GSM Alctel
Transcript of GSM Alctel
GSM SYSTEM Network Switching Subsystem
EVOLIUMTM GSM NSS
CIRCUIT SWITCHED CORE NETWORK
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GSM SYSTEM Network Switching Subsystem
TABLE OF CONTENTS
1. INTRODUCTIONINTRODUCTION.............................................................................................4
2. GSM CORE NETWORK OVERVIEWGSM CORE NETWORK OVERVIEW.............................................................5
2.1. GSM ENVIRONMENT.............................................................................6
2.2. MAIN NSS COMPONENTS OVERVIEW................................................7
2.3. COMMUNICATION INTERFACES.......................................................17
3. MOBILE SWITCHING CENTER (MSC)MOBILE SWITCHING CENTER (MSC)........................................................20
3.1. MSC OVERVIEW...................................................................................21
3.2. RCP DESCRIPTION...............................................................................23
3.3. SSP DESCRIPTION................................................................................34
4. HOME LOCATION REGISTER (HLR)HOME LOCATION REGISTER (HLR)..........................................................46
4.1. HLR FUNCTIONS..................................................................................47
4.2. HLR HARDWARE DESCRIPTION........................................................52
4.3. HLR SOFTWARE DESCRIPTION.........................................................55
5. CSCN SERVICES AND FUNCTIONSCSCN SERVICES AND FUNCTIONS...........................................................58
5.1. BASIC TELECOMMUNICATIONS SERVICES....................................59
5.2. SUPPLEMENTARY SERVICES............................................................64
5.3. NON-GSM SUPPLEMENTARY SERVICES..........................................68
5.4. SECURITY FUNCTIONS.......................................................................69
5.5. MOBILE NUMBER PORTABILITY FUNCTION (MNP)......................72
5.6. CHARGING FUNCTION........................................................................72
5.7. ROAMING..............................................................................................73
5.8. ANNOUNCEMENTS..............................................................................74
6. CSCN OPERATION AND MAINTENANCECSCN OPERATION AND MAINTENANCE.................................................75
6.1. OPERATION AND MAINTENANCE IN NSS........................................76
6.2. GENERIC OMC FEATURES..................................................................77
6.3. OPERATION AND MAINTENANCE TASKS.......................................83
6.4. NSS O&M DOCUMENTATION.............................................................85
6.5. OPERATION AND MAINTENANCE ARCHITECTURES....................87
7. CSCN DEFENSECSCN DEFENSE............................................................................................88
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7.1. CSCN DEFENSE OVERVIEW...............................................................89
7.2. NETWORK ELEMENT LEVEL DEFENSE............................................89
7.3. NETWORK LEVEL DEFENSE..............................................................91
8. CSCN PERFORMANCES AND TECHNICAL CHARACTERISTICSCSCN PERFORMANCES AND TECHNICAL CHARACTERISTICS...........94
8.1. STATIC CAPACITIES............................................................................95
8.2. PHYSICAL CHARACTERISTICS..........................................................98
8.3. POWER.................................................................................................102
8.4. ENVIRONMENTAL CONDITIONS.....................................................106
8.5. INSTALLATION...................................................................................107
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GSM SYSTEM Network Switching Subsystem
11 INTRODUCTIONINTRODUCTION
This document presents the Alcatel EVOLIUMTM Circuit-Switched Core Network solution for GSM. It provides an overview of:
- environment,
- application of GSM standards,
- functionalities,
- interfaces,
- technical characteristics and performances.
This product description will enable you to understand the environment, architectures and functions of the NSS, and how the Alcatel offer complies with GSM standards.
The Alcatel Network Subsystem presented in this document provides to the network operators solutions to all levels of their booming business:
A Mobile Switching Center (MSC) offering:
A full range of mobile services;
A Fixed-mobile convergence, this means that a single equipment connects mobile as well as fixed subscribers;
Access to IN services through standard interfaces such as CAMEL and ETSI core INAP;
A Home Location Register (HLR) offering:
Features beyond GSM phase 2+;
GPRS support.
A centralized Operation & Maintenance Center (OMC) offering:
Full management of the network from a central point.
The above products are under continuous development to match the evolutions of the standards and the migration towards wideband mobility.
This document does not present the Alcatel GPRS NSS solution. For more information on this solution please refer to the "Alcatel GPRS Product Description".
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GSM SYSTEM Network Switching Subsystem
22 GSM CORE NETWORK OVERVIEWGSM CORE NETWORK OVERVIEW
This chapter provides:
A description of the GSM global environment,
An overview of the main NSS components,
A description of the communications interfaces.
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3 GSM ENVIRONMENT
A GSM public mobile network consists of two subsystems:
The radio subsystem (BSS) which comprises:
mobile stations,
base transceiver stations (BTS),
base station controllers (BSC).
The Network SubSystem (NSS), based on the Alcatel 1000 EVOLIUMTM service switching point, is part of the Alcatel 900/1800/1900 offering. This system incorporates a complete infrastructure and the services of a public land mobile network (PLMN) operating in the 900/1800/1900 MHz band. It complies with ETSI GSM/DCS (global system for mobile communications/digital communication system) standards.
The NSS is the interface between the public switched telephone network (PSTN) or integrated services digital network (ISDN) and base station systems (BSS) . It provides speech and data transmission in circuit mode (GSM services). It can also provide the general packet radio service (GPRS) over the GPRS NSS network.
As described in the following figures, the NSS comprises the following subsystems:
Mobile Switching Centre (MSC),
Home Location Register (HLR),
Authentication Centre (AUC),
Operation & Management Centre (OMC),
Equipment Identity Register (EIR),
Added value services: voice mail, GSM messaging centre and commercial administration centre.
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PSTN/ISDN
BTS
BSC
BTS
PDN
RCP
SSP
MSC
SCP
VMS
SMSC
EIR
HLR
CDRCollector
SGSN
SMIM
InterceptionNode
OMC
General organization of the GSM network
4 MAIN NSS COMPONENTS OVERVIEW
5 MOBILE SWITCHING CENTER (MSC)
The MSC is the main component of the NSS. It provides switching functions for calls between mobile subscribers, and between mobile and fixed network subscribers. It is interconnected to and provides interfaces with the PSTN, ISDN and public packet or circuit switched data networks.
Each MSC in the network plays a part in updating the HLR and VLR databases with the latest information.
Since the signalling traffic in a GSM PLMN is due mainly to the subscriber’s mobility and not to the ‘pure’ call processing, the Alcatel solution for the MSC/VLR has been split into two parts: the SSP and one (or several) Evolium Mobile Server (so-called RCP), such an architecture relying on an IN one. The SSP main task is to perform the switching functions, whereas the RCP handles all functions linked to the mobility.
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Alcatel 1000 EVOLIUMTM SSP
The SSP product is based on the Alcatel 1000 EVOLIUMTM digital switching centre. This switching platform, already used in many Alcatel telecommunication networks, is highly standardized, powerful, multiprocessing, multi-tasking, secured (thanks to hardware and software redundancies), reliable, and may easily evolve.
Alcatel 1000 EVOLIUMTM is a multi-service exchange allowing telecom networks to be developed to meet requirements for future telecommunication networks related to :
PSTN functions
- Local (subscriber) exchange;
- Transit exchange
- International gateway exchange
IN functions
Service Switching Point for intelligent networks
PLMN functions
Service Switching Point for mobile networks
Alcatel has designed its Multiservice exchange architecture to satisfy ever increasing demands for high-power processing and connectivity capabilities. To that respect, two technologies for the switching matrix can be used indifferently:
RCX (Narrow Band) switching matrix. The maximum configuration of that technology in terms of PCMs is 2048 PCMs.It corresponds to Alcatel OCB283 SSP
RCH (ATM Broad Band) switching matrix. The maximum configuration of that technology in terms of PCMs is 16384 PCMs. It corresponds to Alcatel E10 MM SSP
The Alcatel 1000 EVOLIUMTM can incorporate a Signalling Transfer Point (STP) function.
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Alcatel 1421 RCP
The RCP/VLR, Alcatel 1421, integrates the Radio Control Function (RCF) and the Visitor Location Register (VLR) in the same A8360 rack.
The RCF handles:
Interworking with the BSS
All operations relating to mobility management,
Interworking with the SSP to manage physical resources associated with:
Originating and terminating calls
Telephony events such as off-hook, on-hook, etc…
The VLR is a database operating in conjunction with the HLR.
It stores dynamic information relating to mobile subscribers roaming in the MSC’s coverage area.
In the VLR, a subscriber is defined by an identifier and a location. Each time the subscriber’s location area code (LAC) changes, the network must update the VLR in the visited network.
This RCP system, already used in several Alcatel telecommunication applications, is highly standardized, powerful, multiprocessing, multi-tasking, secured (thanks to hardware and software redundancies), reliable, and may easily evolve.
The RCP can also incorporate the SCCP (signalling connection control part) gateway. It provides the SCCP gateway and relay functions if they are not handled in the network by a standalone SCCP gateway.
6 HOME LOCATION REGISTER (HLR) / AUTHENTICATION CENTER (AUC)
The HLR is a database storing information relating to mobile network subscribers.
The NSS can incorporate more than one database according to capability, availability and the operating criteria selected.
A static record in the HLR describes each subscription, giving details of options and supplementary services accessible to the subscriber.
This static information is combined with dynamic information concerning the sub-scriber’s latest known location or the operational status of the MS.
The HLR stores all the data characterising the subscriber (MSISDN, access rights, etc.).
The HLR is a protected database. It must be located on premises with access restricted to authorized personnel.
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Authentication center (AuC):
The AuC is a database storing confidential information, such as the Ki (the sub-scriber’s individual authentication key) used by the network to certify the sub-scriber’s identity. The Ki is stored in coded form which can be deciphered only by the AuC.
The AuC is located in a room with controlled access. Data access is password-protected.
The AuC supplies the VLR with data required for subscriber authentication and ciphering interchanges between the MS and BSS. Checks are run each time the subscriber requests a service. The AuC provides protection to the network operator, service provider and subscribers.
The Alcatel solution for GSM has implemented HLR and AuC on a common platform, based on Alcatel 8360 and within the same equipment. Hence the wording HLR/AuC, because both functions are co-located in the same hardware machine.
7 COMBINED STATION HLR/RCP
Allows the coexistence in a single physical machine of the HLR, RCP and SCCP Gateway functions, which is specially adapted for optimisation of small configurations.
The main advantage of this Combined Station is it reduced footprint.
The combined HLR-RCP-SCCP gateway is based on Alcatel 8360 machine.
8 OPERATION AND MAINTENANCE CENTER-SWITCHING (OMC-S)
The OMC-S is the NSS operation and maintenance component. It combines sub-scriber administrative management functions and equipment technical management functions. It provides interfaces based on the Q3 protocol stack with network elements.
Network administrative and customer care management entails:
creating subscriptions
deleting subscriptions
changing subscriptions
collecting charging tickets.
The network equipment management function provides overall monitoring to guarantee equipment availability and correct hardware configuration. The equipment management function handles:
supervision of alarms sent by equipment,
elimination of malfunctions,
software version management,
performance management,
security management.
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9 CDR COLLECTOR /FILE COLLECTOR
The Alcatel Call Detail Record (CDR) collector manages billing information from various mobile network elements. The Alcatel CDR collector is the Alcatel 1338. According to its logical configuration, CDR functions can include:
real-time CDR collection,
validation of collected CDRs,
storage, backup and restoration of CDRs,
re-direction of CDRs to an Operation Support System (OSS) such as a Customer Care and Billing System (CCBS),
CDR reformatting.
Alcatel furnishes Alcatel 1338 CDR collectors in two different versions depending on operator requirements:
CDR collector,
The CDR collector offers a full set of functions including new features.
File collector,
The File collector offers a smaller range of functions resulting in faster processing and easier integration into existing billing chains.
10 EQUIPMENT IDENTITY REGISTER (EIR)
The EIR is an optional database accessible to the MSC. It contains lists of permitted MSs and barred MSs (stolen or disturbance-generating). Each MS is assigned an IMEI (international mobile equipment identity) providing information not relating to the subscriber identity, such as the factory serial number or software version.
The MSC interrogates the EIR to check the mobile station’s IMEI status. The EIR responds with the following information:
white-listed: equipment permitted to use the network,
grey-listed: equipment being tracked,
black-listed: equipment barred from using the network.
Calls are allowed on the first two lists and barred on the last.
11 SCP
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The Service Control Point (SCP) is a network server necessary for the provision of Intelligent Network (IN) services to the CSCN. The Alcatel solution for the SCP is the Alcatel 1425.
Intelligent Networks
Network operators using Intelligent Networks can create special categories of supplementary services known as Operator Specific Supplementary Services (OSSS). Unlike standard GSM supplementary services, international standards agreements do not specifically define OSSSs. Instead, standards define Intelligent Network architectures and functions, that operators use to produce unique value-added services to attract clients.
The SCP acts as a command point for Intelligent Network services. Calls to and from a subscriber who has IN services, are analyzed in the MSC. If the call requires the allowed IN service (the OSSS), the MSC initiates a dialog with the SCP that contains the related service information. The SCP then initiates the necessary procedures to complete service for the call.
CAMEL
Customized Application for Mobile network Enhanced Logic (CAMEL) is an enhancement of IN service access that enables subscribers to use the services to which they have rights, even when roaming outside their home network. CAMEL definitions now exist in three phases, each phase adding functions to the previous one. The most recent CAMEL release, phase 3, mainly extends CAMEL features to include GPRS subscribers.
A well known example of an IN service is the prepaid service. IN and CAMEL also enable operators to offer various versions of call screening, call dialling abbreviation and location services.
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12 STANDALONE INTERWORKING MODULE (SMIM) / IWF
The SMIM is necessary for the transmission of circuit-switched data between GSM mobile stations and fixed networks. The SMIM is the physical platform that supports the InterWorking Function (IWF). The IWF converts the protocols used on the GSM radio interface to those used in the targeted fixed network, and vice versa.
Common applications that require the SMIM/IWF in GSM networks are:
fax transmissions,
Web access,
e-mail.
SMIM functions vary according to the requirements of different bearer services. These functions can include:
rate adaptation,
frame adaptation,
insertion of a modem.
The Radio Control Point (RCP) supervises the SMIM for GSM call control, and operation and maintenance.
13 HLR/AUC SECURISATION SERVER (SSH)
This is a cost-effective solution against the total destruction of the site (e.g. a fire). Indeed, using mated pairs of HLRs or a distributed architecture makes it is possible to restore an HLR database to another site.
