TN_SS001_E1_0 NE System Structure-135.doc

7/27/2019 TN_SS001_E1_0 NE System Structure-135.doc

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TN_SS001_E1_0 NE System Structure

Course Objectives:

Understand the working principle of the ZXWN MSCS and

MGW

Understand the hardware structure of the ZXWN MSCS

and MGW

Understand the software structure of the ZXWN MSCS and

MGW

Master the networking configuration of the ZXWN MSCS

and MGW

Master the board structure of the ZXWN MSCS and MGW

Master the hardware cable configuration of the ZXWN

MSCS and MGW


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Contents

1 MSC Server System Architecture ........................................................................................................1

1.1 System Background ...................................................................................................................... 1

1.2 MSC Server Features ................................................................................................................... 1

1.3 Main Functions of MSC Server.................................................................................................... 2

2 MSC Server Working Principle .............................................................................................................5

2.1 System Working Principle............................................................................................................. 5

2.2 Hardware Structure........................................................................................................................ 8

2.3 Software Structure ....................................................................................................................... 10

2.4 System Networking Configuration............................................................................................. 15

2.4.1 Networking Mode.............................................................................................................. 15

2.4.2 Physical Indices ................................................................................................................ 20

2.4.3 System Configuration....................................................................................................... 21

2.5 Board Structure ............................................................................................................................ 26

2.5.1 Board Description and Structure .................................................................................... 26

2.5.2 Boards of the ZXWN MSCS............................................................................................ 29

2.5.3 Boards ................................................................................................................................ 31

2.6 Hardware Cables ......................................................................................................................... 40

2.6.1 System Clock Cable......................................................................................................... 40

2.6.2 Line Reference Clock Cable ........................................................................................... 41

2.6.3 IP Access Cable................................................................................................................ 41

2.6.4 Control Plane Interconnection Cable............................................................................. 41

2.6.5 PD485 Cable ..................................................................................................................... 42

2.6.6 OMC Ethernet Cable........................................................................................................ 42


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2.6.7 Fan Monitoring Cable ...................................................................................................... 42

2.6.8 External Cables and Components of the Cabinet ....................................................... 42

3 MGW System Principle ........................................................................................................................ 53

3.1 Main Functions of MGW in R4 ................................................................................................... 53

3.2 System Working Principle ........................................................................................................... 54

3.2.1 MGW System Background ............................................................................................. 54

3.2.2 Compliant Standards ....................................................................................................... 55

3.2.3 MGW Functions................................................................................................................ 56

3.2.4 System Working Principle ............................................................................................... 56

3.3 Hardware Structure ...................................................................................................................... 57

3.3.1 MGW Hardware Principle ............................................................................................... 57

3.3.2 MGW Subsystem Functions........................................................................................... 58

3.3.3 Functions of the Logical Modules of the MGW ............................................................ 62

3.4 Software Structure........................................................................................................................ 69

3.4.1 BSP Subsystem................................................................................................................ 69

3.4.2 Operating Subsystem ...................................................................................................... 70

3.4.3 Database Subsystem ...................................................................................................... 70

3.4.4 Bearer Subsystem ........................................................................................................... 70

3.4.5 Microcode Subsystem ..................................................................................................... 71

3.4.6 Signaling Subsystem ....................................................................................................... 71

3.4.7 System Control Subsystem ............................................................................................ 71

3.4.8 Network Management Subsystem................................................................................. 72

3.4.9 PP Subsystem .................................................................................................................. 72

3.4.10 CS User Plane Subsystem........................................................................................... 73

3.5 System Networking Configuration ............................................................................................. 73

3.5.1 Different Networking Modes of the MGW ..................................................................... 73


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3.5.2 System Configuration....................................................................................................... 75

3.5.3 Example ............................................................................................................................. 83

3.6 Board Structure ............................................................................................................................ 85

3.6.1 MGW Boards..................................................................................................................... 85

3.7 Hardware Cable ......................................................................................................................... 104

3.7.1 System Clock Cable....................................................................................................... 104

3.7.2 Reference Clock Cable.................................................................................................. 104

3.7.3 IP Access Cable.............................................................................................................. 105

3.7.4 Control Plane Interconnection Cable........................................................................... 105

3.7.5 PD485 Cable ................................................................................................................... 105

3.7.6 OMC Ethernet Cable...................................................................................................... 105

3.7.7 Fan Monitoring Cable..................................................................................................... 106

3.7.8 External Cables and Components of the Cabinet ..................................................... 106

4 Hardware Configuration Instance.................................................................................................... 117

4.1 MSC Server System Configuration ......................................................................................... 117

4.1.1 Configuration Calculation of Boards ............................................................................ 117

4.1.2 Board Quantity Calculation Method............................................................................. 117

4.1.3 Typical Single Shelf Configuration ............................................................................... 118

4.1.4 Typical Single Rack Configuration ............................................................................... 119

4.2 MGW System Configuration..................................................................................................... 120

4.2.1 VMGW Typical Configuration........................................................................................ 120

4.2.2 GMGW Typical Configuration ....................................................................................... 123

Appendix A Terms ................................................................................................................................... 127

Appendix B Abbreviations.................................................................................................................... 129


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1 MSC Server System Architecture

1.1 System Background

The ZXWN system adopts the architecture of integrated management and distributed

processing, which boasts powerful processing capability and facilitates the control and

management of the large-capacity mobile network. The ZXWN system boasts flexible

networking, so smooth increase of the processing capability can be implemented, and

the flexible and economical network optimization plan can be provided for operators.

The ZXWN system adopts the ZET all IP unified platform, which is the

next-generation platform adopted by ZTE to improve its market competitive power.

This platform adopts the leading IP switching technology, improving the integration

level of the system and the processing capability of the board, providing the QoS

guarantee technology, improving the performance-to-price ratio of the system, and

facilitating fusion of the fixed and mobile NGN networks. Under the all-IP unified

platform, different functional Network Elements (NE) can be created by combining

different boards and functional software, so the NE upgrade can be implemented onlythrough changing hardware boards and upgrading the software. This platform can be

used for all the core equipment and the RNC/BSC equipment of 3G WCDMA,

CDMA2000 and TD-SCDMA, NGN SS/TG/AG equipment and upgrade and

improvement of the existing 2G equipment.

1.2 MSC Server Features

The ZXWN MSCS system implements the functions of the Mobile Switching Center

Server (MSC Server), the Visitor Location Register (VLR) and the Service Switching

Point (SSP). The ZXWN MSCS system supports the Media Gateway Control Function

(MGCF), co-existence of the MGCF and the GMSC Server, and smooth upgrading to

the MGCF from the MSC Server.

Being the core of the CN system, the MSCS controls Mobile Stations(MS) within its coverage and implements speech channel switching.

The MSCS also serves as an interface between mobilecommunication systems and circuit switching networks such as PSTN,ISDN and PSPDN. It implements functions such as network interface,common channel system and billing. Also, it manages SS7, auxiliary


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radio resources and mobility management between RNS and CN. Toestablish call routes to MSs, each MSCS can function as a GatewayMSCS (GMSCS).

The VLR is a database, storing the required information for the MSCSprocessing incoming and outgoing calls of MSs within its coverage,such as subscriber numbers, ID of the location area wheresubscribers are located, and services provided to subscribers.

The SSP is a service switching point of the intelligent network,providing measures for identifying the call request processing of theCAMEL OSS service, interacting with the MSC Server call processingand call services, modifying call/connection processing function asrequired, and processing requests of the intelligent services underthe Service Control Point (SCP).

