BSC6900 UMTS Technical Description(V900R013C00_04)(PDF)-En

BSC6900 UMTSV900R013C00

Technical Description

Issue 04

Date 2012-02-27

HUAWEI TECHNOLOGIES CO., LTD.

Copyright © Huawei Technologies Co., Ltd. 2012. All rights reserved.No part of this document may be reproduced or transmitted in any form or by any means without prior writtenconsent 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. NoticeThe purchased products, services and features are stipulated by the contract made between Huawei and thecustomer. All or part of the products, services and features described in this document may not be within thepurchase scope or the usage scope. Unless otherwise specified in the contract, all statements, information,and recommendations in this document are provided "AS IS" without warranties, guarantees or representationsof any kind, either express or implied.

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

Huawei Technologies Co., Ltd.Address: Huawei Industrial Base

Bantian, LonggangShenzhen 518129People's Republic of China

Website: http://www.huawei.com

Email: [email protected]

Issue 04 (2012-02-27) Huawei Proprietary and ConfidentialCopyright © Huawei Technologies Co., Ltd.

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http://www.huawei.com

mailto:[email protected]

About This Document

PurposeThis document describes the structure, working principles, signal flows, and transmission andnetworking of the BSC6900. It helps the reader understand the implementation and workingprinciples of the BSC6900.

Product VersionThe following table lists the product version related to the document.

Product Name Product Version

BSC6900 V900R013C00

Intended AudienceThis document is intended for:

l Network plannersl System engineersl Field engineers

Organization1 Changes in the BSC6900 UMTS Technical Description

This document describes the changes in the BSC6900 UMTS Technical Description.

2 Overall Structure

This chapter describes the interactions between the modules in the BSC6900.

3 Working Principles

This chapter describes the working principles of the BSC6900 in the following ways: powersupply, environment monitoring, clock synchronization, and OM.

BSC6900 UMTSTechnical Description About This Document


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4 Signal Flow

The BSC6900 signal flow consists of the user-plane signal flow, control-plane signal flow, andOM signal flow.

5 Transmission and Networking

The transmission and networking between the BSC6900 and other NEs can be classified intothe following types: transmission and networking on the Iub interface and on the Iu/Iurinterface.

6 Parts Reliability

The BSC6900 guarantees its operation reliability by means of board redundancy and portredundancy.

ConventionsSymbol Conventions

The symbols that may be found in this document are defined as follows.

Symbol Description

Indicates a hazard with a high level of risk, which if notavoided, will result in death or serious injury.

Indicates a hazard with a medium or low level of risk, whichif not avoided, could result in minor or moderate injury.

Indicates a potentially hazardous situation, which if notavoided, could result in equipment damage, data loss,performance degradation, or unexpected results.

Indicates a tip that may help you solve a problem or savetime.

Provides additional information to emphasize or supplementimportant points of the main text.

General Conventions

The general conventions that may be found in this document are defined as follows.

Convention Description

Times New Roman Normal paragraphs are in Times New Roman.

Boldface Names of files, directories, folders, and users are inboldface. For example, log in as user root.

Italic Book titles are in italics.



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Courier New Examples of information displayed on the screen are inCourier New.

Command Conventions

The command conventions that may be found in this document are defined as follows.


Boldface The keywords of a command line are in boldface.

Italic Command arguments are in italics.

[ ] Items (keywords or arguments) in brackets [ ] are optional.

{ x | y | ... } Optional items are grouped in braces and separated byvertical bars. One item is selected.

[ x | y | ... ] Optional items are grouped in brackets and separated byvertical bars. One item is selected or no item is selected.

{ x | y | ... }* Optional items are grouped in braces and separated byvertical bars. A minimum of one item or a maximum of allitems can be selected.

[ x | y | ... ]* Optional items are grouped in brackets and separated byvertical bars. Several items or no item can be selected.

GUI Conventions

The GUI conventions that may be found in this document are defined as follows.


Boldface Buttons, menus, parameters, tabs, window, and dialog titlesare in boldface. For example, click OK.

> Multi-level menus are in boldface and separated by the ">"signs. For example, choose File > Create > Folder.

Keyboard Operations

The keyboard operations that may be found in this document are defined as follows.

Format Description

Key Press the key. For example, press Enter and press Tab.



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Format Description

Key 1+Key 2 Press the keys concurrently. For example, pressing Ctrl+Alt+A means the three keys should be pressed concurrently.

Key 1, Key 2 Press the keys in turn. For example, pressing Alt, A meansthe two keys should be pressed in turn.

Mouse Operations

The mouse operations that may be found in this document are defined as follows.

Action Description

Click Select and release the primary mouse button without movingthe pointer.

Double-click Press the primary mouse button twice continuously andquickly without moving the pointer.

Drag Press and hold the primary mouse button and move thepointer to a certain position.



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Contents

About This Document.....................................................................................................................ii

1 Changes in the BSC6900 UMTS Technical Description........................................................1

2 Overall Structure...........................................................................................................................42.1 Switching Subsystem..........................................................................................................................................72.2 Service Processing Subsystem............................................................................................................................92.3 Interface Processing Subsystem.......................................................................................................................112.4 Clock Synchronization Subsystem...................................................................................................................122.5 OM Subsystem.................................................................................................................................................12

3 Working Principles.....................................................................................................................143.1 Power Supply Principle....................................................................................................................................153.2 Environment Monitoring Principle...................................................................................................................163.3 Clock Synchronization Principle......................................................................................................................19

3.3.1 Clock Sources..........................................................................................................................................193.3.2 Structure of the clock synchronization subsystem..................................................................................203.3.3 Clock Synchronization Process...............................................................................................................223.3.4 RFN Generation and Reception...............................................................................................................23

3.4 OM Principle....................................................................................................................................................243.4.1 Dual OM Plane........................................................................................................................................253.4.2 OM Network............................................................................................................................................263.4.3 Active/Standby Workspaces....................................................................................................................273.4.4 Data Configuration Management............................................................................................................293.4.5 Security Management..............................................................................................................................333.4.6 Performance Management.......................................................................................................................363.4.7 Alarm Management.................................................................................................................................383.4.8 Loading Management..............................................................................................................................393.4.9 Upgrade Management..............................................................................................................................41

4 Signal Flow...................................................................................................................................444.1 User-Plane Signal Flow....................................................................................................................................45

4.1.1 CBC Signal Flow.....................................................................................................................................454.1.2 UMTS Signal Flow Between Iub and Iu-CS/Iu-PS.................................................................................46

4.2 Control-Plane Signal Flow...............................................................................................................................484.2.1 Signaling Flow on the Uu Interface.........................................................................................................48

BSC6900 UMTSTechnical Description Contents


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4.2.2 Signaling Flow on the Iub Interface .......................................................................................................504.2.3 Signaling Flow on the Iu/Iur Interface ...................................................................................................51

4.3 OM Signal Flow...............................................................................................................................................52

5 Transmission and Networking.................................................................................................535.1 Transmission and Networking on the Iu/Iur Interface .....................................................................................54

5.1.1 ATM-Based Networking on the Iu/Iur Interface.....................................................................................545.1.2 IP-Based Networking on the Iu/Iur Interface..........................................................................................58

5.2 Transmission and Networking on the Iub Interface.........................................................................................615.2.1 ATM-Based Networking on the Iub Interface.........................................................................................625.2.2 IP-Based Networking on the Iub Interface..............................................................................................645.2.3 ATM/IP-Based Networking on the Iub Interface....................................................................................66

6 Parts Reliability...........................................................................................................................686.1 Concepts Related to Parts Reliability...............................................................................................................69

6.1.1 Backup.....................................................................................................................................................696.1.2 Resource Pool..........................................................................................................................................706.1.3 Port Trunking...........................................................................................................................................706.1.4 Port Load Sharing....................................................................................................................................70

6.2 Board Redundancy...........................................................................................................................................706.2.1 Warm Backup of AEUa Boards..............................................................................................................716.2.2 Resource Pool of NIUa Boards...............................................................................................................726.2.3 Warm Backup of OMUa/OMUc Boards.................................................................................................726.2.4 Warm Backup of PEUa Boards...............................................................................................................736.2.5 Warm Backup of SCUa/SCUb Boards....................................................................................................746.2.6 Warm Backup of AOUa/AOUc Boards..................................................................................................746.2.7 Warm Backup of FG2a/FG2c Boards.....................................................................................................756.2.8 Warm Backup of GCUa/GCGa Boards...................................................................................................766.2.9 Warm Backup of GOUa/GOUc Boards..................................................................................................776.2.10 Warm Backup of POUa/POUc Boards..................................................................................................786.2.11 Warm Backup of UOIa/UOIc Boards...................................................................................................796.2.12 Warm Backup of SPUa/SPUb Boards...................................................................................................806.2.13 Resource Pool of DPUb/DPUe Boards.................................................................................................80

6.3 Port Redundancy...............................................................................................................................................816.3.1 STM-1 Optical Port Backup....................................................................................................................816.3.2 Ethernet Port Backup...............................................................................................................................826.3.3 Ethernet Port Load Sharing.....................................................................................................................836.3.4 Ethernet Port Trunking............................................................................................................................83

BSC6900 UMTSTechnical Description Contents


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1 Changes in the BSC6900 UMTS TechnicalDescription

This document describes the changes in the BSC6900 UMTS Technical Description.

04 (2012-02-27)

This is the fourth commercial release of V900R013C00.

Compared with issue 03 (2012-01-05), this issue does not include any new topics.

Compared with issue 03 (2012-01-05), this issue incorporates the following changes:

Content Description

5.1.2 IP-Based Networking onthe Iu/Iur Interface

The description of SDH-Based networking is deleted.

3.1 Power Supply Principle The description and figure of power input part aremodified.

Compared with issue 03 (2012-01-05), this issue does not exclude any topics.

03 (2012-01-05)

This is the third commercial release of V900R013C00.



Content Description

3.4.6 PerformanceManagement

The description of the save days and capacity aboutperformance data obtained by running MML commandsis modified.

BSC6900 UMTSTechnical Description 1 Changes in the BSC6900 UMTS Technical Description


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Content Description

6.1.1 Backup The description of the backup-related concept ismodified.

6.2 Board Redundancy The description of board switchover on the system ismodified.

6.3 Port Redundancy The description of port redundancy is modified.


02 (2011-08-31)This is the second commercial release of V900R013C00.



Content Description

3.1 Power Supply Principle The power input part of the BSC6900 ismodified.


01 (2011-04-25)This is the first commercial release of V900R013C00.

Compared with issue Draft B (2011-03-21), this issue does not include any new topics.

Compared with issue Draft B (2011-03-21), this issue incorporates the following changes:

Content Description

6.2 Board Redundancy The description of the BSC6900 interfaceboards have an effective mechanism for faultdetection and automatic recovery is modified.

3.3.2 Structure of the clocksynchronization subsystem

The description of boards that can extractclock signals is added.

Compared with issue Draft B (2011-03-21), this issue does not exclude any topics.

Draft B (2011-03-21)This is the Draft B release of V900R013C00.



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Compared with issue Draft A (2011-01-31), this issue includes the following new topics:l 6.2.2 Resource Pool of NIUa Boards

Compared with issue Draft A (2011-01-31), this issue incorporates the following changes:

Content Description

6.2 Board Redundancy The description of the BSC6900 interfaceboards have an effective mechanism for faultdetection and automatic recovery is added.

2.1 Switching Subsystem The description of the inter-subrackswitching principle when the SCUb isconfigured is modified.

Compared with issue Draft A (2011-01-31), this issue does not exclude any topics.

Draft A (2011-01-31)This is the Draft A release of V900R013C00.

Compared with issue 03 (2010-09-20) of V900R012C01, this issue does not include any newtopics.

Compared with issue 03 (2010-09-20) of V900R012C01, this issue incorporates the followingchanges:

Content Description

2.1 Switching Subsystem The description of the inter-subrackswitching principle when the SCUb isconfigured is added.

6.2.5 Warm Backup of SCUa/SCUbBoards

The description of the SCUb board is added.

6.2.3 Warm Backup of OMUa/OMUcBoards

The description of the OMUc board is added.

Compared with issue 03 (2010-09-20) of V900R012C01, this issue does not exclude any topics.



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2 Overall Structure

About This Chapter

This chapter describes the interactions between the modules in the BSC6900.

Physical StructureThe BSC6900 cabinet consists of power distribution boxes and subracks, as listed in Table2-1.

Table 2-1 Components of the BSC6900 cabinet

Component Configuration

MPS One MPS must be configured.

EPS Zero to five EPSs can be configured.

Independent fan subrack Each cabinet must be configured with one independent fansubrack.

Power distribution box Each cabinet must be configured with one power distributionbox.

NOTE

If the customer purchases the Nastar product of Huawei, the customer needs to install the SAU board in the MPSor EPS of the BSC6900 cabinet (the SAU board occupies two slots that work in active/standby mode). For detailson how to install the SAU board, how to install the software on the SAU board, and how to maintain the SAUboard, see the SAU User Guide of Nastar documents.

Software StructureThe software of the BSC6900 has a distributed architecture. It is classified into the host softwareand OMU software.

l Host software

BSC6900 UMTSTechnical Description 2 Overall Structure


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The host software is distributed on the service boards. It consists of the operating system,middleware, and application software. See Figure 2-1.

Figure 2-1 Structure of the host software

– Operating system

The VxWorks real-time embedded operating system runs on each service board.

– Middleware

The Versatile Protocol Platform (VPP) and the Virtual Operating System (VOS)function as the middleware. The middleware enables the upper-layer applicationsoftware to be independent from the lower-layer operating system so that softwarefunctions can be transplanted between different platforms.

– Application software

Boards of different types can be installed with different application software. Theapplication software is classified into radio resource processing software, resourcecontrol-plane processing software, base station management software, andconfiguration maintenance management software.

l OMU software

The Operation and Maintenance Unit (OMU) software runs on the OMUa board and OMUcboard. The OMU is responsible for the operation and maintenance of the BSC6900. TheOMU software consists of the operating system and the OMU application software. SeeFigure 2-2.

Figure 2-2 Structure of the OMU software

– Operating system

The Windows Server 2003 operating system is used.

– OMU application software

The OMU application software runs on the lower-level operating system and providesvarious service processes, including the LMT process, fault diagnosis process, andauthentication process.



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Logical StructureFigure 2-3 shows the logical structure of the BSC6900.

Figure 2-3 Logical structure of MPS/EPS

SubsystemsLogically, the BSC6900 consists of the following five subsystems:

2.1 Switching SubsystemThe switching subsystem performs switching of traffic data, signaling, and OM signals.

2.2 Service Processing SubsystemThe BSC6900 service processing subsystem performs the control functions defined in the 3GPPprotocols and processes services of the BSC6900.

2.3 Interface Processing SubsystemThe interface processing subsystem provides transmission ports and resources, processestransport network messages, and enables interaction between the BSC6900 internal data andexternal data.

2.4 Clock Synchronization SubsystemThe clock synchronization subsystem provides clock signals for the BSC6900, generates theRNC Frame Number (RFN), and provides reference clock signals for base stations.

2.5 OM SubsystemThe OM subsystem enables the management and maintenance of the BSC6900 in the followingscenarios: routine maintenance, emergency maintenance, upgrade, and capacity expansion.



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2.1 Switching SubsystemThe switching subsystem performs switching of traffic data, signaling, and OM signals.

Position of the Switching Subsystem in the BSC6900 SystemThe switching subsystem consists of logical modules of one type: MAC switching. Figure2-4 shows the position of the switching subsystem in the BSC6900 system, with the moduleshighlighted in apricot.

