Abstract:
A method for distributing management information in a management network for monitoring and controlling a communications system, whereby the management network comprises managers “NMC” and agents “OMC 1 - 3 ” configured as devices on different management levels, with management information being transmitted as event reports between said devices of the management network.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is based on and hereby claims priority to PCT Application No. PCT/EP2005/050934, filed on Mar. 3, 2005 which claims priority to German Application No. 10 2004 015 558.5, filed on Mar. 30, 2004, the contents of which are hereby incorporated by reference. 
     
    
     BACKGROUND 
       [0002]    The invention relates to a method for distributing management information in a management network for monitoring and controlling a communications system. 
         [0003]    The principles of a management network, also referred to as TMN principles (TMN: Telecommunications Management Network), define several management layers for the management of a communications system—for example, a mobile communications system—, whereby each layer, with the exception of the topmost and bottommost layer, has a dual function. In the managing system, each level, apart from the bottommost one, exercises a manager function for the next level down. In the managed system, each level, except for the topmost one, is given an agent function for the next layer up. 
         [0004]    The ITU-T Standards of the Series X.73x define different systems management functions for the management of telecommunications networks, which can be used by application processes in a centralized or decentralized management environment. 
         [0005]    The manager-agent communication is made via so-called management interfaces or manager-agent interfaces, which can be identified in an object-oriented environment by a communications protocol (e.g. CMIP (Common Management Information Protocol according to ITU-T X.711) or CORBA (Common Object Request Broker Architecture)) and an object model. 
         [0006]    Such interfaces exist, for example, between, on the one hand, the element management level and, on the other hand, the network element level. An example for network devices to this interface (OMC BSS interface) is given by the operation and maintenance centers (OMC) on the element management level side and the base stations, for example, of the base station system (BSS) in a GSM mobile radio network on the network element level. The base stations of a second generation GSM network are referred to here by way of example. Base stations of other communications networks can also be affected, for example node B of a UMTS mobile network (UMTS Universal Mobile Telecommunication System) or radio access points of a WLAN system (WLAN Wireless Local Area Network) for example to one of the IEEE 812.11-standards. 
         [0007]    Management interfaces or manager-agent interfaces do exist, but especially also between, on the one hand, the network management level and, on the other hand, the network element management level. These interfaces are central to the management network. An example for network devices to these interfaces (NMC-OMC interfaces or NM-EM interfaces) is given by the network management centers (NMC) on the network management level side and the operation and maintenance centers (OMC) on the element management level e.g. in the GSM mentioned or in another mobile radio network. 
         [0008]    Services within the management network, which, for example, allow the operator to change the structure and hence the behavior of a telecommunication network, relate as a rule to instances of managed objects, which model network resources in an object-oriented environment and in all, form the network specific management information base (MIB). 
         [0009]    A cellular structure is a basic principle for the configuration of the radio subsystem of a mobile network that has at least zone wide coverage. One precondition for the functionality of a mobile network is the correct definition of relationships between neighboring cells, also called adjacent cells. 
         [0010]    From a “Management Information” perspective, such relationships are basically defined with the help of two object categories:
       Cell: one instance of these managed object classes (MOC) defines one (reference) cell in a mobile network.   AdjacentCell: one instance of these managed object classes (MOC) defines one neighboring cell, which, relating to the reference cell, can be used for handover and/or reselection purposes.       
 
         [0013]    In summary, it can be noted that complex telecommunication networks (such as, for example, mobile networks) commonly use management hierarchies in which element managers (OMC systems) play the agent role and network managers (NMC systems) play the manager role. Operations are carried out and management information is processed and stored both in network management centers (NMC) as well as in operation and maintenance centers (OMC). 
         [0014]    In a multi-manager environment, each agent must be able, if need be, to handle requests from several managers, which requests run parallel to each other. A manager can only optimally fulfill its function if all relevant event reports from the subordinate agents are received. Under normal conditions, i.e. when the communication between an agent and the higher managers functions correctly, this occurs via a so-called event reporting mechanism. The task of said event reporting mechanism is to route to the manager only those event reports which satisfy certain filter criteria. 