The MGCF is the NE of implementing interworking between IPMultimedia Subsystem (IMS) services, and CS domain services and

PSTN services, implementing conversation between the controlsignaling SIP in the IMS domain and the signaling BICC/ISUP in theCS domain.

The ZXWN MSCS system has advantages of modularized design, high reliability, and

standard signaling interface.

The ZXWN MSCS system is designed to provide solution to the products of the CN

control plane of the UMTS system, supporting GSM CN, UMTS R99/R4-phase

protocol and the related functions at the same time. It can also provide a completeevolution plan from the GSM CN to 3GPP 99, and then to 3GPP R4.

1.3 Main Functions of MSC Server

The ZXWN MSCS has the following functions:

Mobility management function

Supports network attachment, location update and IMSIdetachment of 2G and 3G subscribers; supports the roaming ofa dual-mode terminal between the 2G network and 3G network;

supports the authentication encryption arithmetic of the 2Gnetwork and 3G network as well as their mutual conversion.

Basic call function

Supports various calls made between mobile subscribers and

between a mobile subscriber and a PSTN subscriber.

Handoff function

Supports various intra-system handoffs, relocations andinter-system handoffs, such as UMTSUMTS, GSMGSM

and UMTSGSM.

Data service function


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Supports the circuit-type transparent and non-transparent data

services of maximum 64kbps.

Short message service function

Supports the SMS originated and terminated by mobilesubscribers.

Multi-media service function

Supports video telephone services between mobile terminalsand between a mobile terminal and an ISDN terminal, SCUDIFfunction, and video telephone service decreasing to the voice

service.

Supplementary service function

Supports the abundant supplementary services, such as CallingNumber Identification Presentation (CNIP), call forwarding, call

deflection, call transfer, conference call, Advice Of Charge (AOC),priority call, Closed User Group (CUG), call holding and callwaiting.

Monitoring function

Provides CS lawful interface function, and supports monitoringon calls of the specified subscribers.

CAMEL function

The ZXWN MSCS can act as a gsmSSP to access the gsmSCP,

supporting CAMEL4 function at present. Location service function

Supports the standard interface with the GMLC, and variouslocation services such as MO, MT and NI.

Multi-area-code networking function

The ZXWN MSCS can simultaneously manage multiple localnetworks, which facilitates region networking adopted and canreduces the cost of network construction.

Dual-home networking function

Supports dual-home networking of the MGW.

Interworking between IMS and CS

Supports the MGCF function, and combination of the

GMSCServer and MGCF, which facilitates the interworkingbetween IMS and CS.

The ZXWN MSCS system adopts fully distributed power system,and each board has its own power module to implement

conversion from -48V power to the working power.


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2 MSC Server Working Principle

2.1 System Working Principle

MSC Server (MSCS for short) is the core of the CN system. The MSCS is a function

entity used to control and complete voice channel switching of MSs within its coverage,

and serves as an interface between the mobile communication system and circuit

switched networks such as PSTN, ISDN and PSPDN. It can implement network

interface, public channel system and charging functions, and complete SS7 andauxiliary wireless resource management and mobility management between RNS and

CN. In addition, to set up the call route to the MS, each MSCS can complete the

gateway MSCS (GMSCS) function.

The MSCS also has the visitor location register (VLR) function and implements the

service switching point (SSP) function for intelligent calls, with the advantages of

modular design, high reliability and signaling interface standardization. The VLR is a

database containing the information that the MSCS needs to retrieve for managing

incoming and outgoing calls of the MS in its coverage, such as user number, locationarea identifier and services provided for users. The SSP is the intelligent network

service switching point. It provides the means to identify and process CAMEL OSS

service call request, interacts with MSCS call processing and call service logic,

modifies call/connection processing function according to requirements and processes

intelligent services under the control of the service control point (SCP).

Fig. 2.1-1 shows the working principle of the MSCS. In this figure, the MSCS consists

of various signaling interface boards and MP pool. The interface board is used to

interconnect with the signaling network. The SPB is used to access the SS7 network.

The APB is used to access the ATM signaling network. The IPI is used to access the

SIGTRAN signaling network. The MP pool is used to process upper-layer signaling

and services.

The SPB provides E1/T1 interface, processes MTP2 signaling, and forwards MTP3

signaling packet through the FE interface to the signaling MP for processing. Through

the interface provided by the SPB, the MSCS can implement the interconnection with

the BSC, HLR, STP, SCP, other MSCS and SC.


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The APB provides the STM-1 interface, processes ATM adaptation and broadband SS7

underlying signaling such as AAL5-SAR, SSCOP and SSCF, and forward MTP3b

signaling packet through the FE interface to the signaling MP for processing. Through

the interface provided by the APB, the MSCS can implement the interconnection

between the RNC and MGW (when using the ATM as the signaling bearer).

The IPI provides FE interface, implements IP packet forwarding of the SIGTRAN

underlying signaling interface, and forwards the SCTP packet received from the IP

network to the signaling MP for processing. Through the IPI board, the MSCS can

interconnect with the MGW, other MSCS and SG. The IPI board processes IP packets

with the network processor, supporting the line rate. After receiving route packets, the

IPI board forwards route packet to the RPU. The RPU maintains the routing table.

Swi t ch

SPB APB I PI CLKG

OMP

JF

Server

USIRPU

NO. 7 Si gnal l i ng

Net work

ATM Si gnal

Net work Si gTran NetworkBI TS SYN Si gnal I nput

FE FE FE FE FE

FE FE FE FE

FESTM- 1E1/ T1

FE

NMS

SYN Si gnal I nput

Si gnal

MP

SYN Si gnal Out put

JF

Cent er

Q3 or COBRA FTP or FTAM

OMMServer

OMM

Cl i ent

FE

FEFE

OMM

Cl i ent

Servi ce

MP

ZXWN MSCS

Fig. 2.1-1 Working Principle of the MSCS


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The CLKG board is a clock board, providing stratum-2 enhanced clock. The CLKG

board can get locking clock signals from the BITS or SPB, provide 8 kHz/s clock

reference signals for the SPB, APB and IPI, and ensure the synchronization of the

clock of the whole equipment and the external network.

The MP pool includes various MP boards. In physical, they are the same board. In

logical, they are divided into OMMP, service MP and signaling MP, with different

functions.

The signaling MP needs to process the signaling from various interfaces:

Narrowband SS7: MTP3, SCCP, TCAP, TUP and ISUP.

Broadband SS7: MTP3B, B-SCCP.

A interface access signaling: BSSAP.

Iu interface access signaling: RANAP.

BICC signaling.

H.248 signaling.

SIGTRAN signaling: SCTP, M3UA, M2UA and STC.

After receiving the signaling packet from the signaling interface board, the signaling

MP processes the packet layer by layer according to the signaling protocol stack, and

then sends it to the application layer signaling or service MP.

The service MP processes various application layer signaling: mobility management

signaling, call processing signaling, SMS processing signaling, MAP signaling and

CAP signaling. It also has charging, call observation and statistics functions.

When the service MP needs to send signaling, it transmits the signaling packet to the

signaling MP. The signaling MP forwards the packet layer by layer according to the

signaling protocol stack, and finally forwards it to other NEs through the signaling

interface boards.

The RPU is responsible for maintaining the routing table of the whole NE. When the

IPI board receives a route packet, it forwards the packet to the RPU for processing. The

RPU refreshes its own routing table in real time, creates a forwarding table according

to the routing table, and synchronizes the forwarding table to the IPI boards.


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The OMMP is the OMM Server maintenance proxy, saving configuration information

and version file of the equipment. It also serves as the information channel between the

boards and the OMM Server to transmit alarm information and statistics information.

