HUAWEI SGSN9810 System Description HUAWEI SGSN9810 System Description Document Version T2-030214-20060430-C-8.60 Product Version V800R006 Huawei Technologies Co., Ltd. provides customers with comprehensive technical support and service. Please feel free to contact our local office or company headquarters. Huawei Technologies Co., Ltd. Address: Administration Building, Huawei Technologies Co., Ltd., Bantian, Longgang District, Shenzhen, P. R. China Postal Code: 518129 Website: http://www.huawei.com Copyright © 2006 Huawei Technologies Co., Ltd. All Rights Reserved. No part of this manual may be reproduced or transmitted in any form or by any means without prior written consent of Huawei Technologies Co., Ltd. Trademarks and other Huawei trademarks are the trademarks or registered trademarks of Huawei Technologies Co., Ltd. in the People’s Republic of China and certain other countries. All other trademarks and trade names mentioned in this document are the property of their respective holders. Notice The information in this manual is subject to change without notice. Every effort has been made in the preparation of this manual to ensure accuracy of the contents, but all statements, information, and recommendations in this manual do not constitute the warranty of any kind, express or implied. HUAWEI SGSN9810 System Description Table of Contents Chapter 1 Introduction to the SGSN9810........................................................................................1 1.1 About This Chapter ................................................................................................................1 1.2 Structure of a GPRS/UMTS Network ....................................................................................1 1.3 Huawei GPRS/UMTS CN-PS Solution ..................................................................................2 1.3.1 SGSN ..........................................................................................................................2 1.3.2 GGSN..........................................................................................................................2 1.3.3 HA ...............................................................................................................................3 1.3.4 CG ...............................................................................................................................4 1.3.5 AAA Server..................................................................................................................4 1.3.6 DNS Server .................................................................................................................4 1.3.7 BG ...............................................................................................................................4 1.4 Overview of the SGSN9810...................................................................................................5 Chapter 2 Key Benefits .....................................................................................................................6 2.1 About This Chapter ................................................................................................................6 2.2 Large Capacity and High Degree of Integration ....................................................................6 2.3 High-Speed Hardware Forwarding ........................................................................................6 2.4 Standard Protocol Interfaces .................................................................................................6 2.5 Abundant Physical Interfaces ................................................................................................7 2.6 Rich Services and Functions .................................................................................................7 2.7 Easy Operation and Maintenance .........................................................................................8 2.8 High Reliability .......................................................................................................................9 Chapter 3 System Structure ...........................................................................................................11 3.1 About This Chapter ..............................................................................................................11 3.2 Hardware Configuration.......................................................................................................11 3.2.1 Switching Subrack.....................................................................................................13 3.2.2 Basic Subrack ...........................................................................................................14 3.2.3 Extended Subrack ...................................................... 