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TMCnews Featured Article
October 03, 2006
Billing and Enhanced Services for the Next-Generation Network - RADIUS or SIP?
By TMCnet Special Guest
Barry Sher
A comparison of two leading protocols for the provision of billing and enhanced services for the next-generation network
With SIP-based trunking, creative end-user empowering services, and the efficiencies associated with IP-based networks, the prepaid calling card market is as lucrative as ever for the next-generation ITSP and TDM based carrier migrating to IP
. According to a recent report by Frost & Sullivan, a global growth consulting company, in 2005 the market for prepaid calling card topped $3.2 billion in North America alone.
. According to a recent report by Frost & Sullivan, a global growth consulting company, in 2005 the market for prepaid calling card topped $3.2 billion in North America alone.Any prepaid service, whether it be calling card or primary/second line services will require a real-time billing system, and these billing systems are primarily based on two effective, yet differing protocols. The first is Remote Authentication Dial-In User Service, or RADIUS, which was developed by Livingston Enterprises, and as the name implies was originally designed to authenticate dial-up modem users. It was later adapted by companies like Cisco to provide authentication, authorization, and accounting (AAA) for voice over IP networks. The second protocol is the session initiation protocol, or SIP, which is an application-layer control (signaling) protocol for creating, modifying, and terminating sessions such as Internet telephone calls and multimedia conferences.
, which is an application-layer control (signaling) protocol for creating, modifying, and terminating sessions such as Internet telephone calls and multimedia conferences. Both of these protocols are based upon open standards and are managed by the Internet Engineering Task Force (IETF). RADIUS is based around a client/server model where the access device, for example a gateway, is the RADIUS client and the RADIUS server is either the billing system or an intermediary to the billing system. SIP is a server-side approach that can be deployed in a centralized or decentralized manner with billing and signaling both occurring at the call control layer.
A RADIUS billing system requires that the gateway, proxy or softswitch it communicates with supports the RADIUS protocol, and lower density devices like softphones, IP phones or IADs must be aggregated by a higher density device in order to support billing. Since RADIUS is above the call control layer it is signaling agnostic and can provide its billing services for different signaling protocols like H.323, MGCP, or SIP, as the billing is abstracted from the signaling by the gateway.
, or SIP, as the billing is abstracted from the signaling by the gateway.A SIP-based billing system, because it is part of the call control layer, can provide billing for any density SIP-based device from a single line softphone or IAD to a trunking gateway, proxy, or softswitch. However, as a SIP-based solution it requires the SIP protocol in order to provide its billing services, therefore for MGCP or H.323 networks it requires aggregation and protocol internetworking by a session border controller, softswitch or gateway.
networks it requires aggregation and protocol internetworking by a session border controller, softswitch or gateway.Open standards based solutions like RADIUS and SIP should, in theory, interoperate “out-of-the-box” but interoperability testing with both protocols, due to the multi-vendor nature of the solutions, is highly recommended. In addition, with RADIUS’ reliance on attributes, called Vendor Specific Attributes or VSAs, to communicate account and billing information between the billing server and edge devices there is some degree of integration and validation testing required.
Another difference between the two billing methods is when it comes to enhanced services, like prepaid calling card. In this regard the RADIUS solution is more decentralized as it relies on the gateway and/or external servers to provide the interactive voice response and media. The SIP-based solution is more centralized by providing billing, media, and enhanced services within a single platform. The RADIUS approach may increase management overhead in globally deployed networks because each gateway needs to be independently managed for application changes and new service deployments. In addition, in the absence of a common application language heterogeneous networks will have inconsistencies between different vendors’ gateways, for the same type of service.
To remain competitive, service providers need to continually improve their service offerings by differentiating enhancements and new services, and both protocols provide the necessary flexibility and extensibility to do so. It is important to note that with RADIUS solutions when new enhancements or services are added that necessitate a new custom VSA, it does require coordination with the gateway, RADIUS server and billing vendors. With the SIP-based solution, because media, billing, and applications occur within a single platform, new and enhanced services are usually performed by a single vendor.
Conclusion
The RADIUS and SIP protocols provide rich billing solutions and the opportunity to capture tremendous revenue, but in very different ways. Both protocols are evolving and addressing security and fault tolerance and we look forward to RADIUS’ replacement, the DIAMETER protocol and the advances coming with SIP as it matures and emerges as the de-facto signaling protocol.
With each protocol embodying its own strengths and weaknesses the selection process should not be based on the underlying protocol but rather on a given solution’s ability to meet your current and future needs based on your existing infrastructure, your future network plans, your market strategy as well as the topology and administrative resources of your network.
With the important financial role performed by these solutions, and the impact associated with the misstep of a poor or ill-fitting one, you should ensure that the billing system is well supported as well as robust and scalable. The solution should also provide a rich and extensible feature-set that can easily adapt to the changing market needs to ensure your business remains competitive through creative services that empower and retain customers.
Barry Sher is Vice President of Business Development at IVR Technologies, Inc. (www.ivr.com), a leading vendor of application, media and real-time billing solutions. Mr. Sher has been actively involved in telecommunications since 1994 and has a successful track record in building innovative telecommunication software development companies. Prior to IVR Technologies, Mr. Sher was President and Co-founder of Telephony Experts, Inc., an Inc. 500 company.
Technologies, Inc. (www.ivr.com), a leading vendor of application, media and real-time billing solutions. Mr. Sher has been actively involved in telecommunications since 1994 and has a successful track record in building innovative telecommunication software development companies. Prior to IVR Technologies, Mr. Sher was President and Co-founder of Telephony Experts, Inc., an Inc. 500 company.