Figure 2-4 Position of the switching subsystem in the BSC6900 system

Functionsl Provides intra-subrack Medium Access Control (MAC) switchingl Provides inter-subrack MAC switching and TDM switchingl Distributes clock signals and RFN signals to the service processing boards

Hardware InvolvedThe switching subsystem consists of the SCUa/SCUb boards, high-speed backplane channelsin each subrack, and crossover cables between SCUa/SCUb boards.

Network topologies between subracksThe BSC6900 subracks can be connected in the star or chain topology. In Figure 2-5, (1) and(2) represent the star and chain topologies respectively, where the dots represent subracks.

l Star topologyOne node functions as the center node and it is connected to each of the other nodes. Thecommunication between the other nodes must be switched by the center node.

l Chain topology



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There is a connection between every two adjacent nodes. If an intermediate node is out ofservice, the communications between the other nodes are affected. The bandwidthutilization in this topology is high.

Figure 2-5 Network topologies between subracks

In the switching subsystem of the BSC6900, the star or chain topology is established among theMAC switching logical modules.

Inter-Subrack Connection

The MAC switching logical module switches the ATM-based or IP-based traffic data, OMsignals, and signaling. Switching is performed by the SCUa boards and the Ethernet cablesbetween the SCUa/SCUb boards.

The MPS functions as the main subrack, and a maximum of five EPSs function as extensionsubracks. The star interconnections between the MPS and the EPSs are established through theEthernet cables between the SCUa boards, as shown in Figure 2-6.

Figure 2-6 Interconnections between subracks through the crossover cables between the SCUaboards (MPS/EPS)

The MPS functions as the main subrack. Star interconnections are established between the MPSand the EPSs in the MPR through the Ethernet cables between the SCUb boards. Chaininterconnections are established between the EPSs in the MPR and other EPSs through theEthernet cables between the SCUb boards, as shown in Figure 2-7.



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Figure 2-7 Interconnections between subracks through the crossover cables between the SCUbboards (MPS/EPS)

For example, as shown in Figure 2-7, subracks 0, 1, and 2 are in the same cabinet and starinterconnections are established between them through the Ethernet cables between the SCUbboards. Chain interconnections are established between subracks 1 and 3 through the Ethernetcables between the SCUb boards. Data is exchanged between subrack 0 and subrack 3 throughsubrack 1. The detail by referring to Installing the Inter-SCUb SFP+ High-Speed Cables BetweenDifferent Subracks.

2.2 Service Processing SubsystemThe BSC6900 service processing subsystem performs the control functions defined in the 3GPPprotocols and processes services of the BSC6900.

Position of the Service Processing Subsystem in the BSC6900 SystemThe service processing subsystem mainly consists of two logical modules: RNC control plane(CP) and RNC user plane (UP). Figure 2-8 shows the position of the service processingsubsystem in the BSC6900 system, with the modules highlighted in apricot.

NOTE

For details about the definitions of CP and UP, see 4 Signal Flow.



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Figure 2-8 Service processing subsystem

FunctionsThe service processing subsystem performs the following functions:

l User data transferl System admission controll Radio channel ciphering and decipheringl Data integrity protectionl Mobility managementl Radio resource management and controll Cell broadcast service controll System information and user message tracingl Data volume reportingl Radio access managementl CS service processingl PS service processing

Service processing subsystems communicate with each other through the switching subsystemto form a resource pool and perform tasks cooperatively. They can be increased as required,according to the linear superposition principle, thereby improving the service processingcapability of the BSC6900.

Hardware InvolvedThe service processing subsystem consists of the SPUa, SPUb, DPUb, and DPUe boards. TheSPUa and SPUb boards process signaling. The DPUb and DPUe boards process services.



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2.3 Interface Processing SubsystemThe interface processing subsystem provides transmission ports and resources, processestransport network messages, and enables interaction between the BSC6900 internal data andexternal data.

Position of the Interface Processing Subsystem in the BSC6900 SystemThe interface processing subsystem consists of two types of interfaces: ATM interfaces and IPinterfaces. Figure 2-9 shows the position of the interface processing subsystem in theBSC6900 system, with the interfaces highlighted in apricot.

Figure 2-9 Position of the interface processing subsystem in the BSC6900 system

Functionsl The interface processing subsystem provides the following types of IP and ATM interfaces.

– E1/T1 electrical ports– Channelized STM-1/OC-3 optical ports– Unchannelized STM-1/OC-3 optical ports– FE/GE electrical ports– GE optical ports

l The interface processing subsystem processes transport network messages and, also hidesdifferences between them within the BSC6900.

l On the uplink, the interface processing subsystem terminates transport network messagesat the interface boards. It also transmits the user plane, control plane, and managementplane datagram to the corresponding service processing boards. The processing of the signalflow on the downlink is the reverse of the processing of the signal flow on the uplink.

Hardware InvolvedThe interface processing subsystem consists of the Iu, Iur, and Iub interface boards.



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2.4 Clock Synchronization SubsystemThe clock synchronization subsystem provides clock signals for the BSC6900, generates theRNC Frame Number (RFN), and provides reference clock signals for base stations.

Position of the Clock Synchronization Subsystem in the BSC6900 SystemFigure 2-10 shows the position of the clock synchronization subsystem in the BSC6900 system,with the clock module highlighted in apricot.

Figure 2-10 Position of the clock synchronization subsystem in the BSC6900 system

FunctionsThe clock synchronization subsystem provides the following clock sources for the BSC6900and ensures the reliability of the clock signals:l Building Integrated Timing Supply System (BITS) clockl Global Positioning System (GPS) clockl External 8 kHz clockl LINE clock

The BSC6900 provides reference clock sources for base stations. Clock signals are transmittedfrom the BSC6900 to base stations over the Iub interface.

Hardware InvolvedThe clock synchronization subsystem consists of the GCUa/GCGa board.

2.5 OM SubsystemThe OM subsystem enables the management and maintenance of the BSC6900 in the followingscenarios: routine maintenance, emergency maintenance, upgrade, and capacity expansion.



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Position of the OM Subsystem in the BSC6900 SystemFigure 2-11 shows the position of the OM subsystem in the BSC6900 system, with the OMmodule highlighted in apricot.

Figure 2-11 Position of the OM subsystem in the BSC6900 system

FunctionsThe OM subsystem provides:

l 3.4.4 Data Configuration Managementl 3.4.5 Security Managementl 3.4.6 Performance Managementl 3.4.7 Alarm Managementl 3.4.8 Loading Managementl 3.4.9 Upgrade Management

Hardware InvolvedThe OM subsystem consists of the OMUa board or OMUc board.



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3 Working Principles

About This Chapter

This chapter describes the working principles of the BSC6900 in the following ways: powersupply, environment monitoring, clock synchronization, and OM.

3.1 Power Supply PrincipleThe power supply subsystem of the BSC6900 adopts the dual-circuit design and point-by-pointmonitoring solution. It consists of the power input part and the power distribution part.

3.2 Environment Monitoring PrincipleThe environment monitoring subsystem of the BSC6900 comprises the power distribution boxand the environment monitoring parts in each subrack. This subsystem monitors and controlsthe power supply, fans, and operating environment.

3.3 Clock Synchronization PrincipleThe clock synchronization subsystem of the BSC6900 consists of the GCUa/GCGa board andthe clock processing units of each subrack. It provides clock signals for the BSC6900 andreference clocks for base stations.

3.4 OM PrincipleOM is performed in the following scenarios: routine maintenance, emergency maintenance,troubleshooting, device upgrade, and capacity expansion. In addition, OM can be performed torapidly adjust device status.

BSC6900 UMTSTechnical Description 3 Working Principles


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3.1 Power Supply PrincipleThe power supply subsystem of the BSC6900 adopts the dual-circuit design and point-by-pointmonitoring solution. It consists of the power input part and the power distribution part.

The power supply subsystem of the BSC6900 consists of the -48 V DC power system, DC powerdistribution frame (PDF), and DC power distribution box (PDB) at the top of the cabinet.

If a site has heavy traffic or more than two switching systems, two or more independent powersupply systems should be provided. In the case of a communication center, independent powersupply systems should be configured on different floors to supply power to different equipmentrooms.

Power Input PartThe power input part leads the power from the DC PDF to the PDB in the cabinet. It consists ofthe DC PDF, PDB, and cables between them.

Figure 3-1 shows the power input part of the BSC6900.

Figure 3-1 Power input part of the BSC6900

NOTE

The DC PDF is not regarded as the components of the BSC6900.

The working principle of the power input part is as follows:

l The DC PDF provides each cabinet with dual two-route -48 V DC inputs and one route forPGND connection.

l Typically, the two power inputs work concurrently. If one power input is faulty, the otherpower input continues to supply power to the system to ensure stable operation. You canrectify the faulty power input without interrupting the services, thereby ensuring theoptimum reliability and availability of the power supply subsystem.



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Power Distribution Part

The power distribution part distributes power from the PDB to various components in the cabinet.It comprises the PDB, power distribution switches, and various components in the cabinet.

The working principle of the power distribution part is as follows:

l The PDB performs lightning protection and overcurrent protection on the dual two-route-48 V DC inputs. Then, it supplies power to all the components in the cabinet.

l The PDB monitors each input in real time. After the PDB detects abnormal power supply,it reports the relevant alarms to the OMU. The OMU, then, forwards the alarms to the LMTor M2000.

l The power distribution varies according to the type of cabinet. For details, see Connectionsof Power Cables and PGND Cables in the Cabinet.

3.2 Environment Monitoring PrincipleThe environment monitoring subsystem of the BSC6900 comprises the power distribution boxand the environment monitoring parts in each subrack. This subsystem monitors and controlsthe power supply, fans, and operating environment.

Power Monitoring

Power monitoring involves monitoring the power subsystem in real time, reporting the operatingstatus of the power supply, and generating alarms when faults occur.

Figure 3-2 shows the working principle of power monitoring.

Figure 3-2 Working principle of power monitoring

The power monitoring process is as follows:

1. The PAMU in the power distribution box monitors the operating status of the powerdistribution box and sends the monitoring signals to the signal transfer board through theserial port.



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2. The signal transfer board transmits the power monitoring signals to the independent fansubrack at the bottom of the cabinet through the monitoring signal cable of the powerdistribution box. Then, the fan subrack forwards the power monitoring signals to the activeSCUa board in the power monitoring subrack.

3. The SCUa board processes the monitoring signals. If faults occur, the SCUa board generatesalarms and reports the alarms to the OMUa board. The OMUa board then forwards thealarms to the LMT or M2000.

Fan Monitoring

Fan monitoring involves monitoring the operating status of the fans in real time and adjustingthe speed of the fans based on the temperature in the subrack.

Each subrack is configured with a built-in fan box. The temperature sensor next to the air outletcan detect the temperature in the subrack.

Besides the built-in fan box in the subrack, there is an independent fan subrack at the bottom ofthe cabinet. This improves the heat dissipation capability of the cabinet.

Figure 3-3 shows the working principle of fan monitoring.

Figure 3-3 Working principle of fan monitoring

The fan monitoring process is as follows:

1. The built-in fan box in the subrack and the fan monitoring unit PFCU in the independentfan subrack monitor the operating status of the fans in real time and reports the monitoringsignals to the signal transfer board through the serial port.

2. The signal transfer board transmits the monitoring signals to the active SCUa board.

l In the case of built-in fan box in the subrack, the signal transfer board transmits themonitoring signals to the active SCUa board through the backplane of the subrack.

l In the case of independent fan subrack, the signal transfer board transmits the monitoringsignals to the active SCUa board in the fan monitoring subrack through the monitoringsignal cable.



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3. The SCUa board processes the monitoring signals. If faults occur, the SCUa board generatesalarms and reports them to the OMUa board. The OMUa board then forwards the alarmsto the LMT or M2000.

Environment MonitoringEnvironment monitoring involves monitoring the temperature, humidity, operating voltage, doorstatus, water damage, smoke, and infrared. The environment monitoring function is performedby the Environment Monitor Units (EMUs).

Figure 3-4 shows the working principle of environment monitoring.

Figure 3-4 Working principle of environment monitoring

If the power distribution box can transfer signals, the environment monitoring process is asfollows:

1. The sensors monitor the environment in real time and send the monitoring signals to theEMU.

2. The EMU sends the monitoring signals to the power distribution box through the serialcable.

3. The signal transfer board in the power distribution box transmits the monitoring signals tothe active SCUa board in the power monitoring subrack through the monitoring signal cableof the power distribution box.

4. The active SCUa board in the power monitoring subrack transmits the monitoring signalsto the SCUa board in the MPS through the Ethernet cables between the SCUa boards.

5. The SCUa board in the MPS processes the monitoring signals. If faults occur, the SCUaboard generates alarms and reports the alarms to the OMUa board. The OMUa board thenforwards the alarms to the LMT or M2000.

If the power distribution box cannot transfer signals, the environment monitoring process is asfollows:



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1. The sensors monitor the environment in real time and send the monitoring signals to theEMU.

2. The EMU sends the monitoring signals to the active SCUa board in the lowest subrackthrough the serial cable.

3. The active SCUa board in the lowest subrack transmits the monitoring signals to the SCUaboard in the MPS through the Ethernet cables between the SCUa boards.

4. The SCUa board in the MPS processes the monitoring signals. If faults occur, the SCUaboard generates alarms and reports the alarms to the OMUa board. The OMUa board thenforwards the alarms to the LMT or M2000.

3.3 Clock Synchronization PrincipleThe clock synchronization subsystem of the BSC6900 consists of the GCUa/GCGa board andthe clock processing units of each subrack. It provides clock signals for the BSC6900 andreference clocks for base stations.

3.3.1 Clock SourcesThe BSC6900 can use the following clock sources: Building Integrated Timing Supply System(BITS) clock, external 8 kHz clock, LINE clock, and Global Positioning System (GPS) clock.

External ClocksThe external clocks of the BSC6900 are of two types:l BITS Clock

– The BITS clock signals are of three types: 2 MHz, 2 Mbit/s, and 1.5 Mbit/s. The 2 MHzand 2 Mbit/s clock signals are E1 clock signals, and the 1.5 Mbit/s clock signals are T1clock signals.

– The BITS clock has two inputs: BITS1 and BITS2. BITS1 and BITS2 work in active/standby mode and correspond to the CLKIN0 and CLKIN1 ports on the GCUa/GCGaboard respectively. The BSC6900 obtains the BITS clock signals through the CLKIN0or CLKIN1 port.

l External 8 kHz ClockThrough the COM1 port on the GCUa/GCGa board, the BSC6900 obtains 8 kHz standardclock signals from an external device.

LINE ClockThe LINE clock is an 8 kHz clock that is transmitted from an interface board in the MPS to theGCUa/GCGa board through the backplane channel. The LINE clock has two input modes:LINE0 and LINE1.

NOTE

LINE0 and LINE1 correspond to backplane channel 1 and backplane channel 2 respectively.

GPS ClockThe GPS clock provides 1 Pulse Per Second (PPS) clock signals. The BSC6900 obtains the GPSclock signals from the GPS system. The GCGa board is configured with a GPS card, and theBSC6900 receives the GPS signals at the ANT port on the GCGa board.



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NOTE

The GCUa board is not configured with a GPS card. Therefore, when the BSC6900 is configured with the GCUaboard instead of the GCGa board, the GPS clock is unavailable to the BSC6900.

Local Oscillator

If the BSC6900 fails to obtain any external clock, the BSC6900 can obtain its working clocksignals from the local oscillator.

3.3.2 Structure of the clock synchronization subsystemThe clock synchronization subsystem consists of the clock board, backplanes, clock cablesbetween subracks, and clock module in each board.

NOTE

Select a board according to the board function. For more information, see Boards. All the boards listed inthis chapter are used as examples for your reference.

Figure 3-5 shows the structure of the clock synchronization subsystem.

