Network management: Emerging trends and challenges

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Bell Labs Technical Journal OctoberDecember 1999 3IntroductionBell Labs has played a historical role in bringingreliability and dependability to the telecommunica-tions infrastructure of the 20th century. A key compo-nent of this possibly unique capability is anunderstanding of the systems employed to managethese networks and services. The current challengefacing Bell Labs is to effectively harness this expertiseto bring public switched telephone network (PSTN)-level reliability and dependability to data networksand services of today and tomorrow. This issue of theBell Labs Technical Journal is devoted to bringing wideexposure to the ongoing work in network managementin Bell Labs and Lucent Technologies business units. This paper is organized as follows. In the sectionimmediately below, we describe the evolution of net-work management and the role of network manage-ment functions. The section following it provides thekey components of a network management system(NMS) and lays a foundation for understanding thepapers in the issue. The next section, The NetworkEnvironment: Then, Now, and in the Future, pre-sents an overview of the current trends in networkingand services that have strong implications for therequirements of a management system. Subsequently,A Practical Vision for Managing Networks delvesinto the management requirements induced by thenetworking trends mentioned in the previous sectionand thereby motivates the work described in thisissue. The last major section, A Snapshot of Trendsand Techniques, provides a short summary of thepapers in this issue.Evolution of Network ManagementTelecommunication and services are in theprocess of revolutionary yet evolutionary changes dueto transformation of the regulatory environment thatin turn has given rise to rapid improvements in theunderlying application, networking, computing, and Network Management: Emerging Trends andChallengesShervin Erfani, Victor B. Lawrence, Manu Malek, and Binay SuglaNetwork management is arguably one of the most important challenges faced bythe owners and operators of advanced networks and services. Lucent Technologies,as a major equipment vendor, and Bell Labs, as its R&D arm, have had extensive his-torical experience with designing network management systems for AT&T telecom-munication networks and other associated data networks. This experience enablesLucent to provide unique differentiation to its products and also places it in an excel-lent position to address the network management needs and challenges of theemerging networks and services. This issue of the Bell Labs Technical Journal pro-vides a sample of some of the many the activities, tools, technology trends, anddesigns currently under way in network management in various wings of Lucent.This paper, an introduction to the issue, discusses the evolution of network manage-ment, placing it in the context of underlying networking trends. In addition, it pro-vides a brief introduction to the papers presented in this issue, which togetherprovide a snapshot of Lucents network management activities in support of an efficient, reliable, and flexible networking vision. Copyright 1999. Lucent Technologies Inc.. All Rights Reserved.4 Bell Labs Technical Journal u OctoberDecember 1999transmission technologies. Lucent is supplying serviceproviders with a variety of switching and transporttechnologies capable of delivering voice and high-speed data services. With these changes, networkoperators will soon require next-generation networkmanagement applications that deliver rich automatedfunctionality capable of responding at high speeds, yetflexible enough to rapidly accommodate services thatwill be introduced.The purpose of network management is theassignment and control of proper network resources,both hardware and software, to address service perfor-mance needs and the networks objectives. With theever-increasing size and complexity of underlying net-works and services, it has become impossible to carryout these functions without the support of automatedtools. The progress in network management reflectsthe needs driven by these trends.The evolution of network management is shownin Figure 1. Prior to the 1980s, network managementwas largely proprietary and, due to high developmentcosts, it was considered affordable by only a few verylarge telecommunication carriers. Several develop-ments in the 1980s caused a significant diffusion ofPanel 1. Abbreviations, Acronyms, and TermsAALATM adaptation layerADSLasymmetric DSLATMasynchronous transfer modeB-ISDNbroadband ISDNCATVcommunity antenna televisionCIMcommon information modelCMIPcommon management information protocolCMISEcommon management information service elementCORBA*Common Object Request BrokerArchitectureDENdirectory enabled networkDiffServdifferentiated servicesDSLdigital subscriber lineDMTFDistributed Management Task ForceDWDMdense wavelength division multiplexingEMSelement management systemFCAPSfault, configuration, accounting, performance, and securityGDMOguidelines for the definition of managedobjectsHDSLhigh bit-rate DSLHFChybrid fiber coaxIDLInterface Definition Language*IETFInternet Engineering Task ForceIPInternet protocolISDNintegrated services digital networkITSInternet telephony serverITU-TInternational Telecommunication UnionTelecommunication Standardization SectorLANlocal area networkLDAPlightweight directory access protocolMCNmanagement communications networkMIBmanagement information baseMPLSmultiprotocol label switchingMUXmultiplexerNMSnetwork management systemNMSnetwork management systemNNInetwork-to-network interfaceOAM&Poperations, administration, maintenance, and provisioningONUoptical network unitORBobject request brokerOSoperations systemPONpassive optical networkPOTSplain old telephone servicePSTNpublic switched telephone networkQoSquality of serviceRFCRequest for CommentsRMONremote monitoringRSVPresource reservation protocolRTPreal time protocolSDHsynchronous digital hierarchySLAservice level agreementSMIstructure of management informationSMKshared management knowledgeSMONswitch monitoringSNMPsimple network management protocolSONETsynchronous optical networkSS7Signaling System 7STMsynchronous transfer modeSVCswitched virtual circuitTCPtransfer control protocolTDMtime division multiplexed/multiplexingTDMtime division multiplexing/multiplexedUDPuser datagram protocolVDSLvery high bit-rate DSLxDSLany of various DSL modem technologiesBell Labs Technical Journal u OctoberDecember 1999 5network management technologies. Standards likesimple network management protocol (SNMP)1 andcommon management information protocol(CMIP)/common management information serviceelement (CMISE)2,3 paved the way for a standardizedmethod of communicating with the managed networkelements, while platforms like OpenView* obviatedthe need to develop several core custom modulesrequired in a network management system. By imple-menting a suite of integrated common software mod-ules for topology discovery, map manipulation, drill-down viewing, and database support, these platformsreduced the cost of owning a network managementsystem by an order of magnitude. However, the man-agement functionality still remained in its primitiveform, requiring network managers to observe andinterpret raw variables manually. Given the number ofvariables per managed element and the typically largenumber of managed elements, there was a drivingneed for tools that provided higher levels of function-ality at higher levels of abstraction.Thus, the decade of the 1990s has been devoted tothe realization that the only feasible way to managelarge and increasingly complex networks is to deviseinnovative management applications for all aspects ofmanagement. Consequently, a number of automatedmanagement applications that perform advancedmonitoring functions and attempt to provide an end-to-end network-service-level view of the networkhave been built. However, management at the net-work level is still insufficient, and there is a strongneed to design and implement management applica-tions that address the service level. The current focuson service level agreements (SLAs) is a precursor tothis trend. (It may be noted that the AT&T long dis-tance telephony network that was supported by BellLabs had managed applications that operated at theservice level and performed both monitoring andmanagement applications that required control of thenetwork elements. However, these applications wereproprietary and assumed a single vendor solution.) The general lack of effective, automated manage-ment applications has given rise to an important andfast-growing business opportunitynetwork