A Interface Circuit Management

A Interface Circuit Management Feature Parameter Description

Copyright Huawei Technologies Co., Ltd. 2010. All rights reserved.

No part of this document may be reproduced or transmitted in any form or by any means without prior written consent of Huawei Technologies Co., Ltd.

Trademarks and Permissions

and other Huawei trademarks are trademarks of Huawei Technologies Co., Ltd.

All other trademarks and trade names mentioned in this document are the property of their respective holders.

Notice

The information in this document is subject to change without notice. Every effort has been made in the preparation of this document to ensure accuracy of the contents, but all statements, information, and recommendations in this document do not constitute the warranty of any kind, express or implied.

Huawei Proprietary and Confidential Copyright Huawei Technologies Co., Ltd

BSS A Interface Circuit Management Contents

Issue 01 (2010-01-12) Huawei Proprietary and Confidential Copyright Huawei Technologies Co.,

Ltd

iii

Contents 1 Introduction ................................................................................................................................1-1

1.1 Scope ............................................................................................................................................ 1-1 1.2 Intended Audience ........................................................................................................................ 1-1 1.3 Change History.............................................................................................................................. 1-1

2 Overview of A Interface Circuit Management....................................................................2-1

3 A Interface Circuit Management............................................................................................3-1 3.1 Circuit Assignment......................................................................................................................... 3-1 3.2 Circuit Block .................................................................................................................................. 3-1 3.3 Circuit Unblock .............................................................................................................................. 3-2 3.4 Group Circuit Block ....................................................................................................................... 3-2 3.5 Group Circuit Unblock ................................................................................................................... 3-3 3.6 Circuit Unequipped........................................................................................................................ 3-4 3.7 Circuit Reset.................................................................................................................................. 3-4

4 Parameters .................................................................................................................................4-1

5 Glossary ......................................................................................................................................5-1

6 Reference Documents .............................................................................................................6-1

BSS A Interface Circuit Management 1 Introduction


Ltd

1-1

1 Introduction 1.1 Scope This document describes the A Interface Circuit Management functional area. It provides an overview of the main functions and goes into details regarding A Interface Circuit Management.

1.2 Intended Audience This document is intended for:

z Personnel who need to understand A Interface Circuit Management z Personnel who work with Huawei products

1.3 Change History This section provides information on the changes in different document versions.

There are two types of changes, which are defined as follows:

z Feature change: refers to the change in the A Interface Circuit Management feature of a specific product version.

z Editorial change: refers to the change in wording or the addition of the information that was not described in the earlier version.

Document Issues The document issues are as follows:

z 01 (2010-01-12)

01 (2010-01-12) This is the first commercial release of GBSS9.0.

BSS A Interface Circuit Management 2 Overview of A Interface Circuit Management


Ltd

2-1

2 Overview of A Interface Circuit Management A Interface Circuit Management improves the network quality by ensuring a high success rate of call establishments and handovers, and providing value-added services for telecom operators in terms of operation, maintenance, and transmission quality.

Huawei GBSS provides operators with the function of circuit management through the LMT, which facilitates operators to remotely perform operation and maintenance on the TC, such as locating faults on the TC. Circuit management helps improve the efficiency of and reduce the investment on operation and maintenance on the TC.

Huawei GBSS supports A interface circuit management regardless of whether the TC is locally or remotely configured. Huawei GBSS also supports the blocking and unblocking of a single terrestrial circuit or group terrestrial circuits in the case of operations on the LMT or a device fault. The BSC re-sends BLOCK, UNBLOCK, GROUP BLOCK, GROUP UNBLOCK, and RESET CIRCUIT messages to the MSC if the BSC does not receive an acknowledgement message from the MSC within the timer set at the BSC. In addition, the function of circuit unequipped is supported.

A Interface Circuit Management, which involves circuit assignment, circuit block, circuit unblock, group circuit block, group circuit unblock, circuit unequipped, and circuit reset, controls the operation and maintenance on a single circuit or on the entire PCM group circuits for the terrestrial circuit equipment.

A Interface Circuit Management applies to only the TDM network.

BSS A Interface Circuit Management 3 A Interface Circuit Management


Ltd

3-1

3 A Interface Circuit Management 3.1 Circuit Assignment During a call or handover procedure, the MSC carries the information about requested resource(s) in the Assignment Request or Handover Request Message. If the requested resource(s) is/are for speech or data, it also may indicate the terrestrial circuit that shall be used between the MSC and BSS. The BSC assigns and occupies the A interface circuit as indicated in the signaling from the MSC.

If the A interface circuit is successfully assigned and occupied, the BSC sends the MSC a message, indicating that the A interface circuit assignment is complete.

If the A interface circuit indicated by the MSC is unavailable or blocked at the BSC, the BSC sends the MSC a message, indicating that the A interface circuit assignment fails. In addition, the BSC informs the MSC that the A interface circuit is unavailable in the circuit block procedure.