         [0015]    Ensuring the consistency of management information, even when individual NM-EM interfaces fail, is very important for an efficient network operation, especially in a hierarchical multi-manager configuration. 
       SUMMARY OF THE INVENTION 
       [0016]    One possible object is, therefore, to show a method, network devices and a communications system of the kind mentioned above, which can make an effective distribution of management information to all affected management systems (in particular in a kind of “broadcasting” functionality) via NM-EM interfaces possible. 
         [0017]    The inventor proposes that, in each manager that functions as a network manager common resources of the communication system are identified in an object-oriented management hierarchy and management information is transmitted as event reports to all devices of the management network that are affected by an event and that function as network managers or as element managers, using the identification of the common resources and the interface between the manager and the agent. 
         [0018]    In the case of network management centers (NMC) as managers and the operation and maintenance centers (OMC) as agents, this means that management information is transmitted as event reports to all network management centers (NMC) of the management network that are affected by an event and that function as network managers, and/or to operation and maintenance centers (OMC) of the management network that are affected by an event and that function as element managers, using the identification of the common resources and the NM-EM interface between the network management centre (NMC) and the operation and maintenance centre (OMC). 
         [0019]    The interface to the manager-agent relationship between a network management centres (NMC) and an operation and maintenance centre (OMC) can be developed advantageously as a real-time interface. In this way, it is possible to ensure the consistency of management information between cells in neighboring network regions, using the real-time interface (real-time OMC-NMC management interface). 
         [0020]    The basis for the method is the management and identification of so-called common resources in each network manager (NMC). In an object-oriented management hierarchy, resources of the telecommunication network that are managed in neighboring network regions by instances of different object classes are called common resources. 
         [0021]    By way of example for this, one can regard the modeling of a single cell in a mobile radio network as a reference cell in an OMC region (an instance of the cell object class) and as neighboring cells for the adjacent OMC regions (several instances of the adjacentCell object class). 
         [0022]    In one embodiment, the different object instances of a concrete network resource are given an identical identification, the so-called symbolic name, which represents an identifier that is defined by the operator, is valid network wide and can be modeled by the standardized attribute (ITU-T M.3100) userLabel. Consequently, in the method provision can be made in particular that the identification of a common resource of the communications system is done using the issuing of a symbolic name as an identifier that is valid within the communications system. 
         [0023]    Advantageously in every manager (NMC) that functions as a network manager information on the allocation of the symbolic name to at least one corresponding object instance in the object-oriented management hierarchy can be stored. Because of this allocation information, it is possible to establish in a relatively simple manner, to which devices of the management network the event reports are to be distributed. 
         [0024]    The management information can be transmitted as event reports to the devices (NMC and/or OMC) of the management network by an agent (operation and maintenance centre OMC) as the original sender, or by a manager (network management centre NMC) as the original sender. If the event reports originate from the element manager level (EM Level) of the operation and maintenance centers (OMC), the distribution of the management information starts with a transmission from the relevant operation and maintenance center (OMC) to the connected network management centers (NMC). Consequently, the management information is transmitted as event reports from at least one agent (OMC) to the connected manager (NMC) of the management network. 
         [0025]    If the event reports originate from the network manager level (NM Level) of the network management centers (NMC), the distribution of the management information starts with a transmission from the relevant NMC to the connected operation and maintenance centers (OMC). In that case, the management information is transmitted as event reports from at least one manager (NMC) to the connected agents (OMC) of the management network. 
         [0026]    In a further development, a multiple sending of identical event reports is avoided by each manager (NMC) and each agent (OMC) ignoring the receipt of an event report that has already been received and not forwarding it again to connected devices (NMC or OMC) of the management network. In this way, an unnecessary sending of event reports is effectively prevented. 
