Reality Check: Unleashing the power of SIP in mobile networks

Editor’s Note: Welcome to our weekly Reality Check column. We’ve gathered a group of visionaries and veterans in the mobile industry to give their insights into the marketplace.
On the threshold of this new decade, mobile service providers are in the early stages of a service delivery evolution encompassing both new services and new ways to deliver them. The Session Initiation Protocol (SIP) lies at the heart of this transition. SIP, while not new, has not been widely deployed by mobile service providers to date. But now, mobile service providers are tapping into this sound, proven technology that has been transforming wireline service providers since the turn of the century.
Mobile service providers face a new challenge in today’s era of ubiquitous mobile broadband: how to avoid becoming a dumb pipe to richness of the Internet — the same challenge that fixed line operators have faced since the advent of broadband. Further, relying on wireline substitution to drive revenue growth and market share is inadequate. As 3G and 4G radio technologies increase the broadband speeds available to subscribers, mobile service providers need to innovate their services portfolio to offset average revenue per user pressure and gain share in an increasingly complex competitive marketplace. By tapping into SIP, mobile service providers can realize both enhanced services and reduced costs due to their ability to control the mobile handset and the underlying network infrastructure.
Mobile service providers no longer need to worry about SIP as a “next-generation” signaling protocol. It has proven its mettle and worth and continues to evolve. SIP’s extensibility and flexibility makes it attractive to those service providers seeking an extended competitive advantage. It provides mobile service providers with a multi-purpose, multimedia signaling protocol and gives them the architectural foundation to deploy new services. SIP is the central signaling protocol in 3GPP’s IP Multimedia Subsystem (IMS) architecture and all related IP service delivery architectures. Unlike patchwork efforts such as Bearer Independent Call Control (BICC), which relies on a reworked legacy protocol to deliver legacy services over an IP transport, SIP provides the foundation for long-term cost reduction and new services at the same time.
There are three main areas where SIP can be used to transform networks and services:
1. Network interconnects. Some mobile service providers have already adopted SIP at the interconnect border with the main motivations being capital and operational savings, routing flexibility and improved call quality. SIP trunks between service providers can also allow service providers to deliver end-to-end delivery of new IP interactive communications that will not tolerate a TDM link in the transit path. SIP also enables new interconnect business models, including settlement free peering and multi-lateral environments such as the IP xChange (IPX) carriers with cascading payments and service level agreements.
2. Subscriber services. As a true multiservice signaling protocol SIP provides an integrated voice, messaging, data and video experience for the mobile user. In the endpoint, SIP makes it easier for operators to deploy fixed-mobile convergence applications such as femtocells and dual-mode handsets; fixed line and nomadic services using any access network; and voice messaging and new multimedia communication services (e.g., rich communication suite) over the 3G and 4G RAN. This transformation is nascent, and the most dramatic and transformative of the user experience.
3. Core network. SIP enables a streamlined routing architecture with powerful centralized databases and agile routing proxies for all on-net and off-net traffic routing. A SIP session routing environment enables transcoder-free operation between MSCs, improving voice quality through reduced latency and conversions while reducing transport and infrastructure costs.
The SIP evolution is affecting older next-generation network infrastructure. Thanks to the rise of SIP session routing, ENUM for route resolution, IP interconnects and high-performance routing databases, Class 4 softswitches are becoming relegated to controlling media gateways and are slowly approaching the end of a useful life. With more traffic originating as VoIP and destined for another VoIP network or subscriber, the need to convert to TDM is diminishing rapidly. All these factors will hasten the decline of the traditional VoIP class 4/tandem softswitch (if TDM is legacy, VoIP class 4 is legacy part two). RCS services and mobile VoIP will also accelerate the transition to IP interconnects.
As the evolution to SIP takes shape, mobile service providers have begun taking innovative approaches, including:
–A top 5 mobile service provider streamlines its routing architecture and reduces its interconnect costs by millions of dollars per month in part by dramatically reducing the number of interconnections from over 1,000 DS3s to only a few dozen 10-Gigabit Ethernet ports.
–Vodafone Portugal uses IMS to offer fixed line services, opening up a new market and revenue opportunities.
–A tier-one U.S. mobile service provider pushes farther into the home with fixed SIP-based endpoints versus reusing legacy infrastructure, thereby lowering costs; at the same time, the company is moving to IP interconnects to lower PSTN termination costs.
–TIGO Bolivia reduced congestion at its international interconnect border and uncovered new international long distance revenue.
–Cricket Wireless lowered operating costs and accelerated its time-to-market with VoIP interconnects for off-net origination and termination.
Another beacon for mobile service providers navigating the SIP evolution is Telef