The OMM Server is the maintenance center of the whole system. The OMM Client is

the client of the maintenance system. With the client/server architecture, the OMM

Server saves the configuration data of the whole equipment, and provides various

maintenance functions such as network configuration, alarm management, performance

statistics, signaling tracing and service observation. The OMM Server provides NEF

function, and interconnects with the upper network management system through Q3 or

CORBA interface.

To ensure the reliability of charging, the system provides a JF Server, which is used to

collect CDRs generated by the service MP and signaling MP, and transmit the CDRs to

the charging center through FTP or FTAM interface.

The USI board is a charging information interface board. The MPs transmit CDRs to

the JF Server through the USI board.

The interface boards, MP and USI boards are connected through a high speed switch to

ensure the information transfer between them. In Fig. 2.1-1, the MSCS is a distributed

processing platform, with powerful expansion capability. The MP and interface boards

are connected through a switch, so the maximum capacity of the whole system depends

on the number of ports of the switch. The switch is a 28+2 FE switch. One switch can

provide up to 28 ports. When the number of ports is insufficient, it is possible to

cascade a 46+2 FE switch with up to 11 28+2 FE switches (each lower-level FE switch

is cascaded with the upper-level FE switch through four FE Trunkings) to form a

level-3 switching network providing up to 1128=308 FE interfaces. This can

sufficiently satisfy the application requirement of abundant MP boards and interface

boards.

2.2 Hardware Structure

The MSCS consists of the broadband/narrowband signaling access board, signaling

link layer processing board, upper-layer signaling MP, service MP (including

foreground distributed database) and background commercial database (ORACLE or

SQL Server).

The MSCS provides the call control and mobility management functions of the original


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MSC, and grooms local control domain MS originated call and terminated transactions:

call transaction, SMS transaction and LCS transaction. The MSCS generally works

with the VLR to save the MS user data within the local control domain.

In the CS-MGW application, the MSCS controls the part which holds the media

channel in the call status.

The GMSCS is used to groom the traffic between mobile subscribers and the PSTN or

other carriers network.

The (G)MSCS provides multiple interfaces, and supports only three basic access

modes, ATM, IP and E1. According to actual networking conditions, one mode or acombination of two or three modes can be used flexibly.

In hardware, the MSCS uses the control shelf BCTC as its shelf. To satisfy specific

network requirements, the resource access shelf BUSN can be used. Fig. 2.2-1 shows

the structure of the MSCS. The MSCS consists of three types of units, interface unit,

switching unit and processing unit.

The interface unit provides various external interfaces of the system and implements

the L2 protocol processing. In general, the interface unit involves the L1 physical

interface and related L2 protocol processing.

The processing unit completes the upper-layer protocol processing.

The switching unit is used to connect the interface unit to the processing unit and

implement the interconnection among multiple shelves.

With a comprehensive consideration of system requirements, the MSCS shall be able to

provide these external interfaces:

1. ATM interface: In physical, it can adopt the E1/IMA or STM-1 optical access

modes.

2. IP interface: In physical, it adopts 100M/gigabit Ethernet access mode.

3. SS7 interface: In physical, it adopts the E1/SDH access mode to complete the L2

protocol processing on the logical interface board. The upper-layer protocol is

implemented through a high performance main processing board (MPB).


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...

Data stream

Ethernet

Control

stream

Ethernet

Other

control bus

Other

control bus

Data stream

Ethernet

Control

stream

Ethernet

TDM BUS

TDM BUS

SPB(SS7)

)SPB BSL

OMCMP

SMP SMP SMP

NIC

UIM

To background

OMP

SPB(SS7)

APB MNIC CHUB

CL

KCLKG

Fig. 2.2-1 Hardware Structure of the MSC Server

2.3 Software Structure

The MSCS software system consists of nine subsystems: BSP driving subsystem,

operating subsystem, system control subsystem, database subsystem, bearer subsystem,

microcode subsystem, signaling subsystem, service subsystem and network

management subsystem. Fig. 2.3-1 shows the relationship among these software

subsystems.

Network management subsystem

Systemcontrolsu

bsystem

Databasesubsystem

Operating subsystem

BSP driving subsystem

Bearer subsystem Microcodesubsystem

Hardware platform

Signaling subsystem

Service subsystem

Fig. 2.3-1 Software Structure of the ZXWN MSCS


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The following describes these software subsystems and their relationship:

1. BSP subsystem

The BSP subsystem boots up and drives the hardware of the whole

system. In specific, it involves three aspects of functions, Boot, CPU

minimum system and hardware driving. To keep the software

subsystems above the operating system independent of the hardware,

the BSP can:

1) Shield hardware operation details for the upper-layer software module,

abstract hardware functions, and provide hardware logic function planefor other software modules only.

2) Provide a unified and encapsulated function interface for the upper-layer

software subsystem especially the real-time operating system to shield

unnecessary parameters from the upper-layer software.

3) Support online and offline test of hardware boards and provide

necessary interfaces.

2. Operating subsystem

The operating system runs over the BSP subsystem and under all other

subsystems, shields all device driving interfaces from user processes,

and provides single processor based services including process

dispatching, timer, memory management, file system and multi-processor

based inter-process communication.

3. Database subsystem

The database subsystem runs over the operating system. It is

responsible for managing physical resources of the ZXWN MSCS NE

and configuration information about the service, signaling and protocol.

In addition, it provides a database access interface for other subsystems.

The database is a relational database, which consists of a foreground

database and a background database.

4. Bearer subsystem

The bearer subsystem runs over the operating system and database


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subsystem. It provides ATM, IP and TDM bearer services for the service

subsystem, signaling subsystem, OAM and network management

subsystem. It manages external IP and ATM interfaces of the NE and

provides IP packet and ATM cell communication between NEs. In

addition, it manages the internal user plane communication interface

based on the database configuration data, and provides user plane IP

packet communication among the boards inside the NE.

5. Microcode subsystem

The microcode subsystem is the extension of the bearer subsystem. Its

functions are the same as those of the bearer subsystem. The microcodesubsystem runs on the micro engine of the network processor, and is

independent of the operating system. It provides interfaces for the bearer

subsystem.

6. Signaling subsystem

The signaling subsystem runs over the operating system, database

subsystem and bearer subsystem, implements narrowband SS7

signaling, broadband SS7 signaling, bearer and independent call control

(BICC) signaling, IP signaling (SIGTRAN) and gateway control signaling

(H.248), and provides services for the service processing subsystem.

The broadband, narrowband SS7 signaling link layer protocol, MTP2,

SSCOP and SSCF are processed on the signaling interface board. The

signaling of MTP3 or upper part is processed in the signaling processing

board. The signaling processing board supports 1+1 active/standby

function. The signaling link layer implements the link level load sharing.

In case of large capacity of the system, it supports loading sharing of

multiple pairs of signaling processing boards. The narrowband SS7

supports 64 kbps, 2 Mbps and n64 kbps signaling links. In addition, the

multi-signaling point function over different signaling networks is

supported.

7. System control subsystem

The system control subsystem runs over the operating system and

database subsystem. It is responsible for the monitoring, starting and

version downloading of the whole system. The core processing board,


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such as MP board and switching network board, shall support 1+1

active/standby function. The 1+1 active/standby processing board

transfers active/standby information through the private active/standby

channel instead of the control plane channel. The system control

provides a function for monitoring process execution time.

8. Service subsystem

The service processing subsystem implements various services and VLR

functions provided by the MSC Server. As the core of the MSCS Server,

it runs over the operating system, database subsystem, bearer

subsystem and signaling subsystem.