manage-ment service providers, like Lucents NetcareNetwork Management Services.4 These network man-Proprietary,elementmanagementSNMP enabled,networkmanagementServicemanagementManualMonitoringonlyControl197919881989199819992008SNMP Simple network management protocolFigure 1. Evolution of network management.6 Bell Labs Technical Journal u OctoberDecember 1999agement service providers serve a very useful functionof offloading management tasks from enterprises andnetwork providers who either lack the skilled staff tomanage their own networks or would like to reducethe cost of management.Network Management FunctionsThough this issue of the Bell Labs Technical Journaltakes a broader, more popular view of the meaning ofthe term network management to include aspects of ele-ment and service management, network managementis, strictly speaking, only one layer of the managementsystems hierarchy.Figure 2 shows this hierarchical, layeredapproach for partitioning and organizing managementactivities and tasks, which is aligned with managementprocesses.5 The layers recognize that the managementof a telecommunications network service providermust deal with network elements, networks, services,and business issues. These five layers from the topdown are: Business management layer, Service management layer, Network management layer, Element management layer, and Network element layer.The layers are logical; they do not need to corre-late with any physical implementation. The organiza-tion of management tasks is service-based in the sensethat it will allow a specific service-management-layeritem to become traceable to its correspondingrequired tasks at the network management layer allthe way down to the network element layer. The phi-losophy is that the business requirements are the dri-vers for all management issues. A particular businessgoal dictates a specific set of requirements on theunderlying service management layer, which in turndictates the requirements for integration and interop-erability on the underlying network managementlayer. At the lower layers, activities affect physicalresources; at the higher layers, they affect relativelyabstract entities and processes like SLAs. Thus, imple-mentation occurs in the reverse order. The upper fourlayers distinguish management functions. The lowestlayer (the network element layer) represents themanagement view provided by the network resources(either hardware or software).Business management layer Goal setting, finance, budgeting Planning, product definitionService management layer Customer contact and interface Quality of service Interaction between servicesNetwork management layer Connectivity among nodes Network control and coordination Network statistical log and eventsElement management layer Control of subsets of network elements Gateway access to network elements Maintenance of statistical log and eventsNetwork element layer Implementation of management commands Detection of problemsFigure 2. Network management layers.Bell Labs Technical Journal u OctoberDecember 1999 7Similarly, the required tasks of each managementlayer can be categorized into the following five man-agement functional areas: fault, configuration, account-ing, performance, and security (FCAPS).6 Thesemanagement areas distinguish functions by the kindsof activities they perform. The management functionalareas and organizational layers are orthogonal (mutu-ally independent) classification schemes. For example,fault management, when applied to the network man-agement layer, includes the functions that deal withanalysis of alarms from all the network elementswithin a given network in order to localize the faultwhen functions at the element management layerhave been unable to do so within a particular networkelement and/or limited subnet of network elements.In practice, there can be many element manage-ment systems (EMSs) and network management sys-tems (NMSs) for implementing managementfunctions in each layer, which communicate withfunctions in other layerstypically the layers directlyabove or below the layer in question. The EMSs andNMSs manage a set of network elements or a subnet,respectivelythat is, a domain, may have inter-domaincommunications.The characteristics of inter-layer communicationsbetween management functions are: Lower layers are managed by upper layers. Each layer manages multiple occurrences ofthe layer directly below. Each layer uses network management func-tions/services of lower layers. An FCAPS application in a layer may communi-cate with other FCAPS applications in the samelayer (for example, synchronous optical net-work (SONET) applications may talk to asyn-chronous transfer mode (ATM) applications).This architectural picture has been hard to trans-late in practice due to the inherent technical difficultiesand costs of development.Key Components of a Network ManagementSystemThe key constituents of a network managementsystem are best understood by considering the relation-ship between the manager and the management agentresiding on the management element, as shown inFigure 3. Given the diversity of managed elements likeservers, routers, switches, and the wide variety of oper-ApplicationInstrumentationProcessingAccessibleinformation(MIB)AgentLocal managementand controlAccess mechanismsand protocols(SNMP/CMIP)DataprocessingUserinterface,graphics,andvisualizationInterpretationand modelsManaged element ManagerCMIP Common management information protocolMIB Management information baseSNMP Simple network management protocolFigure 3. Manager-agent model.8 Bell Labs Technical Journal u OctoberDecember 1999ating systems and programming interfaces, it is criticalthat the manager be able to communicate in a mean-ingful way with the managed element. This is done viathe notion of an agent that not only can understandthe communication protocol, but also can organizeinformation in a consistent way so that both the man-ager and agent can refer to the same informationalentity without ambiguity. Standardized communica-tion protocols like SNMP or CMIP/CMISE along withassociated information modelsstructure of manage-ment information (SMI) for SNMP and object-basedmodels for CMIP/CMISEare used for this purpose.Management Information and Knowledge StructureManagement information models are abstractionsof the network resources. They define the structuresand contents of management information that themanagement functions act upon. A managementinformation model provides a common characteriza-tion of the network resources, enables multiple man-agement functions to interact with each other, andsupports different management functions.Management information is exchanged among man-agement systems where management functions areimplemented.Attaining interoperability of network manage-ment systems and a common view of managedresources in a managed network environmentrequires that information models comply with stan-dard models (or be able to map to standard models viaproxy translations).7 The management functions cur-rently exchange management information by meansof techniques defined in the ITU-T X.700 series of rec-ommendations.2,3,6,8-10 These recommendationsincorporate the important object-oriented and man-ager/agent paradigms for information modeling.The object-oriented approach for informationexchange allows for grouping of data and the exe-cutable operations to be fully encapsulated into anobject and object properties to be extended throughinheritance. The data can be manipulated only viathe access operations provided in the object. The guide-lines for the definition of managed objects (GDMO),ITU-T Recommendation X.722,10 allow for a commondata structure for managed objects in the managed andmanaging systems. Managed objects include theirnames, attributes, operations that can be performed onattributes, notifications that objects can emit, andbehavioral descriptions of the objects. By using GDMO,any attribute, operation, notification, and behaviorexposed by managed objects, as well as inheritance andcontainment relationships among managed objects andmanaged object classes, can be defined.The manager/agent paradigm allows for hierarchi-cal exchange of management information betweenfunctions (see Figure 3). A managing system assumesthe role of manager for the purpose of issuing direc-tives and receiving notifications, and a managed sys-tem assumes the role of agent for the purpose ofcarrying out directives and emitting notifications. Thisconcept is well in line with the layered approach to thenetwork management discipline. A system that man-ages a lower-level system may simultaneously bemanaged by a higher-level system, allowing for a cas-caded management hierarchy. The communicating management functions mustshare a