KR20070022680A - Method and devices for distributing management information in a management network of a communication system - Google Patents

Abstract

The present invention relates to a method for distributing management information in a management network for monitoring and controlling a communication system, the management network configured as managers (NMC _i ) and agents (OMC _i ) configured as devices on different levels of management. ). According to the method, management information is transmitted as event reports between the devices NMC _{i ,} OMC _i of the management network. In each manager NMC _i , acting as a network manager, common resources of the communication system are identified in an object-oriented management hierarchy, utilizing the identification of common resources and the interface between the manager NMC _i and the agent OMC _i . Thus, management information is sent to event reports A, B, C, D, E, F, G on all devices NMC _{i ,} OMC _i of the management network that are affected by the event and operate as network managers or element managers. Is sent as).

Description

METHOD AND DEVICES FOR DISTRIBUTING MANAGEMENT INFORMATION IN A MANAGEMENT NETWORK OF A COMMUNICATION SYSTEM}

The present invention relates to a method for distributing management information in a management network for monitoring and controlling a communication system according to the preamble of claim 1.

The present invention also relates to a network device operating as an agent in a management network for monitoring and controlling a cellular communication system according to the preamble of claim 9, in a management network for monitoring and controlling a cellular communication system according to the preamble of claim 10. A network management device operating as a manager, and a communication system having corresponding network devices and network management devices.

Principles of a management network, also referred to as Telecommunications Management Network (TMN) principles, define several management layers for the management of a communication system, e.g., a mobile communication system, each layer except for the top and bottom layers. Has a dual function. In the management system, each level away from the lowest level performs management functions for the next lower level. In managed systems, each level except the highest level is given an agent function for the next higher hierarchy.

The ITU-T standards of series X.73x define different systems management functions for the management of telecommunication networks, which can be used by application processes in a centralized or distributed management environment.

Manager-agent communication can be identified in an object-oriented environment by a communication protocol (eg, Common Management Information Protocol (CMIP) or Common Object Request Broker Architecture (CORBA) according to ITU-T X.711) and an object model. Via so-called management interfaces or manager-management interfaces.

These interfaces, for example, exist between the element management level on one side and the network element level on the other. Examples for network devices for the interface (OMC BSS interface) are shown in the base stations of the base station system (BSS) in the operation and maintenance centers (OMC) at the element management level and in the GSM mobile radio network at the network element level, for example. Is given by Base stations of a second generation GSM network are mentioned here as an example. In the scope of the invention, also the base stations of other communication networks, for example node B of a UMTS Universal Mobile Telecommunication System or wireless access points of a WLAN system are for example one of the IEEE 812.11-standards. May be related to

There are management interfaces or manager-agent interfaces, in particular also between the network management level on one side and the network element management level on the other. Such interfaces are important to the present invention. Examples of network devices for these interfaces (NMC-OMC interfaces or NM-EM interfaces) can be found in the network management centers (NMC) on the network management level side and for example in the mentioned GSM or other mobile wireless networks. It is given by management level operations and maintenance centers (OMC).

For example, services in a management network that allow the operator to change the structure and thus the behavior of the telecommunications network typically model and fully network network resources in an object-oriented environment, creating a network-specific Management Information Base (MIB). It relates to instances of managed objects that form together.

The cellular structure is the basic principle for implementing a wireless subsystem of a mobile network having at least a wide coverage area. One prerequisite for the functionality of a mobile network is the precise definition of the relationships between neighboring cells, also called neighboring cells.

From the "Management Information" perspective, these relationships are basically defined by two object categories:

Cell: An instance of these managed object classes (MOC) defines one (reference) cell of the mobile network.

Adjacent Cell: Defines one neighbor cell in which an instance of such managed object classes (MOC) can be used for handover and / or reselection with respect to the reference cell.

In general, complex telecommunication networks (eg, mobile networks) typically use management layers in which element managers (OMC systems) act as agents and network managers (NMC systems) act as managers. . Operations are performed in the network management centers (NMC) as well as in the operations and maintenance centers (OMC) and management information is processed and stored.

In a multi-manager environment, each agent must handle the requests of multiple managers that request to operate in parallel with each other. The manager can optimally perform his function only when all relevant event reports are received from lower agents. This occurs through so-called event reporting mechanisms under normal conditions, ie when communication between the agent and its managers is being done correctly. The task of the event reporting mechanism is to route only event reports that meet certain filter criteria to the manager.