The functions provided by the Security Server aim to:
Save the active HLR/AuC data base on a front end PC,
Transfer the database files from the active HLR/AuC PC to the mated HLR/AuC PC,
Restore the database on the mated HLR/AuC,
Provide a backup of the database files in Security Server,
Audit the mated HLR/AuC by the active HLR/AuCs to check the working state of the mated HLR.
These functions are triggered from the Security Server Workstation, which may be localized in a centralized site. The Security Server is implemented on top of an OMC as a dedicated application.
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router
WAN
HLR 1
PC
HLR 2
PC
HLR/n
PC
HLR1
HLR2
HLRm
PC
PC
PC
PC
OMC+ Disk-tower
router
router
X.25 X.25
Active site Standby site
CentralizedExploitationSite
LAN
LAN
LAN
Security Server Architecture (example)
Three different levels of security can be offered :
Centralised database backup
‘N to 1’ configuration. In this case, N active machines are secured by a standby HLR/AuC.
‘Mated pair’ configuration, where as many standby HLR as active HLR are implemented.
14 SMSC (SHORT MESSAGE SERVICE CENTER)
The SMS-C is an entity to which mobile subscribers can send short messages using signalling channels; SMS-C entity can also be used to send short messages to a mobile subscriber using signalling channels.
It may allow for notification that messages are in the subscriber's voice mailbox.
15 VMS (GLOBAL VOICE MAIL FOR MOBILE NETWORKS)
With a voice mail system, the subscriber may pay or not the operator a subscription for call forwarding ; the call forwarding to the voice mail service can be conditional or unconditional depending on the subscriber status.
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16 INTERCEPTION EQUIPMENT
The circuit-switched interception network enables operators to comply to the requirements of authorized agencies for the monitoring of the telecommunications activities of mobile subscribers. This network enables operators to monitor local subscribers as well as subscribers roaming from other mobile networks.
The Alcatel circuit-switched interception network consists of:
Interception Management Center (IMC)
The IMC:
- handles configuration of the interception network,
- manages interception requests from authorized law enforcement agencies.
Interception Equipment (IE)
The IE collects and delivers to the law enforcement monitoring facility:
- intercepted related information, such as subscriber location, via the IMC,
- content of intercepted communications.
The main functions of the circuit-switched interception network are:
real-time traffic supervision of the communications of selected subscribers,
real-time delivery of collected information to a selected law enforcement monitoring facility.
17 SIGNALLING TRANSFER POINT (STP)
A Signalling Transfer Point (STP) handles the routing and management of SS Nº 7 signalling on the CSCN.
The STP hosts two basic subfunctions:
transfer function,
The transfer function involves the detection and routing of signaling messages.
The STP analyses the content of incoming signaling packets to determine their destination and specify routing.
management function.
From STPs, operators apply procedures to:
- control the prohibition and permission of signaling transfers,
- test signaling routes,
- control signaling transfers over international routes.
Alcatel offers two hardware solutions for STPs in the CSCN:
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SSP integrated solution:
In this solution, processing boards known as auxiliary and equipment control stations (SMA stations) in the SSP handle STP functions.
Operators must analyze system traffic to be sure that it does not exceed specific limits provided by the constructor.
Standalone solution:
The Alcatel solution for the standalone STP is the IN-fusion Signal Transfer Point C (STP-C). The STP-C is a high-speed switch that receives, routes and transmits signalling messages for call setup and Intelligent Network/CAMEL applications. In addition, the STP-C supports number translations for Local Number Portability (LNP) and Mobile Number Portability (MNP).
Alcatel offers the STP-C in two configurations:
- STP C6, supporting from 12 to 432 links. A fully configured STP C6 sup-ports one Admin/Trunk cluster and five C7 signalling clusters.
- STP C32, supporting from 20 to 512 links. A fully configured STP C32 supports one Administration cluster, one Trunk cluster and 30 SS Nº 7 signaling clusters.
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18 COMMUNICATION INTERFACES
The figure here under shows the protocols used between the main networks elements.
MSC
VLRPSTN/ISDN
PSCN
SCPSMSCEIR
HLR
CDRCollector
SGSN
OMC
BSS
G
E
D
C
Gr
Gs
MSC/PSTN
X.25
X.25CAP
or INAP CS1EF
A
MSC
VLR
GnGGSN
CSCN interfaces and protocols
The following table lists the protocols used in the NSS and indicates the interfaces to which they apply.
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Interface Interface Protocol & Version
“A”: MSC - BSS BSSAP(MTP/SCCP/BSSMAP-DTAP) - GSM TS 04.08 and 08.08.
“B”: MSC - VLR The B interface is the interface between an MSC and its associated Visitor Location Register (VLR). This interface is internal to the MSC/VLR. The B interface is not specifically defined by GSM/UMTS standards. In the Alcatel solution, the MSC and VLR exchange signals using a standard SS Nº 7 protocol stack. The user level protocol for the B interface is the Mobile Application Part B (MAP B) protocol.
“C”: MSC - HLR MAP-C (MTP/SCCP/TCAP/MAP) - GSM TS 09.02 for MAP specification.
“D”: VLR - HLR MAP-D (MTP/SCCP/TCAP/MAP) - GSM TS 09.02 for MAP specification.
“E”: MSC - MSC MAP-E (MTP/SCCP/TCAP/MAP) - GSM TS 09.02 for MAP specification.
“F”: MSC - EIR MAP-F (MTP/SCCP/TCAP/MAP) - GSM TS 09.02 for MAP specification.
“G”: VLR - VLR MAP-G (MTP/SCCP/TCAP/MAP) - GSM TS 09.02 for MAP specification.
MSC - SCP This interface provides Intelligent Network (IN) and Customized Application for Mobile network Enhanced Logic (CAMEL) functions to mobile networks.
The MSC and SCP exchange information using the
IN CS1 Core INAP protocol based on ETS 300374-1, or
CAMEL (GSM TS 09.78).
MSC - SMSC MAP GSM TS 09.02 or SMS-AP.
MSC/VLR – OMC-S Q3 over X.25
MSC/VLR – CDR Collector
Q3 over X.25
HLR - SCP MAP GSM TS 09.02
HLR/AuC – OMC-S Q3ic over X.25
Gc: GGSN - HLR GTP: SM TS 09.60 TSG#7
Gr: SGSN - HLR MAP GSM TS 09.02 SMG#31
Gs: SGSN - MSC BSSAP+: GSM TS 09.16 and TS 09.18.
The Gs interface is the interface between an MSC/VLR of the CSCN and a Serving GPRS Support Node (SGSN) of the Packet-Switched Core Network (PSCN).
The SGSN uses this interface to send location information to the MSC/VLR. The MSC/VLR uses this interface to send paging requests via the SGSN and to indicate to a SGSN that a mobile terminal associated to the SGSN is using a service handled by the MSC.
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1919 MOBILE SWITCHING CENTER (MSC)MOBILE SWITCHING CENTER (MSC)
This chapter describes the functions and architecture of the MSC in the Circuit Switched Core Network. It includes information about MSC:
General architecture,
Individual components,
Functions, hardware and software.
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20 MSC OVERVIEW
The Mobile services Switching Center (MSC) provides control and switching functions for calls between mobile subscribers, and between mobile and fixed network subscribers.
From a functional point of view, it is possible to describe two different roles for the MSC in the CSCN:
Visited MSC (VMSC)
The VMSC is an MSC that interfaces with the Base Station Subsystem (BSS) over the A interface.
The VMSC includes a Visitor Location Register (VLR) which registers subscribers present in the associated Base Station Subsystem.
The VMSC is responsible for subscriber:
mobility management,
security management,
network access.
Gateway MSC (GMSC)
The GMSC is an MSC that interfaces with fixed networks and/or with other mobile networks. When the GMSC receives an incoming call from an external network, it:
retrieves routing information from the HLR,
uses the routing information to direct the call to the VMSC of the terminating subscriber.
According to the network configuration, an MSC may perform visiting functions, gateway functions or both. In the CSCN, the network operator must determine the role of each MSC.
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21 GENERAL ARCHITECTURE
The MSC (mobile services switching center), in the GSM sense, functionally incorporates the:
SSP (service switching point),
RCF (radio control function).
Within the NSS, the VLR (visitor location register) is associated with the MSC to form the MSC/VLR, which in physical terms incorporates the:
SSP,
RCP (radio control point).
The SSP, controlled by the RCP, handles the set-up of all calls to or from an MS (mobile station), the execution of handovers, and the transmission of ISUP/SSURT telephone events from the PSTN or PLMN to the RCP and the other network switches.
Together with an SSP, the RCP handles all mobile radio functions connected with:
RCF,
VLR (visitor location register),
interfaces :
MSC/VLR-BSS,
MSC/VLR-HLR,
MSC/VLR-OMC.
The RCP incorporates the RCF and integrates the VLR function.
The RCF handles:
interworking with the BSS,
all operations relating to mobility management,
interworking with the SSP to manage physical resources associated with:
originating and terminating calls,
telephone events such as off-hook, on-hook, etc.
The VLR is a database operating in conjunction with the HLR (home location register).
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PSTN/ISDN
BSSSSP
RCF
RCP
VLR
MSC
Alcatel’s MSC solution
22 RCP DESCRIPTION
23 RCP FUNCTIONS
RCP functions include:
call security,
location update,
call handling,
charging,
numbering and routing,
supplementary services,
IN and CAMEL service access,
observation,
translation,
radio environment management.
The following sections describe these functions.
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Call security
The RCP applies security procedures to protect GSM mobile radio services from unauthorized call attempts or third party intrusion into transmissions.
The RCP uses these procedures to authenticate the mobile calling and/or called party and to cipher all information (speech, data and signalling) from the radio interface using ciphering keys.
The Radio Control Function (RCF) of the RCP adapts the security information inter-changed between BSS and the VLR. The VLR manages various security procedures relating to:
authentication,
ciphering,
subscriber identity confidentiality.
Location update
The location update function tells the network where the mobile subscriber is at all times. It provides the subscriber with continuity of service throughout the authorized coverage area, regardless of the location of the Mobile Station (MS) of that subscriber. It enables the subscriber to:
receive calls at a permanent directory number,
gain access to the network from any authorized location.
The RCF and VLR functions of the RCP work together with the HLR to provide location updates. When the RCF receives update information from the BSS, it relays this information to the VLR. The VLR then updates mobile subscriber location data. If the subscriber is attached to another VLR, the home VLR transmits this data to the HLR. The HLR returns mobile subscriber subscription data to the VLR.
Call handling
For call handling, the RCF part of the RCP manages:
all operations relating to originating or terminating call setup,
dialog with the SSP and with the RAN to manage the physical resources involved in a call,
operations required for handover.
Charging
For each originating, terminating or rerouted call relating to a mobile subscriber, the MSC generates and transmits Call Detail Records (CDRs) to the Alcatel 1338 CDR collector or File collector. Calls rerouted after call forwarding also result in CDR transmission.
One or more CDRs can be generated, depending on the type of call. For example:
originating call to the PSTN/ISDN: the origin MSC generates a CDR.
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terminating call from the PSTN: the GMSC (gateway MSC) and the destination MSC each generate a CDR. For supplementary services (example: call forwarding), the GMSC and the MSC generate other CDRs.
originating call from one mobile subscriber to another in the same PLMN: the GMSC and the MSC generate other CDRs.
CDRs mainly contain the information below:
IMSI (international mobile subscriber identity),
MSISDN (mobile station ISDN number) and ticket type (MSC or GMSC),
calling mobile subscriber’s location area identity,
called subscriber identity,
type of call (originating, terminating, forwarded),
call status,
teleservices and bearer services,
date and time of beginning and end of call,
call duration,
supplementary services used.
Numbering and routing
The RCP works with the SSP for phone number processing and routing.
Mobile subscribers can dial a standard telephone number or a short number (access to Value Added Services) from their GSM Mobile Station. Depending on the type of subscription, a mobile subscriber may wish to reach:
a national PSTN subscriber,
a subscriber of one or more national PLMNs,
a subscriber of any foreign PSTN,
a subscriber of any foreign PLMN,
an IN or CAMEL server.
When a mobile subscriber dials a number, the RCP analyses the number. The RCP then does one of the following:
transmits the number to the SSP for translation and routing (for example, the received number is national or international),
asks the HLR for a Mobile Station Roaming Number (MSRN) and transmits it to the SSP (for example, the number received is an HPLMN number),
transmits the number of the SSP with the originating geographical area (for example, the number received is an emergency service number).
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The SSP processes numbers received from the RCP in three stages:
preanalysis: selection of a translator (national, international, supplementary services...),
translation: determination of a routing on the basis of the initial digits of the number,
routing: determination of an outgoing circuit group.
Supplementary services
When a mobile subscriber connects to the network, the VLR checks subscriber service rights. The VLR then provides the RCF with the data necessary for service use.
IN and CAMEL service access
During call setup, the RCF analyses dialled numbers and subscriber data for IN and CAMEL service invocation information. When the RCP detects the need for IN or CAMEL service invocation for a call, it initiates a dialog with the appropriate IN or CAMEL server. This server then provides instructions for the continuation of the call.
Observation
The RCF and VLR increment event counters, call attempt counters and procedure failure counters to provide operators with information about network operations.
The RCP periodically transmits the observation results to the OMC-CS.
Translation
The RCP contains translation tables which it scans for the rerouting of certain calls according to the signalling information assigned to that call.
Radio environment management
From the RCP, the operator can configure the radio environment. Operators can create, delete and interrogate from the RCP entities such the BSC, LA, Cells, etc.
24 RCP HARDWARE ARCHITECTURE
The RCP is integrated into Alcatel A83xx racks (xx = 30 or 60). The A83xx control station is a multiple application, multibus and multiprocessor secured (worker/standby) duplex system.
As shown in the following figure ,the A83xx incorporates:
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GSM SYSTEM Network Switching Subsystem
Two processing subsystems:
The Alcatel 83xx provides system security through a redundant system architecture.
In redundant system architecture, parallel processing subsystems assure system functions. When one subsystem is operating in active mode, the other is on standby. The standby subsystem does not run any traffic, but is ready to move into the active mode if the active subsystem fails.
Each Alcatel 83xx subsystem contains a communication bus, processor boards, memory boards and front end line drivers/adapters. The processor boards support Real Time Operating System (RTOS) management software.
One or more external access front ends:
External access front ends are common to both processing subsystems and are assigned to the active subsystem.
They are:
signalling network connections: the HLR and RCP are connected to the signalling network over signalling links support by two to four PCM links.
These links must be physically connected to the SSP. Within the SSP, signalling links are distributed to appropriate destinations by creating SS7 data links.