common view of the available managementinformation as well as a common understanding of thescope of management operations. This is referred to asshared management knowledge (SMK).11 SMK com-prises all data, information, and services that enableand support the management of a network. The mostimportant concepts of SMK are: Integrated naming and addressing schemes forobjects, which allow for both human andmachine readability; Object classes, which allow for extensions tonew services/technologies; Object attributes/services, which allow for ven-dor extensions and options; and Manager/agent/object relationships, whichallow for data abstraction at upper layers. The conceptual repository for management infor-mation is called the management information base(MIB).10 A MIB is defined as a structured collection ofmanaged object classes organized according to a man-agement information model. Conceptually, specificdomain MIBs can be constructed to include manage-ment information concerning data networks, telecom-munication networks, and connected systems as wellas application- and service-related databases. EachBell Labs Technical Journal u OctoberDecember 1999 9MIB presents its own object groups defined for thecorresponding application. For example, more than ahundred standards-based MIB modules are defined bya number of different Internet Engineering Task Force(IETF) Requests for Comments (RFCs).Management Information Exchange ProtocolsCommunicating functions in each managementfunctional layer use network management protocolsand message sets for transferring information betweenthemselves and for triggering actions in other layers(usually, in adjacent layers). The manager and agentare linked by a network management protocol. Formanagement of telecommunication networks, themanagement information exchange is based on CMIP.Nevertheless, because of its complexity and the slow-ness of industry deployment of CMIP chip implemen-tations, alternatives to CMIP have arisen. AlthoughCMIP can in theory be used as a general-purpose dis-tributed computing facility, it is still immature in prac-tice, lacking in software development support. As analternative, Common Object Request BrokerArchitecture (CORBA*), which offers both a commu-nication and computing facility, can be used.The protocol used for management of data net-works in a transfer control protocol (TCP)/Internetprotocol (IP) environment is simple network manage-ment protocol (SNMP),1 which is now expressing itslegitimacy. From the telecommunications networkpoint of view, CMIP provides a flexible template incommunicating messages between manager andagent, which incorporates the needed aspects of theinformation model within a GDMO template.However, the convergence of voice and data networksrequires blending the customer environment ofSNMP-based management with the service providersmore complex environment. The complexity oftelecommunications carrier networks requires com-plete management solutions to support the networkelements, end-to-end layer networks, and subscriber-oriented services. In contrast, in an enterprise networkenvironment, a total solution encompassing the net-work device management and high-level user servicemanagement can be achieved using the SNMP-basedframework. The strength of SNMP is its simplicity.However, simplicity does not come without deficien-cies. Because SNMP relies on user datagram protocol(UDP), which is a connectionless protocol, SNMP isitself connectionless. No ongoing connections aremaintained between a manager and its agents.Clearly, in an integrated network managementenvironment, protocol conversions between SNMPand proprietary solutions or between SNMP and CMIPstacks are needed. The use of protocol adapters haslong been promoted.The Network Environment: Then, Now, and in theFutureTraditionally, there have been two different mar-ket segments, voice and data, with differing character-istics and requirements. Two distinct networks, thePSTN and the Internet, have existed for voice and datatraffic. For voice communications, the sequenceddelivery of voice samples with latency less than a fewhundred milliseconds is essential, but absolute dataintegrity is not necessary. Under these circumstancesthe guaranteed-bandwidth, circuit-switched infrastruc-ture of PSTN was appropriate. For data networking,information integrity is paramount and the real-timetransfer of this information is of less importance. The Development of Integrated Network ArchitecturesThe wish to develop a single integrated networkarchitecture capable of accommodating all types of ser-vices was first addressed with the development of theintegrated services digital network (ISDN). ISDN,introduced in the early 1980s, was meant to providecustomers with unified access to a range of digital ser-vices offered by carriers. The limitations of ISDN dueto its channelized narrowband characteristics causedthe introduction of broadband ISDN (B-ISDN), whichrequired broadband switching and multiplexing tech-niques. By the late 1980s advances in technologymade high-bandwidth information transport networksa realistic prospect. The technology and standard toprovide this broadband switching and multiplexingcapability was ATM, where fixed-size cells are used totransport information, preferably over high-speed andjitter-free synchronous fiber transport using opticalnetwork (SONET/SDH) standards.10 Bell Labs Technical Journal u OctoberDecember 1999The Need for Higher Bandwidth and DifferentiatedServicesDeregulation and de-monopolization have causeda surge in the variety of services and information tech-nologies, resulting in the most dynamic communica-tion and computing network environment in history.The rapid growth of the Internet, as well as intranetsand extranets, has caused a tremendous need forhigher bandwidth both in the access and backbonenetworks. In addition, the relaxation of regulatoryconstraints is enabling network and service providersto offer various multimedia services with differingquality-of-service (QoS) categories. Building the high-capacity optical backbone net-work of the future relies on innovative solutions incor-porating cutting-edge technologies coupled withsound networking principles. Todays time divisionmultiplexed (TDM)-based transport networks havebeen designed to provide an assured level of perfor-mance and reliability for the predominant voice andprivate-line services. SONET/SDH has been widelydeployed in the current transport infrastructure, pro-viding high-capacity transport, scalable to gigabit-per-second rates, with excellent jitter, wander, and errorperformance for 64 kb/s voice connections and private-line applications. In contrast, the IP networks generally lack themeans to guarantee high reliability and predictableperformance. The best-effort service provided by mostpacket-based data networks, with unpredictable delay,jitter, and packet loss, is the price paid to achieve max-imum link utilization through statistical multiplexing.To overcome the shortcomings of IP networks for car-rying time-sensitive packets, such as voice, new proto-cols like real-time protocol (RTP), multiprotocol labelswitching (MPLS), resource reservation protocol(RSVP), and differentiated services (DiffServ) havebeen developed.RTP is a framing protocol that uses the basic trans-port service of UDP but adds the required sequencenumbers and timestamps to ensure ordered deliveryand timely playback of real-time voice and videostreams. RTP complies with ITU H.323 12 for voice andvideo over packet networks; as a result, it has beenwidely adopted for multimedia teleconferencing. WithMPLS, which is applicable to any network layer proto-col, the mapping from packet headers to a bit stream isperformed just once as the packet enters the net-work.13 The stream to which the packet is assigned isencoded with a short fixed-length value known as alabel. The label is used as an index into a routing table,which specifies the next hop and a new label. The oldlabel is replaced with the new label and the packet isforwarded to its next hop. This is very similar toattaching an ATM virtual circuit label to an IP packet.RSVP is an IP signaling protocol that enables thereservation of bandwidth to a particular IP destinationand includes support for multicast applications.14 RSVPis effective only if it is implemented end-to-end,including all intervening points. It ties up networkresources and has scalability issues. Furthermore, onlytwo service classescontrolled load and guaranteedserviceare defined. DiffServ is proposed as a mecha-nism to enable certain users to receive a better servicewithout the large-scale change necessitated by thewidespread deployment of RSVP. The surging demand for high-bandwidth and dif-ferentiated