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Chapter 4 Services and Functions ................................................................................................17 4.1 About This Chapter ..............................................................................................................17 4.2 Services ...............................................................................................................................17 4.2.1 IP/PPP Bearer Services ............................................................................................17 4.2.2 Short Message Services ...........................................................................................18 4.2.3 Location Services ......................................................................................................19 4.2.4 CAMEL Phase 3 Services.........................................................................................20 4.2.5 Lawful Interception ....................................................................................................20 4.3 Functions .............................................................................................................................21 4.3.1 Mobility Management ................................................................................................22 Commercial in Confidence i HUAWEI SGSN9810 System Description 4.3.2 Session Management ...............................................................................................22 4.3.3 Routing ......................................................................................................................22 4.3.4 IPv6 Support..............................................................................................................23 4.3.5 IPSec and LLC Encryption ........................................................................................24 4.3.6 Charging....................................................................................................................25 4.3.7 QoS ...........................................................................................................................25 4.3.8 Iu-FLEX/Gb-FLEX .....................................................................................................27 4.3.9 RAN Sharing in Connected State .............................................................................28 4.3.10 MVNO......................................................................................................................28 4.3.11 UESBI-Iu .................................................................................................................29 4.3.12 Multi-SPs and 2 Mbit/s Signaling Links...................................................................30 4.3.13 NTP Client Functions ..............................................................................................30 4.3.14 Network-Assisted Cell Change ...............................................................................31 4.3.15 SIGTRAN Support...................................................................................................31 4.3.16 Gb over IP ...............................................................................................................34 4.3.17 Differential Services ................................................................................................35 4.3.18 Handover Strategy Control......................................................................................35 Chapter 5 Operation and Maintenance .........................................................................................37 5.1 About This Chapter ..............................................................................................................37 5.2 O&M System........................................................................................................................37 5.3 Configuration Management .................................................................................................38 5.4 Equipment Management......................................................................................................38 5.5 Tracing Management...........................................................................................................39 5.6 Performance Management ..................................................................................................39 5.7 Fault Management...............................................................................................................39 5.8 Security Management..........................................................................................................39 5.9 Online Help ..........................................................................................................................40 Chapter 6 Reliability ........................................................................................................................41 6.1 About this Chapter ...............................................................................................................41 6.2 Hardware Reliability.............................................................................................................41 6.2.1 Board Hot Backup .....................................................................................................41 