TMN connections: the HLR and RCP are connected to the OMC-S over a duplicated synchronous X.25 link. The OSNM is also connected to a workstation over an X.25 link.
terminal connections (PCFS Terminal, printers): the HLR, RCP and OSNM are connected to operation/maintenance terminals over asynchronous links.
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ProcessingChain A
ProcessingChain B
Telecom Bus(X.25 connexions)
PCM Bus(SS7 connexions)
Ethernet
Mass memory(mirrored disks)
Ethernet accesses
External accesses PCM
External accesses Sync/ Async
Simplified description of the A83xx Hardware platform.
The A83xx hardware architecture can be dimensioned to suit the application by adjusting the number of:
processor boards,
memory boards,
front-end adapters,
disk drives,
streamers or PCFS,
magnetic tape drives.
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The mapping of the functional architecture over rack implementation is given below.
Power Supply Monitoring
XBUS AProcessor boards
XBUS BProcessor boards
PeripheralsStreamer, Disks
TBUSSynchronous andAsynchronous linkAdapter boards
XBUSPCM linkAdapterboards
Terminal and alarmconnections
Subrack arrangement in an RCP A83XX rack
In a maximum configuration, an A8360 incorporates:
14 x 2 processor boards, 68060, 66 MHz,
2 x 1 main memory boards (512 Mbytes),
six disk drives, 1.2 Gbyte,
one PCFS,
four PCM links, 120/75 ohms,
8 xa*V.24ports,
4 x b*V.36X21 ports,
4 xc*J.64ports,
inter-subsystem links.
Note : Values a, b and c are defined on dimensioning the system according to the number and type of external port required. The maximum and minimum values are given below:
2 ≤a ≤4, 0 ≤b ≤7, 0 ≤c ≤7, a +b +c ≤9.
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The following table lists the A8360 boards and their functions.
Element Type Function
CS System board which serves for
- supervising a processing chain,
- controlling system initialization and loading procedures,
- executing LOCAVAR operations.
CPU Processor board (14 CPUs for the maximum configuration)
MG General memory board (1 board of 512 Mb for a RCP A8360, with 14 CPU)
CXN X-bus/N-bus coupler board
CBS Coupler board which links an X-bus to two SCSI-buses
FTD
(and IBT)
Front-end data transmission coupler board
Each one has a connection capacity of 128 transmission lines with a maximum throughput of 2.5 Mbits/s in full-duplex mode.
CT Any coupler board connected to the two T-buses
AL Alarm coupler board connected to the two T-buses with two functions:
- Sending signals to the outside (e.g. to the local-alarm panel),
- Receiving incoming signals, connected to environment-infrastructure alarms and subrack-power-supply alarms.
DDH Date and time coupler board connected to the two T-buses
CBX Coupler board connecting the processing-chain X-buses to one PCM X-bus
PCMC PCM line-coupler board
IOP FTD’s I/O processor
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25 RCP SOFTWARE ARCHITECTURE
The specific radio-mobile-application softwares (RCP/VLR, HLR/AuC, SCCP gateway) are developed as dedicated upper application layers.
The RCP basic software allows :
to handle real-time and transaction-processing applications in parallel,
to support applications with heavy real-time requirements (achievement of the performance objectives of the telecommunications software and the file-management system is critical),
to support applications performing on-going service
The basic software is an open Real-Time Operating System (RTOS).
RTOS is an operating system designed to make the A83xx hardware configuration transparent with the application software. It performs:
- Management of the hardware and software entities in an A83xx station,
- Allocation of the resources in a multiprocessor configuration to applications.
RTOS handles objects that are hardware or software entities, such as RTOS applications, tasks, memory blocks, communication lines and so on. They can be created, modified, displayed, resp. deleted. The various objects managed by RTOS are stored in the system data base.
RTOS provides services which support standard data communication protocols:
- Communication Access Method (CAM) supporting the protocol specified in the ISO model,
- Extended Communication Access Method (ECAM) supporting the Signalling System number 7 (SS7) protocols,
- File Transfer Access Method (FTAM) specified by the ISO standard.
All of them are provided by the Network Communications Service (NCS).
The RCP/VLR’s software architecture is described by the following figure.
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PYLX(RCP)
RTDMS
FMS
WAM
SCR
FTAM CMISE
EL AK+TMNK
RTDMS
SOP PMLX
MTP
SCCP
X.25
X.224
TCAP X.225
RTOS Executive
Legend:CMISE : Common Management Information Service ElementEL : Software SetEL AK : application kernel software setFMS: File management systemFTAM : File Transfer Access and Management
RTOS: Real Time Operating SystemSCCP: Signalling Connection Control PointSCR: Network Switching ServiceSOP : System Operation PackageTCAP: Transaction Capabilities Application PartTMNK: Telecommunication Management Network Kernel
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MTP: Message Transfer PartPMLX : RCP function maintenance ELPYLX : RCP function processing EL RTDMS: Real Time Data Management System
WAM: Workstation Access MethodX.224: transport layerX.225: session layerX.25: physical layer.
RCP Software architecture
The components of the RCP software architecture are described in the following table:
NAME DESCRIPTION
SOP A83xx machine system operation package.
PYLX RCP main EL supporting:
All real time call management functions
Static and dynamic data
Collection of observation results for transmission to the OMC-S
PMLX RCP operation and maintenance EL handles mainly:
Management of operator commands relating to RCP permanent data,
Collection of observation results for transmission to OMC-S.
EL AK and Slave TMNK
The EL AK and slave TMNK are the software sets common to all applications based on an A83xx.
RTDMS The RTDMS is a real time data management system.
This comprises the various software modules included in PYLX, SUP and EL AK.
WAM Manages workstation access.
FTAM File transfer, access and management.
CMISE common management information service element, handles file management dialog before transfer
SCR Provides access to X.25 (X.25, X.224, X.225) and signaling (MTP, SCCP, TCAP) network services
FMS File management system
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26 SSP DESCRIPTION
Two generations of the SSP can be offered:
The non-HC generation SSP (SSP with a RCX switching matrix)- Alcatel OCB283 SSP
The HC generation SSP (SSP with a RCH switching matrix)- Alcatel E10 MM SSP
HC stands for High Capacity.
This new generation high capacity MSC offers numerous benefits:
Major capacity increase both in terms of Call Handling (BHCA) and Switching (Erlang) brought by:
A new family of enhanced general purpose control stations (SMB)
A new technology Switching Matrix (based on composite ATM)
A new family of high density SDH based Termination Units
Better compactness (reduced footprint),
Lower electrical consumption,
A platform that already provides UMTS support
The Alcatel EVOLIUMTM MSC HC as an evolutionary step of the Alcatel MSC solution guarantees the availability of the legacy services and interoperability as well as the field-proven platform reliability.
The global architecture of the MSC HC is described in the following figure.
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BSS
PSTNRCHRCH
PCM & SDHTermination
Unit
RCP
Call ProcessingServers
(SMB, SMM)SSPSSP
MSCMSC
27 SSP FUNCTIONS
The main role of the SSP is to physically direct signalling messages and user data across the mobile network. To do this, the SSP receives control information from:
the Radio Control Point (RCP) in the MSC,
the Base Station Controller (BSC) in the GSM BSS.
The CSCN MSC SSP supports the following GSM functions:
Switching functions
The SSP handles:
Conventional switching functions:
- call handling,
- switching network,
- PCM link connection,
- section selection for auxiliaries such as the IWF (interworking function),
- tones and announcements,
- local or national signalling point (SP)
Mobile radio application specific functions:
Setting up and releasing link sections from/to the PSTN/ISDN: the exchange provides call handling related functions under RCP control.
Call transfer on change of radio channel: the exchange can transfer a call set up on one network section to another under RCP control.
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Transaction between RCP and SSP, under RCP control for a call originating from a mobile station,
Selection of circuits to the BSS: specialized circuit groups are created. The SSP selects an incoming or outgoing circuit whose identity is transmitted to the RCP.
Echo cancelling: voice frequency channels established with a mobile station are equipped with an echo canceller to eliminate echo on calls between a PSTN subscriber and a PLMN subscriber. Echo cancellers are connected on an individual call basis. They are integrated into the exchange on the PSTN side.
Functions specific to intelligent network applications.
Operation and maintenance functions:
interface with the OMC-S over asynchronous links,
generation of data required for observation,
generation of call data records (CDR). CDRs are then sent to the OMC-S or to the A1338 ALMA CDR Collector for transmission to a customer care and billing system (CC&BS) to prepare transit call bills.
28 SSP HARDWARE ARCHITECTURE
29 ALCATEL OCB283 SSP
In hardware terms, it consists of a set of multi-purpose control stations (SM) which are interconnected by one or more transmission bearers called communication multiplexes (MAS or MIS) forming a local area network (LAN).
MIS (inter control station multiplexes) and MAS (main control station access multiplexes) provide secure high bit rate communication between EVOLIUMTM functional sub-systems.
SM types
There are several types of control station:
SMC : main control station,
SMA : auxiliary equipment control station handling Nº 7 signalling and auxiliary functions,
SMT : trunk control station handling PCM link connection,
SMX : matrix control station handling switching matrix control,
SMM : maintenance control station handling operation and maintenance functions.
The STS (synchronization and timebase station) handles synchronization and outputs timing signals.
SMT and SMA stations are interconnected, and connected to SMC stations via MAS multiplexes of the LAN.
SMC stations are interconnected by MIS multiplexes of the LAN and via the MAS.
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Control station design is based on a multiprocessor structure.
SM structure
In general terms, a control station comprises:
a main bus to which processors, memories, adapters, etc. are connected,
a main processor and associated memory,
secondary processors and associated memories,
adapters connecting control stations via the LAN (MIS and MAS),
function-dedicated adapters.
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The following figure shows the OCB283 hardware architecture.
RCXRCX
LANLAN
SMX
..
..
..
STS
SMT
..
..
..
SMT
..
..
..
SMA
..
..
..
SMM SMC
TelephoneNetwork
IntelligentNetwork
SignallingNetwork
DataNetwork
TMNTMN
SSP RCXSSP RCX
Subsc
riber
Subsc
riber
Acc
ess
Acc
ess
......
SMC
Alcatel OCB283 SSP – Hardware Architecture
30 ALCATEL E10 MM SSP
The hardware evolutions, with the introduction of the HC technology, consist in:
A new high capacity switching matrix (RCH) based on ATM technology replaces the current RCX matrix.
The existing multiprocessor stations (SMC, SMA, and SMT) are replaced by new multiprocessor stations (SMB) with higher capacities. These general purpose control stations (SMBs) can support one or more functions of the exchange depending on the types of boards installed.
Introduction of high density SDH/STM1 interface (155 Mbit/s) carrying each 63 PCM terminations.
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The following figure shows the hardware architecture of the SSP with HC technology, and the system interfaces. The designations SMB_… are used by way of indication to designate the different function supported by the SMBs.
RCHRCH
LANLAN
SMB_X
..
..
..
STSSMB_T
SMT
..
..
..
SMB_A
..
..
..
SMT
..
..
..
SMA
..
..
..
SMM SMB_C
TelephoneNetwork
IntelligentNetwork
SignallingNetwork
DataNetwork
TMNTMN
SSP HCSSP HC
Subsc
riber
Subsc
riber
Acc
ess
Acc
ess
Alcatel E10 MM SSP High Capacity – Hardware Architecture
SMB Stations
The functions performed in the previous releases (MSC OCB283) by SMC, SMA, SMT and SMX stations can be handled by an SMB (general purpose control station) with:
SMB_C handling the control function,
SMB_A handling N°7 signalling auxiliary function,
SMB_T handling the termination function (including the connecting Exchange Termination Units (ETU)),
SMB_X handling the matrix function (including the ETUs of the high rate switching network).
Depending on the site’s configuration, an SMB will handle one or more of the above functions. In small configurations, the designation SMB_CAXT represents an SMB supporting the control, auxiliary, matrix and termination functions.
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GSM SYSTEM Network Switching Subsystem
At hardware level, a new Power PC processor is offered, providing a processing power multiplied by 7.
High Capacity Matrix RCH
The new Alcatel E10 MM Switching Matrix (RCH) uses composite ATM (Asynchronous Transfer Mode) technology. The ATM scheme used minimizes transit-time in the switching network.
The RCH has a maximum connection capacity of 16 384 PCMs.
This new high-capacity switching core provides a seven-fold increase in traffic handling capacity to the MSC.
The next figure illustrates the switching network (RCH) structure, composed of:
A native ATM switching matrix,
Matrix interfaces adapting synchronous to/from asynchronous switching modes when the connection of a narrowband physical interface (NB-TU) is required:
TDM to Composite ATM (TCA),
Composite ATM to TDM (CAT).
TCATCA
TCATCA
CATCAT
CATCAT
Native ATMNative ATM
Switching MatrixSwitching Matrix
MatrixMatrix
InterfaceInterface
MatrixMatrix
InterfaceInterface
128 links
128 links
128 links
128 links
128 max 128 max
622 Mbit/ sATM Link
622 Mbit/ sATM Link
622 Mbit/ sATM Link
622 Mbit/ sATM Link
Synchronous Asynchronous Synchronous
Alcatel E10 MM matrix architecture
The RCH is duplicated for system availability and defence reasons.
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GSM SYSTEM Network Switching Subsystem
The RCH matrix is controlled by the SMB stations, called SMB_X (general purpose control stations – matrix function).
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PCM over SDH-STM1 Termination Unit
First used in the system with Exchange Termination Units (ETUs) for connecting PCM links in the SMT2Gs, the ETUs are now used in all SMB type stations. The term ETU covers:
ETUs for connecting SDH links (PCM over SDH-STM1),
ETUs for high rate switching network, as described in 4.3, for:
Time division multiplex channel/ composite ATM cell switching element (TCA),
ATM switching element (ASE).
ATC ETUs, for the transcoding function of the UMTS SSP (see chapter 5),
For the first case, the SDH-STM1 interfaces (155 Mbit/s) can be used when payloads are to be transported over a synchronous transmission network. When carrying TDM payloads, as described with the figure here under, this interface is the means for the MSC to provide a higher 2Mbit/s interfacing capacity.
MSC HCMSC HC
TDMTDM
(PCM, SDH)(PCM, SDH)
TDM/ATMTDM/ATMadaptationadaptation
TDMTDM
(PCM, SDH)(PCM, SDH)
NB callNB callcontrolcontrol
RCHRCH
TDM TUTDM TU
PCM or 63 x 2 Mbps (VC.12/STM- 1)
PCM orPCM or
63 x 2 63 x 2 MbpsMbps (VC.12/STM- 1) (VC.12/STM- 1)
TDM TUTDM TU
PSTN & PLMNPSTN & PLMNnetworknetwork PSTN & PLMNPSTN & PLMN
networknetwork
The PCM over SDH-STM1 Termination Unit, has the following characteristics:
SDH-STM1 interface (155 Mbit/s) carrying 63 PCMs terminations (VC 12 extraction).