Figure 3-5 Structure of the clock synchronization subsystem

The structure of the BSC6900 clock synchronization subsystem is described as follows:



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l The clock board of the BSC6900 can be the GCUa or GCGa board. The BSC6900 cannotbe configured with both the GCUa and GCGa boards simultaneously. Depending on theclock type, it can have either the GCUa board or the GCGa board.

l If the MPS extracts the clock signals, the clock signals enter the MPS in any of the followingways:

– The clock signals enter the port on the panel of the GCUa/GCGa board.

– The clock signals enter the port on the panel of an interface board that can extract lineclock signals, include AEUa/AOUa/AOUc/PEUa/POUa/UOIa/UOIc board. The clocksignals are then switched to the GCUa/GCGa board through the backplane.

– The GCUa/GCGa board generates oscillator clock signals.

l If the EPS extracts the clock signals, the interface board that extracts clock signals must bethe AEUa/AOUa/PEUa/POUa/UOIa board.

Figure 3-6 shows the connections of the clock cables between the clock boards in the MPS andthe SCUa boards in the EPS when the BSC6900 is configured with active and standby clockboards and SCUa boards.

Figure 3-6 Structure of the clock synchronization subsystem

The active and standby clock boards in the MPS are connected to the active and standby SCUaboards in the EPS through the Y-shaped clock signal cables. This connection mode ensures thatthe system clock of the BSC6900 works properly in the case of a single-point failure of the clockboard, Y-shaped clock signal cable, or SCUa board. In addition, the Y-shaped clock signal cableensures the proper working of the SCUa boards during the switchover of the active and standbyclock boards.

NOTE

In the MPS, the clock board sends clock signals to the SCUa board in the same subrack through the backplanechannel. Therefore, a Y-shaped clock signal cable is not required.



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3.3.3 Clock Synchronization ProcessThe BSC6900 processes external clock signals before sending them to its boards. The clocksynchronization process varies slightly from one subrack to another.

NOTE


Process of Clock Synchronization in the MPS/EPSThe clock signals of the MPS/EPS are provided by the clock board. The clock board can extractclock signals from an external device or extract LINE clock signals from the A interface. TheGCGa board can extract clock signals from the GPS.l Figure 3-7 shows the process of clock synchronization in the MPS/EPS when the clock

board extracts clock signals from an external device or from the GPS.l Figure 3-8 shows the process of clock synchronization in the MPS/EPS when the clock

board extracts LINE clock signals from the Iu-CS interface.

Figure 3-7 Process of clock synchronization in the MPS/EPS (1)



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Figure 3-8 Process of clock synchronization in the MPS/EPS (2)

As shown in Figure 3-7 and Figure 3-8, the process of clock synchronization in the MPS/EPSis as follows:

1. If an external clock is used, external clock signals travel to the clock board through the porton the panel of the clock board. If the GPS clock is used, clock signals travel to the clockboard through the GPS antenna port. If the LINE clock is used, clock signals travel to theclock board through the backplane.

2. The clock source is phase-locked in the clock board to generate clock signals. The clocksignals, then, are sent to the SCUa board in the MPS through the backplane and to the SCUaboard in each EPS through the clock signal output ports.

3. The SCUa board in the MPS/EPS transmits the clock signals to the other boards in the samesubrack through the backplane.

NOTEThe Iub interface boards transmit the clock signals to the base stations.

3.3.4 RFN Generation and ReceptionRNC Frame Number (RFN) is used to synchronize NodeBs with the BSC6900. The nodesynchronization frames from the BSC6900 to the NodeBs carry the RFN information.

NOTE


Figure 3-9 shows the process of RFN generation and reception. This figure takes the GCUaboard as an example.



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Figure 3-9 Process of RFN generation and reception

The GCUa/GCGa board in the MPS sends the 1 PPS signals and synchronization time packetsto the SCUa board in each subrack. The SCUa board in each subrack then sends the 1 PPS signalsand synchronization time packets to the other boards in the same subrack. The boards generatethe required RFN signals according to the received 1 PPS signals and synchronization timepackets.

NOTE

l The 1 PPS signals can be generated by the GCUa/GCGa board.

l When the BSC6900 is configured with the GCGa board, it can obtain the GPS synchronization signalsthrough the GPS card to generate the 1 PPS signals that are synchronized with the satellite signals.

3.4 OM PrincipleOM is performed in the following scenarios: routine maintenance, emergency maintenance,troubleshooting, device upgrade, and capacity expansion. In addition, OM can be performed torapidly adjust device status.



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3.4.1 Dual OM PlaneThe BSC6900 has a dual OM plane to prevent single-point failure from affecting the normaloperation and maintenance.

NOTE


Figure 3-10 shows this dual OM plane design.

Figure 3-10 Dual OM plane

If the internal network and external network are on different network segments, ensure thatthe two networks are isolated.

The dual OM plane design is implemented by the hardware that works in active/standby mode.When an active component is faulty but the standby component works properly, a switchoveris automatically performed between the active and standby components, to ensure that the OMchannel works properly.

The active/standby OMUa boards use the same external virtual IP address to communicate withthe LMT or M2000 and use the same internal virtual IP address to communicate with the SCUaboard.

l When the active OMUa board is faulty, an active/standby switchover is performedautomatically, and the standby OMUa board takes over the OM task. In this case, theinternal and external virtual IP addresses remain unchanged. Thus, the propercommunication between the internal and external networks of the BSC6900 is ensured.



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l When a single-point failure occurs on the switching network, the active/standby SCUaboards in each subrack are switched over automatically to ensure that the OM channelworks properly.

3.4.2 OM NetworkThe OM network of the BSC6900 consists of the M2000, LMT, OMU, SCUa/SCUb boards,and OM modules in other boards.

NOTE

Either the OMUa or OMUc board can serve as an OMU. This chapter takes the OMUa board as an example foryour reference.Either the SCUa or SCUb board can serve as an SCU. This chapter takes the SCUa board as an example foryour reference.

Figure 3-11 shows the structure of the BSC6900 OM network.

Figure 3-11 Structure of the OM network

NOTE

Figure 3-11 shows some of the boards in the OM network.The SCUa boards in the EPS are connected to the SCUa boards in the MPS through crossover cables. Thecrossover cables transmit OM signals from the MPS to the EPS.

M2000The M2000 is a centralized network management system. The M2000 is connected to theBSC6900 through Ethernet cables. One M2000 can remotely manage multiple BSC6900s.

LMTThe LMT is connected to the OMUa board of the BSC6900 and works on the Windows XPProfessional or Windows Vista operating system. One or more LMTs can be connected to the



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OMUa board directly or through networks. The maintenance of the BSC6900 can be performedlocally or remotely through the LMT. The LMT is connected to an alarm box through a serialcable.

OMUa Board

The OMUa board is the back administration module of the BSC6900. It is connected to anexternal device through the Ethernet cable. The BSC6900 can be configured with one OMUaboard in independent mode or with two OMUa boards in active/standby mode.

The OMUa board functions as a bridge between the BSC6900 and the LMT/M2000. The OMnetwork of the BSC6900 is classified into the following networks:

l Internal network: implements the communication between the OMUa board and the hostboards of the BSC6900.

l External network: implements the communication between the OMUa board and externaldevices, such as the LMT or M2000.

SCUa Board

The SCUa board is the switching and control board of the BSC6900. It is responsible for theOM of the subrack where it is located. If a subrack is configured with two SCUa boards, thenthe two boards work in active/standby mode.

The SCUa board performs OM on other boards in the same subrack through the backplanechannels. The SCUa boards in different subracks are connected through crossover cables.

3.4.3 Active/Standby WorkspacesThis section describes the active/standby workspaces of the OMU and those of the host boards.

Active/Standby Workspaces of the OMU

The active/standby workspaces of the OMU are used for the upgrade and rollback of theBSC6900 versions, thus enabling quick switching between versions.

Concept of the Active/Standby Workspaces of the OMU

The active/standby workspaces of the OMU refer to the active/standby workspaces for storingthe version files on the OMU. Each workspace is used to store files of different versions.

The relation between the active/standby workspaces is relative. The active/standby relationdepends on the storage location of the running version. The workspace that stores the runningOMU version files is the active workspace, and the other is the standby workspace.

Working Principles of the Active/Standby Workspaces of the OMU

The working principles of the OMU active/standby workspaces in the case of the OMU versionupgrade are as follows:

1. The standby workspace of the active OMU is upgraded to a new version.2. The standby workspace of the standby OMU is upgraded to a new version.



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3. A switchover is performed between the active and standby workspaces of the active OMU.The standby workspace that stores the new version of files becomes active, and the otherworkspace becomes standby.

4. The active OMU runs the upgraded version.5. A switchover is performed between the active and standby workspaces of the standby OMU

to ensure that the versions of the workspaces are consistent with those of the active OMU.6. The OMU version upgrade is complete.

After the OMU version upgrade, the standby workspaces of the active and standby OMUs storethe files of the old version. In this case, version rollback can be performed as required.

The working principles of the OMU active/standby workspaces in the case of version rollbackare as follows:

1. A switchover is performed between the active and standby workspaces of the active OMU.The running version of the active OMU is rolled back to the pre-upgrade version.

2. The active OMU runs the pre-upgrade version.3. A switchover is performed between the active and standby workspaces of the standby OMU

to ensure that the versions of the workspaces are consistent with those of the active OMU.4. The OMU version rollback is complete.

Relation Between Intra-OMU Active and Standby WorkspacesThe active and standby workspaces of the OMU are independent of each other. The operationof the active workspace does not change any information in the standby workspace.

Relation Between Inter-OMU Active and Standby WorkspacesThe active and standby workspaces of the active OMU correspond to the active and standbyworkspaces of the standby OMU respectively. Between the active and standby OMUs, the filesin the active workspaces are automatically synchronized in real time, but those in the standbyworkspaces need to be synchronized manually.

Relation Between the Active/Standby Workspaces of Host Boards and the Active/Standby Workspaces of the OMU

On the active workspaces of the host boards, files can be loaded only from the active workspaceof the OMU. On the standby workspaces of the host boards, files can be loaded only from thestandby workspace of the OMU.

Active/Standby Workspaces of Host BoardsBSC6900 host boards refer to all the boards except the OMU. The active/standby workspacesof host boards are used for file loading, version upgrade, and version rollback.

Concept of the Active/Standby Workspaces of Host BoardsThe active/standby workspaces of host boards refer to the active/standby workspaces for storingdifferent versions of programs, data, and patch files in the board flash memory.

The relation between the active/standby workspaces is a relative concept. The active/standbyrelation depends on the running version. The workspace that stores the running version files ofa board is the active workspace, and the other is the standby workspace.



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Working Principles of the Active/Standby Workspaces of Host Boards

Before loading programs and data files, host boards choose the loading mode according to theloading control parameter. For details, see 3.4.8 Loading Management.

Relation Between Intra-Board Active/Standby Workspaces

The active and standby workspaces of a host board are independent of each other. The operationof the active workspace does not change any information in the standby workspace.

Relation Between Inter-Board Active/Standby Workspaces

The active and standby workspaces of the active board are independent of the active and standbyworkspaces of another host board. The operation of the active board does not change anyinformation in the standby board.

Relation Between the Active/Standby Workspaces of Host Boards and the Active/Standby Workspaces of the OMU

On the active workspaces of the host boards, files can be loaded only from the active workspaceof the OMU. On the standby workspaces of the host boards, files can be loaded only from thestandby workspace of the OMU.

3.4.4 Data Configuration ManagementThe data configuration management involves managing the data configuration process of theBSC6900 so that configuration data is properly sent to the related boards in a secure manner.

Data Configuration Modes

The BSC6900 supports two data configuration modes: effective mode and ineffective mode.

Effective Mode and ineffective Model Effective mode

If data configuration is performed on the BSC6900 in effective mode, then the relevantconfiguration data takes effect on the host boards in real time.

l Ineffective mode

If data configuration is performed on the BSC6900 in ineffective mode, then the relevantconfiguration data takes effect only after the BSC6900 is reset or is switched to the effectivemode.

Principle of Effective Mode Configuration

Effective mode configuration is applied to dynamic modification of the BSC6900 configurationdata.

Figure 3-12 shows the principle of effective mode configuration.



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Figure 3-12 Principle of effective mode configuration

The process of effective mode configuration is as follows:

1. The BSC6900 is switched to effective mode.

2. The configuration console (LMT or M2000) sends MML commands to the configurationmanagement module of the OMU.

3. The configuration management module of the OMU sends the configuration data to thedatabase of the related host board and writes the data to the OMU database.

Principle of Ineffective Mode Configuration

Ineffective mode configuration is applied to BSC6900 initial configuration.

Figure 3-13 shows the principle of ineffective mode configuration.

Figure 3-13 Principle of ineffective mode configuration

The process of ineffective mode configuration is as follows:

1. The BSC6900 is switched to ineffective mode.

2. The configuration console (LMT or M2000) sends MML commands to the configurationmanagement module of the OMU.

3. The configuration management module sends only the configuration data to the OMUdatabase.



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4. When a subrack or the BSC6900 is reset, the OMU formats the configuration data in thedatabase into a .dat file, loads the file onto the related host boards, and then activates theconfiguration data.

Data Configuration Rollback

Data configuration rollback is performed to recover configurations when errors occur. If themodified data configuration fails to reach the expected result or even causes equipment ornetwork failure, you can perform rollback to recover the configurations and to ensure the properoperation of the BSC6900.

WARNINGData configuration rollback cannot be performed when the CM control enable switch is set toON, when the fast configuration mode is selected, or when batch configuration is performed.

Data configuration rollback consists of the following types of operation:

l Undoing a single configuration command

After you undo the latest ten commands one by one, the system rolls back to theconfiguration before each command is executed.

l Redoing a single configuration command

After you redo the latest ten commands one by one, the system rolls back to theconfiguration after each command is executed.

l Undoing configuration commands in batches

This operation is performed to undo all the configuration commands that were executedafter a specified rollback savepoint. After this operation, the system rolls back to theconfiguration at the specified rollback savepoint.

l Redoing configuration commands in batches

This operation is performed to redo the configurations that were rolled back in batches.After this operation, the system returns to the configuration at the specified rollbacksavepoint or the configuration after the commands were executed.

Data Configuration Rights Management

The data configuration rights management controls the data configuration rights and the numberof users that simultaneously perform data configuration on the BSC6900 through the LMT orM2000. This ensures the security of data configuration.

The principles of data configuration rights management are as follows:

l The data configuration rights management enables only one user to perform dataconfiguration on the BSC6900 through the LMT or M2000 at a time.

l The user must have data configuration rights.

With the data configuration rights management, users cannot configure data for the BSC6900at the same time.



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Data Configuration Check

The data configuration check involves the data validity check and data consistency check. Thisensures the normal operation of the BSC6900.

Data Validity Check

The data validity check involves checking whether a configuration complies with theconfiguration rules and whether an MML script file complies with the syntactic rules. When aconfiguration is performed or an MML command is executed, the data validity check isperformed. If there is an error in the configuration, the BSC6900 stops the configuration or therunning of the command. At the same time, a warning message is displayed.

Data Consistency Check

The data consistency check consists of two parts:

l Check of the data consistency between the active and standby OMUs

If the BSC6900 is configured with the active and standby OMUs, the data on the activeOMU must be the same as that on the standby OMU, thus ensuring the reliability of theBSC6900. If the active OMU is faulty, the standby OMU takes over the tasks after an active/standby switchover.

l Check of the data consistency between the OMU and the host boards

The data on the host boards must be the same as that on the OMU. Otherwise, the systemcannot run stably. In addition, some data modified by users cannot take effect. Figure3-14 shows the procedure for the data consistency check.