Basic switching module of mobile service subscribers: It completes the

mobile subscriber paging access, RAB assignment, call connection,

traffic control and GMSC function, and provides fixed network (PSTN,

ISDN and PSPDN) oriented call connection functions. Mobility

management and security management module: It completes location

area registration and validity check of mobile subscribers. Relocation

processing module: It completes the service processing when the local

area of mobile subscribers changes during the call. Supplementary

service module: It is used to register, delete, activate, deactivate, and

query supplementary services, and add or get password. SMS

processing module: It completes the SMS transmitting and receiving

processing. In addition, it completes information interaction and

implements various MAP services. The user related information is

queried from the DB module, and the DB module is notified of the latest

user data for updating. The mobile intelligent service module implements

the CAMEL function and upgrades the MSC Server to be an SSP. It

consists of gsmCCF module, gsmSSF module, gsmSRF and smsCCF

modules.

9. Network management subsystem

The network management subsystem runs over all subsystems. The

operation and maintenance personnel configure, analyze, charge,

diagnose and test the equipment running in the network and get alarm


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and statistics data through network management subsystem. The

network management subsystem consists of foreground module, server

module, client module and charging module.

The foreground part is resident on each managed NE. It works with the

operation and maintenance server to provide NE operation information

interaction, including alarm information collection and report, alarm

information synchronization, man-machine command execution,

diagnosis command execution, configuration management data

processing, performance statistics data collection and various services

and signaling information collection. The foreground program

communicates through the Ethernet port and network management

server, responds to the instructions sent from the server, and returns the

results.

The server module is the core of the operation and maintenance

subsystem. It resolutes and executes various operation instructions sent

from the client. After the execution, the instructions are sent to the

foreground. The foreground feedback results are sent to the client. This

module implements the network management function, network proxy

function, NE integration and adaptation function, upper network

management access function and FTP server function. It is a network

management function center to implement the performance management,

configuration management, alarm management, network diagnosis and

local maintenance function. In addition, it supports the network

management cascading, integrated control and reverse operation.

The client module is the user interface of the operation and maintenance

subsystem, which provides a visual interface for the client. It operates

and controls various NE maintenance interfaces, forms operation

commands and sends them to the server.

Charging management module: It collects and transmits CDRs.

According to functions, it involves foreground original CDR collection and

transmission, original CDR collection processing and backup and CDR

transmission. The MSC Server provides accurate and detailed charging

data instead of completing the charging function by itself.


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2.4 System Networking Configuration

2.4.1 Networking Mode

2.4.1.1 As a VMSC/GMSC Sever

According to the control and bearer separation principle, the MSC NE is separated into

two NEs, MSCS and MGW. The MSCS is responsible for implementing the service

and call control function, and the MGW is responsible for the bearer control function.

The MSCS can serve as a VMSC Server used for accessing mobile subscribers. The

MSCS also can serve as a GMSC Server to interconnect with other networks, for

example, to interconnect with the PSTN. The related MGW also can be used as an

MGW and GMGW. Fig. 2.4-1 shows the networking model of the MSCS as a

VMSC/GMSC Server:

UTRAN

BSS

MSC SERVER

MGW MGW

Iu/A

IW/GMSC

SC

MAP

HLR

MAP

SCP

CAP

Mc Mc

Nb

GMSC

SERVER

GMGW

Nc

Nb

McPSTN

Ai

MAP MAP CAP

Fig. 2.4-1 Typical Networking of the VMSC/GMSC Server

When the MSCS serves as a VMSC Server, it has these interfaces:

1. Iu/A interface to the UTRAN/BSS. It is used to provide mobile subscriber

access function. The interface between the VMSC Server and the UTRAN is the

Iu interface. The underlying bearer is AAL5/ATM. It supports service and call

related control signaling. The interface between the VMSC Server and the BSS

is the A interface. The underlying bearer is TDM. It supports service and call

related control signaling.

2. MAP interface to the IW/GMSC+SC. The underlying bearer is based on TDM.


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It is used to send and receive SMS related signaling.

3. MAP interface to the HLR. The underlying bearer is based on TDM. It is used toget route information about the terminating user.

4. CAP interface to the SCP. The underlying bearer is based on TDM. It is used

interact with the SCP when users trigger intelligent services. In this case, the

VMSC Server has the embedded SSP function.

5. Nc interface to the GMSC Server and other VMSC Server. The underlying

bearer can be based on TDM/ATM/IP. It is used to transmit semi call signaling

for inter-office calls, fixed-to-mobile calls and mobile-to-fixed calls, and to

transmit BICC signaling in the R4 networking.

6. Mc interface to the MGW. The underlying bearer can be based on ATM/IP. It is

used to transmit standard H248 signaling. One MSCS can manage multiple

MGWs.

When the MSCS serves as a GMSC Server, it has these interfaces:

1. MAP interface to the IW/GMSC+SC. The underlying bearer is based on TDM.

It is used to send and receive SMS related signaling.

2. MAP interface to the HLR. The underlying bearer is based on TDM. It is used to

get route information about the terminating user.

3. CAP interface to the SCP. The underlying bearer is based on TDM. It is used to

interact with the SCP when users trigger intelligent services. In this case, the

VMSC Server has embedded SSP function.

4. Nc interface to the GMSC Server and other VMSC Server. The underlying

bearer can be based on TDM/ATM/IP. It is used to transmit semi call signaling

for inter-office calls, fixed-to-mobile calls and mobile-to-fixed calls, and to

transmit BICC signaling in the R4 networking.

5. Mc interface to the GMGW. The underlying bearer can be based on ATM/IP. It is

used to transmit standard H248 signaling.

6. Ai interface to the PSTN. The underlying bearer is based on TDM. It is used to

transmit inter-office TUP/ISUP signaling.


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18

independent equipment are greatly improved in comparison to those of the MSC with

combined bearer and control. In the mobile networking planning, it is possible to

promote the MSCS to regional or provincial network level. The same MSCS controls

multiple small-capacity MGWs distributed in local networks and implements the

access control of the UTRAN access network associated with the MGWs.

For 3G R4, the evident difference is that the capacity and networking location of the

MSCS exceed the local network, and the MSCS is endowed with the concept of

cross-region management or virtual MSC. In R99, one local network has one or more

MSC NEs, that is, the MSC only manages the resources of the local network. In R4,

because the MSCS processing capability is enhanced, during the initial networking,

one MSCS can manage the resources of multiple local networks, as shown in Fig.

2.4-3:

MSC SERVER/GMSC SERVER

MGW/GMGW

RNS PSTN

Location network 1

MGW

RNS PSTN

Location network N

GMGW

Iu Iu

Nb

Mc Mc Mc

BSS

A

A

Fig. 2.4-3 Large-area Networking

2.4.1.4 Disaster Recovery Networking Mode

The large-capacity MSCS has many advantages in networking. However, there are

some problems. The centralized management of user information and service control

significantly affects the network system, so the reliability of the centralized points of

the large-capacity MSCS shall be enhanced. Otherwise significant influence may be

caused if a large-capacity MSCS fails. In addition to improving the reliability of the

MSCS, different networking modes can be used to improve the reliability of these NEs.

For example, the multi-MSCS load sharing mode can be used, that is, these NEs work


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simultaneously in normal status. When an NE becomes abnormal, other NEs take over

the services of the abnormal NE. The active/standby mode can also be adopted, that is,

in normal status, the active NE is responsible for processing services, while the standby

NE is not responsible for processing services. When the active NE fails, the standby

NE can take over the services of the active NE immediately. In this way, the loss can be

minimized. It is recommended to use the 1+1 backup mode. During the backup, the hot

backup or warn backup mode can be used for data synchronization.