Even if individual NM-EM interfaces fail, ensuring consistency of management information is especially important for efficient network operation, especially in hierarchical multi-manager configurations.

Therefore, an object of the present invention is to provide a method, network apparatus as mentioned above, which enables the effective distribution of management information via NM-EM interfaces for all related management systems (especially the kind having "broadcast" functionality). And a communication system.

The problem is solved according to the invention with respect to a method according to the features of claim 1, a network device according to the features of claim 9, a network management device according to the features of claim 10, and a communication system according to the features of claim 12. Is solved. Further refinements and embodiments of the invention useful can be found in the dependent claims.

According to the present invention, in each manager acting as a network manager, common resources of the communication system are identified within the object-oriented management hierarchy, and management information is generated using the identification of common resources and the interface between the manager and the agent. It is sent as event reports to all devices in the management network affected by and operating as network managers or element managers.

In the case of network management centers (NMC) as managers and operation and maintenance centers (OMC) as agents, this means that all network management centers (NMC) of the management network whose management information is affected by events and act as network managers, and In the operations and maintenance centers (OMC) of the management network affected by the event and acting as element managers, identification of common resources and the NM- between the network management center (NMC) and the operations and maintenance center (OMC). It is sent as event reports using the EM interface.

The interface to the manager-agent relationship between the Network Management Centers (NMC) and the Operations and Maintenance Center (OMC) can be usefully developed as a real time interface. In this way, it is possible to use a real time interface (real-time OMC-NMC management interface) to ensure consistency of management information between cells in neighboring network areas.

The basis for the method according to the invention is the management and identification of the so-called common resources at each network manager (NMC). In an object-oriented management hierarchy, the resources of a communication network managed by instances of different object classes in neighboring network regions are called common resources.

As an example therefor, OMC region as a reference cell of the (instance of the cell object class) and the adjacent OMC regions can consider the model of the individual cells of the mobile radio network as neighboring cells for the (adjacent to the multiple instances of the cell object class) have.

In an embodiment of the present invention, different object instances of actual network resources are defined by the operator and represent an identifier that is valid in a wide area network and represents an identifier that can be modeled by a standardized characteristic (ITU-T M.3100) userLabel, so-called It has a symbolic name. As a result, in the method according to the invention, in particular the identification of the common resources of the communication system can be made by issuing a symbolic name as a valid identifier in the communication system.

Advantageously, each manager (NMC), acting as a network manager, may store allocation information of symbolic names for at least one corresponding object instance in the object-oriented management hierarchy. The assignment information makes it possible to establish in a relatively simple way which event reports should be distributed to which devices of the management network.

The management information is sent to devices (NMC and / or OMC) of the management network as event reports by the agent (Operation and Maintenance Center (OMC)), which is the original sender, or by the manager (Network Management Center (NMC)), which is the original sender. Can be sent. If event reports originate from the element manager level (EM Level) of the Operations and Maintenance Centers (OMC), the distribution of management information begins with transmission from the relevant Operations and Maintenance Center (OMC) to the connected Network Management Centers (NMC). do. As a result, the management information is sent as event reports from at least one agent (OMC) of the management network to the connected manager (NMC).

If the event reports originate from the Network Manager Level (NM Level) of the Network Management Centers (NMC), the distribution of management information begins with transmission from the relevant NMC to the connected Operations and Maintenance Centers (OMC). In this case, management information is sent as event reports from at least one manager (NMC) of the management network to connected agents (OMC).

In another refinement of the invention, multiple transmissions of the same event reports ignore each receipt of an event report that has already been received and each manager (NMC) and each agent that do not forward it back to the connected devices (NMC or OMC) of the management network. Prevented by (OMC). In this way, unnecessary transmission of event reports is effectively prevented.

Against the background of the described criteria, it is possible to automate the distribution of management information in a relatively simple manner. Management information is distributed bidirectionally through the NM-EM interfaces by all affected management systems, that is, a kind of "broadcast" function can be used. In addition to the redundancy of communication links, this also allows the consistency of management information to be ensured hierarchically as well as horizontal level (eg between neighboring OMCs).

At each manager (NMC) operating as a network manager, information about the assignment of symbolic names to at least one corresponding object instance in the object-oriented management hierarchy may be stored in a table form. Each time after the NM-EM link is established, the NM system synchronizes the configuration data. Thus, each network manager center (NMC) forms its own table, each of the lines of the table including an assignment between the symbolic name and the corresponding object instance (distinct name). Common resources are recognized when multiple instances (different object classes) in a table line are assigned to exactly one symbolic name.