         [0027]    Against the background of the measures described, it is possible to automate a distribution of the management information in a relatively simple way. The management information is distributed bidirectionally by all affected management systems via NM-EM interfaces, i.e. a kind of “broadcasting” functionality is made available. In addition to the redundancy of the communication links, this also enables the consistency of management information to be ensured both hierarchically (between OMCs and NMCs) as well as on the horizontal level (e.g. between neighboring OMCs). 
         [0028]    In each manager (NMC) that functions as a network manager, information about the allocation of the symbolic name to at least one corresponding object instance in the object-oriented management hierarchy can be stored in the form of a table. Each time after an NM-EM link has been established, the NM system synchronizes the configuration data. Thus each network manager centre (NMC) builds up its own table, the lines of which each contain the allocation between a symbolic name and the corresponding object instance (distinguished name). A common resource is recognized if, in one table line, several instances (different object classes) are allocated to exactly one symbolic name. 
         [0029]    The foregoing assumes that a network device (operation and maintenance centre OMC) is designed to function as an agent in a management network for monitoring and controlling a cellular communications system for at least one manager-agent relationship between a manager (network manager centre NMC) of a network management level (NM level) and the network device (operation and maintenance centre OMC) as an agent of the element management level (EM level). Management information is distributed as event reports to all devices (Network manager center NMC) of the management network that are affected by an event and that function as network managers (network manager centre NMC), using the identification of the common resources and the interface (NM-EM interface) between the manager (network manager centre NMC) and the agent (operation and maintenance centre OMC). 
         [0030]    In the function as manager in a management network for monitoring and controlling a cellular communication system, there is a network management device (network manager centre NMC), which is designed for at least one manager-agent relationship between the network management device (NMC) of a network management level (NM LEVEL) and a network device (operation and maintenance centre OMC) as an agent of the element management level (EM LEVEL). Management information is transmitted as event reports to all devices (operation and maintenance centre OMC) of the management network that are effected by an event and that function as network element managers, using the identification of the common resources and the interface (NM-EM interface) between the manager (network manager centre NMC) and the agent (operation and maintenance centre OMC). 
         [0031]    Further, the network management device (network manager centre NMC) may store information on the allocation of the symbolic name to at least one corresponding object instance in the object-oriented management hierarchy. 
         [0032]    A communication system has a management network for monitoring and controlling the cellular communications system comprises both network devices described above (operation and maintenance centre OMC) functioning as agents and also network management devices described above (network manager centre NMC) functioning as managers, configured as devices on different management levels (EM LEVEL, NM LEVEL). 
         [0033]    In principle, the method can be used in all communications networks and in particular telecommunication networks (in particular wireless, but also wire-bound). In the multi-manager configuration there are a large number of managers and a large number of agents. 
         [0034]    In principle, the method can be used for all kinds of manager-agent interfaces. By way of example it is explained below using embodiments for a CMIP based NMC-OMC interface. However, the method can also be used in the same way or accordingly with other interface protocols (e.g. SNMP or CORBA). 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0035]    These and other objects and advantages will become more apparent and more readily appreciated from the following description of the preferred embodiments, taken in conjunction with the accompanying drawings of which: 
           [0036]      FIG. 1  the basic block diagram of a management network for a (mobile) communications system with agent-manager relationship between operation and maintenance centers and several network management centers, 
           [0037]      FIG. 2  a block diagram of an exemplary cutout of a management network for a communications system with agent-manager relationship between four operation and maintenance centers and four network management centers, 
           [0038]      FIG. 3  a schematic diagram of examples of different ways of distributing the management information in the form of event reports for the block diagram in  FIG. 2 , 
           [0039]      FIG. 4  a schematic diagram of an exemplary distribution path for the management information in the form of event reports for the block diagram in  FIG. 2  where the link between NMC 1  and OMC 2  fails, 
           [0040]      FIG. 5  a schematic diagram of an exemplary distribution path for the management information in the form of event reports for the block diagram in  FIG. 2  where the link between OMC 1  and NMC 2  fails. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0041]    Reference will now be made in detail to the preferred embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. 