Connected to ATM switch matrix with High bit rate links
Interface: Optical S1.1 (ITU-T G957) or Electrical (ITU-T G703)
1+1 optical line protection (APS) and Laser emission protection (ALS)
N+1 Equipment Protection Switch (EPS)
31 SSP SOFTWARE ARCHITECTURE
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The SSP software is built around independent software modules. Some software modules are combined into software machines (ML) designed to handle a particular function (example: charging, call handling). Depending on the application, the SSP incorporates the MLs below:
- ML supported by an SMC or SMB_C (main control station) for control functions. It is instantiated by n + 1 SMCs or SMB_Cs, based on n + 1 redundancy. The system operates on a load sharing basis.
- ML supported by an SMT or SMB-T (trunk control station) handling PCM link connection functions. It is duplicated and operates in active/standby mode.
- ML supported by an SMM (maintenance control station) handling operation and maintenance functions. It is duplicated and operates in active/standby mode.
- ML supported by an SMA or SMB_A (auxiliary equipment control station) handling Nº 7 signalling auxiliary equipment.
- ML supported by an SMX or SMB_X (matrix control station) handling connection control functions and providing the interface with other SMs.
The software is stored on disk where it is organized into archives.
It is loaded into the SMs via the local area network when the system is initialised.
The software is developed using:
- CHILL,
- C.
Some software is generated automatically based on specifications written in SDL (specification and description language).
The functional MLs represent the exchange's main functions. These are the functions that are defended by central defence. The functional MLs have the following characteristics:
- an ML is supported by an SM,
- several MLs can be present on the same SM,
- the redundancy principle is applied to the MLs,
- an ML exists in as many copies as load and dependability require,
- the various copies of a single ML can operate in load sharing mode,
- if a station fails, an ML can migrate from one SM to another,
- the MLs are stored on disk and loaded when the SMs are initialised.
These characteristics provide a high level of configuration flexibility and facilitate system defence.
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Figures hereunder show, on the basis of configurations of the SSP, the different functional MLs and an example of their location in the system.
LAN
STS
RCH
SMB_XSMT
…
SMMSMM
SMC
…
SMA
…
SMA
…
ML COM
ML PUPE
ML ETA
ML OC
OM
ML URM
ML AN
ML TX
SMC
ML PCML GXML MQML TR
SMC
ML GSML CCML MR
Software Architecture of the SSP with ALCATEL OCB283 technology.
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GSM SYSTEM Network Switching Subsystem
LAN
STS
RCH
SMB_Xand/orSCH
SMT2G
…
SMMSMM
SMB- C
…
SMA…
SMB- T
SMB- A
……
ML COM
ML AN
ML ETA
ML OC
OM
ML URM
ML HD
ML PUPE
ML TX
SMB- C
ML PCML GXML MQML TR
ML URM
SMB- C
ML GSML CCML MR
Software Architecture of the SSP with ALCATEL E10MM technology.
ML : Software Machine ML AN : Access Network ML
ML CC : Call Control ML ML COM : Matrix switch control ML
ML ETA : auxiliary equipment manager ML ML GS : IN and GSM server management ML
ML GX : matrix system handler ML ML MQ : message distributor ML
ML MR : call handler ML ML OC : message router ML
ML PC : SS N°7 controller ML ML PUPE : SS N°7 protocol handler ML
ML TR : subscriber and analysis database manager ML
ML TX : call charging and traffic measurement ML
ML URM : PCM controller ML
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3232 HOME LOCATION REGISTER (HLR)HOME LOCATION REGISTER (HLR)
This chapter describes the functions and architecture of the HLR/AuC in the CSCN.
It includes information about:
HLR/AuC functions,
HLR/AuC hardware,
HLR/AuC software,
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GSM SYSTEM Network Switching Subsystem
33 HLR FUNCTIONS
Together, the Home Location Register (HLR) and the Authentication Register (AuC) form the main database of the CSCN. Because HLR and AuC functions are complementary, Alcatel combines them in a single network element called the Alcatel 1422 HLR/AuC.
The HLR/AuC stores data and performs real-time authentication, mobility and authorization operations during network call procedures.
The Alcatel HLR/AuC is fully compliant with GSM and UMTS standards, and thus can be integrated in any multi-vendor environment that complies with the standards.
Note: The GSM/UMTS HLR/AuC is a direct evolution of the GSM HLR/AuC. This HLR/AuC provides a new set of security and service definition protocols for UMTS networks. GSM and UMTS functions remain so closely linked that it is impossible to separate them completely.
A single HLR can handle:
GSM and UMTS subscribers in their home networks,
GSM subscribers who roam in UMTS networks,
UMTS subscribers who roam in GSM networks,
subscribers of networks where UMTS is deployed in ’islands’. When a mobile subscriber travels away from a UMTS island into a GSM area in the same network, the operator must provide the subscriber with GSM services.
The following figures shows the functional environment of the HLR/AuC.
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GSM SYSTEM Network Switching Subsystem
SSP
RCP
MSC
VLRRCF
HLR/AuC
AuCHLR
SP
SP
HLR
SGSN
SCP
SMS- SCSMS-
I WMSC
PSTNI SDN
X25
SSH
OMC- S
SP
SPOne or more SPs
A single SP
X.25 signalling
Shaip
MAP D
MAP C
Q3ic
Q3ic
Q3ic
MAP C
MAP D
MAP
MAP Gr
SSAP
SSAP
MAP
34 HLR SPECIFIC FUNCTIONS
HLR functions include:
data storage,
authentication management,
location management,
call handling,
Short Message Service (SMS),
supplementary services,
observation,
translation,
subscriber management,
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GSM SYSTEM Network Switching Subsystem
data protection.
The following paragraphs describe these functions.
Data storage
The HLR stores the following types of information:
subscription data:
International Mobile Subscriber Identity (IMSI),
Mobile Subscriber Integrated Services Digital Network (MSISDN) number,
Mobile subscriber type indicator.
mobility related data (MS registration, Visitor Location Register (VLR) address, MSC identity, roaming restriction subscription, roaming restriction flag, roaming restriction due to unsupported feature…),
subscribed services and supplementary services and their status,
authentication and ciphering vectors,
subscriber administration data (for example, blocking of the MS),
Authentication management
The HLR stores sets of authentication data that the VLR requires for the verification of subscriber identities. The VLR requires a new set of authentication data for each new authentication procedure. The HLR obtains these sets of data from the AuC, and furnishes them, upon request, to the VLR.
Location management
When a mobile subscriber travels to an area controlled by an MSC other than the previous MSC, the CSCN updates the subscriber information stored in the HLR. This location updating is necessary to ensure correct routing of calls and data.
The activities of the HLR during a location update include:
updating of the mobile location in the HLR,
cancellation of the mobile subscriber data in the old VLR,
provision of all requested data to the new VLR.
The HLR can refuse location update requests to mobile subscribers who enter areas where they have no access agreements.
Call handling
During call handling, the HLR answers routing data requests from MSCs that interface with external networks and serve as gateway routers (GMSCs). To complete a GMSC routing data request on a mobile terminating call, the following events occur:
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1. The GMSC sends a routing data request to the HLR. This request includes identification information about the called party (MSISDN).
2. The HLR uses the IMSI (correlated to the received MSISDN) to identify the called party and to confirm the availability of the correct bearer service.
3. The HLR checks called party entitlements, call barring (terminating call barring) and unconditional call forwarding.
4. The HLR requests routing information from the VLR where the called party is located.
5. The VLR replies with an Mobile Subscriber Roaming Number (MSRN) identifying the MSC where the user equipment (UE) of the called party is currently attached.
6. The HLR returns the MSRN furnished by the destination VLR to the GMSC.
In case of inter-PLMN roaming, the HLR checks whether the visiting subscriber is allowed in the visited PLMN.
When the subscriber possesses a regional subscription, the HLR may also send a list of authorized zones to the visited VLR, so that roaming permission can be checked by the VLR.
Short message service
The HLR provides the Short Message Service-Service Center (SMS-SC) with message routing addresses and manages message waiting indications. The SMS-SC uses this information to deliver originating or terminating short messages it has stored.
Supplementary services
The HLR manages subscriber data relating to supplementary services. It takes into account modifications set either by the operator or by the subscriber. It transmits the information required to the VLR in which the subscriber is registered. It screens incoming data for possible supplementary service actions and checks that the subscriber is entitled to the services activated.
The HLR is also responsible for testing the compatibility between the miscellaneous services a subscriber activates. For example, it checks forwarded-to numbers for possible call restrictions such as call barring.
Observation
HLR observation counters tally HLR related events. The HLR periodically transmits the observation results to the OMC–CS.
Translation
The HLR contains translation tables which it scans for the rerouting of certain calls according to the signalling information assigned to that call.
The HLR translation is a common service which is invoked by the system during forwarded-to-number registration and interrogation, retrieving information on a remote
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entity, handling call barring/call forwarding/location registration, Operator determined barring check,…
Subscriber management
The HLR can manage all subscriber data (creation, modification, deletion, assignment of supplementary services...). When an operator modifies subscriber data in the HLR, the network notifies the VLR in which the subscriber is currently registered.
Data protection
The HLR:
immediately saves to disk permanent data supplied by the operator,
periodically saves dynamic data generated by the subscriber,
periodically saves location data.
35 AUC SPECIFIC FUNCTIONS
AuC functions include:
data storage,
authentication.
The following paragraphs describe these functions.
Data storage
The AuC stores the following types of information:
an International Mobile Subscriber Identity (IMSI),
versions of applicable algorithms,
authentication keys.
Authentication
The AuC generates the sets of data necessary for ciphering and for the confirmation of subscriber identity.
These sets of authentication data are known as Authentication Vectors (AVs). The AuC generates AVs in the form of triplets for GSM transactions. It generates AVs in the form of quintets for UMTS calls.
The parameter of the quintet are RAND, SRES, CK, IK, AUTN. The first three parameters correspond to the GSM triplet information. The two other parameters are an integrity key and a sequence information.
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If a mobile station is under GSM coverage, the HLR may deduce the triplet needed from the quintet information available.
The AuC supplies five replacement AVs to the HLR each time the HLR sends an AV request.
36 HLR HARDWARE DESCRIPTION
For previous GSM circuit-switched core network releases Alcatel has offered an Alcatel 1422 HLR/AuC built on Alcatel 8330 and 8360 machines. Operators already deploying Alcatel GSM core networks can adapt exiting Alcatel 8330 and Alcatel 8360 platforms to support new release level HLR software.
Note : The Alcatel 8330 platform supports GSM-only HLR functions. The Alcatel 8360 platform supports GSM, UMTS and integrated GSM/UMTS HLR functions.
The Alcatel 1422 HLR/AuC is capable of handling GSM and UMTS networks both in independent and integrated configurations. Alcatel bases the GSM/UMTS HLR on the Alcatel 8360 platform. The Alcatel 8360 platform provides a high level of field-proven security and reliability. It is a multiple application, multibus, multiprocessor system. The following sections describe some of its most important features.
System redundancy
The Alcatel 8360 provides system security through a redundant system architecture.
In redundant system architecture, parallel processing subsystems assure system functions. When one subsystem is operating in active mode, the other is on standby. The latter does not run any traffic, but is ready to move into the active mode if the active subsystem fails.
Each subsystem contains a communication bus, processor boards, memory boards and front end line drivers/adapters. The processor boards support Real Time Operating System (RTOS) management software.
Data Storage
A functional block known as the secondary memory provides HLR/AuC data storage in the Alcatel 8360. The secondary memory consists of disk drives, magnetic tape drives and a streamer. A SCSI bus provides access to the secondary memory for each processing subsystem. Redundant disk drives work in mirror mode to ensure data security.
External OAM interfaces
The Alcatel 8360 communicates with operation and management equipment over one or more external access front ends. The Alcatel 8360 redundant processing subsystems share external access front ends. The front end serves the active sub-system.
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Front ends serve as ports for communication with signalling networks and the management network. Types of connections include:
signalling network connections. Two to four Pulse Code Modulation (PCM) connections support the signalling between the HLR and the SSP. The SSP creates data links to distribute signalling to appropriate destinations.
Telecommunications Management Network (TMN) connections. A duplicated synchronous X.25 link connects the HLR to the OMC-CS.
terminal connections (PCFS, printers). Asynchronous links connect the HLR to operation/maintenance terminals.
Hardware elements
The Alcatel 8360 platform for the CSCN HLR/AuC includes, for each redundant subsystem:
14 processor boards,
one main memory board with a capacity of 1Gb.
Note: A new hardware configuration is introduced with the NSS Release R6E for the HLR A8360, 14UC : the current MG board (with 512 Mo memory) is replaced by a new MG with 1024 Mo. The aim is to support 800 000 MS UMTS mobiles in the HLR product.
More details on boards or racks arrangement are provided in section 3.2.2 (RCP Hardware Architecture) of the present document, as they are ported on the same platform.
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37 HLR SOFTWARE DESCRIPTION
The specific radio-mobile-application softwares (RCP/VLR, HLR/AuC, SCCP gateway) are developed as dedicated upper application layers.
The HLR basic software allows :
to handle real-time and transaction-processing applications in parallel,
to support applications with heavy real-time requirements (achievement of the performance objectives of the telecommunications software and the file-management system is critical),
to support applications performing on-going service
The basic software is an open Real-Time Operating System (RTOS).
More details on RTOS are provided in section 3.2.3 (RCP Software architecture) of the present document, as they are ported on the same platform.
The HLR/AuC’s software architecture is described by the following figure.
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HLT(HLR)
RTDMS
FMS
WAM
SCR
FTAM CMISE
ACT(AuC)
RTDMS
EL AK+TMNK
RTDMS
AES HLM(HLR)
ACM(AuC)
MTP
SCCP
X.25
X.224
TCAP X.225
RTOS Executive
Legend:
ACM: AuC function maintenance ELACT: AuC function processing ELAES : system operation packageCMISE : Common Management Information
RTDMS: Real Time Data Management SystemRTOS: Real Time Operating SystemSCCP: Signalling Connection Control PointSCR: Network Switching ServiceTCAP: Transaction Capabilities Application PartTMNK: Telecommunication Management Network KernelWAM: Workstation Access MethodX.224: transport layer
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Service ElementEL : Software SetEL AK : application kernel software setFMS: File management systemFTAM : File Transfer Access and ManagementHLM : HLR function management ELMTP: Message Transfer Part
X.225: session layerX.25: physical layer.