data services is challenging this dual archi-tecture model of TDM-based transport and best-effortpacket data networks.15Lucents View of Network R/Evolution: Network ofNetworksThe Lucent vision is to provide a network of net-works that will work together to deliver future servicesseamlessly and reliably. The elements of this vision are: One network that will be characterized by: Coexistence and convergence of data net-working and voice networking; Optical backbone networking; Multiple protocols and services support,including frame relay, IP, ATM, and virtualprivate networking; A variety of broadband access mechanisms;and Flexible bandwidth and service capabilities. Open software platforms for network and servicemanagement that will make possible: A system that greatly simplifies operationsby managing broadband pipes (rather thanindividual trunk groups);Bell Labs Technical Journal u OctoberDecember 1999 11 Lowering of OAM&P costs through a com-mon packet backbone; Utilization of topology management andflow-through provisioning techniques; Creation (operationally) of a single networkswitch; and A new style of network management basedon active directories and policy managers.To satisfy new network requirements, Lucent hasformulated a coherent strategic view of how a net-work satisfactorily delivers a full range of services tocustomers and proposed the Lucent NetworkArchitecturea data-centric optical transport networkarchitecture16as shown in Figure 4. Next-genera-tion network architectures for cost-effective, reliable,and scalable evolution will employ both transport net-working and enhanced service layers, workingtogether in a complementary and interoperable fash-ion. Building a network capable of providing QoS con-trols requires accommodation of four protocols:Internet protocol (IP), asynchronous transfer mode(ATM), synchronous transfer mode (STM) such asSONET or SDH, and dense wavelength division multi-plexing (DWDM).16Transport networking enables the service layers tooperate more effectively, freeing them from the con-straints of physical topology and allowing them tofocus on the challenge of meeting service require-ments. Hence, optical transport networking will pro-vide a unified, optimized layer of high-capacity,high-reliability bandwidth management, creating theso-called optical data networking solutions forhigher-capacity data services with guaranteed quality.In this architecture, integrated voice and data traf-fic is carried over the ATM/IP core network.Multiprotocol devices are connected via DWDM sys-tems. The optical core will evolve over time to utilizeoptical add/drop multiplexers and cross-connect sys-tems. Below is a brief description of the architecturalelements in Figure 4.ATM core network. Some public service providersare planning to use their ATM networks to supportintegrated voice and data traffic. ATM is a high-speedconnection-oriented switching technology that isintended to support the concurrent transmission of allservicesvoice, video and data trafficby segmentingtheir streams into small fixed-size of cells of 53 bytes.Voice traffic will be routed through an end-officeswitch to a tandem/toll switch, then carried throughthe constant bit rate of ATM adaptation layer 1 (CBRAAL-1) circuit emulation virtual circuits or variable-bit-rate real time of ATM adaptation layer 2 (VBR-rtAAL-2) virtual circuits in the ATM backbone network.In this architecture, a function converts between TDMand ATM voice traffic, with possible employment ofvoice compression and silence suppression. This func-tion can be an integral part of either the tandem/tollswitch or the ATM switch, or it can be implementedby a separate network element in the ATM network.In Figure 4, the 7R/E gateways, as part of the endoffices, support a full range of packet and circuit con-nections to the core packet network. The lower half ofFigure 4 indicates that the customer premises equip-ment is connected to an end office, that is, a 7R/Enode, which in turn is connected to an ATM data edgeMUX/switch, then connected to an ATM core switch.It is possible that the toll/tandem switch can be collo-cated with an ATM edge multiplexer (MUX)/switch.Thus, voice traffic may be aggregated with data trafficin the same ATM edge MUX/switch before beingtransported to the backbone network.IP core network. Some Internet service providersare considering providing voice service over their IPbackbone network. In this architecture, voice trafficfrom residential customers and/or businesses will befirst routed through a 7R/E node, then carried throughthe IP backbone networks. In this case, the lower halfof Figure 4 is the same as the IP network architecturesupporting data services. Voice traffic is routedthrough a 7R/E node (an end office), encapsulated inRTP/UDP/IP, carried to the IP edge router, and thentransferred through the IP core network.IN/SS7 network. For the ATM backbone net-work, a signaling gateway performs the transla-tion between Signaling System 7 (SS7) and ATMnetwork-to-network interface (NNI) signalingprotocols for the dynamic set up of switched vir-tual circuits (SVCs) for carrying voice traffic.The same signaling gateway will be able to controlthe dynamic allocation of network servers and12 Bell Labs Technical Journal u OctoberDecember 1999resources. The signaling gateway can be part of thetandem/toll switch.For the IP core network, a gatekeeper performsthe translation between SS7 and the IP session man-agement protocol to set up sessions dynamically forcarrying the voice traffic. The gatekeeper, Internettelephony server (ITS) gateway, and edge router func-tions can be combined with the voice edge functionperformed by a 7R/E gateway node.Broadband access. Various technologies are usedfor access to the backbone network by various types ofend users. These range from traditional circuit-switchednarrowband access to PSTN to broadband wirelessaccess for mobile users. These technologies includexDSL, HFC, and the passive optical network (PON).New access nodes are needed to provide inte-grated multi-service, multi-technology access to thebackbone network. These edge nodes may need toATM Asynchronous transfer modeHFC Hybrid fiber coaxIP Internet protocolMUX MultiplexerNIU Network interface unitPPA Packet phone adapterPSTN Public switched telephone networkSTB Set-top boxxDSL Any of various digital subscriber line modem technologiesNetwork andservice managementServersOpticalbackboneATM/IP corenetworkIntranetbroadband accessserver/MUXBroadbandwirelessLargebusiness accessAccessserverResidence/small-business accessxDSLIPFixed wirelessNIUCable accessAccessserverHFCplantPPACablemodemSTBMobilewireless accessAccessserverPublicinternetPSTN7R/EnodeWiredFigure 4. Lucents Network Vision Architecture.Bell Labs Technical Journal u OctoberDecember 1999 13perform conversion between circuit and packetdomains. Some new telecommunications carriers willbuild packet-based networks from the ground up andtherefore will not have to deal with integration oflegacy voice/TDM networks. On the other hand, thevast majority of carriers must integrate their currentnetworks with the emergent network infrastructuresbased on the optical layer.A family of digital subscriber line (DSL) technolo-gies, collectively referred to as xDSL, allows a fewmegabits per second to be carried over the existingcopper plant (unshielded twisted pair) in a relativelyfast and cost-effective way. The recently proposedADSL-Lite runs at about 1.5 Mb/s, and asymmetricdigital subscriber line (ADSL) at 6 Mb/s. Very high bit-rate digital subscriber line (VDSL) operates at higherdata rates. Except for high bit-rate digital subscriberline (HDSL), xDSL is predominantly seen as an overlaytechnology, operating on the same pairs as narrow-band services such as plain old telephone service(POTS) or ISDN. This is achieved by using the fre-quency spectrum beyond that used for POTS on thecopper wire. The narrowband signal uses the low partof the spectrum, while the broadband signal uses thehigher frequencies. The signals from the two are com-bined using a POTS splitter. At the customer premises,a POTS splitter allows these separate signals to bepassed to an xDSL modem and to the telephones.Depending on the type of DSL and the bandwidthsrequired by the customer, different deployment archi-tectures are possible for this technology.Another widespread system that is being used foraccess to high-rate digital services is the coaxial cable-based distribution used by cable television operators. Acable modem allows a few megabits per second of datato be carried over hybrid fiber coax (HFC) access sys-tems. The frequency spectrum is split both at the cus-tomer site and at the cable headend, thereby allowingaccess to community antenna