6.2.2 ASIC Technology ......................................................................................................41 6.2.3 Quality Components..................................................................................................42 6.2.4 Load Sharing .............................................................................................................42 6.2.5 Power Supply Reliability............................................................................................42 6.3 Software Reliability ..............................................................................................................42 6.3.1 Reliability Building at Different Phases .....................................................................42 6.3.2 Error Tolerance .........................................................................................................43 6.4 Charging Reliability..............................................................................................................43 Chapter 7 Technical Specifications...............................................................................................45 7.1 About This Chapter ..............................................................................................................45 Commercial in Confidence ii HUAWEI SGSN9810 System Description 7.2 Performance Specifications .................................................................................................45 7.3 Engineering Specifications ..................................................................................................45 7.3.1 Power Consumption..................................................................................................45 7.3.2 Dimensions and Weight of Cabinets .........................................................................46 7.3.3 Environment Requirements.......................................................................................46 7.4 Reliability Specifications ......................................................................................................47 7.5 Physical Interfaces...............................................................................................................47 Chapter 8 Installation ......................................................................................................................49 Appendix Acronyms and Abbreviations .......................................................................................50 Commercial in Confidence iii HUAWEI SGSN9810 System Description Chapter 1 Introduction to the SGSN9810 1.1 About This Chapter This chapter describes the structure of a general packet radio service / universal mobile telecommunications system (GPRS/UMTS) network where the Huawei SGSN9810 Serving GPRS Support Node (referred to as the SGSN9810 in the following sections) is located. The chapter also introduces the network elements used in the Huawei GPRS/UMTS core network-packet switching (CN-PS) solution. 1.2 Structure of a GPRS/UMTS Network The current wireless technology is evolving from 2G global system for mobile communications (GSM) to 3G UMTS by way of 2.5G GPRS. Mobile communication networks now cover large areas, realize high-speed wireless data transfer, and offer access to the Internet. They provide wide range of multimedia services (such as voice, data, and video) and enable access anytime and anywhere. Figure 1-1 shows the structure of a GPRS/UMTS network. CN-CS RAN GSM/GPRS BSS BSC HLR/AuC/EIR SMS-GMSC MSC/VLR SMS-IWFMSC GMSC PSTN, ISDN BTS MS UMTS UTRAN SS7 Billing Center RNC CG NodeB Firewall Firewall SGSN DNS Core Network Other PLMN BG DNS GGSN/ HA FA CN-PS Internet, Intranet, etc. WAP Gateway AAA Server Figure 1-1 Structure of a GPRS/UMTS network Commercial in Confidence Page 1 of 1 HUAWEI SGSN9810 System Description As shown in Figure 1-1, a GPRS/UMTS network consists of the following parts: Mobile station (MS): User equipment capable of originating and receiving calls over the air interface. To handle data services, the MS establishes a logical link with the packet switched (PS) domain. Radio access network (RAN): handles all radio-related functions. Core network-circuit switching (CN-CS): provides circuit services and connects to external circuit switched networks such as a public switched telephone network (PSTN). CN-PS: provides packet data services and connects to external public data networks (PDNs) such as the Internet. 1.3 Huawei GPRS/UMTS CN-PS Solution The Huawei GPRS/UMTS CN-PS consists of the following main network entities: Serving GPRS support node (SGSN) Gateway GPRS support node (GGSN) and foreign agent (FA) Home agent (HA) Charging gateway (CG) Authentication, authorization, accounting (AAA) server Domain name system (DNS) server Border gateway (BG) The CN-PS offers the means for an MS to access an external PDN. It provides packet data services and charging service (including prepaid and postpaid services). The following sections describe the functions of these entities. 