality of service. IMS enables voice over IP, instant messaging and presence (a subscription/notification mechanism to provide information to selected group of users). IMS is also deployed to provide rich communications suite to enable users to share content, chat using audio and video, and to be notified if their contacts are available (presence).

In addition to needing faster networks to pass more data rapidly, we also need tighter security mechanisms, more flexible billing management and protection against unauthorized network use. These enhanced mechanisms also require comprehensive testing.

Let's examine for a moment the mobile user. Accessing content, to which the user is entitled, requires authentication of mobile user devices from wherever they wish to connect to the network and download applications or content. For example, a user may find himself in a location that is covered by a roaming network. There needs to be a secure, reliable and efficient method to authenticate the user on his or her home network so that the full range of services subscribed to by the user can be accessible from his or her current location. In the future, a subscriber identity will be associated with software rather than a proprietary hardware device. So identity needs to be verified using a more robust authentication and authorization mechanism. We need to test not only that the user can be authenticated, but also that the correct authentication mechanism has been used, and if not, authentication is denied.

It is necessary to test and monitor the network to ensure that:

·         network security is provided;

·         users are authenticated correctly, and

·         services are provided in an optimal way.

Access is controlled as some services may not be provided in the visited network while permitted in the home network, according to pre-defined policies implemented by network operators in the home and visited networks.

Only certain devices may authenticate groups of users. The flow of authentication messages or registration messages must flow through specific network elements, i.e. call session control function, to ensure subscribers’ accounts are not being cloned or hijacked by a rogue user. Users must only be allowed to access the features and services they have subscribed to and each service must benefit from the quality of service that it needs to ensure satisfactory user experience and has been configured for it by the network administrator.

IMS involves complex message flows over a system under test which comprises multiple network elements – for example proxy CSCF (P-CSCF); interrogating CSCF (I-CSCF); serving CSCF (S-CSCF) and home subscriber server (HSS) plus interconnection to the legacy SS7 network. Although testing in the laboratory prior to deployment in the network is usually extensive, there may not be the necessary test infrastructure available comprising multi-vendor equipment with a range of switch software releases or implementations. Testing must be an ongoing process that extends into network operations or first office application to test with high load and traffic patterns sometimes only experienced in a live network. This phased or continuous approach to testing leads to accelerated new IMS-based services deployment. The challenge with IMS-based service deployment is that it requires reliable correlation of events happening at different parts of the network and stateful observation. In other words, we need to ensure that events happen in a specified precise order or sequence.

For example, it would be valuable to know that an I-CSCF is not allowing services to a roaming user endpoint before that user has effectively authenticated on his or her home HSS. Conversely, it would be valuable to know that if a user has authenticated on his or her home HSS, that he or she can use the services subscribed to. Say for example, the home HSS sees a REG from a roaming network for their own subscribers but never sees any subsequent use of service either through a billing event or a session on content delivery service on the home network. Could this be that the roaming network is denying service due to a network problem or other reason? It is in the interest of the home network to work with the roaming network to solve the problem and accelerate billable events or minutes.

All these scenarios and more will be addressed at the upcoming NGN Forum Plugfest 9 to be held during the second half of this year. This event will be attended by all the leading infrastructure vendors. Don’t miss this opportunity to test your equipment and services over these extensive next-neneration networks.

In 2011 NGN Forum working group documents will develop business models illustrating different technologies such as 4G, IMS, service delivery platform, NGN IT with cloud, M2M and smart grid.

We are also working on the test plan for our next IMS Plugfest and NGN Plugfest interoperability test event, which will test out many of these business models along with others.

Registration for this Plugfest and Working Groups is now open to any service providers, integrators, vendors, apps developers, utility companies and governmental agencies that would like to participate to determine the final test plan (www.IMSforum.org/Plugfest).  For additional information please contact [email protected]
Michael Khalilian (News - Alert) is president of NGN, IMS and Smart Grid Forum (www.NGNforum.org).<italics>

Contributions for this article were provided by Richard Jobson NGN Forum Plugfest PM (Teraquant), Jean-Luc Bouthemy (T-Mobile (News - Alert)) and Leslie D'Souza (Tech Mahindra).