IMS and NGN Forum
In cooperation with the University of New Hampshire InterOperability Lab
November 2008
Executive Summary
This document seeks to dispel confusion and misinformation regarding the IP Multimedia Subsystem (IMS) and Next Generation Network (NGN) migration strategies and to present a true testament from our unique vantage point as to the readiness of the technology. Despite a flood of conflicting information about IMS, much has been done to demonstrate its practical realities. Vendors from around the world have come together at the IMS NGN Forum's IMS Plugfest interoperability events and have built IMS networks with real applications running over them in a matter of days.
By its nature, IMS demands interoperability in a way that the PSTN never did. This involves interoperability between new components and also with legacy networks. The access agnostic nature of the specification makes it one of the most ambitious and comprehensive standardization efforts to date specifically addressing the evolution to next-generation telecom infrastructures. Although an all-IP platform at first may appear more complicated, IP networks make it easier to create, add, manage, bill for, and modify multiple services across various platforms and access technologies. As was the case with the Internet and VoIP, IMS is evolving and maturing beyond its early hype and is now in the process of being deployed in various forms in carrier networks around the world.
Introduction
The IMS architecture was one of the most hyped developments within the networking industry throughout 2006 and 2007, but the technology became "real" in 2008. Early, conflicting information from some vendors and service providers, both in favor of and against, distorted the understanding of IMS. Proprietary IMS architectures created the illusion of inherent interoperability, reliability, or availability problems in IMS-based services, while numerous companies claimed IMS capabilities for products that delivered little or nothing new.
IMS provides a standards-based approach for deploying multiple NGN and mobile IP services over a common architecture. The coming year (2009) promises a strong push toward, if not actual deployment of, carrier-branded and bundled services over NGN technologies driven by the practical success of IMS architectures.
Proponents thus see IMS as an open and practical standards-based blueprint for IP-enabling the carriers. For example, carriers providing video over IP could use IMS to easily deliver branded IPTV or related services regardless of the customer's location and access device. IMS's ability to measure IP streams, provide QoS, and utilize service intelligence allows the network to know what services to supply and how much bandwidth to use based on who is requesting them and whether the customer is watching IPTV in their living room or opening a video chat on a smart phone far from home.
Despite the lack of consensus, most service providers have begun either exploring or deploying IMS architectures of various stripes in staging as well as working networks. RFPs are being generated, roll-outs are being scoped, and IMS is delivering on its promise of a cost-effective common platform for delivering converged IP services over wireline, cable, DSL, GSM, UMTS, 3G, Wi-Fi and WiMAX networks.
Objections to the IMS architecture on the grounds of its lack of interoperability, its immaturity, or its complexity are no longer tenable. Work is ongoing to port additional standards and protocols, such as IPTV. Operators are making slow and steady progress toward simplifying their network architecture to all-IP based routers and soft switches. Meanwhile, the true benefits and the business case for IMS are only now beginning to become clear.
It is one of the missions of the IMS/NGN Forum to seek and find common ground, those intersections that are common to most carriers. Proprietary enterprise solutions and carrier back-office systems that are unique to each service provider are at the moment beyond the scope of the IMS/NGN Forum's activity. These back-office systems will need to be integrated and tested against IMS interfaces for example, and the process will be different for every service provider. It should be pointed out that this is no different from other technologies that service providers have had to integrate over time, as in the evolution to softswitching and VoIP technologies. IMS by itself poses no significant new challenges in this regard and in fact is almost entirely based upon SIP, the VoIP handshake protocol used in networks the world over.
The purpose of the IMS Report Card is to provide factual information based on the IMS Plugfests to clarify the state of IMS as a technology.
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