1.3.1 SGSN The SGSN is a functional entity that provides packet data services. It forwards incoming and outgoing internet protocol(IP) packets to the mobile stations (MSs) within its service area. The SGSN provides the following functions: Routing and forwarding of data packets Encryption and authentication Session management Mobility management Logical link management Generation and output of call detail records (CDRs) 1.3.2 GGSN The GGSN is also a functional entity that provides packet data services. It routes and encapsulates packet data between the GPRS/UMTS network and an external PDN. Commercial in Confidence Page 2 of 2 HUAWEI SGSN9810 System Description The GGSN provides the following functions: Interface to an external public data network(PDN) The GGSN functions as a gateway for an MS accessing an external PDN. From the point of view of the external network, the GGSN serves as a router for all equipment IP addresses in the GPRS/UMTS network. GPRS/UMTS session management The GGSN helps in setting up communications between the MS and the external PDN. Data routing and forwarding The GGSN receives data from the MS and then forwards the data to the external PDN. It also receives data from the external PDN and selects a transport channel in the GPRS/UMTS network based on the destination address to forward the data to the SGSN. FA functions To support mobile Internet Protocol (IP) services, the GGSN is embedded with FA functions. In this case, the GGSN/FA serves as a gateway of the GPRS/UMTS network and an FA of the network visited by the MS. Charging for postpaid services The GGSN generates and outputs CDRs based on the usage of the external network by the subscriber. Call control and service switching functions for prepaid services For prepaid services, the GGSN serves as a service switching point (SSP) that connects a mobile network and an intelligent network. It provides call control and service switching functions. 1.3.3 HA The HA is a new entity that is used to support mobile IP access. It is an enhanced router that also maintains the current location information of MSs. The main functions of the HA are as follows: Sending broadcast messages to MSs so that the MSs know if they are on the home network. Handling and replying to the registration requests from an MS. Establishing mobility binding records (MBRs) between the MS home address and care-of address. Agency and forwarding: The HA reports the availability of network prefixes for the MS home address so that the packets destined for the MS home address can be routed to the home network. After encapsulating the packets, the HA tunnels them to the GGSN/FA, which finally forwards the packets to the MS. Commercial in Confidence Page 3 of 3 HUAWEI SGSN9810 System Description 1.3.4 CG The CG is a new device added to the GPRS/UMTS network. It collects, consolidates and pre-processes CDRs generated by the SGSN or GGSN. It provides an interface to the billing center. CDRs are generated by several network entities when a GPRS or UMTS subscriber visits the Internet. Each entity may generate several CDRs. The CG is used to reduce the work load of the billing center by consolidating and pre-processing the CDRs before sending them to the billing center. With the CG used in the network, the SGSN or GGSN need not provide the charging interface to the billing center. 1.3.5 AAA Server The AAA server performs authentication, authorization and accounting according to the Remote Authentication Dial-In User Service (RADIUS) protocol. The AAA server is not specific to the GPRS/UMTS system. 1.3.6 DNS Server Two types of DNS server exist in the GPRS/UMTS network. The first is the DNS between the GGSN and the external PDN. Like an ordinary DNS on the Internet, this DNS resolves the domain name of the external PDN. The second is the DNS on the GPRS/UMTS CN. The main functions of the DNS server include the following: Resolves the GGSN IP address from the access point name (APN) to set up communication with the MS when the MS attempts to access the external PDN. Resolves the SGSN IP address from the old routing area code during the inter-SGSN routing area update. Resolves the SGSN IP address from the new radio network controller (RNC) identity(ID) during RNC relocation. The DNS server is not specific to the GPRS/UMTS system. 1.3.7 BG The BG is a router. In addition to security functions, it provides a routing function between the SGSN and the GGSN in different PLMNs. The BG is not specific to the GPRS/UMTS system. Commercial in Confidence Page 4 of 4 HUAWEI SGSN9810 System Description Note: The FA and the HA are mandatory for mobile IP access. If the mobile IP access function is not required, the FA and HA are not required. 