Figure 3-14 Check of the data consistency between the OMU and the host boards

The procedure for checking the data consistency between the OMU and the host boards is asfollows:



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1. On the LMT, a data consistency check command is sent to the OMU automatically on aregular basis or manually.

2. The OMU analyzes the parameters of the command and checks whether the data in theboard databases is the same as that in the OMU database.

3. The OMU generates a result file and sends it to the LMT.

3.4.5 Security ManagementThe security management ensures the security of user login and helps to identify equipmentfaults. It involves rights management, log management, and inventory management.

Rights Management

The rights management is performed to identify a user and define the rights of the user.

The BSC6900 supports multi-user operations. It performs hierarchical rights management forusers to ensure security. The BSC6900 authorizes users at multiple levels and assigns certainrights to the users at each level. To log in to the LMT of the BSC6900, a user must enter theregistered user name and password, through which the BSC6900 identifies the user.

l User types

– Local users: refer to the accounts (including the default local account admin) managedby only the BSC6900 LMT. This type of LMT users can log in to the LMT during theBSC6900 installation and during the disconnection from the M2000.

– Domain users: refer to the accounts that are created, changed, authenticated, andauthorized on the M2000. Domain users can manage the BSC6900 after logging in tothe LMT or after logging in to the M2000 server through the M2000 client.

l User rights

Table 3-1 Definitions of the user rights

Class Rights CommandGroup

Description

Guest Guest can onlybrowse data.

G_0 The objects in this command group are used toquery system information, such as users,command groups, logs, NTP, EMS, and timezones.

G_2 The objects in this command group are used toquery data configurations and consist of theMML commands of the LST type.

G_4 The objects in this command group are used toquery alarm information.

G_6 The objects in this command group are used toquery performance data, for example, a result fileor a task file.



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Description

G_8 The objects in this command group are used toquery device information such as device statusand consist of the MML commands of the DSPtype.

G_13 The objects in this command group are used toquery the information about base stations, forexample, the attributes and boards of basestations.

User In addition tothe rightsgranted to theGuest, Usercan performsystem OM.

G_7 The objects in this command group are used toperform performance management, for example,to activate a performance task file or to upload aperformance result file.

G_9 The objects in this command group are used toperform device management, for example, toreset, block, unblock, or switch over a board.

G_10 The objects in this command group are used totrace and monitor the signal flow on the controlplane and on the user plane, for example, to querya tracing task or to create/delete/start a tracingtask.

G_11 The objects in this command group are used tomodify device panels.

G_12 The objects in this command group are used toperform software management, for example,patch management.

G_14 The objects in this command group are used toperform base station management, for example,to manage base station software or to reset a basestation.

Operator In addition tothe rightsgranted to theUser, theOperator canperform dataconfigurationon theequipment.

G_3 The objects in this command group are used toconfigure data, for example, the data for a newcell.

G_5 The objects in this command group are used toperform alarm management, for example, toclear an alarm or to set the alarm level.



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Description

Administrator

Administratorhas the highestoperationrights. It canmanage all theother users.

G_1 The objects in this command group are used tomanage system information, for example, tomanage a user, to set the time zone, to set thedaylight saving time, or to perform batchconfiguration.

Custom The rights of this user are defined by the Administrator.

Log Management

Log management records the operation history and saves the related logs about the BSC6900.Thus, it helps analyze and identify faults.

Table 3-2 lists the types of logs that are recorded when the BSC6900 is running.

Table 3-2 Types of logs

Type Description

Running log Records the information on the operating status of the system. Theinformation is used to analyze and locate faults.

Operation log Records the information on operation and maintenance performedby users.

Security log Records the information on the operations that may affect the systemsecurity, for example, the information on the change of userpassword.

The log management provides the following functions:

l Saving log files

You can save the log information to the OMU by setting the log record parameters.

l Uploading log files

You can upload the log files in the OMU to a specified FTP server by setting the uploadingparameters.

l Querying log files

You can view the specified log information in the OMU by setting the querying conditions.

l Extracting the up-to-date logs from the buffer

You can obtain the latest log information by saving the logs stored in the buffer to the logfile.



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NOTE

The OMU saves the log information in the buffer. When the log information reaches the specified limitor the current time reaches the log record period, the OMU records the log file.

Inventory ManagementThe inventory management refers to the efficient and centralized management of the primaryconfiguration information about the equipment in the network.

By exporting and uploading the inventory information files on the M2000, you can learn thephysical and logical configurations of NEs. The inventory management system is deployed onthe M2000. It obtains the required inventory information from NEs through the related interfaces.NEs report inventory information to the M2000 in the form of files, which contain theinformation on the following aspects:

l Equipmentl Connectionl Modulesl Configurationsl Peer equipmentl Host versionl Cabinetsl Subracksl Boards and the Flash electronic labels of the boardsl Slotsl Portsl Antennas

3.4.6 Performance ManagementThe BSC6900 performance management involves collecting, analyzing, and queryingperformance data.

Performance Management ProcessThe boards of the BSC6900 collect performance measurement data and periodically report thedata to the performance measurement module of the OMU. According to the task file, theperformance measurement module reports the measurement data to the M2000 periodically. Youcan run the LST MEASRSTLIMIT command to query the capacity and the number of daysthat performance measurement data can be saved. If the capacity or time is exceeded, the datafor the earliest day is deleted.

Figure 3-15 shows the process of collecting performance measurement data periodically by theBSC6900.



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Figure 3-15 Process of collecting performance measurement data periodically

The process of collecting performance measurement data periodically is as follows:

1. The user registers a performance measurement task and specifies the object, time, and itemattributes of the task on the M2000 client.

2. Based on the performance measurement task, the M2000 server modifies the measurementtask file, sends it to the OMU, and issues a command to activate the modified measurementtask file.

3. Based on the modified measurement task file, the OMU requests host boards to collect dataaccording to the new requirements. The OMU receives the measurement results from thehost boards and saves them as files.

4. The OMU notifies the M2000 server of the measurement results and uploads the files intothe M2000 server. The M2000 server processes the files and saves them into the database.

5. Based on the performance measurement task registered by the M2000 client, the M2000server obtains the relevant results from the database, performs certain calculation on them,and then sends the result to the M2000 client.

Measurement Types

Performance measurement objects are of three types: default measurement objects, optionalmeasurement objects, and real-time measurement objects.

l Default measurement objectsThe BSC6900 automatically measures all objects of this type. The default measurementtask file supports three periods:

– Normal measurement period with a default duration of 30 minutes or 60 minutes. Aproper measurement period can be selected on the M2000.

– Short measurement period with a default duration of 5 minutes or 15 minutes. A propermeasurement period can be selected on the M2000.

– Long measurement period with a default duration of 24 hours.You cannot add objects to or remove objects from the list of default measurement objectson the M2000.

l Optional measurement objectsBy default, the BSC6900 does not measure the optional measurement objects. The purposeof defining optional measurement objects is to avoid measuring these objects every timebecause they are of a large quantity. You can add objects to or remove objects from the listof optional measurement objects on the M2000.



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l Real-time measurement objectsThe BSC6900 measures real-time measurement objects in a short measurement period. Thepurpose is to monitor the changes in performance counters in real time. Under specialconditions, the BSC6900 measures the target KPIs in one minute. The M2000 can start orstop real-time measurement tasks. Real-time measurement data is reported to the M2000through messages.

3.4.7 Alarm ManagementThe alarm management helps to monitor the running status of the BSC6900 and informs you offaults in real time so that you can take proper measures in time.

Alarm Management Functionl Setting the storage capacity and time limit for alarm logs

The BSC6900 can store the information of the alarms generated in the latest 90 days anda maximum of 100,000 alarm logs. You can set the storage capacity and time limit asrequired.

l Alarm shieldingYou can shield an alarm by alarm ID. Alternatively, you can shield a specific alarm or allalarms of a BTS, cell, board, port, or DSP by setting alarm shielding conditions, thusreducing the number of reported derivative alarms.

l Alarm alertWhen a fault alarm occurs, the BSC6900 can notify you by Email, icon flash, short message,terminal sound, and audible and visual indication of alarm box.

l Alarm information processingYou can browse alarm information in real time, query history alarm information, and handlealarms based on the handling suggestions available on the online help.

Alarm Management ProcessThe alarm management process consists of alarm generation, alarm reporting, alarm handling,and alarm clearance. Figure 3-16 shows the process of alarm management.

Figure 3-16 Alarm management process

Each board detects alarms and reports them to the OMU automatically. The OMU then classifiesthese alarms into different severity levels and sends them to the LMT or the M2000 server. Youcan view and manage alarm information on the LMT or M2000 client.



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The alarm management module of the OMU provides the following functions:

l Alarm storageThe alarm management module stores the alarms in the database of the OMU.

l Alarm processingThe alarm management module processes the operation commands from the LMT orM2000 client and then returns the operation results to the LMT or M2000 client. Thesecommands include querying active alarms, querying alarm logs, and modifying alarmconfiguration items.

l Alarm triggeringIf the generation of an alarm triggers another alarm, the alarm management module reportsthe two alarms to the LMT or M2000 client.

l Alarm recoveryAfter an alarm is handled, the system automatically clears the alarm. At the same time, thealarm management module clears the alarm information from the LMT or M2000.

Alarm BoxThe alarm box generates audible and visual alarms. The red, orange, yellow, and green alarmindicators on the alarm box indicate the critical, major, minor, and warning alarms respectively.Different alarm severity levels have different alarm sounds. Figure 3-17 shows the workingprinciple of the alarm box.

Figure 3-17 Working principle of the alarm box

The alarm box is connected to the LMT through a serial cable. When an alarm is reported, theLMT forwards it to the alarm box. The alarm box then generates an audible and visual alarm.You can stop alarm sounds, turn off alarm indicators, and reset the alarm box through the LMT.

3.4.8 Loading ManagementThe BSC6900 loading management involves managing the process of loading program and datafiles onto boards after the boards (or subracks) start or restart.

NOTE

Either the OMUa or OMUc board can serve as an OMU. This chapter takes the OMUa board as an example foryour reference.

Either the SCUa or SCUb board can serve as an SCU. This chapter takes the SCUa board as an example foryour reference.

Principle of LoadingThe OMUa board and the active SCUa board in each subrack play important roles during theBSC6900 loading process.



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l The OMUa board functions as the center of the entire BSC6900 loading managementprocess. The loading and power-on of the OMUa board are independent of other boards.The OMUa board processes the loading control requests of other boards.

l The active SCUa board functions as the subcenter of the BSC6900 loading managementprocess. If the OMUa board is not in position, the active SCUa board in a subrack processesthe loading control requests from the other boards in the same subrack. If the SCUa boardsin an extension subrack are not started, the active SCUa board in the main subrack processesthe loading control requests from the boards in the extension subrack.

Loading ModeTo negotiate the loading mode for program files, the BSC6900 compares the versions of theprogram files stored in the active and standby workspaces of the flash memory of a board withthe versions of the current program files in the OMU.

l If the versions are inconsistent, the board loads program files from the OMU and writesthe files to the active workspace of the flash memory of the board.

l If the versions are consistent, the board loads program files directly from the active orstandby workspace of the flash memory of the board.

NOTE

If the board loads program files from the standby workspace of the flash memory, the standby workspacebecomes active automatically, and the other workspace becomes standby.

To negotiate the loading mode for data files, the BSC6900 compares the Cyclic RedundancyCheck (CRC) value of the data files in the active workspace of the flash memory of a board withthat in the active workspace of the OMU.

l If the CRC values are inconsistent, the board loads the data files from the active workspaceof the OMU and writes the files to the active workspace of the flash memory of the board.

l If the CRC values are consistent, the board loads data files directly from the activeworkspace of the flash memory of the board.

NOTE

If a board fails to load program files or data files from the flash memory after negotiation, the board loadsthe files from the OMU and writes the files to the flash memory.

Loading ProcessFigure 3-18 shows the loading process.



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Figure 3-18 Loading process

l If the OMUa board is online, the loading process is as follows:

1. After a board is started, it broadcasts a BOOTP request.2. After receiving the BOOTP request message from the board, the OMUa board

generates a BOOTP response message and sends it to the board. The response messagecontains the loading control parameter, IP address, and version information.

3. After receiving the response message, the SCUa board loads the program files anddata files according to the loading control parameter.

4. The SCUa board processes the BOOTP requests from the other boards in the MPSand from the SCUa board in the EPS.

5. After the SCUa board in the EPS loads the program files and data files, it processesthe BOOTP requests from the other boards in the same subrack.

6. After receiving the response messages, the other boards load program files and datafiles according to the loading control parameter.

7. The loading is complete.l If the OMUa board is offline or is not started, the loading process is as follows:

1. After a board is started, it broadcasts a BOOTP request.2. If no response is received from the OMUa board 30s after the broadcast, the SCUa

board in the MPS loads program files and data files from its flash memory.3. The SCUa board in the MPS processes the BOOTP requests from the other boards in

the MPS and from the SCUa board in the EPS.4. After the SCUa board in the EPS loads the program files and data files, it processes

the BOOTP requests from the other boards in the same subrack.5. After receiving the response messages, the other boards load program files and data

files according to the loading control parameter.6. The loading is complete.

3.4.9 Upgrade ManagementThe upgrade management involves managing the procedures for upgrading the OMU softwareand patch.



41

Upgrade Scenarios

The BSC6900 needs to be upgraded to rectify the existing defects and to support new functions,higher specifications, and later protocol standards. The upgraded version can provide better QoS.

Upgrade Mode

You can use the dedicated upgrade tool to upgrade the BSC6900 through the OM network ofthe BSC6900. See Figure 3-19.

Figure 3-19 Upgrade through the OM network

NOTE

The upgrade tool supports the upgrade of multiple BSC6900s in batches.

Upgrade Process

The BSC6900 is upgraded remotely by using the dedicated upgrade tool, which consists of theupgrade client and the upgrade server. Figure 3-20 shows the upgrade process.

Figure 3-20 Upgrade process



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NOTE

Client PC refers to the PC on which the upgrade client software runs.

1. The user sends the upgrade version files and the upgrade server program to the specifieddirectories of the active OMU through the network.

2. The user connects the client PC to the active OMU and then starts the upgrade client onthe client PC and the upgrade server on the active OMU to set up the connection betweenthe upgrade client and the upgrade server.

3. The upgrade server synchronizes the version files of the standby OMU with those of theactive OMU.

4. The user starts the upgrade server on the standby OMU and sets up the connection betweenthe upgrade server on the standby OMU and the upgrade server on the active OMU.

5. The upgrade server on the active OMU performs health check on the data and files in theactive workspace of the active OMU and then backs them up before the upgrade.

6. The upgrade server of the active OMU upgrades the software in the standby workspace ofthe active OMU. At the same time, the upgrade server of the standby OMU upgrades thesoftware in the standby workspace of the standby OMU.

7. The upgrade server of the active OMU upgrades the data in the standby workspace of theactive OMU.

8. The upgrade server of the active OMU issues a command to load the host program, DSP,BOOTROM, and data files in the standby workspace of the active OMU onto the standbyworkspaces of the host boards so that the standby workspaces of the boards aresynchronized with the standby workspace of the active OMU.

9. The upgrade server of the active OMU issues a command to switch over the active andstandby workspaces of the active OMU to upgrade the active OMU.

10. The upgrade server of the active OMU issues a command to reset all the standby boards ofthe BSC6900.

11. After the reset, all the standby boards of the BSC6900 automatically load the program filesand data files from the standby workspaces of their flash memories to upgrade the boards.

12. After the upgrade server of the active OMU detects that all the standby boards are started,it issues a command to reset all the active boards of the BSC6900.

13. When the active boards are being reset, the original standby boards become active.Similarly, after the reset, all the original active boards automatically load the program filesand data files from the standby workspaces of their flash memories to upgrade themselves.

