6 Elementary Procedures

12.213GPPNetwork Management (NM) procedures and messages on the A-bis interfaceRelease 1998TS

The operational procedures applicable to the BTS consist of bringing BTS equipment and software into (or taking them out of) service, initiation of tests at the BTS, collection of test results made at the BTS, reporting and clearing of any BTS faults, and reporting of any BTS external alarms. Bringing into service of equipment at the BTS will include manual operations, including turning the switch on, and performing local testing where relevant at the BTS, followed by an indication of the availability of the equipment to the BTS via some man-machine interface (MMI terminal, telephone). It is then a BSC function to ensure that relevant data on the existence of the equipment is resident at the BTS, and to activate (bring into service) the new equipment. Manual procedures may also be employed for software loading, at least initially.

As far as software is concerned, all operational software used at the BTS shall also be kept at the BSC, and can be downloaded from the BSC. At the BTS there may be either single instance of the software, or there may also be back-up versions.

6.1 Definition of the Procedures

All the procedures covered in the present document are based on formatted O&M messages. Most formatted O&M messages initiated by the BSC (or by a BTS) will receive a response or acknowledgement at Layer 3. A pair of such messages, or single message if a response is not required, is referred to as an elementary procedure. All messages shall be sent using I frames at Layer 2.

A number of procedures, referred to as structured procedures (see GSM 12.22), are based on a multiplicity of elementary procedures. Some structured procedures may also involve MMI messages, but these are not defined in the present document. For all elementary procedures described in Subclauses 6.2 through 6.10, the protocol scenarios are illustrated with no further explicit reference made from their corresponding subclauses because of their self-explanatory nature.

Descriptions of the messages and the direction of transmission are given in the following subclauses.

No elementary procedure shall be initiated to an object instance which has not yet replied to a previously initiated elementary procedure with a response, an ACK or a NACK within a layer 3 time-out. The layer 3 timeout for ACK, NACK and responses shall have a default value of 10 seconds.

An ACK message is returned to inform the application which initialized the message that the command is performed or will be performed.

The whole message must be rejected if there is something not understood/supported in the original message.

A NACK may not be relevant for some elementary procedures.

The most relevant Nack causes, not covered by the general causes (which are used for understanding of header fields), are given for each elementary procedure with reference to the coding of the Nack causes in subclause 9.4.36.

The general Nack causes are relevant for any Nack message and are also found in subclause 9.4.36.

6.2 SW Download Management Procedures

6.2.1 Load Data Initiate

This message shall be sent from the BSC to the BTS to initiate the loading of a file. It indicates the number of segments for which a Layer 3 acknowledgement is required (window size). When receiving data the BTS shall send an ACK after this number of segments, except for the last batch.

BSC BTS

Load Data Initiate

——————————————–>

ACK/NACK

<——————————————–

Meaning of Ack message : Ready to receive the specified file.

Message specific Nack causes (see subclause 9.4.36): 23, 24.

6.2.2 Load Data Segment

These multi-segment messages shall be used to carry the files for the transfer initiated by the Load Data Initiate message. No other file transfer shall be allowed until the current transfer is finished.

BSC BTS

Load Data Segment -+

——————————————–> ¦

Load Data Segment ¦- Window Size

——————————————–> ¦

¦

¦ -+

ACK

<——————————————–

Load Data Segment

——————————————–>

etc.

etc.

An ACK shall be sent from the BTS to the BSC every time when Window Size number of segments specified in the Load Data Initiate message are downloaded. A reception of an ACK must not reset the value of the sequence number of the subsequent message segments (see subclause 8.1.1). When all the expected blocks have been received, an ACK must be sent regardless of the window size. If the timer for a time-out for the Layer 3 acknowledgement expires, the BSC shall send a Load Data Abort message and the file transfer shall be aborted.

Meaning of Ack message: A window of Load data segment messages or a complete file has been received.

6.2.3 Load Data Abort

This message shall be used by either end if the file transfer can no longer be supported. This message shall also be used by the BTS if the received amount of data exceeds the expected amount.

BSC BTS

Load Data Abort

<——————————————->

6.2.4 Load Data End

This message shall be sent by the BSC to the BTS. The BTS sends an ACK when the file has been received in the BTS.

BSC BTS

Load Data End

——————————————–>

ACK/NACK

<——————————————–

Meaning of Ack message : File download is successfully terminated.

Message specific Nack causes (see subclause 9.4.36): 25.