         [0042]      FIG. 1  shows the block diagram of a management network for a mobile communications system with agent-manager relationship between operation and maintenance centers OMC 1 , OMC 2  to OMC n  (operation and maintenance centers) and several network management centers NMC 1 , NMC 2 , NMC 3  to NMC n  (network management centers). In this case, in  FIG. 1  the representation is limited to two levels NM LEVEL and EM LEVEL. Not shown, for example, is a management level of the management network, which level contains the network device level (network element level) with several base station systems. 
         [0043]    The management level EM LEVEL identifies the network element management level, in which the operation and maintenance centers OMC 1 , OMC 2  to OMC n  respectively provide the usually manufacturer specific management functionality for, for example, individual base stations of the base station system not shown in  FIG. 1 . The management level NM LEVEL identifies the network management level, in which network management centers NMC 1 , NMC 2 , NMC 3  to NMC n  respectively realize an integrated management functionality that is usually independent of the manufacturer. Thereby, several network management centers NMC can have access to the same network device of the next lower management level EM LEVEL, in this example, for example, the network management centers NMC 1  and NMC 2  of the next higher management level NM LEVEL to the operation and maintenance centre OMC 2  of the next lower management level EM LEVEL. Between the network devices of different management levels with the operation and maintenance centers OMC 1 , OMC 2  to OMC n  on the one hand and the network management centers NMC 1 , NMC 2 , NMC 3  to NMC n  on the other hand, there are defined interfaces NM-EM-IF (NM-EM interface) for transmitting information.  FIG. 1  shows a multi-manager configuration of a management network. 
         [0044]    In the following we will first look at the distribution of event reports originating on EM LEVEL. 
         [0045]    These are event reports that have either occurred spontaneously in operation and maintenance centers OMC or associated network elements or were triggered by an operator action, e.g.: 
         [0046]    alarms 
         [0047]    alarm acknowledgement (alarm acknowledgement notification in accordance with 3GPP TS 32.111) 
         [0048]    Manual alarm clearing (alarm clearing notification in accordance with 3GPP TS 32.111) 
         [0049]    Change of attribute values. 
         [0050]    For the distribution of event reports from an operation and maintenance centre OMC to the connected network management centers NMC, it is assumed that on each NM-EM interface NM-EM-IF, the network management centre NMC has set up a filter mechanism (e.g. in the form of an EFD Event Forwarding Discriminator) in operation and maintenance centre OMC and has set the filter criteria. 
         [0051]    The operation and maintenance centre OMC forwards each event report (e.g. M EVENT REPORT in the case of a CMIP based NM-EM interface) to all NMC specific filter mechanisms. Thus each network management centre NMC can control the information flow according to its own individual requirements, i.e. from the view of the network management centre NMC, undesired reports are already filtered out in the operation and maintenance centre OMC. 
         [0052]    The event report received by a network management centre NMC is further distributed to other operation and maintenance centers OMC as follows: after receiving an event report, each network management centre NMC checks whether the object instance (to which the current event report refers) exists as a common resource in the table of the configuration data. 
         [0053]    If that is the case, then the event report is also of significance for other neighboring operation and maintenance centers OMC. For each further object instance of this table line the network management centre NMC sends a corresponding request (e.g. M-ACTION or M-SET in the case of a CMIP based NM-EM interface) to the respective connected operation and maintenance centre OMC. 
         [0054]    In one example, a management hierarchy with several EM and NM systems is assumed, whereby only the neighboring EM systems OMC 1 , OMC 2 , OMC 3 , OMC 4  are of relevance here. A scenario of this kind is represented schematically in  FIG. 2 .  FIG. 2  shows a block diagram of a cutout of a management network for a communications system with agent-manager relationship between four operation and maintenance centers OMC 1 , OMC 2 , OMC 3  and OMC 4  and four network management centers NMC 1 , NMC 2 , NMC 3  and NMC 4 . As well as connections of network management centers NMC 1 , NMC 2 , NMC 3  and NMC 4  and operation and maintenance centers OMC 1 , OMC 2 , OMC 3  and OMC 4  portrayed by unbroken lines, connections to additional network devices (NMC or OMC) that may exist in the levels NM LEVEL and EM LEVEL but are not represented in  FIG. 2 , are indicated by dotted lines. 
