Journal of Network and Systems Management, Vol. 3, No. 1. 1995
Guest Editorial
Structured Approach to Network Management: Is TMN the Answer? S. Erfani: and V. Sahin 2
The essence of network management is the assignment and control of proper network resources, both hardware and software, to provide information movement among the end-users and/or network nodes in a timely and cost-effective manner that meets the user's performance needs and/or objectives. In addition to the need for making the network services more globally available, due to the changing multiple-vendor market, international regulations, and competing technologies, a structured approach to network management, independent of underlying services and technologies, is needed. Current trends in society, such as the distributed office, home banking, video conferencing, home entertainment, distant learning, and telecommuting, are creating new computing applications and communications requirements that necessitate more effective management of communications and computing resources. The combined flexibility and capabilities of SONET, ATM, wireless technology, and photonic switching opens the way to the introduction of new commercial services such as HDTV, cellular communications and Personal Communication Services (PCS), Internet, and multimedia communications. We are witnessing more advancements in these areas everyday. Accordingly, network management has become a predominant subject of interest for network and service providers, suppliers, users, and regulatory bodies engaged in communication and computing disciplines. The overall result is that network management schemes cannot afford to be locally optimized toward a particular application; they should, instead, supply a global structure to achieve the interconnection of various Network Management Systems (NMSs) and telecommunications equipment. IAT&T Bell Laboratories, Room 4F-233, 200 Laurel Ave., Middletown, New Jersey 07748. (E-mail:
[email protected]). 2NEC America, Inc., 14040 Park Center Road, Hemdon, Virginia 22071. (E-mail:
[email protected]). 3 I064-7570/95/0300-0003507.50/09 1995 Ptenum PublishingCorporation
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How is a global network made up of diverse components and providing diverse services going to be managed? This is an old question--one which continues to be important, relevant, timely, interesting, and challenging--but we might have a new answer in store: Telecommunications Management Network (TMN). Fortunately, the same technologies that create the service needs provide the opportunity to develop new approaches to network management and control functions. These functions can be viewed as software-based applications distributed over multiple nodes of a network with well-defined architectures, standardized interfaces, and protocol sets called TMN. TMN, established by ITUT, attempts to unify Operations, Administration, Maintenance and Provisioning (OAM&P) for complex and evolving communication networks, independent of their highly diversified network components. TMN identifies a set of functions to manage telecommunication networks and services, and is functionally a separate network from the network that it manages. In fact, ITU-T Recommendation M.3010 describes TMN as " . . . conceptually a separate network that interfaces to one or more individual telecommunications networks at several points in order to send or receive information to or from them and control their operations." This special issue was commissioned by the Editor-in-chief, Manu Malek, almost one and half years ago, when a world-wide reaching creed of global network services was declared by major network providers and operators. At that time the potential benefits of the TMN approach were being appreciated by telecommunication carriers who offered network services and were involved in global network management. The common wisdom has been to adopt the TMN guidelines for the emerging services and start-up telecommunications networks. In other words, if the old network cannot be saved, let us at least spare the new ventures. Papers in this issue reflect an international perspective on realization and implementation of TMN. Larry Bernstein in his Thresholds column argues that a fundamental aspect of TMN will be in its underlying software platform and its reliability. He considers software reliability a key to TMN success. This is a very different, and yet, valid view of TMN. Admittedly, TMN should aim for standardized high quality, reliable, and testable software components for its functional blocks. The leading article in this issue, " A n Introduction to T M N , " provides a historical perspective and overview of TMN as a hierarchical integration of management systems. We have chosen this paper because we believe that to appreciate TMN, from the structural and also from the practical point of view, is to start from the history leading to its development. There has been great progress since launching the first international effort to develop standards for management of telecommunication networks in 1985. Managing the global network is becoming a wider concept and it will be more so in the future demand-
