6 CM functions

32.106-13GPPConfiguration Management (CM)Part 1: Concept and requirementsRelease 4Telecommunication managementTS

6.1 System modification functions

The requirements of CM and their usage lead to basic CM functions to be defined for the network. These describe the required actions on managed elements (NEs or NRs) and the expected reactions. The system modification functions identified are:

– Creation of Network Elements (NEs) and Network Resources (NRs);

– Deletion of NEs and NRs;

– Conditioning of NEs and NRs.

For all identified functions, the following major requirements apply:

– minimum disturbance of the network by taking the affected resources out of service if needed;

– physical modifications should be independent of the related logical modifications;

– all the required actions to satisfy a defined task should be completed correctly before the resources can be brought into service;

– data consistency checks shall be performed as described in subclause 4.2.1.3.

There are three aspects of NE and NR management, which can be distinguished:

1) Management of the physical aspect (equipment);

2) Management of the executable aspect (SW and FW); and

3) Management of the logical/ functional aspect (data).

All three management aspects are addressed by the present document.

6.1.1 Creation of NEs and NRs

The creation of a NE or NR is used to initially set up a 3G network or to extend an already existing network. The action of creation is a combination of installation, initialisation and introduction of the newly installed equipment to the network and to the OS, which will control it. The creation can affect equipment, SW and data.

Whenever a 3G network or parts of it are installed, the created NEs/NRs requires to be:

– physically installed and tested and initialised with a possible default configuration;

– logically installed by means of introduction to the network, possibly involving changes to related existing NE/NR configurations;

– allowed to be put into service.

The sequence of physical and logical installation may vary depending on the specific 3G network operator strategy.
In case the logical creation takes place before the physical creation no related alarms shall be reported to the operator.

6.1.2 Deletion of NEs and NRs

If a network is found to be over-equipped, the operator may wish to reduce the scale of the network or to re-use the spare equipment elsewhere. This can occur when an operator over-estimates the traffic in one area and, for example, under-estimates the load in a different one.

The deletion of a NE or NR requires:

– taking the affected NEs or NRs out of service;

– logical removal from the network (possibly involving changes to other NE or NR configurations, for example, neighbour cell description);

– if necessary, the physical dismantling of the equipment;

– return of other affected NEs or NRs to service.

The sequence of logical and physical removal will not matter if the affected NEs are taken out of service prior to their removal. This will help to protect the network from error situations.

6.1.3 Conditioning of NEs and NRs

There are three categories of modifications to be regarded with respect to NEs or NRs. It is possible to either modify SW, equipment or data or a certain combination of them. Which aspects are affected by any particular modification is implementation dependent.

When an MO/NR is to be modified the following actions shall be performed:

– Locking or logical removal of the MO/NR (including first clearing it from traffic if necessary);

– Required modification (physical and/or logical); and

– Unlocking or logical re-installation of the MO/NR.

This sequence is recommended to provide protection to the network against fault situations, which may occur during the modification process. By default, locking/modification/unlocking shall be the procedure to follow, and if logical removal/re-installation is necessary for a certain MO/NR, this shall be described in the NRM.

The result of conditioning should be able to be determined by the operator by employing the appropriate mechanisms provided through the System Monitoring functions (see subclause 6.2).

A modification to data, which has a controlling influence on some resources, could influence the resource throughput or its capability to originate new traffic during the modification time. This distinction is made because, for particular modifications, the capacity of the NR can be decreased without influencing the ongoing traffic. Before deciding to perform an action, the operator should consider the effects that a modification might have on capacity, throughput and current activity of a resource.

6.1.3.1 Considerations on conditioning mechanisms

The data, which characterise a 3G network, will not all be subject to the same rate of change or need to be modified using the same mechanism. Changes to the logical configuration may also need to be applied across multiple NEs. These aspects are described in the following subclauses.

Whenever the configuration of the network requires modification, the following questions will be important to the operator:

– What will be the influence on the ongoing traffic?

– What will be the impact on the capacity of the network?

