Vendor Network Architectures�Part IV: Lucent Technologies

The divestiture of AT&T and the breakup of the Bell System spawned a number of new businesses – both large and small. Undoubtedly one of the largest of these is Lucent Technologies, Inc., headquartered in Murray Hill, New Jersey, and employing over 30,000 people worldwide, and with almost $10 billion in revenues in fiscal 2005. Lucent markets to three key business segments: communication service providers, government, and larger enterprises, with three lines of business: Network Solutions, Worldwide Services, and Bell Labs. The Network Solutions group focuses on network service providers, and support for wireline and wireless technologies that integrate voice, data, video and multimedia services. The Worldwide Services group includes a worldwide group of technicians, network designers, consultants and engineers that serve large organizations around the world. Bell Labs has a long history of communications technology innovation, and is focused on the communications networking needs of the U.S. Government and service providers around the world. Bell Labs engineers and scientists have been awarded over 31,000 patents since 1925, making them one of the icons of global technology.

Lucent’s current research covers many technologies, including 3G wireless, optical switching and metropolitan transport, broadband and DSL access, plus multimedia systems and applications. Their softswitch research is part of the Accelerate™ Next Generation Communications Portfolio. This architecture is based upon the IP Multimedia Subsystem (IMS) and the Session Initiation Protocol (SIP), and is focused on the service provider market.

The Lucent architecture recognizes three generations of switching systems. The first was the traditional circuit switch that included all voice services, such as signaling, call control, supplementary applications, and so on, within a single platform. The second generation, typically called the softswitch, decouples some of those traditional operations, and separates call control from media-related functions. The typical softswitch would include the media gateway, media gateway controller, call control agent, and applications servers that we have discussed in previous tutorials. The third generation provides for the integration of mobile and fixed networks, with the IP Multimedia System (IMS) that was developed by the 3rd Generation Partnership Project (3GPP). This latest generation is based upon the Session Initiation Protocol (SIP), and further partitions the call control functions into session control and application control operations.

Lucent, with a focus toward service providers, has developed a migration path from the current softswitch environments to the IMS architecture, which gives the providers greater deployment flexibility and additional capital expenditure oversights. Thus, multimedia services can be provided to the end users in the short term, with an orderly migration to the 3GPP IMS architecture in the longer term.

The Lucent softswitch service architecture includes: the Lucent Network Gateway, which bridges traditional circuit networks with next-generation packet networks; the Lucent Network Controller which provides media gateway and signaling gateway functions; the Lucent Feature Server, which allows the carrier to deliver both new and traditional telephony services to wireline, wireless, IP or SIP subscribers; and the Lucent Communication Manager, which is an end user graphical tool for access to telephony features and applications. The Lucent IMS service architecture adds the Lucent Session Manager, a specialized SIP server which provides communication session setup, tear-down, coordination and media mixing functions; the Lucent Unified Subscriber Data Server, which provides Home Location Record (HLR), Home Subscriber Server (HSS), authentication, authorization and accounting services; and the Lucent Operation and Maintenance Center, which supports the International Telecommunication Union (ITU) Telecommunication Management Network (TMN) network management framework, delivering fault, configuration, accounting, performance, and security management functions.

Lucent has therefore positioned their product line as an evolutionary migration for the service provider community, with single network support for analog, VoIP, and mobile end users, from either H.323 and SIP endpoints. Further details on the Lucent architecture and products can be found at Our next tutorial will continue our examination of vendors’ softswitch architectures.

Copyright Acknowledgement: © 2005 DigiNet ® Corporation, All Rights Reserved

Author’s Biography
Mark A. Miller, P.E. is President of DigiNet ® Corporation, a Denver-based consulting engineering firm. He is the author of many books on networking technologies, including Voice over IP Technologies, and Internet Technologies Handbook, both published by John Wiley & Sons.

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