14. After the service verification is successful, the upgrade server of the active OMU issues acommand to switch over the active and standby workspaces of the standby OMU so as toupgrade the standby OMU. After the switchover, the standby OMU automaticallysynchronizes with the active OMU.

15. The upgrade is complete.



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4 Signal Flow

About This Chapter

The BSC6900 signal flow consists of the user-plane signal flow, control-plane signal flow, andOM signal flow.

Definitionsl User plane

User plane refers to the set of logical functions of the BSC6900 that process the servicedata, including the speech data and packet data.

l Control planeControl plane refers to the set of logical functions of the BSC6900 that process the controlsignaling, including the call control signaling and the connection control signaling.

4.1 User-Plane Signal FlowThe user plane of the BSC6900 processes the user-plane messages on each interface.

4.2 Control-Plane Signal FlowThe control plane of the BSC6900 processes the control-plane messages on each interface.

4.3 OM Signal FlowOM signal flow refers to the messages transmitted between the BSC6900 and the LMT orM2000. The LMT or M2000 maintains and monitors the BSC6900 in real time through the OMsignal flow.

BSC6900 UMTSTechnical Description 4 Signal Flow


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4.1 User-Plane Signal FlowThe user plane of the BSC6900 processes the user-plane messages on each interface.

4.1.1 CBC Signal FlowThe data from the Iu-BC interface to the Iub interface refers to the Cell Broadcast Center (CBC)signal flow.

NOTE


Figure 4-1 shows the signal flow from the Iu-BC interface to the Iub interface.

Figure 4-1 Signal flow from Iu-BC to Iub

NOTE

l The INT in the figure stands for the interface board. You can use different interface boards as required.

l The boards shown in Figure 4-1 are only examples.

The signal flow is as follows:

1. The CBC sends the broadcast data to the Iu-BC interface board of the BSC6900 over theIu-BC interface.

2. The Iu-BC interface board processes the data and then sends it to the SPUa board.3. The SPUa board processes the data according to the Service Area Broadcast Protocol

(SABP) and then sends the data to the target DPUb board. See signal flow 1 in Figure4-1.If the SPUa board cannot process the data, the data travels to the MPS for switching. TheMPS then sends the data to the target SPUa board, which processes the data according tothe SABP. Then, the SPUa board sends the data to the DPUb board. See signal flow 2 inFigure 4-1.

4. The DPUb board processes the data according to the BMC, RLC, and MAC protocols andthen sends the data to the Iub interface board.

5. The Iub interface board processes the data and then sends it to the NodeB.



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6. The NodeB broadcasts the data to the UEs in the cells served by the NodeB.

4.1.2 UMTS Signal Flow Between Iub and Iu-CS/Iu-PSThe UMTS signal flow between Iub and Iu-CS/Iu-PS refers to the data transmitted between theBSC6900 and the MSC/SGSN.

The data flow between Iub and Iu-CS/Iu-PS is categorized into the following types:l Intra-BSC6900 data flow between Iub and Iu-CS/Iu-PSl Inter-BSC6900 data flow between Iub and Iu-CS/Iu-PS

NOTE


Intra-BSC6900 Data Flow Between Iub and Iu-CS/Iu-PS

If the BSC6900 that receives the data from the Iub interface sends the data directly to the MSC/SGSN over the Iu-CS/Iu-PS interface, the data flow is called an intra-BSC6900 data flowbetween Iub and Iu-CS/Iu-PS. Figure 4-2 shows the intra-BSC6900 data flow between Iub andIu-CS/Iu-PS.

Figure 4-2 Intra-BSC6900 data flow between Iub and Iu-CS/Iu-PS

NOTE


l All the communications between the boards are switched by the SCUa boards.

l The boards shown in the figure are only examples.

The signal flow on the uplink is as follows:

1. The NodeB processes the data and then sends it to the Iub interface board of BSC6900 overthe Iub interface.



46

2. The Iub interface board processes the data and sends it to the DPUb board in the samesubrack. See signal flow 1 in Figure 4-2.If the DPUb board that processes the data and the Iub interface board that receives the dataare located in different subracks, the data is switched by the MPS. The MPS then sends thedata to the target DPUb board. See signal flow 2 in Figure 4-2.

3. The DPUb board processes the data according to the FP, MDC, MAC, RLC, and Iu UP orPDCP/GTP-U protocols, separates the CS/PS user-plane data from other data, and thensends the data to the Iu-CS/Iu-PS interface board.

4. The Iu-CS/Iu-PS interface board processes the data and then sends it to the MSC/SGSN.

The downlink flow is the reverse of the uplink flow.

Inter-BSC6900 Data Flow Between Iub and Iu-CS/Iu-PS

If the BSC6900 that receives the data from the Iub interface sends the data to the MSC/SGSNthrough another BSC6900, the data flow is called an inter-BSC6900 data flow between Iub andIu-CS/Iu-PS.

Figure 4-3 shows the data flow between BSC6900-1 and BSC6900-2.

Figure 4-3 Inter-BSC6900 data flow between Iub and Iu-CS/Iu-PS

NOTE



The signal flow on the uplink is as follows:

1. The NodeB processes the data and then sends it to the Iub interface board of BSC6900-1over the Iub interface.

2. The Iub interface board and DPUb board of BSC6900-1 process the data and then send itto the Iur interface board of BSC6900-1.

NOTE

The DPUb board of BSC6900-1 processes the data according to only the FP and MDC protocols.

3. The Iur interface board of BSC6900-1 processes the data and then sends it to the Iurinterface board of BSC6900-2 over the Iur interface between BSC6900-1 and BSC6900-2.

4. The Iur interface board of BSC6900-2 processes the data and then sends it to the DPUbboard.



47

5. The DPUb board processes the data, separates the CS/PS user-plane data from other data,and then sends the data to the Iu-CS/Iu-PS interface board.

6. The Iu-CS/Iu-PS interface board processes the data and then sends it to the MSC/SGSN.


4.2 Control-Plane Signal FlowThe control plane of the BSC6900 processes the control-plane messages on each interface.

4.2.1 Signaling Flow on the Uu InterfaceThe signaling flow on the Uu interface refers to the control plane messages (RRC messages)transmitted between the BSC6900 and the NodeB. RRC messages are signaling messages thattravel between the UE and the BSC6900 when the UE accesses the network or when the UEcommunicates with the BSC6900. The RRC messages are used in the UE activities such aslocation updates and call setup.

NOTE


Intra-BSC6900 Signaling Flow on the Uu InterfaceFigure 4-4 shows the signaling flow on the Uu interface when one BSC6900 performs radioresource management and provides radio links for the UE. See signal flows 1 and 2 in the figure.

Figure 4-4 Intra-BSC6900 signaling flow on the Uu interface

NOTE

l The INT in the figure stands for the interface board. You can use different interface boards as required.l All the communications between the boards are switched by the SCUa boards.l As shown in the figure, the cross symbol in the MPS indicates the switching unit in the MPS.

The signaling flow on the uplink is as follows:



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1. The RRC messages from the UE are processed at the physical layer of the NodeB and thenare sent to the Iub interface board of the BSC6900 over the Iub interface.

2. The Iub interface board processes the messages and then sends them to the DPUb board.See signal flow 1 in Figure 4-4.If the SPUa board that processes the RRC messages and the Iub interface board that receivesthe RRC messages are located in different subracks, the messages travel to the MPS forswitching. The MPS then sends the messages to the target DPUb board. See signal flow 2in Figure 4-4.

3. The DPUb board processes the messages according to the FP, MDC, MAC, and RLCprotocols and then sends the messages to the target SPUa board where the messages areterminated.


Inter-BSC6900 Signaling Flow on the Uu Interface

Figure 4-5 shows the signaling flow on the Uu interface when BSC6900-1 performs radioresource management and BSC6900-2 provides radio links for the UE.

Figure 4-5 Inter-BSC6900 signaling flow on the Uu interface

NOTE




1. The RRC messages sent from the UE are processed at the physical layer of the NodeB andthen are sent to the Iub interface board of BSC6900-1 over the Iub interface.

2. The Iub interface board and the DPUb board of BSC6900-1 process the messages and thensend them to the Iur interface board of BSC6900-1.

NOTE

When the UE performs a cell update across the Iur interface, the RRC messages travel to the Iurinterface board of BSC6900-1 through the SPUa board of BSC6900-1. In any other case, the RRCmessages need not pass through the SPUa board of BSC6900-1.

3. The Iur interface board of BSC6900-1 processes the RRC messages and then sends themto the Iur interface board of BSC6900-2 over the Iur interface between BSC6900-1 andBSC6900-2.



49

4. The Iur interface board of BSC6900-2 processes the messages and then sends them to theDPUb board.

5. The DPUb board processes the messages according to the FP, MDC, MAC, and RLCprotocols and then sends the messages to the target SPUa board where the messages areterminated.


4.2.2 Signaling Flow on the Iub InterfaceThe signaling flow on the Iub interface refers to the control-plane messages transmitted betweenthe BSC6900 and the NodeB.

NOTE


Figure 4-6 shows the signaling flow on the Iub interface.

Figure 4-6 Signaling flow on the Iub interface

NOTE

l The INT in the figure stands for the interface board. You can use different interface boards as required.l All the communications between the boards are switched by the SCUa boards.l As shown in the figure, the cross symbol in the MPS indicates the switching unit in the MPS.


1. The NodeB transmits the control-plane messages to the Iub interface board of theBSC6900 over the Iub interface.

2. The Iub interface board processes the messages and then sends them to the SPUa boardwhere the messages are terminated. See signal flow 1 in Figure 4-6.If the SPUa board that processes the messages and the Iub interface board that receives themessages are located in different subracks, the messages travel to the MPS for switching.



50

The MPS then sends the messages to the target SPUa board. See signal flow 2 in Figure4-6.


4.2.3 Signaling Flow on the Iu/Iur InterfaceThe signaling flow on the Iu interface refers to the control-plane messages transmitted betweenthe BSC6900 and the MSC/SGSN, and the signaling flow on the Iur interface refers to thecontrol-plane messages transmitted between one BSC6900 and another BSC6900.

NOTE


Figure 4-7 shows the signaling flow on the Iu/Iur interface. See signal flows 1, 2, and 3.

Figure 4-7 Signaling flow on the Iu/Iur interface

NOTE



l As shown in the figure, the cross symbol in the MPS indicates the switching unit in the MPS.

The signaling flow on the downlink is as follows:

1. The MSC or SGSN sends the control-plane messages to the Iu interface board of theBSC6900 over the Iu interface, or another BSC6900 sends the control-plane messages tothe Iur interface board of the local BSC6900 over the Iur interface.

2. The Iu/Iur interface board processes the messages and then sends them to the SPUa boardin the same subrack for processing. See signal flow 1 in Figure 4-7.

If the SPUa board in the same subrack as the Iu/Iur interface board cannot process themessages, the messages are switched by the MPS to the SPUa board in another subrack.See signal flow 2 in Figure 4-7.

After being processed by the Iu/Iur interface board, the messages are directly switched bythe MPS to the SPUa board in another subrack. See signal flow 3 in Figure 4-7.

The uplink flow is the reverse of the downlink flow.



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4.3 OM Signal FlowOM signal flow refers to the messages transmitted between the BSC6900 and the LMT orM2000. The LMT or M2000 maintains and monitors the BSC6900 in real time through the OMsignal flow.

Figure 4-8 shows the OM signal flow of the BSC6900.

Figure 4-8 OM signal flow

As shown in Figure 4-8, the OM signal flow in the BSC6900 is as follows:

l OM signal flow in the MPS

1. The OM signal is transmitted from the LMT or M2000 to the OMUa board.

2. After being processed by the OMUa board, the OM signal is transmitted to the SCUaboard through the backplane of the MPS.

3. The SCUa board then transmits the OM signal to the service boards that requiremaintenance.

l OM signal flow in the EPS

1. The OM signal is transmitted from the LMT or M2000 to the OMUa board.

2. After being processed by the OMUa board, the OM signal is transmitted to the SCUaboard through the backplane of the MPS.

3. The SCUa board in the MPS transmits the OM signal to the SCUa board in the EPSthrough the crossover cable between the SCUa boards.

4. In the EPS, the SCUa board transmits the OM signal to the service boards that requiremaintenance.



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5 Transmission and Networking

About This Chapter

The transmission and networking between the BSC6900 and other NEs can be classified intothe following types: transmission and networking on the Iub interface and on the Iu/Iurinterface.

5.1 Transmission and Networking on the Iu/Iur InterfaceMultiple transmission and networking modes, including ATM-based networking on the Iu/Iurinterface and IP-based networking on the Iu/Iur interface, can be adopted between theBSC6900 and the CN or another BSC6900.

5.2 Transmission and Networking on the Iub InterfaceMultiple transmission and networking modes, including ATM-based networking on the Iubinterface and IP-based networking on the Iub interface, can be adopted between the BSC6900and the base station.

BSC6900 UMTSTechnical Description 5 Transmission and Networking


53

5.1 Transmission and Networking on the Iu/Iur InterfaceMultiple transmission and networking modes, including ATM-based networking on the Iu/Iurinterface and IP-based networking on the Iu/Iur interface, can be adopted between theBSC6900 and the CN or another BSC6900.

5.1.1 ATM-Based Networking on the Iu/Iur InterfaceIn ATM-based networking mode, the BSC6900 and the CN or another BSC6900 communicatewith each other through the SDH or ATM network.

SDH-Based Networking with MSP Backup Between Optical Ports

In this networking mode, the UOIa/UOIc board of the BSC6900 functions as the Iu/Iur interfaceboard and provides unchannelized STM-1 optical ports, as shown in Figure 5-1.

Figure 5-1 SDH-based networking with MSP backup between optical ports

In this networking mode, each Iu or Iur interface requires a pair of STM-1 optical cables forMSP 1+1 (single-end or both-end) or MSP 1:1 backup. In some cases rather than directconnection between the BSC6900 and the MSC or SGSN, the section-specific MSP backup atthe BSC6900 protects only the optical channels between the BSC6900 and the ADM, insteadof all the optical channels between the BSC6900 and the MSC or SGSN.



54

SDH-Based Networking with Load Sharing Between Optical PortsIn this networking mode, the UOIa/UOIc board of the BSC6900 functions as the Iu/Iur interfaceboard and provides unchannelized STM-1 optical ports, as shown in Figure 5-2.

Figure 5-2 SDH-based networking with load sharing between optical ports

In this networking mode, the two UOIa/UOIc boards for the Iu or Iur interface are not configuredfor backup. The Iu/Iur control plane PVCs are shared between two optical ports on differentUOIa/UOIc boards. The same is applicable to the Iu/Iur user plane PVCs. Therefore, the twooptical ports share the load. If one of the optical ports is faulty, it is isolated and the servicescarried on it are disrupted. Then, the traffic on the Iu or Iur interface reduces by half.

SDH-Based Networking with STM-1 Shared Between Iu and IurIn this networking mode, the UOIa/UOIc board of the BSC6900 functions as the Iu/Iur interfaceboard and provides unchannelized STM-1 optical ports, as shown in Figure 5-3.



55

Figure 5-3 SDH-based networking with STM-1 shared between Iu and Iur

Generally, the traffic on the Iur interface is light. Therefore, when the BSC6900 has a numberof Iur interfaces where the traffic is light, the Iu and Iur interfaces can share an STM-1transmission resource, and then the MGW separates the Iu PVC from the Iur PVC by using VCor VP switching.

ATM-Based NetworkingIn this networking mode, the UOIa/UOIc board of the BSC6900 functions as the Iu/Iur interfaceboard and provides unchannelized STM-1 optical ports, as shown in Figure 5-4.