6.2.5 SW Activate Request

This message shall be sent by the BTS when the resource represented by the object instance (Site Manager, BTS, Radio Carrier, or Baseband Transceiver) has started up. The initialization of mentioned object instance shall be started with software activation, which may include software download continuing with attribute setting.

BSC BTS

SW Activate Request

<——————————————–

ACK/NACK

——————————————–>

Meaning of Ack message : The request is granted and software activation will be commenced.

Message specific Nack causes (see subclause 9.4.36): None.

6.2.6 Activate SW

This message from the BSC to the BTS shall be used to activate the loaded software, indicating which file (or files) is to be activated. The acknowledgement of the Activate SW indicates that the software can be activated. If the software cannot be activated, a NACK must be sent. The activation may include BTS internal software distribution.

BSC BTS

Activate SW

——————————————–>

ACK/NACK

<——————————————–

Meaning of Ack message: File will be activated.

Message specific Nack causes (see subclause 9.4.36): 23, 26, 27.

6.2.7 SW Activated Report

This message from the BTS to the BSC shall be sent from the addressed object on the BTS at a successful completion of the software distribution to and activation on all indicated destinations in the BTS.

BSC BTS

SW Activated Report

<——————————————–

6.3 A‑bis Interface Management Procedures

These procedures (excluding ‘Establish TEI’) are only relevant with BTSs having flexibility to configure A-bis channels to different Baseband Transceivers. This configuration flexibility is realized with equipment that can be called BTS front-end switch. In other words this switch allows an A-bis channel to be able to be connected in several possibilities.

There must be a default connection to the Site Manager, which manages the front-end switch. The default connection information (AbisLink, TEI) must be (semi-)permanently programmable so that it is available at power up. Through the default connection other A-bis connections are established by configuring the front-end switch.

It is optional for BTS equipment to have front-end switch features.

6.3.1 Establish TEI

When an initial/additional TEI is to be established (see GSM 08.56), this message shall be sent from the BSC on a previously established link giving initial/additional TEI number and the corresponding physical connection. For establishment of additional TEI the procedure specified in specification GSM 08.56 must be performed and the result shall be indicated in the ACK/NACK response message. If an initial TEI assignment fails, it can mean that TEIs cannot be assigned through the default link (e.g., physical implementation doesn’t support transferring TEIs from Site Manager to Baseband Transceivers). In that case there must be subsequent preprogrammed TEIs to establish more links.

BSC BTS

Establish TEI

——————————————–>

ACK/NACK

<——————————————–

Meaning of Ack message: The TEI has been established as specified.

Message specific Nack causes (see subclause 9.4.36): 23.

6.3.2 Connect Terrestrial Signalling

This message shall be used to connect a particular terrestrial transmission circuit to a Baseband Transceiver. The procedure can be used only for a BTS that has the relevant flexibility.

BSC BTS

Connect Terrestrial Signalling

——————————————–>

ACK/NACK

<——————————————–

Meaning of Ack message: The specified signalling link has been connected.

Message specific Nack causes (see subclause 9.4.36): 1E.

6.3.3 Disconnect Terrestrial Signalling

This message shall be used to disconnect a Baseband Transceiver from a terrestrial circuit.

BSC BTS

Disconnect Terrestrial Signalling

——————————————–>

ACK/NACK

<——————————————–

Meaning of Ack message: The specified signalling link has been disconnected.

Message specific Nack causes (see subclause 9.4.36): 20.

6.3.4 Connect Terrestrial Traffic

This message shall be used to relate a terrestrial circuit to a radio time slot, if the BTS has the flexibility. If half rate coding is implemented, two Connect Terrestrial Traffic messages shall be sent for each radio timeslot.

BSC BTS

Connect Terrestrial Traffic

——————————————–>

ACK/NACK

<——————————————–

Meaning of Ack message: The specified traffic link has been connected.

Message specific Nack causes (see subclause 9.4.36): 1E.

6.3.5 Disconnect Terrestrial Traffic

This message shall be used to disconnect a terrestrial circuit from a radio timeslot.

BSC BTS

Disconnect Terrestrial Traffic

——————————————–>

ACK/NACK

<——————————————–

Meaning of Ack message: The specified traffic link has been disconnected.

Message specific Nack causes (see subclause 9.4.36): 20.

6.4 Transmission Management Procedures

These prodecures are used to configure on-site transmission equipment. They may not be sufficient and are subject to further standardization.

6.4.1 Connect Multi-drop Link

This message shall be used to relate two terrestrial circuits (64 kbps timeslot in a 2 Mbps system to a radio time slot), if the BTS has the flexibility of setting up multi-drop configuration.