television (CATV), opti-cal backbone, and optionally, PSTN. Amplifiers mustbe placed regularly along the cable to deliver satisfac-tory television signals to customers. Such systems haveaccess to a majority of homes in the United States, butare not likely to be available for businesses that are notlocated in a residential area.CATV systems are divided into 6 MHz channels inNorth America, corresponding to the analog televisionbandwidth. Each such channel can carry 30 or 40 Mb/swith good performance in the downstream direction(to the customer). However, in the upstream direction(from the customer) the performance is not nearly thatsatisfactory. In fact, most CATV systems today arestrictly one way, downstream only. Upstream capacityis added by using the lower part of the frequency spec-trum, below about 45 MHz. Aside from the smalleravailable bandwidth, the lower frequencies are moresusceptible to interfering signals. Another problemassociated with the shared use of the upstream channelis the cumulative addition of noise originating from allcustomer locations. For these reasons, only relativelylow rates can be carried upstream, and the system isbest used for asymmetric services, such as Internetaccess. Such services are available today.17There is now great interest in using wireless tech-nology to provide higher-rate digital services. The nextgeneration of cellular service (the so-called third gen-eration) will provide digital service at rates up to 5 Mb/s. For residential and small business access, anarchitecture similar to digital cellular radio, but with-out handoffs, is being considered for providing multi-Mb/s access. Base stations can provide a coverageradius of 5 to 10 km, depending on the terrain.Operation in the 2 to 5 GHz region would be mostlikely. The use of steered beam antenna techniquesshould provide sufficient antenna gain to permit oper-ation at approximately 1 watt of power at both thebase station and remote terminal. Current researchindicates that signal processing techniques showpromise of improving the antenna gain from a multi-antenna array. The primary use of this system wouldbe for Internet access as well as voice service.Introduction of this type of access service may be aidedby the use of existing cellular physical sites. For largebusinesses, point-to-point access at up to 100 Mb/s isenvisioned. Using higher frequencies, up to 28 GHz,allows the use of available wide spectral bandwidths,at the expense of shorter distance coverage due to rainattenuation. Distances of 2 to 3 km are feasible. Thesystem can be upgraded to provide point-to-multipointservice using antenna steering or combining.1714 Bell Labs Technical Journal u OctoberDecember 1999Convergence of fixed and mobile access is concernedwith the provisioning of network and service capabili-ties that are independent of access techniques.18Optical access options exist as well. In the nearterm, a technology similar to the packet-based opticalcore, but with lower capacity, will provide metropoli-tan transport and business access to the core networkdescribed above. A promising technique to providesome degree of sharing the use of fiber among multiplecustomers is the PON. In the simplest configuration,only one wavelength is used in each direction. DWDMis a further enhancement to increase capacity. The endfibers in a PON may supply individual customerspar-ticularly small- and medium-sized businessesor mayterminate in optical network units (ONUs) that servesmall clusters of homes in a residential area. The lattercase in frequently referred to as fiber to the curb,where the individual homes may be accessed by wirepairs, possibly using VDSL technology. Passive coaxialcable distribution is another possibility. Because thenumber of homes served by each ONU is small (4 to 8),sharing of capacity is readily achieved. Ultimately, theONUs in a PON may serve individual homes, achievingfiber to the home. An issue in this case, other thancost, is supplying reliable power if the system is to pro-vide primary telephone service.17A Practical Vision for Managing NetworksHow is a global network made of diverse compo-nents and providing diverse services going to be man-aged? Realizing network management architecturesinvolves a careful balancing of a web of tradeoffsamong a set of critical factors to meet associated tech-nical and networking challenges. Implicit in the bal-ancing exercise is the ubiquitous cost/functionalitytradeoffthat is, at what price functionality? Ratherthan a single solution for all applications, a range ofnetwork management architectures will arise as eachmarket segment applies its unique priorities to makefundamental architecture tradeoffs. In this section webriefly describe the new network managementrequirements and the techniques to meet them.New Management RequirementsThe objectives of the traditional NMS/OS havebeen to reduce operations complexity and cost byincreasing flow-through. Reliability, security, and effec-tive presentation techniques have always been desir-able requirements. But the focus of traditional networkmanagement, both in carrier networks and enterprisenetworks, has generally been at the element level, rely-ing on communications protocols and element MIBs.As networks grow in size and as services become morecomplex, scalability issues arise and management at thenetwork level becomes more important.The desire for defining and managing servicesquickly over the network infrastructure has created arequirement for more sophisticated network manage-ment techniques. To support services such as packetvoice, virtual private networks, and multimedia ser-vices, network management systems must be capableof providing mechanisms for managing QoS and SLAs.Moreover, these systems must respond to customers,who more and more require the ability to view theirlogical subnetworks and to be billed commensuratewith the provided QoS.Table I shows some services and their corre-sponding network and management implications.Meeting Management RequirementsTable II shows some of the common practices intraditional network management and their corre-sponding shortcomings. To meet these challenges, thetraditional network management platforms and tech-niques need to be modified and enhanced. Rapidintroduction of new network elements, protocols, andapplications require a highly flexible and responsivemanagement architecture. Some elements of thisarchitecture are described below.Distributed network management. The tradi-tional centralized architecture for management hasreliability and scalability problems. The hierarchicalmanagement architecture somewhat ameliorates thesituation, but this architecture still is not sufficientlyflexible and responsive. Distributed managementarchitectures solve the problems of reliability and scal-ability; however, they are generally more complex andpresent new challenges in terms of security, concur-rent programming, and synchronization.Supporting service requirements on an individualdevice basis is too cumbersome and not cost effective.To deal with the increased complexity of networkBell Labs Technical Journal u OctoberDecember 1999 15management as a result of the growing variety of ser-vice requirements, the focus must be shifted frommanager-agent communication protocols to informa-tion management and distribution. This has resulted inthe growing popularity of CORBA-based distributedmanagement19 and directory-enabled networking(DEN) paradigms.20CORBA provides a flexible platform for manager-agent and manager-manager communication. It con-tains mechanisms for communication between objectsthrough an object request broker (ORB), an interme-diary between client and server. The ORB has thecapability of selecting the server that is best suited forsatisfying the clients requirement, without the clientbeing aware of details about the server. CORBA sup-ports distributed object computing in a variety of pro-gramming languages. CORBA Interface DefinitionLanguage (IDL)* defines services offered by a particulardistributed object. Being vendor independent, CORBAhas gained tremendous popularity for management ina heterogeneous network/systems environment.The directory enabled networks (DEN) vision isto provide network-enabled application informationfrom a single X.500-based directory, using light-weight directory access protocol (LDAP) for access.The proposed information model is CommonService Network implications Management implicationsVoice, video, multimedia Latency of no more than 200 ms Bandwidth management Bandwidth of 6 to 300 kb/s QoS managementElectronic commerce Continuous availability Security management Trust mechanismsConsumer lifeline services Continuous availability Efficient configuration management Low and high