Wimax Network:- Importance AAA

Q) What exactly is AAA?

AAA stands for Authentication, Authorization and Accounting. It is a core part of a service management solution providing control of access, user services and billing in wireless and fixed networks. Many AAA solutions stop there; others on the market go much farther, offering additional values such as subscriber and session management, policy control, voucher management, advanced authentication, intelligent roaming and a more. These additional features are designed to provide a solid foundation for a growing network. They can also help differentiate a business (or service) from a crowded field.

Q) Why is AAA important? Isn't it just an "add-on" feature that comes at the end of building out a wireless service?

We have met with many prospective customers during the past years. Many of those have made the choice of AAA solution an active one, with procurement happening early in the deployment process. Making their AAA selection up-front became a fundamental component in making sure that both their current business models of today as well as future ones would be supported. In essence this is what is required to secure future success for any provider in the market.

All too often, however, we face prospective customers who for some reason have turned the selection of AAA into a non-active choice. In those cases the decision is often made very late in the process, and frequently based on only a very few main criteria, such as number of authentications per second. Even though this of course is an important parameter, making a AAA decision based solely on this single aspect can be fatal for your business, with significant limitations as a consequence.

You could compare it to buying a car using the amount of horsepower as your only selection criteria and then hitting the nearest highway, without even thinking about what your vehicle should be used for or where you want to go. The AAA service management solution should more be regarded as the dashboard of the car combined with a steering wheel, accelerator and brakes, indicators and GPS system. It is in essence where services are defined and personalized, and policies enforced to control which users access the Internet, their service level and billing. In other words AAA should be regarded as your most important node when it comes to defining exactly what services you want to bring to your customers. With this in mind there is no question that AAA should be one of your first thoughts; certainly not a forgotten item.

One should never underestimate the importance of starting with the business aspects and goals, and make the best possible attempt to outline the short- and long-term commercial models, as this can have a direct impact on the entire network and radio equipment selection. Some vendors may simply have difficulty technically supporting the business models you want to implement. So, start with the business aspect of your services and do not settle with only the core functions. While these core functions might be obvious at first thought, it is important to go beyond that to seek the functionality that can really make a difference for your business.

Q) What features do AAA and service management offer that are relevant to today's changing market, specifically for WiMAX?

WiMAX has of course been very inspired by the mobile/cellular world when it comes to technology including its well-defined standard nodes and licensed spectrum. However, it has also been affected by the Wi-Fi hotspot and fixed broadband markets when it comes to business models. The need to deploy nomadic and online signup-types of business models is increasing by the fast-growing number of WiMAX-embedded devices on the market. Developing countries have proven to be the strongest market for WiMAX. In many of these markets it's just not feasible to send an invoice at the end of the month, the credit risk is often all too high.

Instead operators are looking at prepaid business models similar to those used with Wi-Fi hotspots. A complicating factor is that in many of these markets the use of credit cards is not a viable alternative either, so the ability to offer different alternatives with prepaid, including scratch cards and refill of prepaid accounts through ATM machines is a must. It is therefore important to choose a AAA solution with well thought-out APIs and the flexibility to seamlessly integrate with different external payment support systems e.g. an ATM machine-based refill solution.

Interoperability in a changing wireless landscape is also an important feature that a well-built AAA solution can address. There are many existing fixed broadband Internet ISPs deploying WiMAX as a mobile alternative for their clients. They all have some sort of legacy AAA or LDAP user database that cannot support the new WiMAX installation. One option is to implement a new network for the WiMAX deployment with all the back-end systems in parallel with the existing network. This is a costly approach with product investments, the need to build up know-how for the new systems and additional operational costs for running two different parallel solutions.

Fortunately there are AAA vendors that go beyond basic AAA and offer a solution that makes the WiMAX network interoperable with the legacy AAA or LDAP database. One such an example is the Aptilo WiMAX Legacy Connector™ which mediates between the WiMAX-specific AAA attributes and the legacy user database, making it possible to just "plug-in" a WiMAX network on top of the existing legacy ISP back-end.

Q) What is needed in a AAA solution to support next-generation WiMAX services?

A good AAA solution will have interfaces that allow an application to trigger a Change of Authorization (CoA) request to, for instance, increase the bandwidth temporarily for a user. One example of the type of application where this would be a tremendous benefit is next-generation WiMAX services such as Video-on-demand (VoD), where a VoD server can trigger an increase of the bandwidth when a user decides to watch a movie. The only way to accommodate this is to have a AAA solution that is flexible enough to allow a CoA request from the VoD server over the Internet through some sort of provisioning interface. The same interface could potentially also be used for provisioning of new users from external portals or over-the-air OMA-DM systems.