BSC BTS

Connect Multi-drop Link

——————————————–>

ACK/NACK

<——————————————–

Meaning of Ack message: The specified multi-drop link connection has been connected.

Message specific Nack causes (see subclause 9.4.36): 1E.

6.4.2 Disconnect Multi-drop Link

This message shall be used to disconnect a multi-drop configuration in the BTS.

BSC BTS

Disconnect Multi-drop Link

——————————————–>

ACK/NACK

<——————————————–

Meaning of Ack message: The specified multi-drop link connection has been disconnected.

Message specific Nack causes (see subclause 9.4.36): 20.

6.5 Air Interface Management Procedures

6.5.1 Set BTS Attributes

This message shall be sent to provide an object instance on BTS with all the necessary attributes relating to that BTS object. This message does also include common information for all logical channels of one type, e.g., CCCH parameters.

BSC BTS

Set BTS Attributes

——————————————–>

ACK/NACK

<——————————————–

Meaning of Ack message: All specified BTS attributes have been set.

Message specific Nack causes (see subclause 9.4.36): 23.

6.5.2 Set Radio Carrier Attributes

This message shall be used to set a Radio Carrier’s RF-related attributes such as the frequencies and the power.

BSC BTS

Set Radio Carrier Attributes

——————————————–>

ACK/NACK

<——————————————–

Meaning of Ack message: All specified Radio Carrier attributes have been set.

Message specific Nack causes (see subclause 9.4.36): 1B, 23.

6.5.3 Set Channel Attributes

This message shall be sent for each Channel instance to give the channel combination as defined in GSM 05.02 for that time slot. It shall be possible to send one message, if all 8 radio time slots need the same attribute value. This shall be done by not addressing one specific Channel instance in the Instance field in the header, but using a broadcast address. The message may include starting time.

BSC BTS

Set Channel Attributes

——————————————–>

ACK/NACK

<——————————————–

Meaning of Ack message: All specified channel attributes have been set.

Message specific Nack causes (see subclause 9.4.36): 23.

6.6 Test Management Procedures

6.6.1 Perform Test

This message shall be used to tell the BTS to perform a test, if necessary to set a physical configuration for the BSC to carry out a test on the BTS, or to perform a test using a particular configuration. Any measurements may be performed as specific tests. Duration for the test can be given, after which the test report may be autonomously sent if so requested.

Three tests are defined.

1) A radio loop test via the antenna shall be used to test all equipment needed to provide service of one traffic channel. The loop starts and ends in the transceiver baseband parts and loops one traffic channel back in the air interface i.e., using actual antenna equipment. The baseband parts of the transceiver calculate the bit error rate to describe the quality of service that channel provides.

2) A radio loop test via the transceiver shall be used to test most of the equipment needed to provide service of one traffic channel. The loop starts and ends in the transceiver baseband parts and loops one traffic channel back inside the transceiver before the antenna combining equipment. The baseband parts of the transceiver calculate the bit error rate to describe the quality of service that channel provides. This test can be used in conjunction with the previous test to discriminate the location of a possible hardware failure.

3) A functional object self test shall be used to activate an internal self test procedure of a functional object on the BTS made to test equipment that provides the services of the functional object. By its nature this test and its results are proprietary.

BSC BTS

Perform Test

——————————————–>

ACK/NACK

<——————————————–

Meaning of Ack message: Test configuration has been set (if necessary) and the specified test has been started.

Message specific Nack causes (see subclause 9.4.36): 1C, 1D, 1E.

6.6.2 Test Report

This message shall be sent by the BTS giving the result of a test ordered by the BSC and is sent autonomously as soon as the result is available. A Test Report shall also be sent after a specific request from the BSC by a Send Test Report message. The Test Report indicates what was tested, the test type, and the result. No Ack or Nack is returned to the BTS.

BSC BTS

Test Report

<——————————————–

6.6.3 Send Test Report

This message shall be sent from the BSC to ask for the result/report of a test which was not to be sent autonomously now to be started being reported. If the test result was already made to be autonomously reported, this message can also be used to have the present result of the test be reported immediately. The message must include identification of the test.

BSC BTS

Send Test Report

——————————————–>

ACK/NACK

<——————————————–

Meaning of Ack message: The specified test report will be sent.

Message specific Nack causes (see subclause 9.4.36): 1C, 1F.