HLR/AuC software architecture.
The components of the HLR/AuC software architecture are described in the following table:
NAME DESCRIPTION
SOP A83xx machine system operation package.
HLT HLR processing EL. It supports all real time management functions:
functions relating to MAP protocol (terminal call, location registration, subscriber security, retrieval, supplementary services),
static and dynamic data (observation, alarms, defense, translation),
observation result collection for transmission to the OMC-S.
HLM HLR maintenance EL. It supports operation and maintenance tasks relating to:
observation, alarms, defense, subscriber administration, security.
ACT AuC processing EL. It supports all real time management functions:
security (triplet computation),
static and dynamic data (alarms, defence).
ACM AuC maintenance EL. It supports operation and maintenance tasks relating to:
Subscriber security data management,
Subscriber IMSI/Ki combination management,
alarms.
EL AK and Slave TMNK
The EL AK and slave TMNK are the software sets common to all applications based on an A83xx.
RTDMS The RTDMS is a real time data management system.
A set of software modules included in HLT, ACT, SUP and EL AK
WAM Manages workstation access.
FTAM File transfer, access and management.
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CMISE common management information service element, handles file management dialog before transfer
SCR Provides access to X.25 (X.25, X.224, X.225) and signalling (MTP, SCCP, TCAP) network services
FMS File management system
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3838 CSCN SERVICES AND FUNCTIONSCSCN SERVICES AND FUNCTIONS
This chapter describes the main functions of the CSCN. It includes information about:
bearer services,
teleservices,
GSM supplementary services,
non GSM supplementary services,
security functions,
number portability functions,
charging functions,
roaming,
announcements,
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39 BASIC TELECOMMUNICATIONS SERVICES
Basic telecommunications services have the essential role of enabling mobile subscribers to communicate over the network. GSM/UMTS standards divide basic telecommunications services into two categories:
Bearer Services (BS), that provide the capacity to transmit binary signals point-to-point,
Teleservices (TS), that provide complete connection capacities, including terminal equipment definitions, for communications between two or more users.
Operators attribute basic services to a subscriber when creating the subscription for that subscriber.
40 GSM BEARER SERVICES
Operators who deploy CSCNs that include interfaces with GSM Base Station Sub-systems (BSS), must provide GSM Bearer Services (BSs). GSM bearer services depend on transcoders located in GSM BSSs.
CSCN BSs provide GSM subscribers with the capacity to transmit binary data over the circuit-switched mobile network.
When an operator creates a subscription for a user, the operator defines which BSs the subscriber will be able to use. There are two basic categories of BSs:
asynchronous transmission services (BS2x),
synchronous transmission services (BS3x).
GSM operators can provide asynchronous data-transmission services that operate in transparent or non-transparent mode. The following paragraphs explain the differences between these two modes.
transparent mode: the network transmits user data between the terminal and external networks without using a specific data protection protocol over the radio interface. There is no flow control or error checking in the Public Land Mobile Network (PLMN). This provides for constant bit rates, but introduces the possibility of transmission errors.
non-transparent mode: the network uses the Radio Link Protocol (RLP) between the MS and the InterWorking Function (IWF) to assure the transmission. The network places user data in frames which are subjected to flow control and error checking (repetition of frames on transmission failure).
41 ASYNCHRONOUS DATA-TRANSMISSION SERVICES
Asynchronous transmission requires start and stop bits to distinguish individual units of data. ETSI standards group asynchronous data-transmission services under the category BS2x, where the variable x identifies a transmission rate.
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BS User RateUser Rate Information transferInformation transfer capabilitycapability
Quality ofQuality of ServiceService
BS21 0.3 kbit/s 3.1kHz UDI T NT
BS22 1.2 kbit/s 3.1kHz UDI T NT
BS24 2.4 kbit/s 3.1kHz UDI T NT
BS25 4.8 kbit/s 3.1kHz UDI T NT
BS26 9.6 kbit/s 3.1kHz UDI T NT
UDI= Unrestricted Digital Information
T= Transparent / NT= Non Transparent
42 SYNCHRONOUS DATA-TRANSMISSION SERVICES
Synchronous transmission depends on a master clock to co-ordinate the transfer of bits of information between two network nodes. ETSI standards group synchronous data-transmission services under the category BS3x, where the variable x identifies a transmission rate.
Following tables list BS3x services and their corresponding transmission characteristics.
Data circuit duplex synchronous services (BS3x)
BS User RateUser Rate Information transferInformation transfer capabilitycapability
Quality ofQuality of ServiceService
BS31 1.2 kbit/s UDI T
BS32 2.4 kbit/s UDI T
BS33 4.8 kbit/s UDI T
BS34 9.6 kbit/s UDI T
Data circuit duplex synchronous services (BS3x) audio
BS User RateUser Rate Information transferInformation transfer capabilitycapability
Quality ofQuality of ServiceService
BS31 1.2 kbit/s 3.1kHz T NT
BS32 2.4 kbit/s 3.1kHz T NT
BS33 4.8 kbit/s 3.1kHz T NT
BS34 9.6 kbit/s 3.1kHz T NT
Data circuit duplex synchronous services (BS3x), with X.31 Flag stuffing
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BS User RateUser Rate InformationInformation transfertransfer
capabilitycapability
Quality ofQuality of ServiceService
Layer 1Layer 1 protocol userprotocol user informationinformation
BS32 2.4 kbit/s UDI NT X.31 Flag stuffing
BS33 4.8 kbit/s UDI NT X.31 Flag stuffing
BS34 9.6 kbit/s UDI NT X.31 Flag stuffing
43 FUNCTIONS ASSOCIATED WITH CIRCUIT-SWITCHED BEARER SERVICES
Some functions accompany the circuit-switched data transmission services:
data compression,
automatic modem selection.
V.42bis data compression
The data compression function compresses the data on the radio channel when asynchronous circuit-switched data transmission is used. This increases the data signalling rate available to a mobile subscriber depending on the type of data transported (user rates available from 4.8 to 9.6 kbit/s). It is implemented with:
data compression on the fixed network, and/or,
a higher bit rate between the IWF (interworking function) and the remote subscriber.
Data compression on the fixed network side is applicable only in 3.1 kHz audio mode. The V.42 protocol must be implemented and the IWF negotiates V.42bis data compression with the remote modem.
The maximum bit rate between the IWF and the remote subscriber is reached:
In 3.1 kHz audio mode by a modem with a bit rate higher than 9.6 kbit/s (up to 28.8 kbit/s) with implementation at the remote modem end of:
automatic modem type selection (autobauding),
data compression.
In UDI (unrestricted digital information) mode at a rate of 19.2 kbit/s and an intermediate rate of 32 kbit/s towards the remote end.
Automatic selection of modem type (modulation type) and speed
This function involves negotiating the modem type. When the modem has been chosen, the two DCEs choose their transmission speed. This function makes it possible to offer high user rate data transmission on the PSTN between the IWF and the remote modem.
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44 GSM TELESERVICES
Operators who deploy the CSCN in configurations that include interfaces with GSM BSSs, must provide GSM teleservices. GSM teleservices depend on transcoders located in GSM BSSs. These teleservices function independently of the transcoders located in the CSCN MSC.
GSM teleservices include:
speech (TS11),
emergency calls (TS12),
Short Message Service-Mobile Terminated (SMS-MT) point-to-point (TS21),
Short Message Service-Mobile Originated (SMS-MO) point-to-point (TS22),
alternate speech and facsimile (TS61),
automatic facsimile service (TS62).
The following paragraphs describe GSM teleservices functioning through GSM BSS located transcoders:
Speech (TS11)
The speech teleservice (TS11) enables the transmission of voice over the network for telephone conversations. It enables subscribers to:
converse in full duplex (bi-directional) mode,
converse in real time.
Operators can optionally activate one of the following two functions to improve GSM speech quality:
Enhanced Full Rate (EFR),
The EFR function improves speech quality in the conversation phase by using more powerful codecs (coders/decoders). The EFR voice transfer rate over the radio interface is static at 13 kbits/s.
Adaptive Multi Rate (AMR)
The AMR function provides better speech quality by adapting its operating rate according to radio conditions. AMR offers three different operation modes:
- Full Rate (FR) only, offers improved speech quality,
- Half Rate (HR) only, offers enhanced network capacity,
- combined HR and FR, offers a compromise between speech quality and network capacity.
In GSM networks, the AMR codec is located in the transcoder in the BSS.
Emergency calls (TS12)
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Emergency service (TS12) enables all mobile subscribers to contact an emergency service, regardless of the call restriction the operator may have applied to their subscriptions. Subscribers roaming in different countries have access to the emergency services of the countries in which they are located.
SMS-Mobile Terminated (TS21)
The TS21 service is a two-way point-to-point mode short message service. It provides for acknowledgements upon receipt of messages. The network provides this service for messages terminating at the mobile subscriber. Messages may originate from:
- a fixed network subscriber,
- another mobile network subscriber.
This service can operate in store-and-forward mode by using the Short Message Service-Service Center (SMS-SC) as a temporary storage server between the sender of the short message and the receiving subscriber.
SMS-Mobile Originated (TS22)
The mobile originated point-to-point short message service (TS22) service is a point-to-point mode short message service for two-way messaging with acknowledgements. It provides for acknowledgements upon receipt of messages. With this service, a mobile subscriber can send short alphanumeric messages to subscribers of mobile or fixed networks.
Alternate speech / facsimile service (TS61)
The alternate speech and facsimile service (TS61) service enables subscribers to send group 3 (9.6 kbit/s) faxes. Subscribers use this service to initiate fax transmission manually during an established speech service call, or to change from a fax communication towards a speech call, during fax transmission.
Automatic facsimile service (TS62)
The automatic facsimile service (TS62) service enables subscribers to send group 3 (9.6 kbit/s) faxes. Fax transmission with this service is automatic, requiring no subscriber intervention. This service enables only the sending and reception of automatic fax calls. It does not allow transition to speech mode.
45 SUPPLEMENTARY SERVICES
46 GSM SUPPLEMENTARY SERVICES
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Supplementary services modify or enhance basic telecommunications services. Operators offer supplementary services in association with specific teleservices and bearer services. Supplementary services are not offered as stand-alone services. An operator can associate the same supplementary service to more than one basic service group.
The following table lists the supplementary services available for the CSCN.
Supplementary Services GSMGSM acronymacronym
Service descriptionService description
Call Forwarding Services
Call Forwarding CF redirects incoming calls to a predetermined number
Call Forwarding Unconditional CFU redirects all calls to a predetermined number.
Call Forwarding on No Reply from mobile subscriber
CFNRy redirects incoming calls to a predetermined number when the subscriber does not reply.
Call Forwarding on mobile subscriber Not Reachable
CFNRc redirects incoming call to a predetermined number when the subscriber is not reachable.
Call Forwarding on Busy mobile subscriber
CFB redirects incoming call to a predetermined number when the subscriber already occupied with a call.
Pre-Call Deflection PCD redirects an incoming call before the connection is set up to the predetermined number used for the call busy condition.
Default Call Forwarding CFD redirects an incoming call to a predetermined number when the other call forwarding services are not activated.
Call Barring Services
Call Barring CB blocks incoming or outgoing calls with operator or subscriber control options.
Barring of All Outgoing Calls (except to emergency numbers)
BAOC blocks all outgoing calls except calls to emergency numbers
Barring of Outgoing International Calls
BOIC blocks all outgoing international calls
Barring of Outgoing International calls except those directed to the
BOIC-exHC blocks outgoing international calls when the subscriber is not calling the
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Supplementary Services GSMGSM acronymacronym
Service descriptionService description
home PLMN country home PLMN country
Barring of All Incoming Calls BAIC blocks all incoming calls
Barring of all Incoming Calls when roaming outside the home PLMN country
BIC-Roam blocks all incoming calls when the sub scriber is roaming outside the home PLMN country
Call Identification Services
Connected Line Identification Presentation
COLP enables the subscriber making an outgoing call to display the line identification of the called device.
Connected Line Identification Restriction
COLR enables the subscriber to withhold the line identification from a calling party provisioned with the COLP service
Calling Line Identification Presentation
CLIP enables a subscriber to display the number of the calling party
Calling Line Identification Restriction
CLIR enables the subscriber to prevent the transmission of their line identification to a subscriber provisioned with the CLIP service
Malicious Call Identification MCI enables a subscriber to obtain information from an operator concerning the origin of a call
Call Completion Services
call HOLD HOLD enables a subscriber to take a second call while retaining the first call, and to resume the first call if necessary
Call Waiting CW sends notification of a waiting call to a subscriber with an active call.
Explicit Call Transfer ECT enables a subscriber to create a double call, after placing the first call on hold, connecting the two parties, then withdrawing from the call.
Multiparty Services
MultiParTY call MPTY enables call setup between up to six subscribers.
Closed User Group CUG restricts communication access to a defined group of users.
Charging Services
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Supplementary Services GSMGSM acronymacronym
Service descriptionService description
Advice Of Charge-Information AOCI enables a subscriber to estimate the cost of a call based on information displayed on the MS (no contractual value).
Advice Of Charge-Charging AOCC displays the cost of a call on the MS at the end of a call.
Operator Services
Operator Specific Supplementary Services
OSSS enables operators to provide other supplementary services that are specific to that operator
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47 IN SERVICES
Intelligent Network (IN) is a telecommunications architecture that enables operators to flexibly introduce new functions and services that are specific to their PLMN.
IN does not define a specific set of services, but rather a framework for creating and supplying services. IN services can vary from one network operator to another.
Examples of common IN services include:
- Pre-Paid Service (PPS)
- Virtual Private Network (VPN)
- charging and filtering for Short Message Service-Mobile Originated (SMS-MO).
Network operators use INs to create special categories of supplementary services known as Operator Specific Supplementary Services (OSSSs). OSSSs are proprietary services that allow operators to offer a wider range of services by creating services that are specific to their network.
48 CAMEL SERVICES
Customized Application for Mobile network Enhanced Logic (CAMEL) is an IN access technology developed specifically for mobile networks. CAMEL is an enhancement of IN services.
Network operators use CAMEL services to provide subscribers with access to OSSSs outside and inside the operator’s PLMN. Operators, therefore, can deliver personalized services to a subscriber in a consistent way even when the subscriber is roaming in a foreign network.
The table here-under lists the CAMEL functions that provide such services.
Service DescriptionDescription
CAMEL Phase 1 CAMEL phase 1 provides the mobile subscriber with access to specific services provided by his own network operator even when roaming in a foreign PLMN.
This applies to the following call types:
- originating calls (OC),
- terminating calls (TC),
- calls forwarded in the GMSC,
- calls forwarded in the VMSC.