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ing more standards as well as more functions, objects, and messages. This is obvious to anyone who has wandered through a spider web of ITU-T recommendations. Kirk Shrewsbury in this article guides the reader through these interrelated documents. Eventually, he advocates adherence to OMNIPoint requirements for conformance and interoperability among different network management administrations. The author concludes that with the TMN recommendations and OMNIPoint requirements in place, we can achieve a practical method of interoperability of NMSs in a multi-vendor environment as well as in a multiple administrations environment. Optimal allocation of functionalities among TMN functional layers as well as the distribution of Operations System Function (OSF) blocks have raised some implementation issues. These challenging problems have been addressed by Charles Byme et al. in the second paper, Realizing a TMN. They propose some extensions to the existing functions in addition to a further breakdown of current functions dealing with the Element Layer (EL) in order to allocate them between the Network Management Layer (NML) and Element Management Layer (EML). The authors also report on progress made in implementing TMN in a distributed processing environment. The intent of TMN has not been to serve as an implementation specification, a basis for appraising the conformance of actual implementations, nor to provide a sufficient level of detail to define precisely the services of functional layers. Nonetheless, these implementation issues are natural outcomes of TMN realizations, and will continue to exist until the industry agrees on a TMN Implementation Reference Model (TMN IRM) including allocation (or distribution) of TMN functions among Operations Systems, Subnetwork Controllers, and Network Elements. The third paper, Implementation of a CMIP-based Network Management System, by Jung Tjong discusses the experiences of NYNEX in incorporating the TMN concepts into an NMS developed to manage a network of ATM switches with CMIP interfaces, as well as a legacy switching platform supporting both a proprietary interface and SNMP. The author shares some of his frustration in finding out that even at the CMIP protocol-level, multi-vendor interoperability is yet to be achieved, let alone interoperability at the managed object-level. He is not alone when he draws attention to difficulties that one may face in making Application Programming Interfaces (APIs), mostly written in C language, to work within an object-oriented environment like a TMN network. Indeed, this is part of a bigger issue pointing to the incompatibilities in software and programming requirements used in the computing environment and in the telecommunication. The integrated management of distributed computing and data networking environments and the related issues of the interprocess protocols are being worked out by the newly-formed Association for the Integration of Management Systems (AIMS). The fourth paper by Schneider and Donnelly picks up on the interfacing issue by expanding on the role of the " X interface" within an inter-domain
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TMN architecture supporting end-to-end communication management. It focuses on the important issues that need to be addressed for the definition and realization of " X interfaces." The authors report on their experience with the implementation of this interface in the European project PREPARE. They justifiably argue that the creation and management of emerging services will no longer be the responsibility of a single administration, but rather require the cooperation of all parties involved. Therefore, the " X interface" is a key to the creation and end-to-end management of such services. Although TMN architectures represent a good foundation for realizing the appropriate management platforms, additional concepts are needed to integrate telecommunication and enterprise network management functions in an open environment. This is the subject of the last paper in this issue by Micheal Tschichholz et al. who investigate the information aspects of the integrated management networks, services, systems, and databases for the purpose of enterprise management. This paper distinguishes between the management information required locally and the information needed for inter-domain management. This subject is so important that, Doug Zuckerman, the former chair of the IEEE Communications Society's Committee on Network Operations and Management (CNOM), is leading another effort to establish the new technical Committee on Enterprise Networking to bring these disciplines to closure within the IEEE Communications Society. Finally, Phil Johnson reports on current standards activities for TMN and he proclaims a need for their refocusing. He justifies that the new focus should be on enhancements of the functional architecture and management applications. This brings us to the point that one may pause and ask " I f the network providers and operators follow the TMN guidelines and the proposed DCE/ DME model of OSF, as well as the CAE environment of X/Open, and adhere to standard specifications by O M N I P o i n t and X/Open at all conceivable levels and realized interfaces, can they create and uniformly introduce and support a myriad of services and features?" The question may remain unanswered, at least as long as there remain network designers and managers who believe " . . . in the NMS w o r d , there are too many great ideas, but not a single good solution!" We are inclined to answer the question with firm agreement, although, it is hard to pin down. We also think that in the last ten years, enough time has been spent both on management of technology and physical entities and equipment, and on interworking at the protocol-stack level. Now it is time to refocus our efforts and redirect our resources: - - from technology and physical (or network) management to service management, and - - from protocol-level interworking to application-level interworking; i.e., above the protocol stack, communication platforms, and APIs.