6.6.4 Stop Test

This message shall be used by the BSC to stop a continuously recurring test at the BTS, to reset a physical test configuration to the normal configuration, or to stop the test and to restore to the normal physical configuration. The message must include identification of the test being performed.

BSC BTS

Stop Test

——————————————–>

ACK/NACK

<——————————————–

Meaning of Ack message: The specified test has been stopped and test configuration reset to normal (if necessary).

Message specific Nack causes (see subclause 9.4.36): 20, 21, 22.

6.7 State Management and Event Report Procedures

6.7.1 State Changed Event Report

An unsolicited report shall be sent from the BTS to the BSC whenever a change of the operational state or of the optional manufacturer dependent state of a managed object defined in the present document occurs. The message shall be also sent when any site input changes its state.

A failure, causing change of operational state, shall generate two event reports: State Changed Event Report and Failure Event Report.

No Ack or Nack is returned to the BTS.

BSC BTS

State Changed Event Report

<——————————————–

6.7.2 Failure Event Report

An unsolicited report shall be sent from the BTS to the BSC whenever failure events occur in the BTS.

Such failure events are:

– fault in a resource resulting from passing a threshold but not constituting a failure;

– failure of a resource.

Pertaining to a failure, there shall be a report for its start and another for its cease.

A failure causing change of operational state shall generate two event reports: State Changed Event Report and Failure Event Report.

No Ack or Nack is returned to the BTS.

BSC BTS

Failure Event Report

<——————————————–

6.7.3 Stop Sending Event Reports

This inhibition of sending of event reports shall be used by the BSC to prevent a flood of event reports which are of no benefit to the BSC. One example of this occurs at a BTS restart following a power failure. The operational capability of the BTS hardware is unlikely to be different from what it was before the failure, and a flood of reports, each stating that a piece of hardware is operating, will delay the software download. Another example concerns the case of a frequently occurring transient fault.

BSC BTS

Stop Sending Events Reports

——————————————–>

ACK/NACK

<——————————————–

Meaning of Ack message: Sending of specified Event Report has been stopped.

Message specific Nack causes (see subclause 9.4.36): None.

6.7.4 Restart Sending Event Reports

When the BTS is back in normal operation or if it is of interest to check whether the BTS still generates a flood of Event Reports, a Restart Sending Event Reports shall be sent.

BSC BTS

Restart Sending Events Reports

——————————————–>

ACK/NACK

<——————————————–

Meaning of Ack message: Sending of specified Event Report has been restarted.

Message specific Nack causes (see subclause 9.4.36): None.

6.7.5 Change Administrative State

The Change Administrative State message shall be used by the BSC to change the administrative state (as specified by specification GSM 12.20) of a managed object.

BSC BTS

Change Administrative State

——————————————–>

ACK/NACK

<——————————————–

Meaning of Ack message: The specified change of administrative state has been performed.

Message specific Nack causes (see subclause 9.4.36): None.

6.7.6 Change Administrative State Request

This request message shall be sent by the BTS when there is a need to change the administrative state of a managed object at the BTS site. This message can only be initiated as a result of a local MMI command.

BSC BTS

Change Administrative State Request

<——————————————–

ACK/NACK

——————————————–>

Meaning of Ack message: The request is granted and a change administrative state message will be sent.

Message specific Nack causes (see subclause 9.4.36): 28, 29.

6.7.7 Report Outstanding Alarms

This message shall be used by the BSC to ask BTS to report all outstanding alarms related to the object instance indicated in the message. The BTS shall report alarms by sending a series of Failure Event Report messages for all outstanding alarms. Only those alarms previously reported and still outstanding shall be re-reported through this procedure. Any new alarms not yet reported but about to be reported shall be excluded and they shall be reported through a separate Failure Event Report procedure spontaneously initiated by the BTS itself. If there is no outstanding alarm, the BTS shall reply with a NACK with that cause indicated.

BSC BTS

Report Outstanding Alarms

——————————————–>

ACK/NACK

<——————————————–

Meaning of Ack message: Sending of Failure Event Report will start.

Message specific Nack causes (see subclause 9.4.36): 28, 29, 2A.

6.8 Equipment Management Procedures

6.8.1 Change-over

This message shall be sent to change over between active and standby units of equipment. The action may be performed on any addressable BTS entity, manufacturer dependent HW units included. Which type of HW unit to address and how to identify certain units of this type of HW are manufacturer dependent.

BSC BTS

Changeover

——————————————–>

ACK/NACK

<——————————————–

Meaning of Ack message: The specified change-over operation has been performed.