CAMEL Phase 2 CAMEL phase 2 is an enhancement of CAMEL phase 1. It offers the CAMEL phase 1 functions plus additional functions concerning:
- call handling,
- standalone IP in assisting mode which offers
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Service DescriptionDescription
announcements and DTMF interchanges whether the subscriber is located in his home PLMN or is roaming in a foreign PLMN,
- charging.
CAMEL phase 2 services can be invoked on certain preset criteria (example: number, call type, basic services, etc).redirects all calls to a predetermined number.
USSD extension
Information is transmitted between the MS and the SCP using USSD (unstructured supplementary service data) mechanisms even if a call is in progress. The USSD extension allows the interchange of character strings in within message.
USSD operations take place:
- between the MS and the SCP, via the HLR,
- between the SCP and MS, via the HLR.
49 NON-GSM SUPPLEMENTARY SERVICES
50 BARRING OF CALL FORWARDING TO AN INTERNATIONAL NUMBER
Barring of call forwarding to a particular international destination allows the operator to prevent some types of mobile subscriber from forwarding their calls to a foreign country.
51 CALL FORWARDING ABBREVIATED NUMBER TRANSLATION
The facility for translating call forwarding abbreviated numbers into full numbers allows the subscriber to enter forwarded-to numbers using a list of abbreviated numbers.
52 FILTERING OF FORWARDED-TO NUMBERS TO SPECIAL SERVICES
Filtering of forwarded-to numbers is used to bar call forwarding to specific numbers, such as emergency services numbers (emergency call).
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53 ADDITIONAL CALL FORWARDING AUTHORIZED TO VOICE MAIL
Authorizing additional call forwarding to a voice mail service allows a call to be completed if the first forwarding operation fails.
54 SEPARATE ACCOUNT MANAGEMENT
The separate account management service allows a subscriber’s calls to be billed to different accounts. It is based on the use of a call prefix which is stored in the CDR.
55 AUTOMATIC IMSI CHANGE
The automatic IMSI (international mobile subscriber identity) change service allows a new SIM card to be assigned to a subscriber without changing the MSISDN directory number. The assignment is changed when the card is used for the first time.
56 SECURITY FUNCTIONS
The Alcatel CSCN fully complies to the European Telecommunication Standards Institute (ETSI) GSM security standards. The GSM CSCN provides mechanisms that protect the mobile network from unauthorized call attempts or intrusion into a conversation by third parties. These mechanisms are used to authenticate the mobile calling and/or called party and to cipher all information (speech, data, signalling) from the radio interface using a ciphering key which is changed for each call.
57 CONFIDENTIALITY OF SUBSCRIBER IDENTITY
Each mobile subscriber owns a unique identity number called the International Mobile Subscriber Identity (IMSI). With the exception of first time registration and some paging situations, network elements do not send the IMSI over the air interface. Instead, these network elements use a Temporary Mobile Subscriber Identity (TMSI).
The VLR creates TMSIs which it transmits to the MS in encrypted form. The MS and the CSCN use TMSIs for authentication and identification purposes, in place of the IMSI.
58 AUTHENTICATION OF SUBSCRIBERS AND NETWORKS
Each time a subscriber attempts to access the network, the network performs security procedures to positively identify and authenticate the subscriber.
When an operator adds a new subscription to a GSM network, the operator assigns an International Mobile Subscriber Identity (IMSI) and a permanent secret individual authentication key, Ki, to the subscriber. The AuC and the MS both store a copy of the IMSI and the Ki. During authentication, the subscriber and the network prove that they both have knowledge of this confidential information.
Authentication occurs in two phases:
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Phase 1– The AuC supplies a set of authentication data to the VLR.
An individual set of authentication data is known as an Authentication Vector (AV). The GSM AuC produces and stores AVs in the form of triplets.
The GSM AV triplet is 36 bytes long. It contains the following three elements:
RAND = RANDom number,
SRES = Signed RESponse,
KC = ciphering Key.
The AuC generates AVs in sets of five triplets for each subscriber. The triplets are stored in the HLR and sent to the VLR on request. Each triplet is used only once. Its status then changes to “invalid”, meaning that it can only be reused if there is a shortage of triplets (for example, if the HLR becomes inaccessible).
When a VLR has only one remaining AV for a subscriber, the VLR requests up to five new AVs from the HLR. The HLR responds by sending the number of requested AVs, and then requests replacement AVs from the AuC. This way, the HLR always has AVs available for each subscriber, ensuring a rapid response to VLR requests.
Phase 2– The network runs an authentication exchange between the VLR and the subscriber:
1. The VLR selects the next available AV from its stored sets, and sends the RAND to the MS of the subscriber.
2. The MS calculates a unique SRES response based on the RAND received and the subscriber’s Ki key. The MS sends the SRES to the VLR.
3. The VLR authenticates the MS by comparing the stored SRES in the VLR (supplied by the AuC) with the SRES received from the MS. If there is a match, authentication is complete. The VLR then transmits the Kc value to the BSS for ciphering and integrity protection operations.
59 CIPHERING
User data and network signalling information that pass over the air interface between the MS and the BSS require protection procedures. Ciphering is a way to make this information unreadable to intruders.
The MSC tells the BSS whether or not ciphering is required for the MS connection.
If ciphering is required, the MSC sends the ciphering key (Kc) to the BSC and the BTS. The MS and the BSS(that is, each end of the radio link), have the same Kc.
The BTS uses this information to activate the encryption process. This procedure takes place during call set-up. The MSC selects an encryption algorithms that is supported by the MS and the BSS.
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60 MOBILE NUMBER PORTABILITY FUNCTION (MNP)
The MNP function allows a mobile subscriber to subscribe to another PLMN, in the same country while retaining the same telephone number(MSISDN).A new IMSI belonging to the new network is assigned to the mobile subscriber.
Operators can use this function to divert calls or messages to the mobile subscriber’s new network to which the MSISDN number has been ported.
The SRF network architecture based on an SCCP relay entity, supports the MNP function.
Depending on the country’s numbering plan, the flexible NDC (national destination code) support function may be necessary to store numbers assigned by other operators in the HLR.
Flexible NDC support This function extends the number of digits in the MSISDN part registered for each subscriber. The NDC part of the MSISDN which was previously common to all subscribers registered in the HLR becomes subscriber level information.
61 CHARGING FUNCTION
The charging function creates CDRs for the storage of RCP call-related information.
CDRs can also be sent for:
- hot billing,
- intermediate billing,
- on-the-fly billing.
62 HOT BILLING
Hot billing allows the operator to:
collect CDRs (call data records) from subscribers who have subscribed to the HB (Hot Billing) category,
deliver CDRs to the billing center within five minutes.
Operators apply this service is to subscribers renting a mobile station or a SIM card. It is available to up to 20% of an operator’s subscribers.
63 INTERMEDIATE BILLING
For calls exceeding an initial, preset value, CDRs are sent periodically once the initial value has been reached. Intermediate CDRs allow the operator to protect the billing.
Intermediate CDRs contain the same information as standard CDRs, plus the following specific information:
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duration of the call,
time at which conversation began,
intermediate CDR indicator,
intermediate CDR number.
64 ROAMING
65 LOCATION REGISTRATION (LR)
The location registration service provides service continuity for an MS throughout the GSM coverage area. The function enables:
a fixed or mobile subscriber to contact an MS using a directory number, whatever the MS’s location,
an MS to access the GSM network whatever its location,
an MS to be informed of a change of location area.
The intra/inter PLMN roaming function allows information interchanges between HPLMN and VPLMN during roaming.
66 ROAMING RESTRICTION
Operator use roaming restriction to limit subscribers’ PLMN access.
For example, roaming restriction may limit a subscriber’s access to:
access to the HPLMN only,
access to a national PLMN and any foreign PLMN,
access to a PLMN on a predefined list.
67 REGIONAL SUBSCRIPTION
Operator use the regional subscription function to restrict MS services to one or more location areas.
68 ANNOUNCEMENTS
The transmission of announcements applies to calls that are not digital data calls.
On making a call attempt, a mobile or fixed subscriber can receive different types of announcement as listed here after..
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Greeting announcements
Greeting announcements are reserved for some called numbers and are sent to the caller before the call is connected. They are subject to a time-delay during call set-up and before charging.
Example: emergency call numbers (security services).
Information announcements
Information announcements are reserved for certain called numbers and are sent to the caller on connecting the call.
Example: weather service.
Waiting announcements
Waiting announcements are used to encourage the caller to wait for the call to be connected.
Example: notification of call hold, notification of call waiting, notification of paging procedure, etc..
Failure announcements
Failure announcements are connected to the caller if the call cannot be connected.
Example: network congestion.
Call waiting announcement
The call waiting announcement service notifies the caller that the call is queued and waiting to be answered.
Call hold announcement
The call hold announcement service notifies a mobile or fixed subscriber that his call has been placed on hold.
Announcement on call set-up time
Announcement of a call set-up time greater than X seconds is connected in the VMSC to notify the caller when the set-up time exceeds a configurable threshold.
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6969 CSCN OPERATION AND MAINTENANCECSCN OPERATION AND MAINTENANCE
This chapter describes:
operation and maintenance architecture,
operation and maintenance features,
operation and maintenance tasks,
operation and maintenance documentation.
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70 OPERATION AND MAINTENANCE IN NSS
The Alcatel PLMN network's Operation and Maintenance is centralized in an entity called OMC-NSS. The OMC-NSS ensures direct supervision of the Alcatel 900 NSS entities : RCP, HLR, SSP, SCCP gateway and the OMC-NSS itself.
The OMC-NSS is based on Alcatel 1300 TMN platform.
The OMC-NSS also provides an external interface based on ITU-T Q3 protocols stack.
Operation and maintenance system within Alcatel 900 provides facilities to allow the PLMN to be operated and maintained efficiently according to the specific needs of the operator of the network. It provides services :
for efficient execution of the daily operational tasks (e.g. collection of charging data, introduction of new subscribers),
to achieve a sufficient utilization and an appropriate balance of the load in all network elements while keeping up the required quality of service to the subscriber,
to support the network operator in planning the network evolution and in restructuring of the whole network (e.g. by adding network elements),
to support efficient maintenance activities.
Access to the O&M system of Alcatel 900 is available at the location of the network elements and at a dedicated central entity, the OMC-NSS. Vital functions are integrated in the network elements in order to allow operation and maintenance activities on site even in the case of absence of OMC-NSS.
71 ON-LINE BACKUP/RESTORE WITH FRONT-END PC THROUGH ETHERNET
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The backup-restore application is used to:
back up the content of one or more of the NE’s physical disks to the PCFS,
restore the backup files from the PCFS to the NE.
Backups are always carried out on an NE when on-line while data is restored to an NE when off-line.
The PCFS is a site front-end PC. Operators use the PCFS for local operation and maintenance. There is one PCFS for each NE and each OSNM.
The PCFS connect to the HLR, RCP and SSP. It reduces the number of local terminals necessary for management. It uses the operator interfaces of the NE applications.
This terminal hosts all the applications for a given NE:
OMPC for operation,
local backup-restore (HLR and RCP only),
exception procedure downloading (HLR, RCP and SSP),
MSO for remote operation, (option)
SSH for the HLR protection function (option)
72 GENERIC OMC FEATURES
GRAPHICAL VIEW AND NAVIGATION
Common network maps and submaps, organised hierarchically, enable operators to navigate from the maps to the management applications. Symbols on the maps are animated by alarms, propagated to upper views, so that operators can navigate from the map to the current or historical alarm list corresponding to the selected object or to the dedicated Element Manager, thus accessing the management functions.
Graphical views available:
network maps and submaps with animated symbols
alarm animated equipment views
contextual navigation to the management applications
animated symbols with propagation to upper views
FAULT MANAGEMENT
The main functions of fault management are:
Alarm management, with a common X733 alarm format
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Trouble ticketing (option)
Event log management
The fault management function enables continuous monitoring and detection of alarms in the network. Operators can take pro-active maintenance action using test actions, and react quickly to network faults. As an option, operators can also use trouble ticketing to follow up alarm handling.
The OMC receives fault/alarm events coming from the nodes, sets up the fault events to the standard X.733 format and stores for alarm management (such as acknowledgement, clearing state, reservation state, etc…)
Operators are shown alarms by alarm lists, stored in two databases: one for the current alarms and one for historical alarms (those alarms that the operator has acknowledged and cleared).
Current alarm counters present a synthesis of alarm information to the operator. Alarm counters can be defined according to user-defined criteria.
Current Alarm Counter Summary
Some alarm lists are predefined in the OMC, such as a list of all alarms with major severity.
The fault management function also enables operators to define their own alarm lists, based on filters. They can also display contextual alarm lists, depending on the object selected.
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An example of current alarm list window
Alcatel proposes an external open interface based on the X.733 standard for real-time alarm forwarding, with synchronization capability, for network supervision from an external OSS. A similar real-time interface is proposed for maintaining the NE directory, notifying NE creation, deletion and state change.
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TROUBLE TICKETING
Trouble Ticketing is achieved in the OMC-CS thanks to the ARS (Action Request Service) product . ARS is a software that tracks actions that have been done to solve a problem. Once the problem is over, theses traces become a meaningful knowledge base, possibly of reference of good reactions in case of new problem similar to stored one. The aim is to keep in memory the previous actions that solved a problem.
CONFIGURATION MANAGEMENT
The main functions of configuration management are:
Performance of commands in assisted console mode
Scripting capability, with calendar option
Graphical HMI
A powerful object-oriented scripting language allows operators to write or customize command scripts as they need. It is possible to program the automatic launching of command scripts in the calendar.
For equipment management, a hierarchy of alarm-animated equipment views enable operators to navigate inside the hardware of the Network Element, as well as perform operations on the hardware elements.
PERFORMANCE MANAGEMENT
The main functions of performance management are:
Counter-based supervision and monitoring
Performance analysis
The Element Managers provide operators with the ability to supervise and monitor the network performance. This enables them to make an analysis of the performance data, with regard to both data traffic and QoS.
The OMC provides:
Periodic or on-demand counter collection
An open database for the collected counters
Real-time graphical display of counters
Key summary value synthesis
Report generation
QoS supervision, by alarm generation on configurable counter threshold crossing
SECURITY MANAGEMENT
The main functions of security management are:
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Authentication management by Unix login and password
Operator and terminal profile management
Authorization according to the profiles
Command logging
Logging of attempted logins and logouts
Operator access security, profiling and network partitioning are provided using the generic Security Management (SEC) component provided by the ALMAP platform of the OMC.
The SEC component focuses on the security aspects of the system, covering OMC operator access: access to management functions and access to network resources.