According to the present invention, a network device (operation and maintenance center (OMC)) is a manager of a network management level NM LEVEL (network manager center NMC) and an agent of an element management level EM LEVEL. Assume that it is designed to act as an agent of a management network for monitoring and controlling a cellular communication system for at least one manager-agent relationship between centers (OMCs). According to the present invention, using the identification of common resources and the interface (NM-EM interface) between the manager (Network Manager Center (NMC)) and the agent (Operation and Maintenance Center (OMC)), Means are provided for distributing management information as event reports to all devices (network manager center NMC) of the management network operating as network managers (network manager center NMC).

In the function as a manager in the management network for monitoring and controlling the cellular communication system, the network device (operation and maintenance center (NMC) of the network management level (NM LEVEL) and the agent of the element management level (EM LEVEL) OMC) is a network management device (Network Manager Center (NMC)) designed for at least one manager-agent relationship. According to the present invention, the identification of common resources and the interface (NM-EM interface) between a manager (Network Manager Center (NMC)) and an agent (Operation and Maintenance Center (OMC)) are influenced by the event. Means are provided for sending management information as event reports to all devices (operation and maintenance center (OMC)) of the management network operating as network element managers.

In addition, according to the present invention, means for storing the assignment information of the symbolic name for at least one corresponding object instance in the object-oriented management hierarchy may be provided to the network management apparatus (Network Manager Center (NMC)). have.

A communication system according to the present invention having a management network for monitoring and controlling a cellular communication system is implemented as agents on different management levels (EM LEVEL, NM LEVEL), which operate as agents (operation and maintenance centers) OMC) and network management devices according to the present invention (Network Manager Center (NMC)) which also act as managers.

In principle, the method according to the invention can be used in all communication networks and in particular in telecommunication networks (especially wireless, as well as wire-coupled). In a multi-manager configuration, there are a large number of managers and a large number of agents.

In general, the method may be used for all kinds of manager-agent interfaces. As an example is described below using embodiments for a CMIP-based NMC-OMC interface. However, the method can also be used in the same way or in accordance with other interface protocols (eg SNMP or CORBA).

In the following, the invention is described in more detail with reference to the drawings using embodiments.

1 is a basic block diagram of a management network for a (mobile) communication system having an agent-manager relationship between operations and maintenance centers and various network management centers;

2 is a block diagram of an exemplary cutout of a management network for a communication system having an agent-manager relationship between four operations and maintenance centers and four network management centers;

3 is a schematic diagram of examples of different ways to distribute management information in the form of event reports for the block diagram of FIG. 2, FIG.

4 is a schematic diagram of an example distribution path for management information in the form of event reports for the block diagram of FIG. 2 when the link between NMC ₁ and OMC ₂ fails; and

FIG. 5 is a schematic diagram of an example distribution path for management information in the form of event reports for the block diagram of FIG. 2 when a link between OMC ₁ and NMC ₂ fails. FIG.

1 shows operations and maintenance centers OMC ₁ , OMC ₂ through OMC _n (operation and maintenance centers) and several network management centers NMC ₁ , NMC ₂ , NMC ₃ through NMC _n (network management centers). Represents a block diagram of a management network for a mobile communication system having an agent-manager relationship between them. In this case, the representation of FIG. 1 is limited to two levels NM LEVEL and EM LEVEL. For example, the management level of the management network, which level includes the network device level (network element level) with several base station systems, is not shown.

The management level (EM LEVEL) identifies the network element management level, where the operations and maintenance centers OMC ₁ , OMC ₂ through OMC _n provide a typical manufacturer-specific management functionality, for example a base station system not shown in FIG. 1. To each of the individual base stations. The management level (NM LEVEL) identifies the network management level, where the network management centers NMC ₁ , NMC ₂ , NMC ₃ to NMC _n each implement an integrated management functionality independent of the manufacturer. Thereby, several network management centers (NMC) can access the same network device of the next lower level of management (EM LEVEL), in this example the next level of network management centers of the NM LEVEL. (NMC ₁ , NMC ₂ ) can access the same network device at the next lower level of management (EM LEVEL) of the Operations and Maintenance Center (OMC2). Network devices of different management levels with operation and maintenance centers (OMC ₁ , OMC ₂ through OMC _n ) on one side and network management centers (NMC ₁ , NMC ₂ , NMC ₃ through NMC _n ) on the other side In between, interfaces (NM-EM-IF) (NM-EM interface) for transmitting information are defined. 1 shows a multi-manager configuration of a management network.