56

Figure 5-4 ATM-based networking

In this networking mode, each Iu or Iur interface requires a pair of STM-1 optical cables forMSP 1+1 (single-end or both-end) or MSP 1:1 backup. In some cases rather than directconnection between the BSC6900 and the MSC or SGSN, the section-specific MSP backup atthe BSC6900 protects only the optical channels between the BSC6900 and the ATM switch,instead of all the optical channels between the BSC6900 and the MSC or SGSN.

NOTE

l STM-1 sharing between the Iu and Iur interfaces is applicable to the ATM-based networking. In thiscase, the Iu and Iur interfaces share a pair of STM-1 optical cables to transmit data before the ATMswitch separates the Iu PVC from the Iur PVC by using VC or VP switching.

l Load sharing is also applicable to the ATM-based networking. This networking mode is similar to theSDH-based networking with load sharing between optical ports.

Features of Networking Modes

Advantages:

l SDH-based networking with MSP backup between optical ports

The transmission backup function provided by this networking mode helps guarantee hightransmission reliability.

l SDH-based networking with load sharing between optical ports

This networking mode saves the optical ports and optical cables between the BSC6900 andthe ADM, therefore improving the optical resource utilization.

l SDH-based networking with STM-1 shared between Iu and Iur



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In the case of a large number of Iur interfaces, the demand for transmission resources ishigh and the resource usage is low if each Iur interface occupies one STM-1 port. The SDH-based networking with STM-1 shared between Iu and Iur is resource-effective.

l ATM-based networkingThe Iu and Iur interfaces can share a port or board for data transmission, therefore savingthe transmission resources and improving the resource usage.

Disadvantages:l SDH-based networking with MSP backup between optical ports

For transmission backup, this networking mode requires double optical ports and cableresources.

l SDH-based networking with load sharing between optical portsThis networking mode does not provide transmission backup, therefore reducing thetransmission reliability. If an optical port or optical cable is faulty, the services carried onthe faulty part are disrupted.

l SDH-based networking with STM-1 shared between Iu and IurThis networking mode requires VC/VP switching at the MGW, therefore increasing theload of the MGW.

l ATM-based networkingThe market share of ATM networks decreases as the ATM equipment is expensive.Building additional ATM networks for Iu and Iur transmission is not recommended.

5.1.2 IP-Based Networking on the Iu/Iur InterfaceIn IP-based networking mode, the BSC6900 and the CN or another BSC6900 communicate witheach other through the IP network.

Single-Homing Layer 3 NetworkingIn this networking mode, the FG2a/GOUa/FG2c/GOUc board of the BSC6900 functions as theIu/Iur interface board and provides FE/GE ports. Figure 5-5 shows the single-homing layer 3networking .



58

Figure 5-5 Single-homing layer 3 networking

In this networking mode, the FE/GE ports of the BSC6900 work in active/standby mode. Theactive and standby FE/GE ports of the BSC6900 connect to the Provider Edge (PE), which thenconnects to the data network. The active and standby FE/GE ports of the BSC6900 share one IPaddress, that is, IP1-1. On the PE side, the active and standby ports of the BSC6900 are in oneVLAN and share one port IP address of the VLAN, that is, IP1-0.

NOTE

The GE optical ports on the GOUa/GOUc board are used when the distance between the BSC6900 and thePE is longer than 100 meters. The FE/GE electrical ports on the FG2a/FG2c board are used when thedistance between the BSC6900 and the PE is equal to or shorter than 100 meters.

Dual-Homing Layer 3 NetworkingIn this networking mode, the FG2a/GOUa/FG2c/GOUc board of the BSC6900 functions as theIu/Iur interface board and provides FE/GE ports. Figure 5-6 shows the dual-homing layer 3networking.



59

Figure 5-6 Dual-homing layer 3 networking

In this networking mode, the FE/GE ports of the BSC6900 are configured for backup. The activeand standby FE/GE ports of the BSC6900 connect to two PEs, which then connect to the datanetwork. Complying with the Virtual Router Redundancy Protocol (VRRP), the two PEs provideredundancy-based protection for the data received from the BSC6900. One PE connects to theother PE through two GE ports. Link Aggregation (LAG) is applied to the interconnection linksbetween the PEs to increase the bandwidth and reliability of the links. The active and standbyFE/GE ports of the BSC6900 share one IP address, that is, IP1-1. On the PE side, the active andstandby ports of the BSC6900 are in one VLAN and share one virtual VRRP IP address, that is,IP1-0.

NOTE

The GE optical ports on the GOUa/GOUc board are used when the distance between the BSC6900 and thePE is longer than 100 meters. The FE/GE electrical ports on the FG2a/FG2c board are used when thedistance between the BSC6900 and the PE is equal to or shorter than 100 meters.

Direct Connection with Load SharingIn this networking mode, the FG2a/GOUa/FG2c/GOUc board of the BSC6900 functions as theIu/Iur interface board and provides FE/GE ports. Figure 5-7 shows the direct connection withload sharing.



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Figure 5-7 Direct connection with load sharing

When the BSC6900 and the MGW, SGSN, or another BSC6900 are located in the sameequipment room, direct connection through FE/GE ports is applicable to the Iu or Iur interface.This networking mode does not require additional transport network or equipment. The FG2a/GOUa/FG2c/GOUc boards can work in board backup mode, and the FE/GE ports work in loadsharing mode to carry services.

Features of Networking Modes

Advantages:

l Single-homing layer 3 networking

This networking mode provides backup-based protection for FE/GE links. The single PEsaves networking cost.

l Dual-homing layer 3 networking

This networking mode provides backup-based protection not only for FE/GE links but alsofor PE devices.

l Direct connection with load sharing

This networking mode does not require any LAN switch or router, thus featuring lownetworking cost and high transmission reliability.

Disadvantages:

l Single-homing layer 3 networking

The single PE cannot provide PE-level protection.

l Dual-homing layer 3 networking

The dual PEs require high networking costs.

l Direct connection with load sharing

This networking mode does not provide backup for data transmission. A port failure willlead to the decrease of transmission capacity.

5.2 Transmission and Networking on the Iub InterfaceMultiple transmission and networking modes, including ATM-based networking on the Iubinterface and IP-based networking on the Iub interface, can be adopted between the BSC6900and the base station.



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5.2.1 ATM-Based Networking on the Iub InterfaceIn ATM-based networking mode, the BSC6900 and the base station communicate with eachother through the SDH/PDH/ATM network.

ATM over E1/STM-1 Networking (Transparent TDM Transmission)

In this networking mode, the AEUa/AOUa/AOUc board of the BSC6900 functions as the Iubinterface board. The AEUa board provides E1/T1 ports, and the AOUa/AOUc board provideschannelized STM-1 ports. The AOUa/AOUc boards work in active/standby mode or their portswork in MSP 1+1 (both-end) or MSP 1:1 backup mode. Figure 5-8 shows the ATM over E1/STM-1 networking (transparent TDM transmission).

Figure 5-8 ATM over E1/STM-1 networking (transparent TDM transmission)

ATM over E1 Networking (ATM Transmission Convergence)

In this networking mode, the AEUa/AOUa/AOUc board of the BSC6900 functions as the Iubinterface board. The AEUa board provides E1/T1 ports, and the AOUa/AOUc board provideschannelized STM-1 ports. The AOUa/AOUc boards work in active/standby mode or their portswork in MSP 1+1 (both-end) or MSP 1:1 backup mode. Figure 5-9 shows the ATM over E1networking (ATM transmission convergence).

Figure 5-9 ATM over E1 networking (ATM transmission convergence)

The E1/T1 signals from multiple base stations are converged at the ATM switch and then aretransmitted to the BSC6900 through the SDH/PDH network.



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ATM over STM-1 Networking (ATM Transmission Convergence)In this networking mode, the UOIa/UOIc board of the BSC6900 functions as the Iub interfaceboard and provides channelized STM-1 ports. The UOIa/UOIc boards work in active/standbymode or their ports work in MSP 1+1 or MSP 1:1 backup mode. Figure 5-10 shows the ATMover STM-1 networking (ATM transmission convergence).

Figure 5-10 ATM over STM-1 networking (ATM transmission convergence)

The E1/T1 signals from multiple base stations are converged onto one STM-1 channel at theATM switch and then are transmitted to the ATM switch in the BSC6900 equipment roomthrough the SDH/PDH network. Then, the E1 links are converged by the ATM switch andtransmitted to the BSC6900.

Features of Networking ModesAdvantages: This networking mode is mature, QoS-assured, safe, and reliable. The telecomoperators can make full use of the existing SDH, PDH, or ATM transmission network resources.

The advantages of each type of networking are as follows:l ATM over E1/STM-1 Networking (Transparent TDM Transmission)

This networking mode is simple and applies to small-scale networks.l ATM over E1 Networking (ATM Transmission Convergence)

The BSC6900 requires simple cable connections, offers convenient installation andmaintenance, and supports MSP 1:1 backup mode. Compared with the ATM over E1networking (transparent TDM transmission), this networking mode saves transmissionresources and features high reliability.

l ATM over STM-1 Networking (ATM Transmission Convergence)The BSC6900 requires simple cable connections, offers convenient installation andmaintenance, and supports MSP 1+1 or MSP 1:1 backup mode. This networking mode canconverge the E1/T1 traffic from multiple base stations onto one STM-1 channel, thusenabling statistical multiplexing, obtaining convergence gain, saving transmissionresources, and providing high reliability. It applies to the network operators with matureATM technology.

Disadvantages: The cost of the ATM networking mode is higher than that of the IP networkingmode.

The ATM over E1/STM-1 networking (transparent TDM transmission) requires more E1 cablesand features complex cable connections. It does not support port backup or ATM multiplexing,and thus the bandwidth usage is low.



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5.2.2 IP-Based Networking on the Iub InterfaceIn IP-based networking mode, the BSC6900 and the base station communicate with each otherthrough the SDH, PDH, MSTP, or data network.

IP over E1 Networking

In this networking mode, the BSC6900 and the base station communicate with each other throughthe SDH/PDH transmission network. The PEUa/POUa/POUc board of the BSC6900 functionsas the Iub interface board. The PEUa board provides E1/T1 ports, and the POUa/POUc boardprovides channelized STM-1 ports and OC-3 ports. The optical ports of the POUa/POUc boardwork in MSP 1+1 (single-end), MSP 1+1 (both-end), or MSP 1:1 backup mode. Figure 5-11shows the IP over E1 networking.

Figure 5-11 IP over E1 networking

In this networking mode, the BSC6900 and the base station communicate with each other throughthe SDH/PDH network and the IP packets are transmitted through the PPP protocol.

In IP over E1 networking mode, E1 signals are transparently transmitted through the SDH/PDHnetwork, thus ensuring the reliability and security of data transmission and meeting the QoSrequirements of data transmission.

IP over Ethernet Networking (Layer 2)

In this networking mode, the BSC6900 and the base station communicate with each other throughthe IP network, and the data transmitted between them is processed by the switch according tothe data link layer protocol. The FG2a/GOUa/FG2c/GOUc board of the BSC6900 functions asthe Iub interface board and provides FE/GE ports. Figure 5-12 shows the IP over Ethernetnetworking (layer 2).

Figure 5-12 IP over Ethernet networking (layer 2)

Both the BSC6900 and the base station access the IP network through switches.



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In IP over Ethernet (layer 2) networking mode, the Virtual LAN (VLAN) technology is adoptedto divide the BSC6900 and the base station into different subnets. In this case, the BSC6900 andthe base station are part of IP private networks, thus ensuring the security of data transmission.

IP over Ethernet Networking (Layer 3)In this networking mode, the BSC6900 and the base station communicate with each other throughthe IP network, and the data transmitted between them is processed by the router according tothe IP protocol. The FG2a/GOUa/FG2c/GOUc board of the BSC6900 functions as the Iubinterface board and provides FE/GE ports. Figure 5-13 shows the IP over Ethernet networking(layer 3).

Figure 5-13 IP over Ethernet networking (layer 3)

IP Networking Based on Hybrid TransportIn this networking mode, the PEUa or FG2a/POUa/FG2c/POUc board of the BSC6900 functionsas the Iub interface board. The PEUa/FG2a/GOUa/FG2c/GOUc boards work in active/standbymode. The FG2a/FG2c board supports port backup. The optical ports of the POUa/POUc boardwork in MSP 1+1 (single-end), MSP 1+1 (both-end), or MSP 1:1 backup mode. In thisnetworking mode, the Iub interface board provides E1/T1 ports, FE/GE ports, channelizedSTM-1 ports, or OC-3 ports. See Figure 5-14.

Figure 5-14 IP networking based on hybrid transport



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The BSC6900 and the base station in this networking mode communicate with each otherthrough different transmission networks, which carry different types of data. The networks aredescribed as follows:l The SDH/PDH network applies to the data services with high QoS requirements, such as

the real-time data service. The base station obtains clock signals through the SDH or PDHnetwork.

l The data network applies to the data services with low QoS requirements.

Advantages of the Networkingl The cost of the ATM networking mode is higher than that of the IP networking mode.l The IP-based networking provides high bandwidth to meet the requirements of high-speed

data services.l For data services, the transmission efficiency in IP over E1 networking mode is higher than

that in ATM over E1 networking mode.l IP transmission is set to become the most preferred transmission technology in future.

5.2.3 ATM/IP-Based Networking on the Iub InterfaceIn ATM/IP-based networking mode, the BSC6900 and the base station communicate with eachother based on the ATM/IP dual stack. The ATM/IP-based Iub interface allows hybrid transportof services that have different QoS requirements. High-QoS services, such as voice services,streaming services, and signaling, are transmitted on the ATM network. Low-QoS services, suchas HSDPA and HSUPA services, are transmitted on the IP network.

Description of the NetworkingIn this networking mode, the BSC6900 is configured with the ATM interface board and IPinterface board. Figure 5-15 shows the ATM/IP-based networking on the Iub interface.

l The ATM interface board is connected to the ATM network through the E1/T1/STM-1port. For more information about ATM-based networking, see 5.2.1 ATM-BasedNetworking on the Iub Interface.

l The IP interface board is connected to the IP network through the FE/GE port. For moreinformation about IP-based networking, see 5.2.2 IP-Based Networking on the IubInterface.

The base station is connected to the ATM and IP networks through its ATM and IP interfaceboards respectively.

Figure 5-15 ATM/IP-based networking on the Iub interface



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Features of Networking ModesAdvantages:l The ATM network guarantees the QoS.l The IP network reduces the transmission cost and meets the requirement of high-speed data

services for high bandwidth on the Iub interface.

Disadvantages: The ATM/IP-based networking requires maintenance of both ATM and IPnetworks. This increases the difficulty in and the cost for network maintenance to a certain extent.



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6 Parts Reliability

About This Chapter

The BSC6900 guarantees its operation reliability by means of board redundancy and portredundancy.

6.1 Concepts Related to Parts ReliabilityThe concepts related to parts reliability are board backup, port backup, resource pool, porttrunking, and port load sharing.

6.2 Board RedundancyBoard redundancy of the BSC6900 is of two types: board backup and resource pool.

6.3 Port RedundancyPort redundancy has four types: STM-1 optical port backup, Ethernet port backup, Ethernet portload sharing, and Ethernet port trunking.

BSC6900 UMTSTechnical Description 6 Parts Reliability


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6.1 Concepts Related to Parts ReliabilityThe concepts related to parts reliability are board backup, port backup, resource pool, porttrunking, and port load sharing.

6.1.1 BackupBackup is a process of synchronization between the active and standby units. In backup mode,two units of the same type work in active/standby mode, with one working as the active unit andthe other working as the standby unit. When the active unit is faulty, the active and standby unitsare switched over, and the standby unit takes over the tasks from the active unit. In this manner,the impact of unit failure on services is minimized.