The goals of the A1300 NMC security function are to protect the Operation System against the threats of masquerading (in other words, OS penetration using another user’s identity), and unauthorized access to the OS functions and network resources.
Access security functions are implemented at management platform level. They are based on the concept of NAD (Network Access Domain) and FAD (Function Access Domains), which combinations build the access profiles that can be associated to operators. Users can perform various actions and access data or equipment, but at varying degrees, depending on the level of access rights.
Login attempts are recorded in a security log. Repetitive attempts to log on with a non-existent user ID or a wrong password are logged. The security record indicates the user ID, the terminal and the login date.
EVENT AND LOG MANAGEMENT
The application provides a convenient user interface for managing event distribution and logging, ensuring that management notifications arrive where needed and are properly archived in logs. As for alarm management, an operator can define filters for visualizing only the events that interests him.
It is based on the ITU-T X.734 Event Management Function and X.735 Log Control Function.
MACRO-COMMANDS AND CALENDAR MANAGEMENT
With the help of a Macro-language (Java Script), the operator can customise his environment by creating new commands, more powerful than the simple MMC’s.
These macro-commands are analysed by the NMC that then executes the corresponding sequence of MMC's and controls them.
The main possibilities of the Macro-language are:
The insertion of man-machine commands specific to the NE's,
Conditional loops,
Testing of macro-commands: a macro-command can make a call to another one and pass parameters to it,
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Variables internal to macro-commands,
Access to the report following the execution of the last command; the rest of the macro-command might depend on it,
Access to the answer to the last command (to make use of it manually),
Debugging tools before operational use,
Time scheduling parameters: time scheduling parameters can be filled to specify when a command should be processed.
A library of standard functions is provided. It offers services such as searching of a string of characters, reading of the time, etc...
Once written, the macro-commands can be saved for later use. In addition, a text editor facilitates their writing.
Each of these macro-commands can address one or several NE’s : they cater for pretty complex operations on the network. Amongst other is the sending of massive commands towards the NE. An example is the creation of many similar subscribers on a given NE. This also may help in network-wide actions on the traffic when several and consistent commands have to be sent to several NE's in parallel in as short a time as possible.
A calendar facility is supported, allowing commands to be launched at a pre-defined rhythm, starting at a moment in time. Hence commands can be started at a given point in time, or repeated periodically during a specified time span.
ON-LINE HELP AND DOCUMENTATION
On-line help is provided for the different applications.
For alarms, on-line-help is contextual, showing the description and associated repair processes for the selected alarm.
On-line documentation is also available from the OMC.
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73 OPERATION AND MAINTENANCE TASKS
74 OPERATION TASKS
Customer care tasks
Mobile subscriber data management
Subscriber data security management
Technical operation tasks
At the level of the managed network:
- Signaling management (including SS N 7),
- Translation management,
- Circuit group and circuit management,
- Radio environment management,
- Roaming management,
- SMIM management.
At NE level:
- Access management,
- Observation management,
- Charging management,
- Operator system parameters management,
- Unsolicited message management,
- Log management,
- Command management.
At management network level:
- Topology management,
- X.25 link management.
75 MAINTENANCE TASKS
Maintenance tasks at NE level
Controlled switchover for preventive maintenance of the NE,
Running LOCAVAR tests,
System state management,
Station observation,
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Alarms interface,
Disk backup and restore,
PMD (post mortem dump) management,
Anomaly management.
Maintenance tasks at management network level
Alarms management (NE supervised by the OMC-S),
Controlled switchover for preventive maintenance of the NE,
Running LOCAVAR tests,
System state management,
Station observation.
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76 NSS O&M DOCUMENTATION
The Operation and Maintenance documentation includes three levels of documentation:
the descriptive documentation,
the O&M documentation,
the reference and troubleshooting documentation.
Descriptive documentation:
Documentation guide
To explain the structure and content of the customer document collection, giving the principles and tools for browsing through the documentation.
System guide
To give general technical information on a system, for a given version, and the component subsystems so that the reader can:
- learn the technical characteristics and key concepts,
- understand how the system is used in an operational context,
- understand how the system’s main components inter–relate.
Introduction to operation and maintenance
To give information on the organization, functions and tools of operation and maintenance, the tasks performed by the operator.
General description
To give general technical information on a subcomponent of the system for a given release.
Examples: “HLR/AuC general description”, “RCP general description”.
Catalog
To list the documents to be used in a clearly defined context.
Standard utilization sheet
Briefly to describe the actions the operator can consider in the context of a given function.
Examples: “Subscriber operation and security”, “Access administration”,...
Operator guide
To give general information on the various operation/maintenance functions.
Examples: “Subscriber and user line management”, “Translation Management”, “Observation Managemen”t.
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O&M documentation:
User manual
To give technical information on the system’s subcomponents.
Examples: “WAM–PC, installation manual”, “Screen mode terminal, user manual”.
Operating/maintenance sheet (FEX)
To describe one or more processes that are sequences of basic actions.
Examples: Traffic distribution laws, Access administration, installing a local WAM terminal.
Operator sheet (FOP)
To describe the basic actions in a precise parameter usage context, with the syntactical reference of the operator commands.
Reference and troubleshooting documentation
Symbol dictionary
This is a dictionary of all the abbreviations used as parameters in man-machine commands.
MMC malfunction report message dictionary
This dictionary explains all the error messages that the system can issue when a man-machine command is not accepted. The messages are ordered per message number.
Spontaneous message dictionary
A spontaneous message is issued by the system when a warning must be given to the operator, in case of any anomaly. Besides a message explanation, the dictionary gives the operator the action to be undertaken. The messages are ordered per message number.
Alarm message dictionary
Each alarm message has an entry in this dictionary, with an explanation and the action to be undertaken. The alarm messages are ordered per message number.
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77 OPERATION AND MAINTENANCE ARCHITECTURES
To ensure that the operator of a PLMN can operate and maintain his network efficiently, Alcatel provides a centralized Operation and Maintenance Centre (OMC) based on applicable standards specified by the OSI, the ITU-T and the GSM.
That OMC is structured in two building blocks::
the OMC-S which controls the network subsystem (NSS),
the OMC-R which controls the base station subsystem (BSS).
These OMCs have workstations and X terminals.
In small capacity networks, a X terminal can be shared by two OMCs by being connected to a workstation at each of the OMCs (dotted lines in the figure above). From this terminal, both the OMC-S and the OMC-R applications can be accessed via an Ethernet bus.
78 CENTRALIZED OPERATION AND MAINTENANCE
Centralized operation and maintenance provides an overview of the network. It is carried out from a single site via the OMC-S.
Centralized operation and maintenance is conducted from:
an OSNM (network management system) to which are connected WAM terminals, an assistance console or a PCFS (site front end PC),
an OSWS (network management workstation) to which are connected X terminals and a printer.
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7979 CSCN DEFENSECSCN DEFENSE
This chapter describes CSCN features which provide network defense.
This chapter includes:
an overview of CSCN defense,
descriptions of Network Element (NE) level defense functions,
descriptions of network level defense functions.
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80 CSCN DEFENSE OVERVIEW
The CSCN assures system protection and service availability by applying the following principles:
systematic redundancy of hardware and software units forming the:
Service Switching Point (SSP),
Radio Control Point (RCP),
Home Location Register/Authentication Center (HLR/AuC),
Signaling Connection Control Point (SCCP) gateway and relay,
Signaling Transfer Point (STP),
Call Detail Record (CDR) collector,
Standalone Mobile Interworking Module (SMIM).
organization of an automatic defense system for:
detecting hardware and software defects,
isolating defective elements,
reconfiguring Alcatel 83xx elements to maintain traffic handling.
The individual components of the CSCN can assure their own defense by executing dependability mechanisms. A CSCN element can:
detect its own failures,
withdraw from the system,
warn central defense functions so that they can reconfigure the system or switch over to a standby unit.
81 NETWORK ELEMENT LEVEL DEFENSE
82 ALCATEL 83XX NE DEFENSE
The Alcatel 83xx platform offers a set of highly reliable defense features to CSCN elements.
The Alcatel 83xx platform provides:
redundancy and duplication of hardware and software units,
hardware and software reconfiguration,
use of mirror disks,
protection mechanisms at all system levels.
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Duplex configuration
Alcatel 83xx NEs in the CSCN operate in duplex mode, with an architecture featuring two parallel processing subsystems. When one subsystem is operating in active mode, the other is on standby. In the event of a hardware or software failure on the active subsystem, switchover to the standby system re-establishes NE operation without data loss or traffic interruption.
In the event of a hardware or software failure in an active processing subsystem, the system initiates in the following sequence:
switchover from the active subsystem to the standby subsystem,
restart of the active subsystem, by one of two means:
- a fast restart attempt of the active subsystem following an unsuccessful attempt to switch over to the standby subsystem,
- a slow restart attempt of after an unsuccessful fast restart attempt.
Electrical power supply duplication
Two - 48 V redundant sources provide electrical power to the Alcatel 83xx rack.
Converters supplying electrical power to subracks are also duplicated.
Mirror disks
The two Alcatel 83xx station processing subsystems have simultaneous read and write access to two mirror disks. They provide a permanent backup of all files and databases. The mirror disk principle not only protects data but also provides dual accessibility to data.
83 SSP DEFENSE
The principles of SSP defense are:
redundancy of the system components,
automatic fault detection,
limitation of failure damage,
automatic reconfiguration of resources.
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84 NETWORK LEVEL DEFENSE
This section describes network level defense and, more particularly:
CSCN reconfiguration in the event of a failure,
blocking of circuits and circuit groups,
CSCN defense against traffic overloads,
VLR and HLR restore,
RCP supervision of the SSP and HLR.
85 RECONFIGURATION IN THE EVENT OF A FAILURE
HLR protection
The HLR provides defense mechanisms:
at the network element level,
at the network level, when connected to an HLR Security Server (SSH).
If an HLR is connected to an SSH, the SSH periodically backs up the active HLR to a standby HLR. In the event of an HLR failure, the operator can use the SSH to switch over to the standby HLR.
Secured links
The CSCN protects most links connecting network physical entities. Protected links include links between:
NEs and the OMC,
OMC and external management centers.
Links operate in active/standby mode or on a load sharing basis. In the event of a failure, switchover is automatic.
Security profiles
The operator assigns security profiles to the various data streams collected in the network. Operators base profiles on the importance and relative obsolescence of the data. To safeguard against momentary communication outages, the network provides a minimum level of protection to all profile levels.
86 BLOCKING OF CIRCUITS AND CIRCUIT GROUPS
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The MSC needs to be informed of any terrestrial circuits of the GSMBSS that are out of service. This is performed using a blocking/unblocking procedure from the BSC to control the state of a single circuit between the MSC and the BSC.
The following events can require the blocking of a circuit or circuit group:
a particular operation and maintenance procedure,
equipment failure,
radio resource inaccessibility.
The MSC controls all circuits between BSCs and MSC/VLRs. It also controls circuits to the SMIM for handling data transfer.
The MSC blocks circuits when it receives a blocking message for a circuit or circuit group from the BSC via the A interface. When the reason for blocking a circuit or a circuit group disappears, the MSC receives an unblocking message.
87 CSCN DEFENSE AGAINST TRAFFIC OVERLOADS
Certain CSCN network elements measure and react to varying network traffic conditions. One of the roles of these elements is to protect the network from traffic overloads.
Traffic overload detection levels
RCP – BSC: An RCP can reduce traffic between the MSC and the BSC upon receiving an overload message from the BSC.
SSP: The SSP shares the traffic load among different circuit groups.
RCP: The RCP manages processor load and compares it to different traffic regulation thresholds. It progressively disables low priority functions according to the threshold reached.
HLR: The HLR manages processor load and compares it to traffic regulation thresholds. It progressively disables low priority functions according to the threshold reached.
Network: The RCP limits the flow of originating calls to avoid presenting the network with more calls than it can handle.
88 VLR AND HLR RESTORATION
On a restart following a failure, the HLR first reloads subscriber data. With the exception of location data and supplementary services data (which is not backed up in real time by the HLR), this data remains valid.
When a VLR restarts after a failure, it deletes all International Mobile Subscriber Identity (IMSI) records.
After a VLR and HLR failure, the network must carry out data restoration procedures.
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These procedures guarantee that there are no discrepancies between subscriber data in the VLR and in the HLR. In particular, the network must update current subscriber location and supplementary services data in both databases.
Restoration procedures are based mainly on radio contact and require indicators.
VLR supplied restoration indicators for each IMSI record are:
confirmation by radio contact: indicates that the location area and MSC number registered in the VLR have been confirmed by radio contact,
subscriber data confirmation by HLR: indicates whether MS-related subscriber data in the VLR is consistent with the data in the HLR.
location information confirmation by HLR: indicates that VLR and MSC number records have been confirmed by radio contact,
supplementary service verification (optional): indicates that a supplementary services parameter verification request must be sent to the MS.
To avoid executing a restoration procedure after an active/standby processing sub-system switchover, the network must keep location data up-to-date in the standby subsystem. The network requires a standby subsystem update before it can ac-knowledge an update.
89 RCP MONITORING OF THE SSP AND HLR
RCP monitoring of the SSP
The RCP periodically sends messages to the SSP. If the SSP fails to return the expected response, the RCP generates an alarm. When the RCP receives a correct response from the SSP, it generates an “end of alarm” message.
RCP monitoring of the HLR
The RCP monitors the HLR without any interchange of messages. The RCP contains one counter for each HLR in the HPLMN. If an HLR fails to respond to a dialog request, the RCP increments the associated counter and generates a “start of alarm” notice. When the HLR responds again to the dialog request, the RCP decrements the counter and sends an “end of alarm” notice.
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9090 CSCN PERFORMANCES AND TECHNICAL CHARACTERISTICSCSCN PERFORMANCES AND TECHNICAL CHARACTERISTICS
This chapter gives the main technical characteristics of the network elements (NEs).
This chapter describes:
maximum static capacity,
physical characteristics,
power,
environment,
installation.
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91 STATIC CAPACITIES
92 RCP CAPACITY (R6E)
Static Capacity
Configuration Static Capacity
RCP 8360 6UT 150 000 MS
RCP 8360 14UT 500 000 MS
Combined Configuration Static Capacity
RCP/HLR 8360 6UT RCP : 75 000 MS (4UT)
HLR : 200 000 MS (1UT)
RCP/HLR 8360 14UT RCP : 250 000 MS (10 UT)
HLR : 500 000 MS (3UT)
General Traffic Mix used for the RCP static dimensioning
All the values given in the following table impact the dimensioning of the static RCP capacity. They are issued from system specification, software constraints and operator requests.