For the GMSC Server, because the GMSC Server is generally configured in pairs, the

backup is not needed. For the TMSC Server, it is the same. For the VMSC Server,

because it works with the VLR to save user related data, and the RNC within the

control area only communicates with this VMSC Server, once a fault occurs, all users

within the control area of this VMSC Server cannot access services. Here, the

active/standby MSCS refers to active/standby VMSC Server. Fig. 2.4-4 shows the

networking:

VMSC

Server1

LSTP

HLR

MGWRNC

SCP

HLR

BSC

SGSN

PSTN- GW

VMSC Ser ver

TMSC Ser ver

GMSC Ser ver

Mc

I uCS

A

MAP

MAP/ CAP/ Nc/ Gs

Nc

Nc

Ai

Nc

MAP

MAP CAP

MAP/ CAP/ Nc/ Gs

Gs

MGW

Ai

Mc

SCMAP

VMSC

Server 2

Fig. 2.4-4 VMSC Server 1+1 Backup Networking

In this figure, the VMSC Server1 and VMSC Server2 are in 1+1 active /standby mode.

Each NE is connected to these two VMSC Servers. For the SCCP signaling, the SCCP

subsystem backup mode is used to implement the active/standby changeover, that is,

the SCCP SSN of VMSC Server2 is configured as the standby SSN for the SCCP SSN

of VMSC Server1. For the BICC traffic, TUP and ISUP traffic, the route backup mode


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can be used to configure the trunk circuit to VMSC Server2 as the backup route to

VMSC Server1.

2.4.2 Physical Indices

MSC Server adopts 19" standard rack, with maximum internal space capacity of 42 U.

POWER DISTRIBUTE UNIT

ALM

20

00

600

Blank panel (1U)

Power subrack (2U)

Fan subrack(1U)

Service subrack (8U)


Cable subrack (1U)

Cable subrack (1U)Fan subrack(1U)



Cable subrack (1U)

Cable subrack (1U)

Fan subrack(1U)

Air filter

Maximum configuration for single rack is composed of four 8 U serviceshelves, one 2 U power shelf, four 1 U cabling shelves, three 1 U fanshelves and one 1 U blank panel. It totals to 42 U.


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The corresponding modules are configured in the cabinet, such as

cabinet power inlet filter, a set of bus bar, rear horizontal cabling

bracket.

The function of each part is as following:

Parts Functions

Power shelf

The power shelf distributes the input -48V power toeach shelf.

The power shelf has the lightning proof andover-current protection functions, checks the input

power voltage and the distributed output powerstatuses, and gives alarm signal if necessary.

The power shelf also effectively monitors the rackrunning environment, fan heat dissipation system,access control etc., and reports through the RS485interface

Control shelf

It is composed of each kind of control board combinedthrough the backplane.

In addition, the control sub rack also includes the shelfpower filter, which is used to separate and filter -48Vinput power

Fan shelf Provides forced air cooling for the equipment

Cable shelfUsed to arrange fiber, which is leaded to the two sidesof the cabinet through each cable shelf under the

control shelf

Bus barLocated at the internal side of the cabinet. The power is

provided to each shelf through the bus bar

Rearhorizontalcable rack

Used to arrange the cables from the rear of the cabinet

Cabinetpower inputfilter

There are two combined filters on the top of thecabinet, which are used to filter the two lines of -48Vexternal input power

2.4.3 System Configuration

The MSCS supports multiple networking modes and flexible configuration. The

following describes several typical system configurations.

2.4.3.1 Board Configuration Calculation Method

See 3G CS user traffic model (see the appendix). The processing capacity of the boards

is as follows:

1. Service processing unit: It supports 80,000 subscribers/MP.


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2. Signaling processing unit: It supports 60,000 subscribers/MP or 10,000

trunks/MP.

3. Signaling service integrated processing unit: It supports 40,000 subscribers/MP.

4. SPB: It supports 32 64 kbps/board.

1) IPI: It supports 80 Mbps signaling traffic/board.

2) APB: It supports 2 Mbps signaling traffic/board.

For other boards, the calculation can be implemented according to the number of

boards and applied resources. The specific calculation method is as follows:

1. VMSC NE calculation method:

Suppose that the number of supported users is Nuser. Table 2.4-1 shows

the required number of boards:

Table 2.4-1 Method for Calculating the Number of Boards

Board Name Calculation Method Description

Service

processing unit

Ncmp = 2 (Nuser /160,000)

Note 1

When the Ncmp serves as a GMSC, Ncmp =

2 (Nuser /250,000)

Signaling

processing unit

Nsmp = 2 (Nuser / 120,000)

Note 1

The service processing unit can be combined

with the signaling processing unit. Nump =

2 (Nuser / 80,000)

Operation and

maintenance unitNomm = 2 Note 1 A pair of OMMPs is always configured.

Universal

interface board

Nuim = number of shelves

2

Each shelf is always configured with a pair of

UIM boards.

SPB Nspb = number of E1s/16

The SPB is required only when the E1

interface needs to be provided.

In general, the number of E1 interfaces

determines the number of Nspb. At least two

SPBs are needed.

APB

Napb1 = Nuser/100,000

Napb2 = number of

STM-1s/2

The APB is required only when the ATM

interface needs to be provided.

The actual number shall be the maximum

value between Napb1 and Napb2. At least two

APBs are needed.

IPINipi1 = number of FEs/4

Nipi2 = traffic/80M

The IPI is required only when the IP interface

needs to be provided. The actual number shall

the maximum value between Nipi1 and Nipi2.


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Board Name Calculation Method Description

At least two IPIs are needed.

Universal server

interface boardNusi = 2 It is 2.

CLKG Nclkg = 2 It is always 2.

USI Nusi = number of shelves It is always 1.

Route processing

unitNrpu = 2 Note 1, Note 2 A pair of RPUs are always configured.

CHUB Nrpu = 0 or 2

When the number of shelves is larger than or

equal to 3, the CHUB is used for the

cascading of the shelves.

Note 1: 2 indicates that the board is in active/standby mode. Each MP board has two processing units.

Note 2: The RPU and OMMP share one MP. One processing unit serves as the OMMP, and another

processing unit serves as the RPU.

2.4.3.2 Typical Configuration of Single Shelf

A standalone MSCS can be used to set up an office. When it serves as a VMSC Server,

it supports up to 240,000 subscribers, as shown in Fig. 2.4-5:

OMMP

OMMP

UMP

UMP

UMP

UMP

UIM

IPI

UMP

UMP

SPB

SPB

CLKG

USI

1 2 3 13121110987654 17161514

POWER POWER MONTOR

CLKG

UIM

IPI

FAN FAN FAN

Fig. 2.4-5 Typical Configuration of Single Shelf

In this configuration, the service processing unit and the signaling processing unit are

combined to provide IP signaling interface and SS7 interface. If the MSCS serves as a

GMSC Server, the configuration is the same. In this case, it supports up to 480,000

subscribers.