If the A interface circuit indicated by the MSC does not exist at the BSC, the BSC sends the MSC a message, indicating that the A interface circuit assignment fails. In addition, the BSC informs the MSC that the A interface circuit does not exist in the circuit unequipped procedure.

3.2 Circuit Block In the circuit block procedure, the BSC sends the MSC a BLOCK message, indicating that the circuit at the BSS is unavailable.

The BLOCK message contains the Circuit Identification Code (CIC) that identifies the circuit over the A interface. In this way, the state of the circuit at the BSC and that of the circuit at the MSC are consistent.

Figure 3-1 shows the procedure for circuit block.

Figure 3-1 Procedure for circuit block

BLOCK

BLOCK ACK

BSC MSC

Through circuit block, the circuit at the BSS and that at the MSC are blocked at the same time. The procedure for circuit block can be triggered by running the BLK ACIC command and setting Operation Mode to BYCICVALUE in the case of circuit assignment, handover, or device fault.

The BSC sends BLOCK ACK messages to the MSC repeatedly at an interval until the BSC receives a BLOCK ACK message from the MSC. The interval can be set by setting T1 in the SET BSCTMR command.

The circuit at the BSC is blocked even if the BSC does not receive any BLOCK ACK message from the MSC. The circuit is blocked after a call ends. Therefore, circuit block does not affect the circuit on call.

3 A Interface Circuit Management BSS

A Interface Circuit Management

3-2 Huawei Proprietary and Confidential Copyright Huawei Technologies Co.,

Ltd

Issue 01 (2010-01-12)

3.3 Circuit Unblock In the circuit unblock procedure, the BSC sends the MSC a message, informing the MSC of the latest circuit state at the BSC, when a faulty is rectified or a circuit becomes available at the BSC. The UNBLOCK message contains a CIC that identifies the circuit over the A interface.

Figure 3-2shows the procedure for circuit unblock.

Figure 3-2 Procedure for circuit unblock

UNBLOCK

UNBLOCK ACK

BSC MSC

Through circuit unblock, the blocked circuit at the BSC becomes idle. The procedure for circuit unblock can be triggered by running the UBL ACIC command and setting Operation Mode to BYCICVALUE on the LMT.

The BSC sends UNBLOCK messages to the MSC repeatedly at an interval until the BSC receives an UNBLOCK ACK message from the MSC. The interval can be set by setting T1 in the SET BSCTMR command.

The circuit at the BSC is idle even if the BSC does not receive any UNBLOCK ACK message from the MSC.

3.4 Group Circuit Block Group circuit block is used when multiple A interface circuits need to be blocked at the same time. The GROUP BLOCK message contains multiple CICs that identify the circuits over the A interface.



Ltd

3-3

Figure 3-3shows the procedure for group circuit block.

Figure 3-3 Procedure for group circuit block

GROUP BLOCK

GROUP BLOCK ACK

BSC MSC

Through group circuit block, multiple A interface circuits can be blocked at the same time. The procedure for group circuit unblock can be triggered by running the BLK ACIC command and setting Operation Mode to BYCICRANGE on the LMT. Group circuit block applies to only GSM Phase II and GSM Phase II Plus.

The BSC sends GROUP BLOCK messages to the MSC repeatedly at an interval until the BSC receives a GROUP BLOCK ACK message from the MSC. The interval can be set by setting T20 in the SET BSCTMR command.

The circuits at the BSC are blocked even if the BSC does not receive any GROUP BLOCK ACK message from the MSC. The circuits are blocked after a call ends. Therefore, group circuit block does not affect the circuits on call.

3.5 Group Circuit Unblock Group circuit unblock is used when multiple A interface circuits need to be unblocked at the same time. The GROUP UNBLOCK message contains multiple CICs that identify the circuits over the A interface.

Figure 3-4shows the procedure for group circuit unblock.

Figure 3-4 Procedure for group circuit unblock

GROUP UNBLOCK

GROUP UNBLOCK ACK

BSC MSC

Through group circuit unblock, multiple A interface circuits can be unblocked at the same time. The procedure for group circuit unblock can be triggered by running the UBL ACIC command and setting

3 A Interface Circuit Management BSS



Ltd

Issue 01 (2010-01-12)

Operation Mode to BYCICRANGE on the LMT. Group circuit unblock applies to only GSM Phase II and GSM Phase II Plus.

The BSC sends GROUP UNBLOCK messages to the MSC repeatedly at an interval until the BSC receives a GROUP UNBLOCK ACK message from the MSC. The interval can be set by setting T20 in the SET BSCTMR command.

The circuits at the BSC are idle even if the BSC does not receive any GROUP UNBLOCK ACK message from the MSC.

3.6 Circuit Unequipped The BSC sends the MSC an UNEQUIPPED CIRCUIT message if the required circuit indicated by the MSC does not exist in the following processes:

z Circuit block z Circuit unblock z Circuit reset z Circuit assignment z Incoming-BSC handover z BSC reset

Figure 3-5shows the procedure for circuit unequipped.