         [0055]    A reference cell (cell 1 ) is defined in the network area monitored by the operation and maintenance centre OMC 1 . This cell is at the same time an adjacent cell for the network regions monitored by operation and maintenance centers OMC 2 , OMC 3  and OMC 4  and correspondingly defined (adjacentCell 21 , adjacentCell 31 , adjacentCell 41 ). 
         [0056]      FIG. 3  shows a schematic diagram of examples of different paths for distributing the management information in the form of event reports for the block diagram in  FIG. 2 . 
         [0057]    An alarm of the object instance cell 1  occurs and a corresponding alarm report is sent by the operation and maintenance centre OMC 1  to the connected network management centers NMC 1  (broadcasting path  1 , unbroken arrow in  FIG. 3 ) and NMC 2  (broadcasting path  2 , broken arrow in  FIG. 3 ). 
         [0058]    A first distribution path of the management information in the form of event reports (broadcasting path  1 ) goes via the network management centre NMC 1 , which also communicates with the operation and maintenance centre OMC 2 : using its own table on common resources, the network management centre NMC 1  recognizes the relationship between the instances cell 11  and adjacentCell 21  and forwards an “alarm” notification to the connected operation and maintenance centre OMC 2 . Here the alarm (for the adjacentCell 21  instance) is entered into the OMC 2  own alarm list and subsequently forwarded as an alarm notification to all other connected NMC systems (network management centers NMC 2  and NMC 3 ). The network management centre NMC 2  has already received the alarm from the operation and maintenance centre OMC 1 , which is why the alarm notification is ignored by the operation and maintenance centre OMC 2 . 
         [0059]    The network management centre NMC 3 , which has received the alarm from operation and maintenance centre OMC 2  and in addition communicated with the operation and maintenance centers OMC 3  and OMC 4 , recognizes the relationship between the object instances adjacentCell 21 , adjacentCell 31  and adjacentCell 41  in its own table for common resources and forwards an “alarm” notification to the other connected operation and maintenance centers OMC 3  and OMC 4 . 
         [0060]    In operation and maintenance centre OMC 3 , the alarm (for the adjacentCell 31  instance) is entered into the alarm list. The operation and maintenance centers OMC 4  also enters the alarm (for the adjacentCell 41  instance) into its own alarm list and subsequently forwards an alarm notification to the connected network management centre NMC 4 . Thus all affected management systems have taken note of the alarm in the cell cell 1 . 
         [0061]    A similar forwarding of the alarm runs via a second distribution path (broadcasting path  2 , broken arrow in  FIG. 3 ) via the network management centre NMC 2 . 
         [0062]    From  FIG. 3  can be seen that the bidirectional “broadcasting” functionality could cause a doubling of the message transmission. It is, however, possible to avoid multiple sending of the same event reports if each management system in the management network does not forward a notification that has already been received before and simply ignores it (in the way NMC 2  ignores the alarm from OMC 2 —see embodiments above). 
         [0063]    On the other hand, the existing redundancy is important to ensure the consistency of the management information even when a connection between network management centre and operation and maintenance centre (NM-EM connection) has failed. 