Backup Typesl Board backup

In board backup mode, two boards work in active/standby mode, with one working as theactive board and the other working as the standby board. Services can be processed byeither the active board only or both the active and standby boards. If the active board isfaulty, the BSC6900 automatically switches over the active and standby boards.

l Port backupIn port backup mode, two ports work in active/standby mode, with one working as theactive port and the other working as the standby port. Data is transmitted through either theactive port only or both the active and standby ports. If the active port is faulty, theBSC6900 automatically switches over the active and standby ports.

Concepts Related to Backupl 1+1 hot backup

The active and standby units work simultaneously and process the same services, but thestandby unit does not output the processing result. When the active unit is faulty, the standbyunit takes over the tasks from the active unit.When the active and standby units are switched over, services are not affected.

l 1+1 warm backupThe active and standby units work simultaneously, and the standby unit backs up thenecessary signaling and service data of the active unit. When the active unit is faulty, thestandby unit takes over the tasks from the active unit.When the active and standby units are switched over, stable services (for example,established calls) are not affected, but transient services (for example, calls that are beingestablished and handovers that are being performed) are interrupted.

l MSP 1:1 backupIn MSP 1:1 backup mode, the active optical port transmits and receives data. When theactive optical port is faulty, the standby optical port takes over the tasks from the activeoptical port.When the active and standby optical ports are switched over, transmission is interruptedfor one to three seconds. Stable services (for example, established calls) are not interrupted,but service quality deteriorates temporarily. Transient services (for example, calls that arebeing established and handovers that are being performed) are interrupted.



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l MSP 1+1 backupIn MSP 1+1 backup mode, both the active and standby optical ports transmit data, but onlythe active optical port receives data. When the active optical port is faulty, the standbyoptical port takes over the tasks from the active optical port.When the active and standby optical ports are switched over, transmission is interruptedfor one to three seconds. Stable services (for example, established calls) are not interrupted,but service quality deteriorates temporarily. Transient services (for example, calls that arebeing established and handovers that are being performed) are interrupted.

6.1.2 Resource PoolA resource pool is an operating mode in which the resource nodes with the same characteristicsfunction as a resource pool. The resources in this pool are allocated and managed according tothe capabilities and status of each resource node.

In resource pool mode, the system allocates resources nodes to the services that access theresource pool and provides proper service resources.

If a resource node becomes faulty, all services carried by the resource node are interrupted. Newservices are not allocated to the resource node until it recovers and re-enters the resource pool.

6.1.3 Port TrunkingPort trunking is a technique based on which multiple physical ports are aggregated into onelogical port. This technique helps enhance the reliability of data transmission.

Port trunking works in trunk groups. Multiple physical links form a trunk group. If a physicallink in the trunk group becomes faulty, the data carried on the faulty link is transferred to otherlinks in the trunk group. Therefore, the link failure does not interrupt the communication betweenboth ends of the trunk group.

The traffic of the trunk group at the most can reach the total traffic on all the physical links inthe trunk group. Port trunking helps enhance transmission reliability and increase transmissionbandwidth.

6.1.4 Port Load SharingPort load sharing is an operating mode in which the data streams that have the same destinationare distributed to different physical ports so that the load is shared by these ports.

Port load sharing is applicable to data transmission. Each of the ports working in load sharingmode has an independent IP address so that each port can receive and transmit data packets. Ifa port is faulty, the system stops distributing data to the faulty port and transfers the data to otherports.

6.2 Board RedundancyBoard redundancy of the BSC6900 is of two types: board backup and resource pool.



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NOTE

The BSC6900 interface boards have an effective mechanism for fault detection and automatic recovery. Whenthe BSC6900 detects that a certain proportion of resources of an interface board are unavailable for a specifiedperiod of time, the BSC6900 resets the interface board. If the faulty board is the active one in a pair of activeand standby boards, the BSC6900 switches over the active and standby boards. For example,l The BSC6900 resets an Iub interface board if a certain proportion of cells under the Iub interface board are

unavailable for a specified period of time because of a failure in Iub transmission links.l The BSC6900 resets an Iub interface board under the following conditions: The RRC connection setup

success rate in a cell is lower than a predefined threshold because of a failure in Iub transmission links, theproportion of such cells under the Iub interface board reaches a predefined cell threshold, the proportion ofNodeBs having such cells reaches a predefined NodeB threshold, and this situation persists for a specifiedperiod of time.

l If the BSC6900 detects any transmission fault, the BSC6900 reports an alarm instead of resetting the interfaceboard.

6.2.1 Warm Backup of AEUa BoardsWhen two AEUa boards are installed in adjacent active and standby slots in a BSC6900 subrack,the two boards can be configured to work in 1+1 warm backup mode.

When two AEUa boards are configured to work in active/standby mode, either of the two boardscan be active when they start up. The backup mode of the AEUa board is configurable when theADD BRD command is used to add an AEUa board.

The port on the active AEUa board is the active port, and the port on the standby AEUa boardis the standby port. A switchover of the active and standby boards leads to a switchover of theactive and standby ports, and vice versa. Y-shaped E1/T1 cables are used to connect the activeand standby boards to the peer equipment. The E1/T1 ports on only the active board are used totransmit, receive, and process data.

Manual SwitchoverThe SWP BRD command can be used to switch over the active and standby AEUa boards.

Automatic SwitchoverThe active and standby AEUa boards can be switched over only when one of the followingconditions is fulfilled:l The active AEUa board is reset, and the standby AEUa board works properly.l The active AEUa board is faulty, and the standby AEUa board works properly.l The port on the active AEUa board is faulty, and the port on the standby AEUa board works

properly.

Switchover ProcessWhen the active and standby AEUa boards are switched over, the active AEUa board becomesstandby after being reset, and the other AEUa board becomes active.

Impact of Switchover on the SystemWhen the active and standby AEUa boards are switched over, transmission is interrupted forone to three seconds. Stable services (for example, established calls) are not interrupted, butservice quality deteriorates temporarily. Transient services (for example, calls that are beingestablished and handovers that are being performed) are interrupted.



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6.2.2 Resource Pool of NIUa BoardsThe NIUa boards of the BSC6900 work in resource pool mode.

Board Resource PoolAll the NIUa boards of the BSC6900 work as a resource pool. The BSC6900 appropriatelyschedules and allocates resources for services between the NIUa boards.

NIUa boards can be installed in only the MPS or EPS. If NIUa boards are used to process UMTSservices, the NIUa boards preferentially process UMTS services in the local subrack.

Impact of Board Faults on the SystemWhen an NIUa board is faulty, all the services carried by it are interrupted. The capacity of theresource pool to which the board belongs decreases, and new services are not allocated to theboard.

6.2.3 Warm Backup of OMUa/OMUc BoardsWhen two OMUa/OMUc boards are installed in adjacent active and standby slots in theBSC6900 MPS, the two boards work in 1+1 warm backup mode.

When two OMUa/OMUc boards are configured to work in active/standby mode, either of thetwo boards can be active when they start up.

Manual SwitchoverManual switchover can be performed only when the standby OMUa/OMUc board worksproperly and the state of data synchronization between the active and standby OMUa/OMUcboards is Data synchronization is successful.

The SWP OMU command can be used to switch over the active and standby OMUa/OMUcboards.

NOTE

You can run the DSP OMU command to query the state of data synchronization between the active andstandby OMUa/OMUc boards.

Automatic SwitchoverThe active and standby OMUa/OMUc boards are automatically switched over only when oneof the following conditions is fulfilled:

l The standby OMUa/OMUc board cannot detect the heartbeat information about the activeOMUa/OMUc board for five consecutive minutes.

l The active OMUa/OMUc board cannot detect the virtual IP address for three consecutiveminutes, but the standby OMUa/OMUc board works properly.

l Both the active and standby OMUa/OMUc boards work properly for one period, and noswitchover occurs during the period.

NOTE

By default, the period for automatic switchover between the active and standby OMUa/OMUc boardsis 90 days. You can use the SET ASWPARA command to set the period for automatic switchover.



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Switchover Process

When the active and standby OMUa/OMUc boards are switched over, the active OMUa/OMUc board becomes standby, and the other OMUa/OMUc board becomes active.

Impact of Switchover on the System

A switchover between the active and standby OMUa/OMUc boards temporarily interrupts theOM network, but does not affect the services of the BSC6900. The OM network automaticallyrecovers after the switchover.

6.2.4 Warm Backup of PEUa BoardsWhen two PEUa boards are installed in adjacent active and standby slots in a BSC6900 subrack,the two boards can be configured to work in 1+1 warm backup mode.

When two PEUa boards are configured to work in active/standby mode, either of the two boardscan be active when they start up. The backup mode of the PEUa board is configurable when theADD BRD command is used to add a PEUa board.

The port on the active PEUa board is the active port, and the port on the standby PEUa board isthe standby port. A switchover of the active and standby boards leads to a switchover of theactive and standby ports, and vice versa. Y-shaped E1/T1 cables are used to connect the activeand standby boards to the peer equipment. The E1/T1 ports on only the active board are used totransmit, receive, and process data.

Manual Switchover

The SWP BRD command can be used to switch over the active and standby PEUa boards.

Automatic Switchover

The active and standby PEUa boards can be switched over only when one of the followingconditions is fulfilled:

l The active PEUa board is reset, and the standby PEUa board works properly.

l The active PEUa board is faulty, and the standby PEUa board works properly.

l The port on the active PEUa board is faulty, and the port on the standby PEUa board worksproperly.

Switchover Process

When the active and standby PEUa boards are switched over, the active PEUa board becomesstandby after being reset, and the other PEUa board becomes active.


When the active and standby PEUa boards are switched over, transmission is interrupted for oneto three seconds. Stable services (for example, established calls) are not interrupted, but servicequality deteriorates temporarily. Transient services (for example, calls that are being establishedand handovers that are being performed) are interrupted.



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6.2.5 Warm Backup of SCUa/SCUb BoardsWhen two SCUa/SCUb boards are installed in adjacent active and standby slots in a BSC6900subrack, the two boards work in 1+1 warm backup mode.

When two SCUa/SCUb boards are configured to work in active/standby mode, either of the twoboards can be active when they start up. The SCUa/SCUb boards perform maintenance,management, and GE/10GE switching in the local subrack. The active SCUa/SCUb boardprocesses the maintenance and management data, and the active and standby SCUa/SCUb boardsprocess GE/10GE switching data.

Manual SwitchoverThe SWP BRD command can be used to switch over the active and standby SCUa/SCUb boards.

Automatic SwitchoverThe active and standby SCUa/SCUb boards can be switched over only when one of the followingconditions is fulfilled:l The active SCUa/SCUb board is reset, and the standby SCUa/SCUb board works properly.l The active SCUa/SCUb board is faulty, and the standby SCUa/SCUb board works properly.l The clock source of the active SCUa/SCUb board is faulty, and that of the standby SCUa/

SCUb board works properly.

Switchover ProcessWhen the active and standby SCUa/SCUb boards are switched over, the active SCUa/SCUbboard becomes standby after being reset, and the other SCUa/SCUb board becomes active.

Impact of Switchover on the SystemWhen the active and standby SCUa/SCUb boards are switched over, services are not affected.

6.2.6 Warm Backup of AOUa/AOUc BoardsWhen two AOUa/AOUc boards are installed in adjacent active and standby slots in aBSC6900 subrack, the two boards can be configured to work in board backup mode or portbackup mode.

When two AOUa/AOUc boards are configured to work in active/standby mode, either of thetwo boards can be active when they start up. The backup mode of the AOUa/AOUc board isconfigurable when the ADD BRD command is used to add an AOUa/AOUc board. IfBackup is set to YES, both the AOUa/AOUc boards and their optical ports work in backupmode. Therefore, the backup mode of the optical ports does not need to be configured again.

Services are processed by the board where the active port is located. Active ports may be locatedon both the active and standby boards because the switchover between the optical ports on theactive and standby boards does not affect the active/standby relationship between the boards. Inthat case, both the active and standby boards can process services.

Optical ports on AOUa boards work in MSP 1:1 backup mode. Optical ports on AOUc boardswork in MSP 1:1 or MSP 1+1 backup mode. For details about the backup of AOUa/AOUc opticalports, see 6.3.1 STM-1 Optical Port Backup. In addition, the Y-shaped optical cable can be



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used to ensure the proper working of AOUa/AOUc boards during the switchover of the activeand standby optical ports.

Manual Switchover

The SWP BRD command can be used to switch over the active and standby AOUa/AOUcboards.


The active and standby AOUa/AOUc boards can be switched over only when one of thefollowing conditions is fulfilled:l The active AOUa/AOUc board is reset, and the standby AOUa/AOUc board works

properly.l The active AOUa/AOUc board is faulty, and the standby AOUa/AOUc board works

properly.

Switchover Process

When the active and standby AOUa/AOUc boards are switched over, the active AOUa/AOUcboard becomes standby after being reset, and the other AOUa/AOUc board becomes active.

NOTE

After an active/standby switchover, the BSC6900 determines the active and standby ports according to theMSP protocol strategy.


When the active and standby AOUa/AOUc boards are switched over, transmission is interruptedfor one to three seconds. Stable services (for example, established calls) are not interrupted, butservice quality deteriorates temporarily. Transient services (for example, calls that are beingestablished and handovers that are being performed) are interrupted.

6.2.7 Warm Backup of FG2a/FG2c BoardsWhen two FG2a/FG2c boards are installed in adjacent active and standby slots in a BSC6900subrack, the two boards can be configured to work in one of the following two modes: boardbackup with no port backup and board backup with port backup.

When two FG2a/FG2c boards are configured to work in active/standby mode, either of the twoboards can be active when they start up. The backup mode of the FG2a/FG2c board isconfigurable when the ADD BRD command is used to add an FG2a/FG2c board. If Backup isset to YES(YES), the backup mode of the FG2a/FG2c board is board backup with no portbackup.

When the FG2a/FG2c boards are configured to work in board backup mode, you can run theADD ETHREDPORT command to set the backup mode of FE/GE ports. For details about thebackup mode of FE/GE ports, see 6.3.2 Ethernet Port Backup.

The FE/GE ports on the FG2a/FG2c boards can also be configured to work in Ethernet port loadsharing mode or Ethernet port trunking mode. For details about the Ethernet port load sharingmode, see 6.3.3 Ethernet Port Load Sharing. For details about the Ethernet port trunking mode,see 6.3.4 Ethernet Port Trunking.



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Manual Switchover ModesThe SWP BRD command can be used to switch over the active and standby FG2a/FG2c boards.

Automatic Switchover ModesThe active and standby FG2a/FG2c boards can be switched over only when one of the followingconditions is fulfilled:l The active FG2a/FG2c board is reset, and the standby FG2a/FG2c board works properly.l The active FG2a/FG2c board is faulty, and the standby FG2a/FG2c board works properly.

Switchover ProcessWhen the active and standby FG2a/FG2c boards are switched over, the active FG2a/FG2c boardbecomes standby after being reset, and the other FG2a/FG2c board becomes active.

NOTE

If the FG2a/FG2c boards work in board backup with port backup mode, after an active/standby switchover,the BSC6900 determines the active and standby ports and defines the port load sharing policy.

Impact of Switchover on the Systeml If the FG2a/FG2c boards work in active/standby mode and their ports work in active/

standby, port trunking, load sharing, or active/standby route mode, transmission isinterrupted for one to three seconds when the active and standby FG2a/FG2c boards areswitched over. Stable services (for example, established calls) are not interrupted, butservice quality deteriorates temporarily. Transient services (for example, calls that are beingestablished and handovers that are being performed) are interrupted.

l When the FG2a/FG2c boards work in active/standby mode but their ports do not work inactive/standby, port trunking, load sharing, or active/standby route mode, a switchoverbetween the active and standby boards interrupts services.