2.4.3.3 Typical Configuration of Single Rack

One rack can be configured with up to three shelves. Fig. 2.4-6 shows the full


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configuration of single rack:

FAN FAN FAN

POWER POWER MONTOR

O

M

M

P

O

M

M

P

U

M

P

U

M

P

U

M

P

U

M

P

U

I

M

I

P

I

U

M

P

U

M

P

U

M

P

U

M

P

C

L

K

G

U

S

I

1 2 3 13121110987654 17161514

C

L

K

G

U

I

M

I

P

I

FAN FAN FAN

U

M

P

U

M

P

U

M

P

U

M

P

U

M

P

U

M

P

U

I

M

I

P

I

U

M

P

U

M

P

U

M

P

U

M

P

U

M

P

S

P

B

1 2 3 13121110987654 17161514

U

M

P

U

I

M

I

P

I

FAN FAN FAN

U

M

P

U

M

P

U

M

P

U

M

P

U

M

P

U

M

P

U

I

M

S

P

B

U

M

P

U

M

P

U

M

P

U

M

P

C

H

U

B

S

P

B

1 2 3 13121110987654 17161514

C

H

U

B

U

I

M

S

P

B

Fig. 2.4-6 Typical Configuration of Single Rack

As shown in Fig. 2.4-6, 15 pairs of UMPs are configured to provide 15 8 = 1,200,000

subscribers. In addition, four IPI boards are configured to provide 16 FEs and support

320M IP signaling traffic. Four SPBs are configured to provide 4 16 = 64 E1

interfaces and support up to 16 2M signaling links or 4 64 = 256 signaling links.

2.4.3.4 Example

Assumed that there is an office with 200,000 subscribers. This office needs to access

100,000 2G subscribers and 100,000 3G subscribers at the same time, of which 50%

are intelligent users. In addition, the MSCS needs to serve as a GMSC Server.

As shown in Fig. 2.4-7, the MSC Server needs to access both the RNS and the BSS.

The MGW has a built-in SGW, and forwards the IuCS signaling to the MSC Server

through SIGTRAN. The TUP and ISUP signaling of the Ai interface also can be


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forwarded to the MSC Server through SIGTRAN. The BSC transmits the signaling of

the A interface to the MSC Server directly through E1. The MSC Server is connected to

the STP to groom the MAP signaling, CAP signaling and BICC signaling to other NEs.

To ensure the reliability, connect the MSC Server to two STPs, namely STP1 and STP2.

Because the interconnection signaling traffic to the local HLR office direction is high,

the direction interconnection with the HLR can be adopted.

UE BTS BSC

UE

NodeB RNC1

MSCS

MGW1

UE

HLR SCP

STP1 STP2

GW1

GW2

SC

PSTN

Fig. 2.4-7 Networking

According to the above configuration analysis, Table 2.4-2 shows the MSCS device

configuration:

Table 2.4-2 Board Configuration

Board Name Qty

BCTC 1

Rack 1

Shelf 1

CLKG 2

USI 1

OMMP 2

UMP 6


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Board Name Qty

SPB 2

IPI 2

The application features are as follows:

1. Simple and clear network structure.

2. The MGW has a built-in SG. In this case, the MSCS needs to provide IP

interface and TDM interface only.

3. High integration of the MSCS. The single shelf can implement functions.

2.5 Board Structure

2.5.1 Board Description and Structure

The MSCS consists of these units: T network switching unit, ATM switching unit, TC

unit, MP unit, signaling processing unit (SPU), DT unit, resource board, clock unit,

HMS unit and monitoring unit.

According to the design of the MSCS, the user plane is separated from the control

plane. From the perspective of the user plane, the MSCS consists of some interface

boards and switching network, as well as some resource boards, as shown in Fig. 2.5-1.

Userinterfaceboard

User

Resource

board

3G or 2G users

2 G: Trunk unit

3G: ATM interface

Trunk unit

PSTN

Other MSNC

ISDN

Switchingnetwork

Network

interface

board

Fig. 2.5-1 Composition of the MSCS User Plane

The interface board implements the interconnection of user bearer streams between the

MSCS and other node. Because the MSCS can serve as both the edge node (used as the

GMSC to interconnect with the PSTN and ISDN; used as the VMSC to interconnect


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with the UTRAN) and the internal node of the CN (used as the TMSC), the MSCS has

these UNI side interface boards: trunk board (used to interconnect with the BSS), and

ATM interface board (used to interconnect with the RNS), as well as NNI side interface

board: trunk board used to interconnect with other MSCS, PSTN and ISDN.

The MSCS also has resource board ASIG, which is used for the interaction between the

network and users, including DTMF number receiving, ringing current and

announcement function. In actual implementation, the ASIG board and the DT board

are slot compatible.

To implement circuit-type data services, the MSCS needs to interconnect with the

packet network such as ISDN. Therefore, an interconnection unit is required to

implement the protocol conversion of data services. The interconnection function is

implemented through the interconnection board IWF.

The switching network implements the switching of the user bearer streams between

the interface boards. The user bearer streams include voice stream, data stream and

multimedia stream. Because the interface to the RNS is the ATM interface, this system

has two switching networks: narrowband switching network-T net and broadband

switching network-ATM cell switching network. These two networks are

interconnected through the TC unit. For the voice service, the bearer streams of the two

switching networks are different. In the ATM switching network, the user bearer stream

is AMR stream. In the T net, the user bearer stream is PCM stream. Therefore, the TC

board is used to complete the mutual conversion of the AMR stream and PCM stream.

Because the AMR stream is borne over AAL2, one end of the TC unit is the ATM

interface, and the other end is the PCM interface.

The ATM switching network sets up the PVC between the Iu interface board and the

TC and between BSL boards in the SPU. The external PVC is terminated on the ATM

interface board. The ATM interface board exchanges information to the corresponding

TC board through the internal PVC. The TC unit implements the code stream

conversion, that is, the mutual conversion between the AMR code and PCM code.

Accordingly, the TC unit implements the IuUP function. For data services, the TC unit

completes the functions of the IWF.

The T net switching network completes the TS switching between the TC unit and the

resource board, implementing the switching between voice channels. The trunk unit


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implements the interconnection between the external trunk TS and the T net TS. The

TC board implements the interconnection between the CID of the RNC and the T net

TS. Through the T net, the system can implement the switching of the CID of the RNC

and the trunk board TS.

The trunk board not only implements the NNI function, but also implements the

interface function between the MSCS and the BSC. From the perspective of the user

plane, the PCM code stream is transmitted between the MSCS and the BSC. This is

consistent with that at the NNI interface.

From the perspective of the control plane, the MSCS consists of SMP and signaling

interface.

The SPU includes the narrowband signaling link (NSL) board, broadband signaling

link (BSL) board and signaling MP (SMP). The internal Ethernet connection is used.

The NSL and BSL process the signaling of MTPL2 or lower layer. The SMP processes

the signaling of the layer higher than MTPL3. The NSL is connected to the TNET or

the signaling network through E1/HW. The narrowband SS7 link at any office direction

is connected to the NSL through the SPC established by the TNET. The signaling

interface implements various standard signaling and transmits the signaling of the

application layer. The signaling interface is provided by the signaling board. The NSLprocesses the signaling of narrowband MTPL2 or lower layer. It can provide E1

directly and exchange the HW to DT to provide E1 to connect to the TNET or the

signaling network through E1/HW. The narrowband SS7 link at any office direction is

connected to the NSL through the SPC established by the TNET.

The BSL processes the signaling of MTPL2 or lower layer. It connects to the ATM

switching network through STM-1. All signaling links (generally the signaling PVC)

on the Iu interface are switched to the BSL through the internal PVC. The BSL

processes the signaling of MTPL2 or lower layer. The application layer signaling is

sent to the MP by the NSL or BSL through the internal Ethernet, and processed by the

relevant application on the MP.

The SMP is responsible for the interconnection with other MPs to implement the

signaling access function, the allocation and utilization of inter-office trunk resources,

as well as broadband and narrowband compatibility, and to run signaling processes of

MTP3b or upper part.

