Leverage AdvancedTCA To Optimize IMS

May 24, 2007
Move from proprietary to commercial-off-the-shelf components to build next-generation IP networks.

Until recently, telecommunications equipment manufacturers (TEMs) kept major platform design "close to home" via in-house development of proprietary system components. Later, TEMs started to grapple with the proprietary "make versus buy" decision, weighing the pros and cons of producing such components in-house as opposed to purchasing third-party offerings. Today, TEMs aren't hesitating to "leave home" to enjoy the clear time-to-market and cost benefits provided by non-proprietary, standards-based commercial off-the-shelf (COTS) components—wherever and whenever possible.

IP Multimedia Subsystem (IMS) and AdvancedTCA (ATCA)— two emerging telecom architectures gaining wide industry acceptance—are key drivers in the move to open, standards-based COTS products. At the same time, ATCA-based COTS components are ideally suited for IMS deployment, especially when TEMs can leverage the advantages of common building blocks across multiple network elements.

In this article, we'll examine how the capabilities of IMS and ATCA individually are impacting the telecom infrastructure market. Next, we'll consider how TEMS can share COTS components across multiple IMS network elements and best leverage the ATCA ecosystem. Finally, we'll explore how flexible ATCA-based COTS components deliver tangible benefits to communications service providers (CSPs) and TEMs alike.

IMS is a standardized next-generation network (NGN) architecture for CSPs that want to offer converged wireless and fixed multimedia services. Using a Voice-over-IP (VoIP) implementation based on a 3GPP standardized implementation of the session initiation protocol (SIP), IMS runs over the standard Internet Protocol (IP).

Existing phone systems (both packet and circuit-switched) are supported, and users can access all services from their home networks or while roaming. Helping to merge the cellular and Internet worlds, IMS uses mobile technologies to provide ubiquitous "anytime, anywhere" access and IP technologies to deliver compelling triple-play services.

A key driving force behind the move to IMS is the need for service providers to offer an array of services over diverse network and terminal types. Examples of compelling IP-based services include VoIP, push-to-talk over cellular (POC), videoconferencing, multiparty gaming, and content sharing. Subscribers eventually will be able to use the terminal of their choice (wireline, mobile, or IP) based on convenience and personal preference, as well as instantly switch between voice, data, and video modes.

IMS networks offer a number of technical and business advantages to CSPs. Promoting network resource sharing due to its horizontal services architecture, IMS reduces capital expenditures and streamlines resource usage and maintenance. Since the core network is independent of any particular access technology, IMS enables easier migration of applications among fixed, mobile, and cable users. Designed for easy scalability and redundancy, the standardized IMS architecture enables faster deployment of new triple-play services.

The Advanced Telecom Computing Architecture (AdvancedTCA or ATCA) initiative, in which more than 100 companies are participating, is the largest-ever specification endeavor undertaken by the PCI Industrial Computing Manufacturers Group (PICMG).

As defined by PICMG, the ATCA specifications, denoted as PICMG 3.X, are a series of specifications targeted to meet the requirements for the next generation of carrier-grade communications equipment. The ATCA series of specifications incorporates high-speed inter-connect technologies, next-generation processors, and improved reliability, manageability, and serviceability.

One of ATCA's key drivers is the proven success of modular infrastructures in packet-based data networks. Yet communications networks maintain different success criteria, including superior performance and high availability.

ATCA addresses the demanding technical requirements for IMS network elements, including scalable capacity up to 2.5 Tbits/s, full redundancy support for "five-nine" (99.999%) availability, high computer density, rich media content and transcoding, strict regulatory conformance, and support for multiple switching fabric types. Such capabilities make ATCA the platform of choice for telecom infrastructure applications in general, and IMS network elements in particular.

The many advantages of ATCA-based COTS components enable even greater time and cost savings when they're deployed in multiple IMS network elements. For example, take an IMS network configuration with a transport plane composed of a media gateway (MGW), session border controller (SBC), and media resource function (MRF).

These three IMS network elements can share a number of key components, including an ATCA carrier board (Fig. 1). As a result, TEMs can cut down the number of inflexible, time-consuming processes (e.g., development, qualification, regulatory) from three (i.e., one for each network element) to one. And by using ATCA-based COTS products, TEMs can further drive down development time and costs.