In the following, the distribution for event reports from the EM level is shown.

These are event reports that occur naturally in the Operations and Management Centers (OMC) or related network elements or triggered by operator actions, for example:

Alarms

ㆍ Alarm acknowledgment signal (alarm acknowledgment signal according to 3GPP TS 32.111)

ㆍ Manual alarm clearing signal (alarm clearing notification signal according to 3GPP TS 32.111)

• change in attribute values.

In the distribution of event reports from the Operations and Maintenance Center (OMC) to the connected Network Management Centers (NMC), the Network Management Center (NMC) is run by the Network Management Center (NMC) on each NM-EM interface (NM-EM-IF). Assume that you set up a filter mechanism (such as an EFD event forwarding discriminator) within (OMC) and set filter criteria.

The Operations and Maintenance Center (OMC) forwards each event report (eg M EVENT REPORT for CMIP-based NM-EM interfaces) to all NMC-specific filter mechanisms. Thus, each network management center (NMC) can control the flow of information according to its own individual requirements, i.e. reports that are not required from the perspective of the network management center (NMC) are already present in the operation and maintenance center (OMC). Is filtered.

Event reports received by the Network Management Center (NMC) are distributed again to other Operations and Maintenance Centers (OMC) as follows: After receiving the event report, each Network Management Center (NMC) is responsible for object instances (currently Check whether the object instance referred to by the event report exists as a common resource in the configuration data table.

If this is the case, event reports are also important for other neighboring operations and maintenance centers (OMCs). For each other object instance of the table line, the network management center (NMC) is responsible for each associated operation and the corresponding request signal (e.g., M-ACTION or M-SET for CMIP-based NM-EM interfaces). Send to maintenance center (OMC).

In one example, a management hierarchy with several EM and NM systems is assumed to be relevant only to neighboring EM systems (OMC ₁ , OMC ₂ , OMC ₃ , OMC ₄ ). This kind of scenario is shown schematically in FIG. 2 is a block diagram of an exemplary cutout of a management network for a communication system having an agent-manager relationship between four operations and maintenance centers and four network management centers. Levels, as well as connections of network management centers (NMC ₁ , NMC ₂ , NMC ₃ , NMC ₄ ) and operations and maintenance centers (OMC ₁ , OMC ₂ , OMC ₃ , OMC ₄ ) shown in solid lines Connections to additional network devices (NMC or OMC), which may exist in NM LEVEL and EM LEVEL, but are not represented in FIG. 2, are indicated by dotted lines.

The reference cell cell ₁ is defined in the network area monitored by the operation and maintenance center OMC ₁ . The cell is also the adjacent cell ( adjacentCell ₂₁ , adjacentCell ₃₁ , adjacentCell ₄₁ ) for correspondingly defined network areas that are simultaneously monitored by the operations and maintenance centers OMC2, OMC3, OMC4.

3 is a schematic diagram of examples of different ways to distribute management information in the form of event reports for the block diagram of FIG. 2.

Network management centers (NMC ₁ (broadcast path 1, solid arrow in FIG. 3) and NMC ₂ (broadcast path 2, dashed arrow in FIG. 3)) in which an alarm of the object instance cell ₁ is generated and corresponding alarm report is connected. Is sent by the Operations and Maintenance Center (OMC ₁ ).

A first distribution path of the management information of the type of event report (broadcast path 1) through a network management center (NMC _1), said network management center (NMC ₁₎ may also communicate with the operation and maintenance center (OMC ₂₎ Using its own table on common resources, the network management center (NMC ₁ ) recognizes the relationship between the instants ( cell ₁₁ and adjacentCell ₂₁ ) and forwards an "alarm" to the connected operations and maintenance center (OMC2). do. Here the alarm (alarm for adjacentCell ₂₁ instance) is included in the alarm list of OMC ₂ and then forwarded to all other connected NMC systems (network management centers NMC ₂ , NMC ₃ ) as an alarm notification signal. The network management center NMC ₂ has already received the alarm from the operation and maintenance center OMC ₁ because the alarm notification signal is ignored by the operation and maintenance center OMC ₂ .