1.4 Overview of the SGSN9810 The SGSN9810 can be used in a GPRS and a UMTS network. It supports up to 2 million attached subscribers at the same time. The SGSN9810 provides full range of services, functions, protocol interfaces, and physical interfaces. Built on the mature platform of Huawei products, it is highly reliable and easy to operate and maintain. Commercial in Confidence Page 5 of 5 HUAWEI SGSN9810 System Description Chapter 2 Key Benefits 2.1 About This Chapter This chapter describes the key benefits that the SGSN9810 brings to network operators. It includes the following sections: Large Capacity and High Degree of Integration High-Speed Hardware Forwarding Standard Protocol Interfaces Abundant Physical Interfaces Rich Services and Functions Easy Operation and Maintenance High Reliability 2.2 Large Capacity and High Degree of Integration The SGSN9810 supports up to 2 million attached 2.5G or 3G subscribers and 2 million activated packet data protocol(PDP) contexts (2.5G or 3G subscribers) at the same time. When fully configured, it requires five cabinets in a 2.5G network or three cabinets in a 3G network. 2.3 High-Speed Hardware Forwarding The user plane data of the SGSN9810 is forwarded using hardware, which improves the processing efficiency and integration of the system. The hardware supports the traffic at the rate of 600 Mbit/s in a 2.5G system or the traffic at the rate of 10 Gbit/s in a 3G system. 2.4 Standard Protocol Interfaces The SGSN9810 supports a variety of 3rd generation partnership project (3GPP) protocol interfaces to connect to the equipment from different vendors. This makes network deployment easy for operators. The SGSN9810 supports the following protocol interfaces — Ga, Gb, Gd, Ge, Gn, Gp, Gf, Gr, Gs, Iu, and Lg — as shown in Figure 2-1. Commercial in Confidence Page 6 of 6 HUAWEI SGSN9810 System Description SMS-GMSC SMS-IWMSC SM- SC CAMEL GSMSCF GLMC Gd MSC/VLR HLR Ge Lg Gs Gc Gr Iu TE MT Gi UTRAN PDN GGSN SGSN TE Gn Gb TE MT BSS Gn Ga Gp CGF GGSN SGSN Ga Gf Billing System EIR Other PLMN Figure 2-1 Protocol interfaces supported by the SGSN9810 2.5 Abundant Physical Interfaces The SGSN9810 provides the following physical interfaces to improve its adaptability in different network requirements: Gn, Gp, Ga and Iu-PS interfaces: STM-1, STM-4, 10 Mbit/s, 100 Mbit/s, and 1,000 Mbit/s Ethernet interfaces Gb, Gd, Ge, Gf, Gr, Gs and Lg interfaces: E1, T1, STM-1, STM-4, 10 Mbit/s, 100 Mbit/s, and 1,000 Mbit/s Ethernet interfaces For the 1,000 Mbit/s Ethernet interfaces, both optical ports and electrical ports are supported. 2.6 Rich Services and Functions The SGSN9810 provides a full range of services and functions. Basic functions include: IP bearer services Mobility management Security management Session management Charging Quality of service (QoS) and flow management Static and dynamic routing Simple network management protocol (SNMP) support Commercial in Confidence Page 7 of 7 HUAWEI SGSN9810 System Description Optional functions include: Point-to-Point Protocol(PPP) bearer services Short message service (SMS) Customized applications for mobile network enhanced logic (CAMEL) 3 intelligent services Location service (LCS) Internet protocol security extensions (IPSec) function Lawful interception 2 Mbit/s signaling link Multiple signaling points Network time protocol (NTP) Multiple HPLMNs Iu-FLEX Mobile virtual network operator (MVNO) Network assisted cell change (NACC) IP multimedia subsystem (IMS) bearing IPv6 RAN sharing in connected mode UESBI-Iu Enhanced data rates for GSM evolution (EDGE) High speed downlink packet access (HSDPA) Differential service Handover strategy control Gb over IP Signaling transport (SIGTRAN) support 2.7 Easy Operation and Maintenance The SGSN9810 has the following operation and maintenance (O&M) features: Multiple and flexible O&M methods The O&M system can be flexibly built according to the network structure and customer requirements. Multiple maintenance interfaces are supported, including the interfaces to the local maintenance terminal (LMT), the Huawei centralized network management system iManager 2000, and the Simple Network Management Protocol (SNMP) based network management system. Through the Common Object Request Broker Architecture (CORBA) interface provided by the iManager 2000, more network management requirements can be fulfilled. Friendly user interfaces The SGSN9810 provides O&M interfaces that combines the merits of both man-machine language (MML) and graphic user interface (GUI). Powerful signal tracing Commercial in Confidence Page 8 of 8 HUAWEI SGSN9810 System Description The SGSN9810 provides functions to trace the messages of designated subscribers and the signals on the protocol interfaces such as the Iu, Gb, Gs, and Gr. Message explanation and filtering functions are also available. Function-level software patching Through online software patching, software errors can be solved without interrupting services. The SGSN9810 also supports remote patching and version fallback. 