The first, a media gateway (MGW), acts as a bridging unit between the legacy public switched telephone network (PSTN) and the VoIP network. One of its key functions is to convert between different transmission and coding techniques utilized by varying types of voice codecs.

Using the I-TDM (Intelligent Time-Division Multiplexer) protocol, MGWs connect between TDM and IP networks. This protocol allows MGWs to be implemented using ATCA by multiplexing several TDM voice and media channels into one multimedia packet for transport and storage within the platform. MGWs are important elements of IMS networks. The market for media gateways is expected to increase rapidly from $2 billion in 2005 to $6.8 billion in 2012, according to Frost & Sullivan research (2006).

A session border controller (SBC) is a session-aware device used in VoIP networks to exert control over the signaling and media streams involved in setting up, conducting, and tearing down calls. Located on the signaling and/or media path between the calling and called party, SBCs allow their owners to control the kinds of calls that can be placed through the networks on which they reside. In the case of interconnect scenarios, SBCs are located on the border dividing network operators.

Finally, a media resource function (MRF) —located at the heart of the IMS network—processes all types of media (voice, video, and data). The MRF acts as the "media server" of the IMS network, enabling CSPs to offer a wide variety of value-added services. These wide-ranging multimedia services include voice and video conferencing, interactive voice and video response (IVVR) services, voice and video messaging, and Internet Protocol TV (IPTV).

When building an ATCA-based IMS network element, TEMS must choose among a vast array of COTS components, including chassis, power supplies, host processors, network processors, switch fabrics, DSPs, and I/O cards for connecting to different networks.

As such, TEMS should avoid selecting components that can't interoperate with each other, thereby getting locked into a single-vendor solution. Such "proprietary COTS" components increase TEMs' dependence on fewer vendors within the supply chain and keep component costs high.

To enjoy the full benefits provided by COTS products in IMS networks, TEMs should leverage the open ATCA ecosystem based on standards-based interoperable components. Such components should utilize standard hardware and software interfaces, or "API-less" protocols such as SIP for multimedia processing. I-TDM-compliant components enable next-generation IMS network elements to leverage substantial past investments in legacy TDM voice and media networks.

Whenever possible, TEMs should choose pre-integrated components with field-proven interoperability. This open ATCA ecosystem approach enables "mixing and matching" of best-of-breed COTS components, empowering TEMs to build robust, cost-effective IMS systems quickly and efficiently.

An example of an ATCA-based multimedia-processing COTS component that offers distinct advantages to IMS equipment manufacturers is an Advanced Mezzanine Card (AdvancedMC or AMC) developed by Surf Communication Solutions (Fig. 2). Designed according to PICMG AMC standards, the SurfRider/AMC is a fully integrated mezzanine card that has been pre-integrated with leading ATCA and MicroTCA chassis.

This AMC DSP resource board can integrate into various types of network infrastructure equipment to enable the convergence of voice, video, and data across wireline and wireless networks (Fig. 3).

ATCA-based COTS components are extremely well-suited for IMS infrastructure deployment, especially when TEMs can leverage the advantages of common ATCA building blocks across multiple network elements. The combination of IMS architecture and open ATCA-based components delivers powerful benefits to CSPs:

  • Faster time to revenue: Integrating ATCA-based components within IMS network elements enables rapid provisioning and delivery of attractive revenue-generating services to meet evolving customer requirements.
  • Lower total cost of ownership: The reduction of proprietary parts coupled with the increase of shared COTS components across IMS network elements lowers both capital and operating costs.
  • Flexible network evolution: Network elements incorporating industry-standard platforms, such as ATCA, make the migration to an IMS network more flexible and streamlined.

This combination also offers several benefits for TEMs:

  • Decreased development costs and risk: Using cost-effective best-of-breed COTS components reduces development costs and risk.
  • Lower production and maintenance costs: Fewer parts shared across IMS network elements together with greater economies of scale drive down costs.
  • Optimized development resources: Integrating open third-party silicon and board-level components frees up developers to concentrate on TEMs' core business and high value-added applications.
  • Increased supply-chain flexibility: A broader best-of-breed supplier ecosystem reduces vendor dependency and drives down component pricing.
  • Faster time-to-market: Shorter development cycles using available COTS solutions greatly accelerate TTM.

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