The Network Management Center (NMC ₃ ), which received the alarm from the Operations and Maintenance Center (OMC ₂ ) and otherwise communicated with the Operations and Maintenance Centers (OMC ₃ , OMC ₄ ), has an instance of an object in its own table for common resources. Recognize the relationship between adjacent cells ₂₁ , adjacentCell ₃₁ , adjacentCell ₄₁ , and forward the "alarm" notification signal to other connected operations and maintenance centers (OMC ₃ , OMC ₄ ).

In the Operations and Maintenance Center (OMC ₃ ), alarms (alarms for adjacentCell ₃₁ instances) are included in the alarm list. The operations and maintenance centers OMC ₄ also include the alarms (alarms for adjacentCell ₄₁ instances) in their own alarm list and then forward the alarm notification signals to the connected network management centers NMC ₄ . Thus, all relevant management systems note alarms within cell ₁ .

Similar alarm forwarding takes place via a second distribution path (broadcast path 2, dashed arrow in FIG. 3) via the network management center NMC2.

It can be seen from FIG. 3 that bidirectional “broadcast” functionality can cause message transmission to be redundant. However, if each management system in the management network simply forwards the notification signal that it has already received and simply ignores it (in this way NMC ₂ ignores the alarm from OMC ₂ -see the above embodiments), Multiple transmission of event reports can be prevented.

On the other hand, the redundancy that exists is important to ensure the consistency of management information even when the connection between the network management center and the operations and maintenance center (NM-EM connection) fails.

4 shows a schematic diagram of a model distribution path of management information in the form of event reports for the block diagram of FIG. 2 when the connection between the network management center NMC ₁ and the operation and maintenance center OMC ₂ has failed. . 4 shows the forwarding of the above mentioned alarm when the connection between the network management center NMC ₁ and the operation and maintenance center OMC ₂ has failed. This corresponds to the forwarding of the alarm via the second distribution path (broadcast path 2, dashed arrow) in FIG. 3. Specifically, the distribution path of the event report or alarm report includes the following connections:

Connection (or transmission path) A: From OMC ₁ to NMC ₁

Connection (or transmission path) B: OMC ₁ to NMC ₂

Connection (or transmission path) C: NMC ₂ to OMC ₂

Connection (or transmission path) D: From OMC ₂ to NMC ₃

Connection (or transmission path) E: NMC ₃ to OMC ₃

Connection (or transmission path) F: NMC ₃ to OMC ₄

Connection (or transmission path) G: From OMC ₄ to NMC ₄ .

5 is a schematic diagram of another model distribution path of management information in the form of event reports for the block diagram of FIG. 2 when the connection between the operation and maintenance center OMC ₁ and the network management center NMC ₂ fails. Indicates. 5 also reproduces the forwarding of the above-mentioned alarms, in which case the connection between the operation and maintenance center OMC ₁ and the network management center NMC ₂ has failed. This corresponds to the forwarding of the alarm via the first distribution path (broadcast path 1, solid arrow) in FIG. Specifically, the distribution path of the event report or alarm report includes the following connections:

Connection (or transmission path) A: From OMC ₁ to NMC ₁

Connection (or transmission path) B ': NMC ₁ to OMC ₂

Connection (or transmission path) C ': OMC ₂ to NMC ₂

Connection (or transmission path) D: From OMC ₂ to NMC ₃

Connection (or transmission path) E: NMC ₃ to OMC ₃

Connection (or transmission path) F: NMC ₃ to OMC ₄

Connection (or transmission path) G: OMC ₄ to NMC ₄

In addition to distribution of event reports originating on the EM level, there may also be distribution of event reports originating on the NM level.

Here, event reports are triggered by operator actions in the Network Management Center (NMC), for example:

ㆍ Alarm acknowledgment signal (alarm acknowledgment operation according to 3GPP TS 32.111)

ㆍ Manual alarm clearing signal (alarm clearing action according to 3GPP TS 32.111)

• change in attribute values.

Here, an example may be a change in the handover attribute in the cell cell ₁ by the operator in the network management center NMC ₁ . Since the parameter is also related to object instances ( adjacentCell ₂₁ , adjacentCell ₃₁ , adjacentCell ₄₁ ), the change must be reported to all neighboring OMC regions. Distribution (broadcast functionality) proceeds in a similar manner as described above, with the Network Management Center (NMC ₁ ) being the starting point. This means that the distribution via path A of FIGS. 4 and 5 can be reversed from the network management center NMC ₁ to the operations and maintenance center OMC ₁ .