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E n d - t o - e n d s e r v i c e m a n a g e m e n t will not be p o s s i b l e unless applications to m a n a g e e m e r g i n g t e c h n o l o g i e s such as S O N E T , A T M , W i r e l e s s , e t c . , c o m m u n i c a t e and i n t e r w o r k with each other. F u r t h e r m o r e , applications that support different T M N m a n a g e m e n t f u n c t i o n s such as fault m a n a g e m e n t , configuration m a n a g e m e n t , and security m a n a g e m e n t m u s t also i n t e r w o r k with e a c h o t h e r to offer e n h a n c e d n e t w o r k services such as v i d e o - o n - d e m a n d , c u s t o m e r control, and b a n d w i d t h m a n a g e m e n t , to i m p r o v e the quality o f service, and to reduce service p r o v i s i o n i n g time. W e wish to thank all the authors and r e v i e w e r s w h o h e l p e d us put t o g e t h e r this special issue. It is e x p e c t e d that the articles presented in this issue will, in s o m e small w a y , shed light on o u r w a y in T M N world and p a v e the road for a s m o o t h e r ride ahead. A s guest-editors, w e h o p e so; as r e s e a r c h - e n g i n e e r s , w e k n o w so. Please read, e n j o y , and think on the T M N future o u t l o o k and m a k e us aware!
Shervin Erfani is an alumnus of the University of Teheran, where he received his M.S. degree in 1971, and the Southern Methodist University in Dallas, Texas. where he received the M.S. and Ph.D. degrees in Electrical Engineering in 1974 and 1976, respectively. He also studied Operations Research at Stanford University. He has been a Member of Technical Staff at AT&T Bell Laboratories since June 1985, and has been engaged in a variety of projects including network management planning for global and domestic services, packet network design, traffic network engineering, and expert system applications in network operations and management. Prior to joining AT&T, he taught and conducted research at the National University of Iran, Iranian Naval Academy, the Swiss Federal Institute of Technology, and the University of Michigan-Dearborn. He was an AT&T Visiting Professor at the University of Puerto Rico, Mayaguez, Puerto Rico, from 1992 to 1993. Dr. Erfani has authored or coauthored a number of technical papers in the areas of communications and digital signal processing, and he has translated two textbooks. He is a member of Tau Beta Pi, Eta Kappa Nu, and the New York Academy of Sciences, and is currently serving as an associate editor for International Journal of Computers & Electrical Engineering, and Journal of Network and Systems Management.
Veli Sahin was born in Elazig, Turkey, in 1953. He received the B.S. degree in electronics and communications engineering from the Technical University of Istanbul, Turkey, in 1975 and the M.S. degree in computer science, the M.S. degree in electrical engineering, and Ph.D. degree in computer science from the Polytechnic Institute of New York, Brooklyn, in 1978, 1980, and 1981, respeotively. He is currently Director of Network Product Planning Department in the Advanced Product Division at NEC America, Inc. Herndon, Virginia. He joined NEC America in March 1990 as a manager of Network Products, and was promoted to his current position in July 1991. He is responsible for end-to-end integrated network technology/architecture modeling and analysis, product proposals and specifications for both transport and network management products, subnetwork management, platforms, management and internetworking requirements for new technologies and services including ATM, VoD, multimedia, FITH/C, PCN. He was with Bell Laboratories, Holmdel and Bellcore, Red Bank, New Jersey, from 1981 to March 1990, where he worked on digital network synchronization, specifications of digital switching and transmission
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network elements, irttegrated network architectures, packet switching technology analysis and applications, OSI protocols, internetworking, TMN implementation architectures and applications, and Regional Bell Operating Companies network management architecture, functions and features. Dr. Sahin is the author of over 60 publications, and co-author of the book Network Management into the 21st Century. Currently, he is the Technical Program Chair for the IEEE ComSoc CNOM, Network Management Area Editor for the IEEE/ACM Transactions on Networking, Technical Program Committee (TPC) member for DSOM '95, ISINM '95, and organizing committee member for NOMS '96. Dr. Sahin was the TPC chair for the First SONET Symposium in 1989, TPC member for INFOCOM (88/89), NOMS (88-94), KTIS '93, ISINM '93, DSOM '94, and SUPERCOMM/ICC '94, in addition to giving tutorials as an invited speaker.