– How difficult and time-consuming will the modification procedure be?

The answer to these questions will give an idea as to when the modification can be best performed with the aim to keep traffic disturbance as low as possible and to require the modification process itself to cause as little disturbance as possible. On the other hand, it does not seem to be reasonable to invent a "low disturbance" modification algorithm for each single parameter, especially those, which are only modified once or twice during the lifetime of the network. These rare modifications could be performed with an acceptable level of interruption to traffic. Therefore, the system data elements may be classified by:

– modification once or twice during the life time of the system (e.g. protocol supervision timers);

– modification required seldom;

– modification is expected frequently and/or for a short term (telecom parameters).

Depending on this rating the requirements on the modification mechanism for certain data elements should vary.

6.1.3.2 Network traffic considerations

As stated previously, different types of modification mechanisms can be distinguished with regard to their impact on traffic and their extent:

For the impact regarding traffic, the following types can be identified:

no impact on the traffic at all: the modified data values have no relation to the traffic capability;

impact on traffic: the data modification causes for example a change in the volume of allowable traffic without affecting existing traffic.

For the impact regarding extent, the following types can be identified:

– Impact on only the NR or NE The modification of SW, equipment or data is effective for a NR, or a complete NE.

– Impact on more than one NE or different NRs of one NE Certain modifications on SW, equipment or data will require changes to be performed upon more than one NR in one NE or more than one NE. Such changes require consideration of data consistency, data integrity and network integrity. E.g. it should be distinguished between the NR directly affected by a modification and other impacted NRs. The relationships and dependencies between data values should be described and a mechanism defined to protect the system against inconsistency.

6.2 System monitoring functions

A major aspect of CM is the ability of the operator to monitor the operation of the network. This monitoring capability is necessary for the operator to determine the current operational state of the network as well as to determine the consistency of information among various NEs. The monitoring capability requires three functions to support it: the information request function, the information report function and the response/report control function.

6.2.1 Information request function

In order to support the operator’s need to monitor the network, the NM needs to be able to gather information on request from the various EMs and/or NEs. The EM may then act as a mediator for one or more NEs (how this is done is product specific and outside the scope of the present document). The information request function should support the capabilities of the NM to be able to request information for any single attribute defined in the management information base.
In addition, the NM should be able to gather large amounts of information in a single request by providing appropriate scope and filtering constructs in the request.

On receipt of a valid request, the addressed EM/NE shall respond with the current values of the specified data elements. This response will be immediate if so requested by the NM. However, in cases where very large amounts of data are concerned and where the EM and the NE support the capabilities, the NM may request the EM/NE to store the information in a file and transfer it using a file transfer mechanism.

In case there is a communication failure when a response is to be sent, the response shall be safely stored and forwarded as soon as possible after re-establishment of communication. An exception that may inhibit this type of delayed response, is if the transaction has timed out in the requesting NM.

6.2.2 Information report function

In addition to being able to provide information on request, the NE is required to have the capability of reporting notifications about changed/removed information autonomously. Generally this will be performed when some information on the state or operation of the system has changed. The following shall be supported:

  • The following type of events shall be notified to the NM, if enabled by the NM (these three notification types may be enabled/disabled separately by the NM):
  1. Object creation/deletion;
  2. Attribute value change;
  3. State change;
  • Optionally: The above mentioned notifications may be logged locally at the EM/NE. Logged notifications may be requested by the NM to be transferred from the EM/NE. Transfer mechanisms may be by file transfer or using messages;
  • In case there is a communication failure when one or more notifications are to be forwarded, the notification(s) shall be safely stored and forwarded as soon as possible after re-establishment of communication.

6.2.3 Response/report control function

For responses to information requests and for information reports, it should be possible for the operator to specify where and when the information should go. The NM, EM and NE shall provide a capability to configure the response/reporting capabilities such that the following requirements are met at the Itf‑N:

– information forwarding shall be possible to be enabled and disabled;

– information shall be possible to be forwarded to the NM as soon as it is available;

– information shall be possible to be directed to any of various NMs (one or several).