An example of the method is described using the Q3 (CMIP based) interface. However, the present invention can also be applied to other interfaces, for example CORBA based interfaces.

In general, the following features of the method according to the invention or of the invention may generally be known as:

The method enables automatic update of management information between OMCs and NMCs and between neighboring OMCs.

Even if individual NM-EM connections fail, the consistency of data between all EM and NM systems (Operation and Maintenance Centers (OMC) and Network Management Centers (NMC)) is ensured.

In principle, the method can be used for all telecommunication networks.

Claims (12)

A method for distributing management information in a management network for monitoring and controlling a communication system, the method comprising: The management network comprises managers NMC _i and agents OMC _i configured as devices on different management levels NM LEVEL, EM LEVEL, wherein the management information is the devices NMC of the management network. _i , OMC _i ) transmitted as event reports, As a method of distributing management information, In each manager NMC _i that acts as a network manager, common resources of the communication systems are identified in an object-oriented management hierarchy, and management information is identified for common resources and the manager NMC _i and the agent OMC _i. Event reports A, B, and B to all devices NMC _{i ,} OMC _i of the management network that are affected by the event and operate as network managers or element managers using the interface between NM-EM-IF). C, D, E, F, G, B ', C'), How to distribute management information. The method of claim 1, Identification of common resources of the communication system is performed by issuing a symbolic name as a valid identifier within the communication system, How to distribute management information. The method of claim 2, In each manager NMC _i , acting as a network manager, information regarding the assignment of symbolic names for at least one corresponding object instance of the object-oriented management hierarchy is stored. How to distribute management information. The method according to any one of claims 1 to 3, The management information is derived from the agent OMC _i as the original sender or from the managers A, B, C, D, E, F, G, B ', C' as the original sender NMC _i of the management network. Sent as event reports to How to distribute management information. The method according to any one of claims 1 to 4, The management information is transmitted from the at least one agent OMC _i to the connected managers NMC _i of the management network as event reports A, B, D, G, C ', How to distribute management information. The method according to any one of claims 1 to 5, The management information is transmitted from the at least one manager NMC _i to the connected agents OMC _i of the management network as event reports C, E, F, B '. How to distribute management information. The method according to any one of claims 1 to 6, Multiple transmissions of the same event reports (A, B, C, D, E, F, G, B ', C') allow each manager (NMC _i ) and each agent (OMC) to ignore already received event reports upon re-receipt. prevented by _i ) How to distribute management information. The method according to any one of claims 3 to 7, Information regarding the assignment of symbolic names for at least one corresponding object instance of each manager NMC _i operating as a network manager is stored in a table form, How to distribute management information. A network device (OMC _i ) operating as an agent in a management network for monitoring and controlling a cellular communication system, The network device OMC _i is designed for at least one manager-agent relationship between the manager NMC _i of a network management level NM LEVEL and the network device OMC _i as an agent of an element management level EM LEVEL. , As a network device, All devices in the management network that are affected by events and operate as network managers, using identification of common resources and an interface (NM-EM-IF) between the manager NMC _i and the agent OMC _i . Means are provided for transmitting management information as event reports A, B, C, D, E, F, G, B ', C', Network devices. A network management apparatus (NMC _i ) operating as a manager in a management network for monitoring and controlling a cellular communication system, Agents relationship - at least one manager between the network management device (NMC _i) is a network management level (NM LEVEL) network management device (NMC _i) and the element as an agent of a management level (EM LEVEL) network device (OMC _i) of the Designed for As a network management device, All devices in the management network affected by the event and operating as network element managers, using the identification of common resources and the interface NM-EM-IF between the manager NMC _i and the agent OMC _i ( OMC _i ) is provided with means for transmitting management information as event reports A, B, C, D, E, F, G, B ', C', Network management device. A network management device (NMC _i ) according to claim 10, Means are available for storing information regarding the assignment of symbolic names for at least one corresponding object instant in the object-oriented management hierarchy. Network management device. A network device OMC _i operating as an agent according to claim 9, configured as devices on different management levels EM LEVEL, NM LEVEL and also a network management device operating as a manager according to claim 10. NMC _i ) A communication system having a management network for monitoring and controlling a cellular communication system including all of them.

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