The OMMP maintains, monitors and manages the system. The OMMP needs to


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communicate with other boards and processing nodes to get their real-time information

and monitor the system.

Because the MSCS is an internal NE of the PLMN which is a synchronization network,

a clock unit implements the clock synchronization function. The clock unit generates or

traces the synchronization clock source. In addition, it generates sufficient clock

signals and outputs them to other related units to implement the clock synchronization

of the MSCS.

Fig. 2.5-2 shows the logical structure of the hardware of the MSCS.

TC

TC

TC DT unit

ECDT

DT unit

ATM switching unit T net: 64K64K

Iu interface

CS MP SPUResource

A interface, and

PSTN interface

Ethernet line T net HW line

E1 interfaces 155M or 622M interface

ASIG

IWF

To NSPTo BSP

Fig. 2.5-2 Hardware Structure of the ZXWN MSCS

2.5.2 Boards of the ZXWN MSCS

Table 2.5-1 lists the boards of the MSCS.


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Table 2.5-1 Boards of the MSCS

Board

NameFull Spelling Description

BSCBackplane of Circuit

Switch Domain

The BSC is the bearer board of all boards in the CS shelf. It

provides connection function, but does not process input and

output signals.

BPSBackplane of Packet

Switch Domain

The BPS is the bearer board of all packet switched boards. It

provides connection function, but does not process input and

output signals.

TCIATCU Interface of

ATM

The TCIA connects the physical interface of STM-1 to the

ATM switching network. It provides a 100M Ethernet

communication link port between the TCU and the MP, andsupports an adaptation ability of about 8KAAL2.

MTCMultiRate

TransCoder

The MTC and the TCIA form a TCU to complete the

conversion between the AMR code and PCM code

(interconnection between 3G and PSTN users), and to

implement AMR voice rate adaptation (interconnection

between 3G users) and circuit data services. In this way, the

MTC can implement the interconnection between 3G users and

PSTN/2G users.

MDTMultiplicityDigitalTr

unk

The MDT provides 20 E1 interfaces. It can receive 20 channels

of primary rate signals (2048Kb/s) sent from other exchanges

or modules, convert five 8M HWs of signals sent from the T

net board into 20 channels of primary rate signals and send

them to other exchanges, and restore 8K Hz clock and 8M8K

synchronization frame header from the primary signals as the

clock reference of the CLK synchronization clock board.

EMDTThe EMDT offers 20 E1 interfaces with echo suppressor on

one board.

ASIG Analog Signals

The ASIG provides the TONE transmitting, DTMF number

receiving and transmitting, MFC number

receiving/transmitting and conference call functions.

IWFInterWorking

Function

The IWF provides assistance for the interconnection between

the PLMN and other network. It implements the conversion of

transmission protocol.

LVI LVDS Interface The LVI provides the LVDS interface board function.

TNET64K Time Slot

Switch Net

The TNET (64K time slot switching network board)

implements 64K64K non-blocking switching, and supports

256K switching capacity through multi-level switching.

ASC ATM Switching The ASC completes the ATM switching function


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Board

Name

Full Spelling Description

Card independently.

E1TBThe (E1 digital trunk interface board) E1TB provides E1 trunk

connection between the MSC and the RNC.

NSLNarrow Band

Signaling LinkThe NSL processes the MTP2 signaling of SS7.

BSLBroad Band

Signaling Link

The BSL is also called Iu interface protocol processing board.

By using the third processing module of the SSL board, it

processes the Iu interface protocol.

COMA CommunicationAdapter

One COMA can process up to 256 HDLC links.

HMSHundred MAC

Switcher

The HMS exchanges MAC packets for 38 100 M Ethernet

ports. It is a large-capacity HUB with a switching capacity of

up to 11.6 GB.

OMMP

Operation and

Maintenance Main

Processor

The OMMP manages the board versions of the whole system

and the information reported by the service boards and

signaling boards during the operation.

CSMPCircuit domain Main

Processor

The CSMP has the same circuit structure as the OMMP has.

All the upper-layer service programs such as call, changeover

and location update run on the CSMP. The VLR database is

stored in the hard disk of the CSMP board.

SMPSignaling Main

Processor

The SMP completes the main processing of the upper-layer

signaling. In the case of large capacity, the SMP shall be

configured separately. In the case of small capacity, it can be

combined with the OMMP.

CLCK Clock

The CLK provides 16 channels of 8 MHz clock signals and 20

channels of location frame headers at a frequency duty ratio of

8M8K for the whole MSCS.

2.5.3 Boards

2.5.3.1 CLKG

The CLKG board is the clock generation board of the MSCS. The CLKG module

works in active/standby mode. The active/standby CLKG is locked on the same

reference to achieve smooth changeover. The CLKG module takes phase jitter filtering

measures to eliminate possible clock burr or jitter during the changeover. The CLKG

module and the main control unit communicate through the RS485. The CLKG uses


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the 8 kHz frame synchronization signals from the trunk board DTEC or SPB clock

reference, 2MHz/2Mbits signals from BITS, 8k (PP2S, 16CHIP) signals from the

GPSTM board, or 8k clock signals from the UIM as the local clock reference to

synchronize with the clock of the upper-level exchange. For the input reference, the

CLKG board can provide alarm signals of reference loss and distinguish the reference

degradation.

Fig. 2.5-3 shows the principle of the CLKG module.

Local

crystal

oscillator

Active/standby

changeover circuit

CPU subsystem

Phase-

locked loop

frequency

combined

circuit

RS485

Reference

selection

Reference

detection 8K, 16M, 32M and 64M clock signals

GPS, line 8K

2MHz and 2MBits

16CHIP and PP2S

Reference clock signal input PP2S signal output

PP2Sreceives

distrib

uted

circuits

Changeover signal outputChangeover signal input

Fig. 2.5-3 Principle of the CLKG Module

The CLKG board has the following functions:

1. Communicating with the control console through the RS485.

2. Selecting reference sources manually or through the background, including

BITS, line (8K), GPS and local (stratum-2 or stratum-3) clock reference. The

manual changeover can be shielded through the software. The sequence of

selecting reference manually is as follows:

2Mbits1--2Mbits2--2MHz1--2MHz28k18k28k3--NULL

3. Adopting the loose coupling phase-locked system and supporting four working

modes, CATCH, TRACE, HOLD and FREE.


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4. The output clock can be a stratum-2 or stratum-3 clock, which can be

implemented by changing the constant-temperature trough crystal oscillator and

through the software.

5. Providing 15 channels of 16.384M, 8K and PP2S clock for the UIM.

6. Distinguishing clock loss and input reference degradation.

7. Active/standby changeover function. It supports command changeover, manual

changeover, fault changeover and reset changeover modes. In the case of

maintenance changeover, the rate of bit errors occurred to the system shall be

less than 1%.

8. The phase discontinuity between two CLKG boards is less than 1/8 UI code

element.

9. Providing complete alarm function. It supports SRAM failure alarm,

constant-temperature trough alarm, reference and output clock loss alarm,

reference degradation alarm, reference frequency deviation alarm, phase-locked

loop discrimination failure alarm. According to these alarms, you can rapidly

locate current working status and a fault of the clock board.

10. Clock maintainability. The VCXO provides a frequency adjustment rotary

switch. This switch can be used to adjust the frequency after the central

frequency deviates due to the aging of the quartz crystal after several years.

The CLKG board provides these external interfaces:

1. 15 groups of 8k/16M/PP2S system clock output interfaces.