         [0064]      FIG. 4  shows a schematic diagram of a model distribution path of the management information in the form of event reports for the block diagram in  FIG. 2  when the connection between network management centre NMC, and operation and maintenance centre OMC 2  has failed.  FIG. 4  illustrates the forwarding of the above mentioned alarm when the connection between network management centre NMC 1  and operation and maintenance centre OMC 2  has failed. This corresponds to the forwarding of the alarm via a second distribution path (broadcasting path  2 , broken arrow) in  FIG. 3 . In detail, the distribution path of the event report or alarm report comprises the following connections: 
         [0065]    Connection (or transmission path) A: from OMC 1  to NMC 1    
         [0066]    Connection (or transmission path) B: from OMC 1  to NMC 2    
         [0067]    Connection (or transmission path) C: from NMC 2  to OMC 2    
         [0068]    Connection (or transmission path) D: from OMC 2  to NMC 3    
         [0069]    Connection (or transmission path) E: from NMC 3  to OMC 3    
         [0070]    Connection (or transmission path) F: from NMC 3  to OMC 4    
         [0071]    Connection (or transmission path) G: from OMC 4  to NMC 4 . 
         [0072]      FIG. 5  shows a schematic diagram of another model distribution path of the management information in the form of event reports for the block diagram in  FIG. 2  when the connection between operation and maintenance centre OMC 1  and network management centre NMC 2  has failed.  FIG. 5  also reproduces the forwarding of the above mentioned alarm, in the case that the connection between operation and maintenance centre OMC 1  and network management centre NMC 2  has failed. This corresponds to the forwarding of the alarm via the first distribution path (broadcasting path  1 , unbroken arrow) in  FIG. 3 . In detail, the distribution path of the event report or alarm report comprises the following connections: 
         [0073]    Connection (or transmission path) A: from OMC 1  to NMC 1    
         [0074]    Connection (or transmission path) B′: from NMC 1  to OMC 2    
         [0075]    Connection (or transmission path) C′: from OMC 2  to NMC 2    
         [0076]    Connection (or transmission path) D: from OMC 2  to NMC 3    
         [0077]    Connection (or transmission path) E: from NMC 3  to OMC 3    
         [0078]    Connection (or transmission path) F: from NMC 3  to OMC 4    
         [0079]    Connection (or transmission path) G: from OMC 4  to NMC 4    
         [0080]    In addition to the distribution of event reports whose origin is on EM LEVEL, there can also be a distribution of event reports whose origin is on NM LEVEL. Here the event reports are triggered by an operator action at the network management centre NMC, e.g.: 
         [0081]    Alarm acknowledgement (alarm acknowledgement operation in accordance with 3GPP TS 32.111) 
         [0082]    Manual alarm clearing (alarm clearing operation in accordance with 3GPP TS 32.111) 
         [0083]    Change of attribute values. 
         [0084]    An example here would be the changing of a handover attribute in the cell cell 1  by the operator at the network management centre NMC 1 . As this parameter is also relevant for the object instances adjacentCell 21 , adjacentCell 31 , adjacentCell 41 , the change must be notified to all neighboring OMC areas. The distribution (broadcast functionality) proceeds in a similar way to that described above, but this time network management centre NMC 1  is the starting point. This would mean that the distribution via path A in  FIGS. 4 and 5  would reverse direction from the network management centre NMC 1  to the operation and maintenance centre OMC 1 . 
         [0085]    The example of the method is described using a Q3 (CMIP based) interface. The method can also be applied accordingly on other interfaces, such as, for example, CORBA based interfaces. 
         [0086]    In summary, the following features of the method can be noted: 
         [0087]    The method allows automatic updating of management information both between OMCs and NMCs and also between neighboring OMCs. 
         [0088]    The consistency of data across all EM and NM systems (operation and maintenance centers OMC and network management centers NMC) is secured even when individual NM-EM connections fail. 
         [0089]    In principle, the method can be used for all telecommunication networks. 
         [0090]    A description has been provided with particular reference to preferred embodiments thereof and examples, but it will be understood that variations and modifications can be effected within the spirit and scope of the claims which may include the phrase “at least one of A, B and C” as an alternative expression that means one or more of A, B and C may be used, contrary to the holding in  Superguide v. DIRECTV,  358 F3d 870, 69 USPQ2d 1865 (Fed. Cir. 2004).