bandwidth Fault management Low costNetwork access Bandwidth of at least 64 kb/s Efficient configuration management(VPN, wireless, RADIUS) Security Fault management Security managementTable I. Services and their network management implications.VPN Virtual private networkRADIUS Remote authentication dial-in user servicePractice Shortcoming(s)Use of centralized and hierarchical architecture Slow responseNo agent-agent communication RestrictiveScope fixed at element level Static and inflexible, scalability problemsPredefined MIBs InflexibleWeb-based interface Failure to reduce complexity of network managers jobNo application-level QoS management Outdated ways of managing virtual overlaysApplication of policy-based management primarily to single Limited scope; must be extended to otherpoints for authorization, access control, and security areas of managementShortage of management applications Restrictive; no automated QoS management possibleTable II. Practices in network management and corresponding shortcomings.MIB Management information baseQoS Quality of service16 Bell Labs Technical Journal u OctoberDecember 1999Information Model (CIM) put out by the DistributedManagement Task Force.21 The CIM/DEN paradigmis gaining broad support in both carrier and enter-prise network management.Policy-based management. Network manage-ment techniques relying only on communications pro-tocols and device-oriented data stores are not adequatefor coordinating and configuring networks with com-plex layered services. Policy-based management pro-vides a possible solution.22,23 A policy is a formalrepresentation of information affecting network/com-ponent behavior, but specified independent of compo-nents. The enterprise-wide directory advocated byDEN is well suited for policy-based management thatallows coordinating and configuring networks withcomplex services. The policy applications, however,currently have a limited scope: their current focus ison QoS-based congestion management, user-accesssecurity management, and configuration manage-ment. The applications need to be extended to otherareas of management. Policy-based management andrelated issues are covered in detail in one of the papersin this issue.24Intelligent agents in network management. Inboth SNMP-based enterprise network managementand CMIP-based carrier network management, man-agement systems interact with management agentsrunning on network elements. Intelligent agents areautonomous software entities capable of performingfunctions and making decisions on behalf of a user oranother program. A client, such as an NMS, can dele-gate certain tasks to an intelligent agent, which willperform the task with minimal involvement from theclient. Using intelligent agents on network elementsreduces the processing burden on the NMS and thevolume of management traffic. Intelligent agents canbe used, for example, in management by delegation,where they execute programs asynchronously to per-form functions like event correlation, freeing the NMSto perform other tasks. One of the papers in this spe-cial issue provides a tutorial on intelligent agents andhow they may be utilized in network management.25Management of convergent networks. Figure 5shows a conceptual architecture for integrated multi-domain management. With packet voice gainingtremendous momentum in recent years, the challengeis to develop efficient ways of managing multi-domainnetworks. The network elements will include bothTDM and packet components and interfaces, and theelement managers must be able to manage bothdomains. Furthermore, an inter-domain managementfunction is needed to reconcile the differences in para-digms used to manage the legacy TDM elements andthe new multi-domain elements. In the service man-agement layer, issues of end-to-end QoS managementand SLA management need to be addressed. A Snapshot of Trends and TechniquesThis issue of the Bell Labs Technical Journal outlinessome trends, techniques, and applications to managethe evolving network. It describes how some of thenetwork management challenges mentioned in theprevious sections are being addressed, highlightingsome network management activities that are takingplace within Lucent. The papers presented in this issuefall into four major areas: Network management information models andapplications, New techniques and paradigms, Management of large networks, and Management of diverse and convergednetworks.The coverage of innovations here is by no meanscomprehensive or complete; it is only a sample ofLucents activities in facing the challenges of networkmanagement.Network Management Information Models andApplicationsNetwork performance monitoring is an importantpart of effective network management. Three papersin this issue address this important function for next-generation networks. Real-Time PerformanceMonitoring and Anomaly Detection in the Internet:An Adaptive, Object-Driven, Mix-and-MatchApproach by Ho, Macey, and Hiller26 describes apowerful framework capable of automatic and pro-active fault and anomaly detection and performancemanagement in IP networks and for IP services. Thisplatform would facilitate the introduction and auto-matic management of emerging new IP applications.Bell Labs Technical Journal u OctoberDecember 1999 17Switch MonitoringThe New Generation ofMonitoring for Local Area Networks by Romascanuand Zilbershtein27 describes a method to organizedata-collection reports in switches as well as exten-sions to handle layer-3 and above statistics at theswitch level. This paper reviews the development ofthe current and future standards in the area of moni-toring LAN switches. Because standard remote moni-toring (RMON) probes are insufficient to monitorswitched LANs, Lucent has developed new methods toperform switch monitoring (SMON). Building network management applicationswhose scope is network-wide has been a largelyunaccomplished goal of the communications industry.Two potentially complementary and hopefully con-verging efforts under way in the industrythe CIMand DEN initiativesare now both under the aus-pices of the Distributed Management Task Force, asmentioned earlier in this paper. The former initiativedefines object-modeling formalisms for specifying anetwork information model, as well as a set of baseschemas. The latter defines a model schema that isintended for storage using LDAP-accessible directorysoftware technology. The paper by Nissenbaum, A Directory-Hosted Network Management Infor-mation Model: A CIM/DEN Implementation,28describes a prototype of Lucents implementation of aCIM/DEN system. New Techniques and ParadigmsSeveral papers in this issue deal with rather newparadigms in network management. Two papers focuson policy-based network management techniques.The paper Policy-Based Management for IPNetworks by Stevens and Weiss24 contrasts conven-tional approaches to network management with anew, more cohesive approach. The authors describeIP NEFeatureserverSwitchgatewayATM/FR NEMulti-techaccessmanagerDomainmanagerLegacymanagerDomainmanagerDomainmanagerDomainmanagerService ordermanagerBilling andaccountmanagerTroubleticketingCustomerservicemanagerID ConfigurationmanagementID PerformamcemanagementID FaultmanagementCircuit switchIP NESONET/SDH ATM/FR NELegacy/other NEATM Asynchronous transfer modeFR Frame relayID Inter-DomainIP Internet protocolNE Network elementSDH Synchronous digital hierarchySONET Synchronous optical networkFigure 5. A conceptual architecture for integrated multi-domain management.18 Bell Labs Technical Journal u OctoberDecember 1999policy-based network management and techniques forimplementing it. They also describe the challenges andopportunities in implementing effective policy-basednetwork management. The paper Policy-BasedNetwork Load Management by Hossain et al.29describes the design and implementation of the proto-type of a policy-based load management system. Thetechnique used in the prototype can intelligently man-age incoming Internet service requests among a groupof servers, resulting in QoS improvement.Bieszczad et al., in Management of HeterogeneousNetworks with Intelligent Agents,25 provide a brieftutorial on intelligent agents and describe how usingintelligent agents can address some of the shortcomingsof the current approaches to network management andhelp in management of heterogeneous networks. Theauthors address ongoing Lucent work on an intelligentagent platform, LucINA, and its applications.Management of Large NetworksUnless properly engineered, network managementof large SONET/SDH networks can severely stress theembedded data communications network (DCN),resulting in less responsive communication betweenthe network manager and network elements. Budka etal. in their paper, Engineering Large