Message specific Nack causes (see subclause 9.4.36): 19, 1A, 1E, 23.

6.8.2 Opstart

This message shall be sent by the BSC to tell the BTS to attempt to operatethe identified object putting it to an initial normal operational state (i.e., "enabled", see subclause 5.3.2). This message does not affect the object’s administrative state if there exists a value explicitly assigned by the BSC. If there is yet no administrative state value explicitly set by the BSC (e.g., at an initialization time), the object shall be presumed to be administratively locked by default. No BTS function is required to be responsible for testing the operability of the identified resource as a consequence of this message. Prior to this message being issued, all necessary physical and logical preparations (such as repair of equipment, software downloading, parameter setting, etc., as needed) are expected to have been completed. If the object is in fact not ready to be in an enabled state, the object will be in a fault condition as a consequence of this message, and the condition shall be handled by the object’s normal fault handling function as the condition is detected.

BSC BTS

Opstart

——————————————–>

ACK/NACK

<——————————————–

Meaning of Ack message: The BTS has reset the operational state of the specified object to "enabled" state.

Message specific Nack causes (see subclause 9.4.36): 19, 1A, 23.

6.8.3 Reinitialize

This message shall be sent by the BSC to tell the BTS to have specified hardware resource of the indicated object start a re-initialization procedure as sketched in figure 2. The specifics of a re-initialization procedure, which typically takes place at the time of a cold start of the resource, is manufacturer-dependent. For a software reinitialization, Activate SW message shall be used.

BSC BTS.

Reinitialize

——————————————–>

ACK/NACK

<——————————————–

Meaning of Ack message: The BTS has received the message and is about to start a reinitialization of the specified resource.

Message specific Nack causes (see subclause 9.4.36): 19, 1A, 23.

6.8.4 Set Site Outputs

This message shall be sent by the BSC to tell the BTS to set specified site outputs to the specified state.

BSC BTS

Set Site Outputs

——————————————–>

ACK/NACK

<——————————————–

Meaning of Ack message: The outputs have been set.

Message specific Nack causes (see subclause 9.4.36): None.

6.9 Measurement Management Procedures

6.9.1 Measurement Result Request

This message shall be used by the BSC to request the result of a certain measurement which is running in the BTS to be sent to the BSC. After having responded with the current result, the BTS initializes the measurement result buffer (e.g. setting to zero) and continues the measurement.

BSC BTS

Measurement Result Request

——————————————–>

Response/NACK

<——————————————–

Message specific Nack causes (see subclause 9.4.36): 2A, 2B.

6.9.2 Measurement Result Response

This message shall be used by the BTS to successfully respond to the BSC on an associated Measurement Result Request completing a Measurement Result Request elementary procedure. By this message, the presently registered measurement result requested shall be reported. If it is not possible for any reason, a NACK message must be used instead of this.

6.9.3 Stop Measurement

This message shall be used by the BSC to stop a continuously running measurement at the BTS. The message must include identification of the measurement to be stopped.

BSC BTS

Stop Measurement

——————————————–>

ACK/NACK

<——————————————–

Meaning of Ack message: The specified measurement has been stopped

Message specific Nack causes (see subclause 9.4.36): 2A

6.9.4 Start Measurement

This message shall be used by the BSC to start a measurement continuously at the BTS. The message must include identification of the measurement to be started.

BSC BTS

Start Measurement

——————————————–>

ACK/NACK

<——————————————–

Meaning of Ack message: The specified measurement has been started

Message specific Nack causes (see subclause 9.4.36): 2A

6.10 Miscellaneous Procedures

6.10.1 Get Attributes

This message shall be used by the BSC to tell the BTS to send attributes which have previously been set by the BTS. It may be used as a check on accuracy and be incorporated into normal procedures, or may be used by the BSC to recover information which it has lost.

BSC BTS

Get Attributes

——————————————–>

Response/NACK

<——————————————–

Message specific Nack causes (see subclause 9.4.36): None.

6.10.2 Set Alarm Threshold

This message shall be used by the BSC to tell the BTS some threshold parameters related to fault thresholds.

BSC BTS

Set Alarm Threshold

——————————————–>

ACK/NACK

<——————————————–

Message specific Nack causes (see subclause 9.4.36): None.

6.10.3 Get Attributes Response

This message shall be used by the BTS to successfully respond to the BSC on an associated Get Attribute elementary procedure. By this message, the presently set values of all requested attributes shall be reported. Otherwise, a NACK message shall be used instead of this.