Figure 3-5 Procedure for circuit unequipped

UNEQUIPPED CIRCUIT

BSC MSC

Through the circuit unequipped procedure, the BSC informs the MSC that the indicated circuit does not exist and requires the MSC not to use the circuit. The BSC triggers the circuit unequipped procedure in any circuit-associated procedure as long as the BSC receives a message that carries the information element (IE) about unequipped circuit from the MSC. Circuit unequipped applies to only GSM Phase II and GSM Phase II Plus.

There is no acknowledgement message in response to the UNEQUIPPED CIRCUIT message in the circuit unequipped procedure. In addition, the BSC sends the UNEQUIPPED CIRCUIT message to the MSC only once.

3.7 Circuit Reset After part of a system fails, for example, the SCCP link is released abnormally, the circuit at the BSC or MSC can be restored through circuit reset. If a circuit is idle after the SCCP link is released abnormally, the BSC sends a RESET CIRCUIT message to the MSC.

Figure 3-6shows the procedure for circuit reset initiated by the BSC.



Ltd

3-5

Figure 3-6 Procedure for circuit reset

RESET CIRCUIT

RESET CIRCUIT ACK

BSC MSC

After receiving a RESET CIRCUIT message from the BSC, the MSC removes all the calls on the circuit and sets the circuit to idle, and then sends a RESET CIRCUIT ACK message to the BSC.

If the BSC does not receive the RESET CIRCUIT ACK message from the MSC, it re-sends a RESET CIRCUIT message to the MSC only once at an interval. The interval can be set by setting T19 in the SET BSCTMR command.

The circuit at the BSC is idle even if the BSC does not receive any RESET CIRCUIT ACK message from the MSC. The procedure for circuit reset can be triggered by running the RST ACIC command on the LMT.

BSS A Interface Circuit Management 4 Parameters


Ltd

4-1

4 Parameters This chapter describes the parameters related to A Interface Circuit Management.

For the description of each parameter, see . For the default value, value ranges, and MML commands of each parameter, see .

Table 5-1Table 5-2

Table 4-1 Parameter description (1)

Parameter ID Description

AT1 Timer for waiting for a single A-interface circuit blocking or unblocking answer. The BSC6900 starts this T1 timer after sending a single A-interface circuit blocking or unblocking message. If the BSC6900 does not receive a blocking or unblocking answer from the MSC before this timer expires for the first time, the BSC6900 resends the single A-interface circuit blocking or unblocking message to the MSC. If the timer expires for the second time, the BSC6900 reports an alarm for BSC circuit blocking or unblocking failure.

AT19 Timer for waiting for an A-interface circuit reset answer. The BSC6900 starts this timer after sending an A-interface circuit reset message. When this timer expires for the first time, the BSC6900 resends the circuit reset message to the MSC. If this timer expires for the second time, the BSC6900 reports an alarm for BSC circuit resetting failure.

OPMODE It is one key filed of identifying A interface CIC status and indicates the alignment mode of A interface circuit.

AT20 Timer for waiting for an A-interface circuit group blocking or unblocking answer. After sending a CIC group blocking/unblocking message over the A interface, the BSC6900 starts the timer T20. If the BSC6900 fails to receive a response from the MSC before the first expiry of T20, the BSC6900 resends the CIC group blocking/unblocking message. If no response is received before the second expiry of T20, the system reports the BSC Unable to Block Group Circuits or BSC Unable to Unblock Group Circuits alarm.

Table 4-2 Parameter description (2)

Parameter ID Default Value GUI Value Range

Actual Value Range

Unit MML Command

Configuration on

AT1 30 1~300 1~300 s SET BSCTMR

BSC

AT19 30 1~300 1~300 s SET BSCTMR

BSC

AT20 30 1~300 1~300 s SET BSCTMR

BSC

OPMODE None BYCICRANGE(BY CIC

BYCICRANGE, None BLK ACIC;UBL

E1/T1 link

4 Parameters BSS



Ltd

Issue 01 (2010-01-12)

Parameter ID Default Value GUI Value Actual Value Unit MML Configuration Range Range Command on RANGE), BYCICVALUE(BY CIC VALUE)

BYCICVALUE ACIC

BSS A Interface Circuit Management 4 Parameters


Ltd

4-1

BSS A Interface Circuit Management 5 Glossary


Ltd

5-1

5 Glossary For the acronyms, abbreviations, terms, and definitions, see the Glossary.

BSS A Interface Circuit Management 6 Reference Documents


Ltd

6-1

6 Reference Documents z BSC6900 Feature List z BSC6900 Basic Feature Description z BSC6900 GSM Parameter Reference z BSC6900 GSM MML Command Reference

1 Introduction 1.1 Scope 1.2 Intended Audience 1.3 Change History 2 Overview of A Interface Circuit Management 3 A Interface Circuit Management 3.1 Circuit Assignment 3.2 Circuit Block 3.3 Circuit Unblock 3.4 Group Circuit Block 3.5 Group Circuit Unblock 3.6 Circuit Unequipped 3.7 Circuit Reset

4 Parameters 5 Glossary 6 Reference Documents