2. 10 groups of 8k/32M/64M system clock output interfaces.

3. One or two groups of DTEC, SPB, APBE and SDTEC module line 8k reference

input interfaces.

4. One group of GPS module 8K reference input interfaces.

5. One group of GPS module PP2S and 16CHIP reference input interfaces.

6. Two groups of 2 Mbps and 2 MHz reference clock input interfaces.

2.5.3.2 MPx86

The MPx86 is used in the processor shelf of the distributed processing platform. It


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supports mobility management, MAP and CC sublayers and VLR distributed database.

The MPx86 has powerful processing performance and is configured with 1 GB

memory. In addition, it provides abundant external interfaces such as IDE, 10/100M

Ethernet, RS485, RS232 and USB interfaces. The MPx86 can connect to various

peripheral components through standard PCI bus to implement active/standby MP

changeover. Its control register and data register can be used to set functions or

exchange status data through the main control software.

Fig. 2.5-4 shows the principle of the MPX86 module.

BA

C

K

P

L

A

N

E

Power

management

Logical timesequence

adjustment, controlmanagement

CPU

subsystem 1

PCI bus

Bridging chip2*USB

IDE

Ethernet

interface

circuit

BIOS

Peripheral

memorySerial

port chip

Logical timesequence

adjustment, controlmanagement

CPU

subsystem 2

Ethernet

interface

circuit

BIOS

Panel

PCI bus

Control stream Ethernet

Media stream Ethernet

OMC Ethernet

Active/standby Ethernet

Control stream Ethernet

Media stream Ethernet

OMC Ethernet


Backplane ID

Power management

RS485

GPS management RS485

Backup RS485

Fig. 2.5-4 Principle of the MP

Two CPU systems are designed on one MPX86 module, which are called CPU_A and

CPU_B respectively. The two CPU systems are independent. The CPU_A is the main

control CPU system which manages modules.

In addition to two CPU systems, the module has the public power supply used to

provide power for the whole module. The MPX86 module also provides an Ethernet

switching chip for the external control stream, media stream, active/standby and OMC

Ethernet.

When the MPX86 module serves as an OMP, it provides two external 100M OMC


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When the MNIC serves as an interface board, at least two MNICs working in 1+1

backup or load sharing mode shall be configured.

Fig. 2.5-5 shows the principle of the MNIC module.

Control stream

Ethernet

Network processor

subsystem

Control stream

Ethernet

Control stream

Ethernet

Gigabit Ethernet

100M Ethernet

Time sequence,

logical processing

circuit

4*100M

100M

100M

1000M

1000M

B

A

C

K

PL

A

N

E

RS485

ID, clock signal

4*100M

Panel

Internalbus

PCIbus

Fig. 2.5-5 Principle of the MNIC Module

The MNIC module consists of network processor system, physical interface part and

CPU system. The network processor minimum system and Ethernet interface part are

placed on the backplane. The CPU subcard is adopted, and the data is transmittedbetween the subcard and the network processor system through the PCI bus and

internal bus.

The components mounted on the PCI bus of the network processor include CPU

subcard and Ethernet chip. The coprocessor is connected in the standard subcard mode.

One of the two Ethernet chips serves as the data backup channel. When the CPU

subcard exists, there is no need to install the data channel which can be provided by the

CPU. When the CPU subcard does not exist, that channel can be used to back up


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active/standby data. The other Ethernet chip serves as the control stream channel to

communicate with the UIM, and is used for debugging and code downloading.

The MNIC board provides these functions:

1. Providing 1100M control stream Ethernet interface.

2. Providing 1100M Ethernet data backup channel.

3. Providing RS485 backup control channel interface.

4. 1+1 active/standby logic control.

5. Providing one gigabit interface (the gigabit module is required) or up to four100M Ethernet interfaces for the external network.

The MNIC module provides one gigabit or 4~8 100M Ethernet interfaces for the

external network.

2.5.3.5 UIM

The UIM implements the internal Ethernet level-2 switching of the control shelf and

the resource shelf management, and provides an external Ethernet cascading interface

for the control shelf, including the packet data interface (GE optical interface)

connected to the core switching unit and to the control plane data Ethernet interface

(four FEs) of the distributed processing platform.

Fig. 2.5-6 shows the principle of the UIM.


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CPU

subsystem

Peripheral

memory

PCI bus

Control planeEthernet

Logic control

circuit

User planeEthernet

RS485

Media plane

control planeinterconnection

Media plane

gigabit optical

interface

Media plane

gigabit electrical

interface

RS232


Debugging Ethernet

GCS subcard

GXS subcard

GTS subcard

24 100M+2 1000M

control plane

Ethernet

24 100M+2 1000M

media plane

Ethernet

Internal bus

Fig. 2.5-6 Principle of the UIM

The UIM has these functions:

1. Providing two 24+2 switching HUB. One is the control plane Ethernet HUB,

providing 20 internal control plane FE interfaces to interconnect with the

internal modules of the resource shelf and four external control plane FE

interfaces for the interconnection between resource shelves or between the

resource shelf and the CHUB. One user plane Ethernet HUB provides 23interface FE interfaces for resource shelf interconnection, and provides one

external FE interface.

2. Providing one user plane GE optical interface for the interconnection between

the resource shelf and core switching unit through an optional GXS subcard. The

GE channel adopts the active/standby backup mode to provide 1+1 backup of

the core switching unit. The UIM provides one ore two internal user plane GE

interfaces (the GTS subcard shall be configured when the UIM provides two GE


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39

electrical interfaces) for the resource shelf as its GE slots.

3. Providing one internal user plane GE interface. This interface can be used to

cascade with the CHUB in the control shelf.

4. Providing control plane and user plane Ethernet GE interconnection mode for

the UIM of the distributed processing platform.

5. The internal FE port of the active/standby module adopts the high impedance

multiplexing backup mode on the backplane.

6. Providing resource shelf management function, the RS-485 management

interface for the resource shelf, and resource shelf module reset and reset signal

collection function.

7. Resource shelf clock driving. The PP2S, 8K and 16M signals are inputted. After

the phase locking and driving processing, the signals are distributed to the slots

of the resource shelf. The UIM provides 16M, 8K and PP2S clock for the

resource module.

8. Reading cabinet number, shelf number, slot number, device number, backplane

version number and backplane type number.

9. MAC configuration, VLAN and broadcast packet control.

10. Compatible with the commercial HUB.

The UIM provides these external interfaces:

1. Four 100M Ethernet interfaces.

2. One or two GE interfaces.

2.5.3.6 SPB

The SPB module is a multi-CPU processing board with 16 E1s and four 8M Highway

interfaces. It is used as the narrowband signaling processing board to process the

HDLC of multiple channels of SS7 and the signaling of MTP-2 or lower layer.

The SPB module integrates 16 channels of E1/T1 LIU and Framer, communication

processing unit consisting of four CPUs, two 100M Ethernet switches used for the user

plane and control plane, and time slot switching chip. The SPB module supports the

E1/T1 mode and 120 ohms and 75 ohms impedance configuration.


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According to different system configurations, the SPB module can be used for E1

access or Highway access, and simultaneous E1 and Highway access. The single-chip

CPU can be connected through the switching chip, E1 and Highway, to support

signaling forwarding. The CPU system is configured in the system in the form of

subcard.

The module provides two external Ethernet switching planes at an egress rate of 100M.

The two Ethernet ports of the CPU are mounted on these two Ethernet planes. The

module provides two channels of external clock for the clock board as the 8 kHz

referen

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TN_SS001_E1_0 NE System Structure-135.doc

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