SONET/SDHManagement Networks,30 explore the demands largenetworks place on the SONET/SDH operations net-work and the ways an operations network can bemade robust. The authors present the characteristics oflarge SONET/SDH management networks and describethe engineering principles for improving their stabilityand performance. They also describe how these princi-ples are incorporated during the design and testing ofsome Lucent product families.The management of todays optical transport net-works typically includes some or all of FCAPS man-agement. Carrying this management informationacross the network requires the presence of a manage-ment communications network (MCN), also referredto as the DCN. The MCN itself needs FCAPS manage-ment. For instance, when an optical fiber cut isdetected on a fiber carrying data at a rate of hundredsof gigabits per second, it is imperative that the detec-tion of the fiber cut be reliably and quickly relayed tothe management systems through the MCN. A well-managed MCN can give a better guarantee of doingthis than an unmanaged MCN.The availability of management for the MCN isvery sparse in todays management systems, andManaging the Management CommunicationsNetwork in Optical Transport Systems by Shankarand Chatterjee31 is a right step toward addressing theproblem. This paper describes algorithms for planning,designing, and analyzing the MCN. We envision thiswork as forming the basis for a suite of applicationsthat can improve the management of the communica-tions infrastructure in optical transport networks.The software that supports telecommunicationsnetwork elements encompasses a multitude of differ-ent functions. Besides the features and functionalitythat support service, call, and connection control,there is a vast amount of software that is required tosupport network management functionality. This,although frequently overlooked during initial systemspecification, often comprises the majority of the effortduring software design and construction. ReusableManagement Frameworks for Third-GenerationWireless Networks by Choy et al.32 describes somework that has been done to analyze common manage-ment functionality using design pattern and frame-work technology. This paper describes how theseassets are being used in the management of CORBAand SNMP-based third-generation wireless networks,supporting both voice and high-speed data services.Management of Diverse and Converged NetworksRapid evolution of the telecommunicationsindustry has resulted in the convergence of voice anddata transport over many diverse architectures andtechnological domains such as TDM, ATM, SONET,SDH, frame relay, DWDM, and IP. Lucent is workingto provide an inter-domain network managementsolution such that diverse technologies from multiplevendors can be managed in an integrated manner andthe differences among the heterogeneous networkequipment become transparent. A Network Manage-ment System Solution for Diverse and ConvergedVoice and Data Networks by Bagga et al.33 gives anoverview of the proposed Inter-Domain ManagementSystem Architecture.Todays multiple network architectures support-Bell Labs Technical Journal u OctoberDecember 1999 19ing voice and data services can be consolidated usingpacket technologies. This should result in operationalsavings, but it introduces the challenges of managingmulti-domain integrated networks. NetworkElement Management Architecture for the 7R/ETrunk Access Gateway by Whang, Jain, and Chan34addresses the challenges of managing an integratedgateway element and describes the system require-ments, features, information models, manager/agentarchitectures, and major components of the elementmanagement system (EMS) for the 7R/E TrunkAccess Gateway. The authors describe how thedesigned EMS meets the challenges. Network management has traditionally been cen-tralized and executed by a select group of technicians.Management of todays multi-service multi-vendornetworks requires new architectures and techniquesand often involves different platforms that need to beintegrated. In NetCare Network ManagementServicesManaging Multi-Vendor Networks,Denison and Giovannetti4 present the successfulapproach of NetCare Network Management Servicesto multi-vendor network management and describehow, through these services, the status of every com-ponent in the network is tracked, regardless of thetype of network or the manufacturer.In todays IP networks, network operators lackthe tools to monitor use of network services by indi-vidual customers, to measure the type and quality ofservice these customers receive, and ultimately toestablish SLAs and bill for the services rendered.Blott et al. in User-Level Billing and Accounting inIP Networks,35 present an approach to accountingin IP networks based on a special-purpose networkprobe, which the authors term a NetCounter. The keyfunctionality of a NetCounter is real-time, in-networkcorrelation of network traffic with the individualusers that generated it. This approach, adopted byLucent, has several technical advantages over alter-native approaches: NetCounter achieves substantialin-network aggregation, reducing the volume ofusage data generated by between two and fourorders of magnitude (when compared to flow-loggingsystems). In addition, it captures usage data at thelevel of individual users and records detailed, user-and service-specific performance metrics.The network and computer vulnerabilities inLucent, if left unidentified or unmitigated, will resultin serious and costly compromises to Lucents intellec-tual properties. Given the voluminous nodes and hostsin the Lucent intranet, it is not operationally feasible toscan the entire network. The final paper in this issue,Managing Cyber Security Vulnerabilities in LargeNetworks by Chang et al.,36 describes a statisticalsampling and analysis methodology combined with anetwork and host security discipline for developingLucents cyber security profile in an effective and effi-cient manner. Through root cause analyses, asexplained in this paper, Lucent developed a focusedplan for mitigating vulnerabilities effectively and effi-ciently. These patent-pending methodologies willbecome the enablers of cyber security management ina large networked environment.Other Related Lucent Activities Management applications that control the net-work based on monitored information are rare.However, Bell Labs has recently built automated man-agement applications that perform advanced monitor-ing and control functions on an end-to-endnetwork/service level. The IP Network Configurator isan example of a novel management tool that config-ures a network taking into account the interdepen-dencies between network elements.37,38 In addition,the NetViz system provides a framework for construct-ing interactive visualization of complex hierarchicaland time-varying networks.39Novel approaches to management are required tomeet the twin requirements of simplicity and morepowerful functionality. Two unique Bell Labs solutions, Active Bell Labs Engine (ABLE)40 andExtensible Network and Application ManagementInstrumentation (XNAMI),41 achieve this goal by offer-ing solutions that are simple, powerful, flexible, andcapable of being implemented in a distributed setting.ConclusionWe have reviewed the evolution of network man-agement as well as the essentials of network manage-ment and its functions and components. We have alsohighlighted the requirements for managing the net-20 Bell Labs Technical Journal u OctoberDecember 1999work as it continues to evolve. We hope this cross-sectional view of network management activities willinspire continued excellence in network managementresearch and development at Lucent Technologies.*TrademarksCORBA is a registered trademark and InterfaceDefinition Language (IDL) is a trademark of theObject Management Group.OpenView is a registered trademark of Hewlett-Packard Company.References1. W. Stallings, SNMP, SNMPv2, SNMPv3, andRMON 1 and 2, 3rd ed., Addison Wesley,Reading, Mass.,1999.2. International Telecommunication Union,Common Management Information ProtocolSpecification for CCITT Applications, Rec.X.711, 1991, International Telecommunication Union,Common Management Information ServiceDefinition for CCITT Applications, Rec. X.710,1991, B. A. Denison and F. Giovannetti, NetCareNetwork Management ServicesManagingMulti-Vendor Networks, Bell Labs Tech. 