General Data
Number of basic service Group (BSG) per subscriber principal for 100 % subscribers 6
Average number of forwarding numbers or sub-addresses per subscriber (every subscriber has 3 forwarding numbers for speech, even if the forwarding is not activated)
3 + 1.5
Average number of TMSI per IMSI 1.2
% Subscribers with Call Barring 100 %
% Subscribers with messages (SMS) 100 %
% Subscribers with Call Waiting 100 %
% CUG 20 %
Maximum number of subscribers with trace activated 200
% Subscribers with Regional Subscription 100 %
Maximum number of RSZC (regional zone subscription code) 32
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Maximum number of PLMN allowed for national roaming 16
CAMEL Data
% Subscribers with CAMEL profile 100 %
% CAMEL subscribers with a criteria 100 %
Each of these subscribers can have as criteria:
-a maximum number of destination numbers equal to
-a maximum number of destination number lengths equal to
-a maximum number of basic services equal to
-a maximum number of SS-CSI notifications equal to
10
3
5
2
93 HLR CAPACITY (R6E)
Static Capacity
Configuration Static Capacity
HLR 8360 6UT 600 000 MS
HLR 8360 14UT 1 000 000 MS
This static capacity depends on the percentage of GPRS and CAMEL subscriptions as described in the following table
Configuration Traffic Mix Static Capacity
HLR 8360 14UT, 1MG, 1Go 25% GPRS
100% CAMEL
1 000 000 MS
HLR 8360 14UT, 1MG, 1Go 100% GPRS
100% CAMEL
800 000 MS
General Traffic Mix used for the HLR static dimensioning
All the values given in the following table impact the dimensioning of the static HLR capacity. They are issued from system specification, software constraints and operator requests.
Two configuration are defined:
Config 1 :Static Configuration Full IN and 25% GPRS
Config 2: Static Configuration Full IN and GPRS
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Config 1 Config 2
General Data
Average number of Basic service per subscriber MSISDN
1.3 1.3
Average number of forwarding numbers per subscriber 5.4 5.4
% Subscribers with SMS 100 % 100 %
% CUG (closed user group) 10 % 10 %
% Subscribers with trace possibility 0,1 % 0,1 %
% Subscribers with Regional Subscription 100 % 100 %
% Subscribers with more than 4 restriction lists 10 % 10 %
Maximum number of RZSI 5000 5000
Maximum number of CUG interlock code 4000 4000
% forwarding numbers with sub-address 3 % 3 %
% Subscribers with a linked IMSI 4 % 4 %
CAMEL phase 2 Data
% Subscribers with CAMEL profile 100 % 100 %
% CAMEL subscribers with destination number as criteria
100 % 100 %
Average number of destination number per CAMEL subs.
5 5
% CAMEL subscribers with U-CSI Data 50 % 50 %
Average number of U-CSI service codes per CAMEL subs
3 3
% CAMEL subscribers with basic service as criteria 5 % 5 %
% CAMEL subscribers with SS-CSI notification 1 % 1 %
GPRS Data
% Subscribers with GPRS profile 25 % 100 %
Average number of PDP context per GPRS subscriber 5 5
Global number of PDP models 10 000 10 000
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94 SSP CAPACITY (R24.2)
The SSP with HC (high capacity) technology offers performance levels that are significantly different from those of the SSP with non-HC technology. The HC technology, broadly speaking, multiplies:
maximum connection capacity by 8,
maximum call handling capacity by 7.
Static Capacity
The maximum static capacities of the SSP in a GSM environment are given in BHCA in the following table:
Configuration Static Capacity in BHCA
SSP R24.2 (Alcatel OCB283)
615 000 BHCA
SSP R24.2 (Alcatel E10 MM)
4 307 000 BHCA
(*) The static capacity of the SSP is given in Busy Hour Call Attempts (BHCA) for a traffic mix corresponding to a “Middle GSM Traffic with 0% of IN”.
These static capacities will evolved according to your traffic mix and the introduction of IN services.
The following table provides static capacities with 100 % of IN-CS1 subscribers or 100% of CAMEL subscribers, for Alcatel OCB283 and Alcatel E10 MM.
MIX Max Static Capacity in BHCA
OCB283 SSP E10 MM SSP
Middle GSM traffic, 100 % IN-CS1
350 000 BHCA 2 460 000 BHCA
Middle GSM traffic, 100 % CAMEL
555 000 BHCA 3 880 000 BHCA
95 PHYSICAL CHARACTERISTICS
96 BOARDS
The boards are of the following standard sizes:
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8 U (233.68 mm x 350.52 mm, 1.6 mm thick).
Six to eight layers with one internal layer reserved for 5 V power feed, another for logical earth. The two corresponding copper layers completely cover the surface of the board to minimize electromagnetic interference, improve transmission of signals and ensure low impedance for power distribution.
Printed circuit fabrication is in accordance with UTE class 5 (Union Technique Electrique).
All passive components are surface mounted.
The buried via technique for boards with high component densities (links between layers being internal through plated-through holes that do not go right through to the external layers) is used. This reduces the space requirement by approximately 30% and makes it possible to raise the component capacity from 1000 to approximately 1500 per board.
A hard plastic board header is used to avoid direct electrostatic discharge and to lock the board in its slot and unlock it easily.
Alcatel 900/1800 boards contain on average four custom circuits and consume less than 7 W.
The 35 types of board used in the Alcatel 900/1800 are sufficient to cover all equipment situations for the whole NSS.
97 SUBRACKS AND BACKPLANES
The boards are mounted in standard size subracks:
8 U high (1U = 30.48 mm),
154 pitch widths (1 pitch width = 5.08 mm).
The subrack backplanes consisting of multi-layer printed circuits have the following features:
3.2 mm thick,
six layers as standard,
flexible insert connectors.
Two layers are reserved for the 5 V power supply feed and the electrical earth. The copper layers providing these functions completely cover the corresponding layers to reduce the level of electromagnetic radiation. For the same reason the free parts of the external layers are covered by an earthing grid. No active component is directly soldered to the backplanes.
The boards are connected in two ways:
by two HE11 DIN connectors with 3 x 32 pin per connector and one eight-pin power connector,
by an HE17 DIN connector with 320 pins, some of which are reserved for the boards power supply.
Inter-rack links are always by removable cables with the same connectors as the boards whereas the point-to-multipoint links (looms) use piggyback connectors (multistage).
All inter-subrack links in a rack or all inter-rack links use shielded cables.
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98 RACKS: MAIN FEATURES
All Alcatel 900/1800 racks have the following dimensions:
height: 2200 mm
width: 900 mm
depth: 650 mm
maximum weight: approximately 400 kg.
Each rack can house up to six subracks separated by air baffles, the cooling being by natural convection.
Power supply level (interface and supervision)
Deflector
Subrack
8U format cardlockableIndividualcard guide
896
2098
650
101.6
273
Rack layout
For heat protection, a baffle is installed between each subrack and the doors and upper and lower grilles are perforated.
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Upper EMI screen
Upper EMI strip
Support structure
Subrack
DeflectorAir path
Door
Bottom grid
Lower EMI strip
EMI rack suite end panel
- Hyperfrequency sealsbetween all dismountableparts- Integral cable tray
Rack shielding
It has a dual power supply and double protection so that the converters are powered from two entirely separate directions.
A cable way incorporated in the rack is created by juxtaposing the racks in the row and is completed by inter-row cable troughs. The cable way is at racktop level. External rack shielding for the row forms a Faraday cage. All the inter-rack and inter-row cabling is inside the unique Faraday cage produced by linking the different rows using fully enclosed inter-row cable troughs.
All possible sources of radiation at the likely points (doors, grill connectors, cable inlets) are eliminated. Particular care has been taken to filter out interference where the power supply enters and where the charges collected by cable shielding linking with the outside flows to the frame earth (power supply, PCM link).
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GSM SYSTEM Network Switching Subsystem
99 POWER
The electrical power supply of an exchange has three levels:
Primary power derived from the local public electricity network (for example: 50 Hz AC for a voltage of 230/400 V).
Secondary power for telephony: DC for a typical voltage of 48 V.
Tertiary power for the switching system itself.
Each power level involves a set of equipment to convert the power available at the inlet to electrical power suitable for the next lower level.
100 ORGANIZATION
The three electrical power levels are used in an Alcatel 900/1800 NSS network subsystem as follows.
PRIMARY LEVEL
This consists of:
HV/LV transformer station,
generating set,
LV distribution board.
SECONDARY LEVEL
There are two possible configurations according to whether the power supply is centralized or decentralized.
Centralized power
This consists of (see Figure 23):
For the DC part:u a number of rectifiers,u a number of outlets,u secondary power source tester,u batteries.
For the AC part:u at least one inverter,u a power supply unit.
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GSM SYSTEM Network Switching Subsystem
48 V DC
I/O devices
230 V AC
Inverters
= =48 V misc.(Transmission,buildings...)
POWER PLANT
Transformer
AC mains
BatteriesRectifiers
Generatingset
AC PDB
SWITCHING ROOM OPERATION ROOM
Tertia
ry p
ower
leve
lSe
cond
ary
pow
er le
vel
Prim
ary
pow
er le
vel
DC PDB AC PDB
SDE SDE
Figure 11 - Centralized power distribution
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GSM SYSTEM Network Switching Subsystem
Decentralized power
This consists of (Figure 24) modular power supply stations (SAM rack) each comprising:
rectifiers,
batteries (included or not included),
an optional inverter,
a power distribution panel.
I/O devices
Transformer
AC mains
Generatingset
SWITCHING ROOM OPERATION ROOM
Tertia
ry p
ower
leve
l
Seco
ndar
y pow
er le
vel
Prim
ary
pow
er le
vel
AC PDB
SAM
AC PDB
Figure 12 - Decentralized power distribution
TERTIARY LEVEL
There are two possible configurations according to whether the power supply is centralized or decentralized.
Centralized power
This consists of:
Power distribution stations (SDE rack).
Alcatel 900/1800 rack internal converters. Each rack has a two leg 48 V supply derived from two SDE rack modules.
Rack input modules.
Decentralized power
This consists of:
Alcatel 900/1800 rack internal converters. Each rack is powered by two 48 V outlets from the SAM rack.
Rack input modules.
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GSM SYSTEM Network Switching Subsystem
The tertiary power level is part of the exchange. An earth distribution network completes the equipment.
101 POWER CHARACTERISTICS
The characteristics described below are the values required for correct operation of an Alcatel 900/1800 NSS. In other words, they are the power characteristics at the inlet to the tertiary level. These values take into account the voltage drop, at maximum throughput, in the distribution cables between the output from the secondary level and the inlet to the tertiary level.
Alcatel 900/1800 has a very low power consumption.
48 V supply
The quality of the 48 V supply is defined by three values:
Steady-state conditions
Under steady-state conditions, the operating range is between a minimum of 42.7 V and a maximum of 57 V.
Degraded conditions
A failure condition such as the blowing of a fuse in secondary level equipment will cause the voltage to undulate for a few seconds. The extreme values during this undulation are a minimum of 35 V and a maximum of 60 V.
Ripple
Under steady-state conditions, there is an AC ripple voltage consisting of harmonics of the public network frequency.
By definition, the allowable RMS voltage for this ripple depends on the level of the harmonic observed.
230 V supply
The AC power supply is single-phase. It has two characteristic values:
Voltage : 230 Volts +/- 10%
Frequency : 50 Hertz +/- 2%
The rating of the 230 V uninterruptible power supply required for an Alcatel 1000 EVOLIUMTM exchange is generally less than 2 kVA.
102 EARTH SYSTEM
It is essential to have a single earth point or to interconnect the different earth points for the safety of personnel and to protect the equipment.
The metalwork of the building must be connected to this earth system.
The section of the conductors linking the earths of the installations to the earth connection plate must be sufficient to support the maximum possible level of fault currents and to enable the protective devices to operate.
The earth conductor system must be designed so that no potential difference generated by a fault current in a cable can be transferred to an unimpaired part of the installations.
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GSM SYSTEM Network Switching Subsystem
The route taken by the earth cables must be as short as possible and as straight as possible to present the lowest possible impedance.
The earth resistance must be less than 2 ohms.
103 ENVIRONMENTAL CONDITIONS
The NSS is designed to operate in a normally protected room. The racks of the Alcatel 900/1800 system are cooled by natural convection in the ambient air of the room in which they are installed. This means that, as for any other system, limit environmental conditions must be respected to achieve optimum operational performance and normal reliability.
More severe ambient conditions can be endured when the equipment is packed for transport, storage or is being installed with no power connected.
104 CLIMATIC CONDITIONS
There are four types of climatic conditions:
Normal operating conditions
These are defined by all the "temperature-relative humidity" combinations for which the equipment must operate indefinitely without impaired performance.
Exceptional operating conditions
These are defined by the set of "temperature-relative humidity" combinations, outside normal conditions, under which the equipment must be able to operate for a consecutive period of 72 hours with certain performance levels impaired.
Packaged equipment transport and storage conditions
These conditions essentially concern the transport and handling of equipment on site. These conditions must not exceed 30 days.
Unpackaged equipment storage conditions
Alcatel 900/1800 equipment may be warehoused without packaging. These conditions must not exceed 2000 hours.
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GSM SYSTEM Network Switching Subsystem
105 OPERATING CONDITIONS
Appropriate climatic conditions are applicable to each of the states described above:
Normal operating conditions
Air temperature : 5°C - 40°C
Relative humidity : 5% - 85%
Exceptional operating conditions
Air temperature : 0°C - 45°C
Relative humidity : 5% - 90%
Packaged equipment transport and storage conditions
Air temperature : -35°C - 70°C
Relative humidity : 5% - 100%
Unpackaged equipment transport and storage conditions
Air temperature: -5°C - 45°C
Relative humidity: 5% - 92%
106 INSTALLATION
Alcatel skills in installation techniques offer the best guarantees of fast, trouble free commissioning. These operations are made still simpler through thorough factory checking of the hardware and software to be installed on site. The complete testing of an exchange with its software prior to shipment to site significantly reduces commissioning time and complexity.
With the simplifications achieved in commissioning and extending exchanges, increasing use is made of local labour under Alcatel supervision or under local management.
The physical characteristics of Alcatel 900/1800 equipment mean that it can be installed in conventional buildings, with no particular room height or floor loading requirements.
The racks are arranged in rows. Alcatel can offer standard installation drawings which can be adapted to most situations. However, specific installation drawings are prepared on request to take into account the actual configurations of buildings.
The low heat dissipation of the equipment means that no centralized pulsed air cooling devices are required. However, like any modern electronic system, the switchroom must be air conditioned.
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