6.2.8 Warm Backup of GCUa/GCGa BoardsWhen two GCUa/GCGa boards are installed in adjacent active and standby slots in theBSC6900 MPS, the two boards work in 1+1 warm backup mode.

When two GCUa/GCGa boards are configured to work in active/standby mode, either of thetwo boards can be active when they start up.

Manual SwitchoverThe SWP BRD command can be used to switch over the active and standby GCUa/GCGaboards.

Automatic SwitchoverThe active and standby GCUa/GCGa boards can be switched over only when one of the followingconditions is fulfilled:l The active GCUa/GCGa board is reset, and the standby GCUa/GCGa board works properly.l The active GCUa/GCGa board is faulty, and the standby GCUa/GCGa board works

properly.



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l The clock source of the active GCUa/GCGa board is faulty, and that of the standby GCUa/GCGa board works properly.

NOTE

The GCGa board supports the GPS clock. If the satellite card in the active GCGa board is faulty but thatin the standby GCGa board works properly, the active and standby GCGa boards are switched over.

Switchover Process

When the active and standby GCUa/GCGa boards are switched over, the active GCUa/GCGaboard becomes standby after being reset, and the other GCUa/GCGa board becomes active.


A switchover between the active and standby GCUa/GCGa boards does not affect services.

6.2.9 Warm Backup of GOUa/GOUc BoardsWhen two GOUa/GOUc boards are installed in adjacent active and standby slots in aBSC6900 subrack, the two boards can be configured to work in one of the following two modes:board backup with no port backup and board backup with port backup.

When two GOUa/GOUc boards are configured to work in active/standby mode, either of thetwo boards can be active when they start up. The backup mode of the GOUa/GOUc board isconfigurable when the ADD BRD command is used to add a GOUa/GOUc board. If Backup isset to YES(YES), the backup mode of the GOUa/GOUc board is board backup with no portbackup.

When the GOUa/GOUc boards are configured to work in board backup mode, you can run theADD ETHREDPORT command to set the port backup mode. For details about the port backupmode, see 6.3.2 Ethernet Port Backup.

The FE/GE ports on the GOUa/GOUc boards can also be configured to work in Ethernet portload sharing mode or Ethernet port trunking mode. For details about the Ethernet port loadsharing mode, see 6.3.3 Ethernet Port Load Sharing. For details about the Ethernet porttrunking mode, see 6.3.4 Ethernet Port Trunking.

Manual Switchover

The SWP BRD command can be used to switch over the active and standby GOUa/GOUcboards.


The active and standby GOUa/GOUc boards can be switched over only when one of thefollowing conditions is fulfilled:

l The active GOUa/GOUc board is reset, and the standby GOUa/GOUc board worksproperly.

l The active GOUa/GOUc board is faulty, and the standby GOUa/GOUc board worksproperly.



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Switchover Process

When the active and standby GOUa/GOUc boards are switched over, the active GOUa/GOUcboard becomes standby after being reset, and the other GOUa/GOUc board becomes active.

NOTE

If the GOUa/GOUc boards work in board backup with port backup mode, after an active/standbyswitchover, the BSC6900 determines the active and standby ports and defines the port load sharing policy.

Impact of Switchover on the Systeml If the GOUa/GOUc boards work in active/standby mode and their ports work in active/

standby, port trunking, load sharing, or active/standby route mode, transmission isinterrupted for one to three seconds when the active and standby GOUa/GOUc boards areswitched over. Stable services (for example, established calls) are not interrupted, butservice quality deteriorates temporarily. Transient services (for example, calls that are beingestablished and handovers that are being performed) are interrupted.

l When the GOUa/GOUc boards work in active/standby mode but their ports do not workin active/standby, port trunking, load sharing, or active/standby route mode, a switchoverbetween the active and standby boards interrupts services.

6.2.10 Warm Backup of POUa/POUc BoardsWhen two POUa/POUc boards are installed in adjacent active and standby slots in aBSC6900 subrack, the two boards can be configured to work in 1+1 warm backup mode or portbackup mode.

When two POUa/POUc boards are configured to work in active/standby mode, either of the twoboards can be active when they start up. The backup mode of the POUa/POUc board isconfigurable when the ADD BRD command is used to add a POUa/POUc board. If Backup isset to YES, both the POUa/POUc boards and their optical ports work in backup mode. Therefore,the backup mode of the optical ports does not need to be configured again.


Optical ports on POUa/POUc boards work in MSP 1:1 or MSP 1+1 backup mode. For detailsabout the backup of POUa/POUc optical ports, see 6.3.1 STM-1 Optical Port Backup.

Manual Switchover

The SWP BRD command can be used to switch over the active and standby POUa/POUc boards.


The active and standby POUa/POUc boards can be switched over only when one of the followingconditions is fulfilled:

l The active POUa/POUc board is reset, and the standby POUa/POUc board works properly.

l The active POUa/POUc board is faulty, and the standby POUa/POUc board works properly.



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Switchover ProcessWhen the active and standby POUa/POUc boards are switched over, the active POUa/POUcboard becomes standby after being reset, and the other POUa/POUc board becomes active.

NOTE

If optical ports work in MSP 1:1 or MSP 1+1 backup mode, the BSC6900 determines the active and standbyoptical ports according to the MSP protocol after the active and standby POUa/POUc boards are switchedover,

Impact of Switchover on the SystemWhen the active and standby POUa/POUc boards are switched over, transmission is interruptedfor one to three seconds. Stable services (for example, established calls) are not interrupted, butservice quality deteriorates temporarily. Transient services (for example, calls that are beingestablished and handovers that are being performed) are interrupted.

6.2.11 Warm Backup of UOIa/UOIc BoardsWhen two UOIa/UOIc boards are installed in adjacent active and standby slots in a BSC6900subrack, the two boards can be configured to work in 1+1 warm backup mode or port backupmode.

When two UOIa/UOIc boards are configured to work in active/standby mode, either of the twoboards can be active when they start up. When the ADD BRD command is executed to add aUOIa/UOIc board, the backup mode of the UOIa/UOIc board is configurable. If Backup is setto YES, both the UOIa/UOIc boards and their optical ports work in backup mode. Therefore,the backup mode of the optical ports does not need to be configured again.


Optical ports on UOIa/UOIc boards work in MSP 1:1 or MSP 1+1 backup mode. For detailsabout the backup of UOIa/UOIc optical ports, see 6.3.1 STM-1 Optical Port Backup. Inaddition, the Y-shaped optical cable can be used to ensure the proper working of UOIa/UOIcboards during the switchover of the active and standby optical ports.

Manual SwitchoverThe SWP BRD command can be used to switch over the active and standby UOIa/UOIc boards.

Prerequisites for SwitchoverThe active and standby UOIa/UOIc boards can be switched over only when one of the followingconditions is fulfilled:l The active UOIa/UOIc board is reset, and the standby UOIa/UOIc board works properly.l The active UOIa/UOIc board is faulty, and the standby UOIa/UOIc board works properly.

Switchover ProcessWhen the active and standby UOIa/UOIc boards are switched over, the active UOIa/UOIc boardbecomes standby after being reset, and the other UOIa/UOIc board becomes active.



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NOTE

If optical ports work in MSP 1:1 or MSP 1+1 backup mode, the BSC6900 determines the active and standbyoptical ports according to the MSP protocol after the active and standby UOIa/UOIc boards are switchedover.


When the active and standby UOIa/UOIc boards are switched over, transmission is interruptedfor one to three seconds. Stable services (for example, established calls) are not interrupted, butservice quality deteriorates temporarily. Transient services (for example, calls that are beingestablished and handovers that are being performed) are interrupted.

6.2.12 Warm Backup of SPUa/SPUb BoardsWhen two SPUa/SPUb boards are installed in adjacent active and standby slots in a BSC6900subrack, the two boards work in 1+1 warm backup mode.

When two SPUa/SPUb boards are configured to work in active/standby mode, either of the twoboards can be active when they start up.

Manual Switchover

The SWP BRD command can be used to switch over the active and standby SPUa/SPUb boards.


The active and standby SPUa/SPUb boards can be switched over only when one of the followingconditions is fulfilled:l The active SPUa/SPUb board is reset, and the standby SPUa/SPUb board works properly.l The active SPUa/SPUb board is faulty, and the standby SPUa/SPUb board works properly.

Switchover Process

When the active and standby SPUa/SPUb boards are switched over, the active SPUa/SPUb boardbecomes standby after being reset, and the other SPUa/SPUb board becomes active.


When the active and standby SPUa/SPUb boards are switched over, stable services (for example,established calls) are not affected, but transient services (for example, calls that are beingestablished and handovers that are being performed) are interrupted.

6.2.13 Resource Pool of DPUb/DPUe BoardsThe DPUb/DPUe boards of the BSC6900 and the Digital Signal Processors (DSPs) of eachDPUb/DPUe work in resource pool mode.

Board Resource Pool

All the DPUb/DPUe boards of the BSC6900 form a resource pool. The BSC6900 appropriatelyschedules and allocates resources for services between the boards.



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Services in a subrack are preferentially processed by DPU boards in the same subrack. If theDPU boards in the subrack are unavailable, the services are allocated to the DPU boards inanother subrack.

DSP Resource PoolAll the DSPs in the DPUb/DPUe boards of the BSC6900 form a resource pool. The status of theDSPs is managed by the Main Processing Unit (MPU) subsystem in the main control DPUb/DPUe board. The MPU subsystem appropriately schedules and allocates resources for theassociated services among the DSPs.

The priorities of DSPs to be allocated in descending order are DSPs in the same board, DSPs inthe same subrack, and DSPs in different subracks.

Impact of Board or DSP Faults on the SystemWhen a DPUb/DPUe board or a DSP is faulty, the services carried by the board or DSP areinterrupted.

When a DPUb/DPUe board or a DSP is faulty, the capacity of the resource pool to which theboard or DSP belongs decreases, and new services are not allocated to the board or DSP.

Board or DSP Fault RectificationWhen a DPUb/DPUe board is faulty, run the RST BRD command to reset the board. When aDSP is faulty, run the RST DSP command to reset the DSP.

6.3 Port RedundancyPort redundancy has four types: STM-1 optical port backup, Ethernet port backup, Ethernet portload sharing, and Ethernet port trunking.

6.3.1 STM-1 Optical Port BackupOptical ports on the BSC6900 AOUa/AOUc/POUa/POUc/UOIa/UOIc boards can work in MSP1:1 or MSP 1+1 backup mode.

In MSP 1:1 backup mode, the active optical port transmits and receives data.

In MSP 1+1 backup mode, both the active and standby optical ports transmit data, but only theactive optical port receives data.

The SET MSP command is used to set the attributes of MSP backup.

Manual SwitchoverThe SET MSPCMD command is used to switch over the active and standby optical ports.

Automatic SwitchoverThe active and standby optical ports can be switched over only when one of the followingconditions is fulfilled:l A switchover at the peer end triggers a switchover at the local end.



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l The board where the active optical port is located is reset.l The active optical port is faulty, and the standby optical port works properly.l The active board is faulty, and the standby board works properly.l The optical transmission device connected to the active optical port is faulty, and the optical

transmission device connected to the standby optical port works properly.

Switchover Process

When the active and standby optical ports are switched over, the active optical port stopsreceiving data and becomes standby, and the original standby optical port starts to receive dataand becomes active.


When the active and standby optical ports in MSP 1:1 or MSP 1+1 backup mode are switchedover, transmission is interrupted for one to three seconds. Stable services (for example,established calls) are not interrupted, but service quality deteriorates temporarily. Transientservices (for example, calls that are being established and handovers that are being performed)are interrupted.

6.3.2 Ethernet Port BackupWhen the FG2a/GOUa/FG2c/GOUc boards work in board backup mode, the FE/GE ports onthe active and standby boards can be configured to work in Ethernet port backup mode.

In Ethernet port backup mode, only the active optical port transmits and receives data.

When the boards work in active/standby mode, you can use the ADD ETHREDPORTcommand to configure the FE/GE ports on the active and standby boards to work in Ethernetport backup mode.

Manual Switchover

The SWP ETHPORT command is used to switch over the active and standby ports on the FG2a/GOUa/FG2c/GOUc boards.


The active and standby ports can be switched over only if one of the following conditions isfulfilled:l The active port is faulty, and the standby port works properly.l The active board is faulty, and the standby board works properly.l The board where the active port is located is reset.l A fault is detected after a BFD/ARP detection is started by using the STR IPCHK

command with the parameter Whether affect the port swapping set to YES(YES).

Switchover Process

When the active and standby ports are switched over, the active port stops receiving data andbecomes standby, and the original standby port starts to receive data and becomes active.



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Impact of Switchover on the SystemWhen the active and standby ports are switched over, transmission is interrupted for one to threeseconds. Stable services (for example, established calls) are not interrupted, but service qualitydeteriorates temporarily. Transient services (for example, calls that are being established andhandovers that are being performed) are interrupted.

6.3.3 Ethernet Port Load SharingThe FE/GE ports on the BSC6900 FG2a/GOUa/FG2c/GOUc board support load sharing.

PrerequisitesThe BSC6900 supports load sharing between FE/GE ports that are located either on the sameboard or on active and standby boards.

NOTE

l The BSC6900 does not support load sharing between the FE/GE ports on non-active/standby boards.

l The BSC6900 does not support load sharing between active and standby ports.

Working PrinciplesEthernet port load sharing can be implemented by configuring multiple routes with the samepriority between FE/GE ports and the same destination address.

NOTE

One data stream is transmitted only through one FE/GE port.

Application ScenarioWhen the FE/GE ports of the BSC6900 work in load sharing mode, different IP routes must beconfigured if the data towards the same destination IP address needs to be transmitted throughdifferent ports. For example, load sharing between two FE/GE ports requires two IP routes. TheIP routes must have the same destination IP address, subnet mask, and priority, but differentnext-hop IP addresses.

NOTE

l The ADD IPRT command can be used to add an IP route.

l The BSC6900 supports load sharing between a maximum of three FE/GE ports.

Impact of Port Faults on the SystemWhen a port is faulty, services carried on the port are interrupted for one to three seconds. Stableservices (for example, established calls) are not interrupted, but service quality deterioratestemporarily. Transient services (for example, calls that are being established and handovers thatare being performed) are interrupted.

When a port is faulty, the capacity of the resource pool to which this port belongs decreases.

6.3.4 Ethernet Port TrunkingThe GE/10GE ports on the SCUa/SCUb boards and GE/FE ports on the FG2a/FG2c/GOUa/GOUc boards support port trunking.



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Application of Port Trunking in the BSC6900Port trunking is applicable to the switching subsystem and interface processing subsystem ofthe BSC6900.l In the same subrack, the ports serving the communication between the SCUa/SCUb and

the other boards work as a trunk group to implement port trunking.l The ports serving the communication between the SCUa/SCUb boards in different subracks

work as a trunk group to implement port trunking.l The FE/GE ports on the FG2a/FG2c/GOUa/GOUc board or the FE/GE ports on active and

standby FG2a/FG2c/GOUa/GOUc boards can be configured to form a trunk group by usingthe ADD ETHTRK and ADD ETHTRKLNK commands to implement port trunking. Allthe FE/GE ports in a trunk group communicate with external devices with the same IPaddress.

Benefitsl In a trunk group, the bandwidth is evenly allocated to the FE/GE ports, implementing load

balancing.l If an FE/GE link in a trunk group is faulty, the data stream carried by the link is

automatically switched to other FE/GE links.l When port trunking applies to the switching subsystem, no associated switchover occurs

if the SCUa/SCUb board or another service board is faulty.



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Documents

BSC6900 UMTS Technical Description(V900R013C00_04)(PDF)-En