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X.722/ISO 10165,1992, International Telecommunication Union,Principles for a TelecommunicationsManagement Network, Rec. M.3010, 1993, International Telecommunication Union,Packet-Based Multimedia CommunicationsSystems, ITU-T Rec. H.323, Feb. 1998,http://www.itu-int/ITU-T/index.html13. E. C. Rosen, A. Vishwanathan, and R. Callon,MultiProtocol Label Switching Architecture,IETF Internet-Draft, IETF, Aug. 1999, R. Braden, L. Zhang, S. Berson, S. Herzog, andS. Jamin, Resource ReSerVation Protocol(RSVP) Version 1Functional Specification,IETF RFC 2205, Sept. 1997, R. C. Alferness, P. A. Bonenfant, C. J. Newton,K. A. Sparks, and E. L. Varma, A PracticalVision for Optical Transport Networking, Bell Labs Tech. J., Vol.4, No.1, Jan.Feb. 1999,pp. 318.16. D. C. Dowden, R. D. Gitlin, and R. L. Martin,Next-Generation Networks, Bell Labs Tech. J.,Vol.3, No.4, Oct.Dec. 1998, pp. 314.17. K. G. August, V. B. Lawrence, and B. R. Saltzberg, An Introduction to FutureCommunications Services and Access, Bell LabsTech. J., Vol.4, No.2, April-June 1999, pp. 320.18. F. G. Harrison and S. R. Hearnden, TheChallenge to Realize Convergence of Fixed and Mobile Communications, Electronics &Commun. Engineering J., Vol. 11, No. 3, June 1999, pp.164168.19. Object Management Group, The Common ObjectRequest Broker: Architecture and Specification,December 1993. Directory-Enabled Networking (DEN), W. Bumpus, DMTF Expands Its Role inDeveloping Information Model Standards, J. of Network and Systems Management, Vol. 6, No. 3, Sept. 1998, pp. 357360.22. M. Sloman, Policy Driven Management forDistributed Systems, J. of Network and SystemsManagement, Vol. 2, No. 4, 1994, pp. 333360.23. E. C. Lupu and M. Sloman, Towards a Role-Based Framework for Distributed SystemsBell Labs Technical Journal u OctoberDecember 1999 21Management, J. of Network and SystemsManagement, Vol. 5, No. 1, 1997, pp. 530.24. M. L. Stevens and W. J. Weiss, Policy-BasedManagement for IP Networks, Bell Labs Tech. J.,Vol. 4, No. 4, Oct.Dec. 1999, pp. 7594.25. A. Bieszczad, P. Biswas, W. Buga, M. Malek,and H. Tan, Management of HeterogeneousNetworks with Intelligent Agents, Bell LabsTech. J., Vol. 4, No. 4, Oct.Dec. 1999, pp. 109135.26. L. L. Ho, C. J. Macey, and R. Hiller, Real-TimePerformance Monitoring and AnomalyDetection in the Internet: An Adaptive Object-Driven, Mix-and-Match Approach, Bell LabsTech. J., Vol. 4, No. 4, Oct.Dec. 1999, pp. 2341.27. D. Romascanu and I. E. Zilbershtein, SwitchMonitoringThe New Generation ofMonitoring for Local Area Networks, Bell LabsTech. J., Vol. 4, No. 4, Oct.Dec. 1999, pp. 4254.28. H. D. Nissenbaum, A Directory-HostedManagement Information Model: A CIM/DENImplementation, Bell Labs Tech. J., Vol. 4, No. 4,Oct.Dec. 1999, pp. 5574.29. A. Hossain, H. F. Shu, C. R. Gasman, and R. A. Royer, Policy-Based Network LoadManagement, Bell Labs Tech. J., Vol. 4, No. 4,Oct.Dec. 1999, pp. 95108.30. K. C. Budka, R. J. DiPasquale, B. W. A. Rijsman,and A. B. Sripad, Engineering Large SONET/SDH Management Networks, Bell Labs Tech. J.,Vol. 4, No. 4, Oct.Dec. 1999, pp. 136-154.31. R. V. Shankar and A. K. Chatterjee, Managingthe Management Communications Network inOptical Transport Systems, Bell Labs Tech. J.,Vol. 4, No. 4, Oct.Dec. 1999, pp. 155170.32. K.-C. Choy, M. S. Halkyard, S. Krishnamoorthy,and M. R. Panda, Reusable ManagementFrameworks for Third-Generation WirelessNetworks, Bell Labs Tech. J., Vol. 4, No. 4,Oct.Dec. 1999, pp. 171189.33. Y. S. Bagga, A. Chaudhury, C. Hird, T. Lee, W. Pretyka, D. Puseljic, S. Russo, R. Shafie-Khorasani, T. Tignor, and R. Ting, A NetworkManagement System Solution for Diverse andConverged Voice and Data Networks, Bell LabsTech. J., Vol. 4, No. 4, Oct.Dec. 1999, pp. 190-203.34. K. K. W. Whang, R. Jain, and P. Chan,Network Element Management Architecturefor the 7 R/E Trunk Access Gateway, Bell LabsTech. J., Vol. 4, No. 4, Oct.Dec. 1999, pp. 204224.35. S. M. Blott, C. E. Martin, Y. J. Breitbart, J. C. Brustoloni, T. R. Gramaglia, H. F. Korth, D. M. Kristol, R. H. Liao, E. L. Scanlon, and A. Silberschatz, User-Level Billing andAccounting in IP Networks, Bell Labs Tech. J.,Vol. 4, No. 4, Oct.Dec. 1999, pp. 237-251.36. E. S. Chang, A. K. Jain, D. M. Slade, and S. L. Tsao, Managing Cyber SecurityVulnerabilities in Large Networks, Bell LabsTech. J., Vol. 4, No. 4, Oct.Dec. 1999, pp. 252-272.37. B. Sugla and P. Krishnan, IP NetworkConfigurator: Advancing the State of the Art in IP Network Deployment and Operations,Lucent Technologies White Paper, November1998.38. T. He and S. Eick, Constructing InteractiveNetwork Visual Interfaces, Bell Labs Tech. J.,Vol. 3, No. 2, Apr.June 1998, pp. 4757.40. D. Raz and Y. Shavitt, An Active NetworkApproach for Efficient Network Management,The First Intl. Workshop on Active Networks(IWAN99), July 1999, Berlin, Germany, LNCS1653, pp. 220231.41. A. John, K. Vanderveen, and B. Sugla, AnXML-based Framework for Dynamic SNMPMIB Extension, Proc. 10th IFIP/IEEE Intl.Workshop on Distributed Systems: Operations& Management (DSOM99) October 1999,Zurich, Switzerland, LNCS1700, pp. 107120.(Manuscript approved January 2000)SHERVIN ERFANI is a member of technical staff in theData Communication Technologies Depart-ment at Bell Labs in Holmdel, New Jersey.He holds a combined B.S. and M.S. degreein electrical engineering from the Universityof Tehran in Iran and M.S. and Ph.D. degrees,also in electrical engineering, from Southern MethodistUniversity in Dallas, Texas. Since joining Bell Labs, Dr. Erfani has been engaged in network management,service provisioning, network design and planning, andnetwork security management. He has published morethan 50 technical papers, holds a patent, and is thesenior technical editor of the Journal of Network andSystems Management. Dr. Erfani also teaches coursesat Stevens Institute of Technology in Hoboken, New Jersey.22 Bell Labs Technical Journal u OctoberDecember 1999VICTOR B. LAWRENCE is director of the AdvancedCommunications Technology Center at BellLabs in Holmdel, New Jersey. He holds bothB.Sc. and Ph.D. degrees in electrical engi-neering from the University of London inthe United Kingdom. At Bell Labs, he hasheld various assignments in the areas of signal process-ing, data communications, and exploratory develop-ment of transmission products and services. He iscurrently responsible for technology transfer, systemsengineering, and exploratory development of multi-media systems over wire and wireless networks. An IEEEFellow and a Bell Labs Fellow as well, Dr. Lawrenceholds 17 patents and has published over 40 technicalpapers. For several of the papers, he has received spe-cial recognition. In addition, he is the author of a chap-ter in Introduction to Digital Filtering, co-editor ofTutorials in Modern Communications, and co-author ofboth Intelligent Broadband Multimedia Networks andEngineering of Intelligent Communication Systems.MANU MALEK, a distinguished member of technicalstaff in the Next-Generation NetworkSystems Engineering and CALA NetworkPlanning Department at Bell Labs inHolmdel, New Jersey, holds a Ph.D. in elec-trical engineering and computer sciencefrom the University of California at Berkeley. Dr. Malekis currently working on operations and managementplanning for next-generation networks. He is theauthor, co-author, or editor of 7 books, the author orco-author of over 50 published technical papers, and aco-holder of 2 patents in multimedia and networkmanagement. An IEEE Fellow and an IEEECommunications Society Distinguished Lecturer, Dr. Malek is the founder and editor-in-chief of theJournal of Network and Systems Management.BINAY SUGLA is currently department head of Networkand Services Management Research at BellLabs in Holmdel, New Jersey. He joined BellLabs after receiving a Ph.D. in electrical andcomputer engineering from the Universityof Massachusetts in Amherst. At Bell Labs,Dr. Sugla first designed and implemented CAPER, avisual parallel programming environment. He laterworked on Network Flight Simulator, a real-time simu-lator of the dynamics of telephony network. For thepast few years, he has been involved in the manage-ment of IP networks and services. uIntroductionEvolution of Network ManagementNetwork Management FunctionsKey Components of a Network ManagementManagement Information and Knowledge StructureManagement Information Exchange ProtocolsThe Network Environment: Then, NowThe Development of Integrated Network ArchitecturesThe Need for Higher Bandwidth and DifferentiatedLucents View of Network R/Evolution: ATM core networkIP core networkIN/SS7 networkBroadband accessA Practical Vision for Managing NetworksNew Management RequirementsMeeting Management RequirementsDistributed network management.Policy-based management.Intelligent agents in network management.Management of convergent networks.A Snapshot of Trends and TechniquesNetwork Management Information ModelsNew Techniques and ParadigmsManagement of Large NetworksManagement of Diverse and Converged NetworksOther Related Lucent Activities ConclusionReferences


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