2.8 High Reliability The SGSN9810 is highly reliable because of the following features: Backup of important data The SGSN9810 automatically backs up important data, such as the configuration data, performance data, and operation logs. Operation security management Different management privileges are assigned to different users. Stringent user identity checks are performed upon user login, and a comprehensive operation log is maintained after user login to ensure system security. CG redirection and bill buffering When the active CG or the link to the active CG fails, the SGSN9810 automatically sends the bills to the standby CG. If the standby CG is also faulty, the SGSN9810 stores the bills in its buffer. Hardware redundancy design All critical boards are configured in the 1+1 backup or N+1 redundancy to ensure the high reliability of the system. Protection against exceptions The SGSN9810 provides comprehensive protection mechanisms against system exceptions including: − System power-off − Maloperation on system power switch − Lightning surge on the system power − High voltage and low voltage − Short circuit of power supply − Lightning surge on E1/T1 links − Current surge and high voltage on the power supply and interfaces System overload control In the case of center processing unit (CPU) overload or resource congestion, the SGSN9810 adjusts the traffic smoothly to avoid system down. Board locking and system shutdown Commercial in Confidence Page 9 of 9 HUAWEI SGSN9810 System Description This function enables a slow service exit from a board or the system if required, and thus guarantees that services are not disrupted suddenly. Commercial in Confidence Page 10 of 10 HUAWEI SGSN9810 System Description Chapter 3 System Structure 3.1 About This Chapter This chapter describes the structure of the SGSN9810 system. It includes the following sections: Hardware Configuration 3.2 Hardware Configuration Figure 3-1 shows the hardware configuration of the SGSN9810. Commercial in Confidence Page 11 of 11 HUAWEI SGSN9810 System Description Power Distribution Box U F C U U F C U U F C U U F C U U F C U U F C U U R C U U R C U U C D R U C D R U G F U U G F U U L I P U L I P U A L U U P W R U P W R U G B I U G B I U G B I U A L U U P W R U P W R U G B I U G B I U A L U U P W R U P W R U G T P U G T P U A L U U P W R U P W R PSM subrack Air deflector U I C P U I C P U S P U U S P U U S P U U S P U U R C U U R C U U S P U U S P U U G B I PSM subrack Air deflector U G B I U G B I U G B I U G B I U S P U U S P U U R C U U R C U U S P U U S P U U G B I PSM subrack Air deflector U G B I U G B I U G B I U G B I U S P U U S P U U R C U U R C U U O M U U O M U U G T P U G T P PSM subrack Dummy panel Figure 3-1 Hardware configuration of the SGSN9810 Commercial in Confidence Page 12 of 12 HUAWEI SGSN9810 System Description The SGSN9810 uses a standard 19-inch cabinet. Each cabinet houses four standard 19-inch subracks that are called Packet Service Module (PSM) subracks. Each PSM subrack has 21 slots. Boards can be inserted from both the front side and the rear side of the subrack. Based on the functions, PSM subracks are classified into the switching subrack, basic subrack, and extended subrack. 3.2.1 Switching Subrack The switching subrack implements the following functions: Interconnection between the basic subrack and extended subracks, and data exchange between these two types of subrack External Gn, Gp, and Iu-PS interfaces Transfer of user plane data Figure 3-2 shows the configuration of boards in the switching subrack. U P I U U P I U U P I U U P I U U P I U U P I U U B I U U F C U U F C U U F C U U F C U U F C U U F C U U R C U U A C U U B I U U R C U U A C U U B S U U B S U U P I U U P I U U C D R U C D R U U G G F F U U U L I P U L I P U P W R U P W R U P W R U P W R U A L U Figure 3-2 Boards in the switching subrack Note: In Figure 3-2, the boards in the upper half of the subrack are inserted from the rear, and the boards in the lower half are inserted from the front. Table 3-1 briefs the functions of the boards in the switching subrack. Table 3-1 Functions of the boards in the switching subrack Board Sub-rack control unit (URCU) Commercial in Confidence Function Implements bus mediation, board configuration, maintenance, and management of the PSM subrack. Page 13 of 13 HUAWEI SGSN9810 System Description Board Function PSM back interface unit (UBIU) Provides optical ports, network ports, and serial ports for the Subrack Control Unit (URCU). Auxiliary control unit (UACU) Helps the URCU board control the two buses in the PSM subrack. Controls hot swapping of the service processing boards in the PSM subrack. Controls the switchover of URCU boards. PSM alarm unit (UALU) Monitors the power module of the PSM subrack. Monitors back board status. Monitors subrack temperature. PSM power module (UPWR) Provides power supply for the PSM subrack. Frame connect unit (UFCU) Forwards service subrack data. Packet interface unit (UPIU) Receives and forwards Asynchronous Transfer Mode (ATM) data and Ethernet link data. GTP forwarding unit (UGFU) Forwards GPRS Tunneling Protocol (GTP) data. Charging detail record unit (UCDR) Collects, encodes, and sends CDRs, and stores CDRs in the buffer. Back storage unit (UBSU) Provides external interfaces and a hard disk for the UCDR. Lawful interception processing unit (ULIP) Provides interfaces for lawful interception, including the interfaces for receiving interception requests and the interfaces for collecting and transmitting interception messages. 3.2.2 Basic Subrack The basic subrack implements the maintenance and management functions of the SGSN9810 and processes various services. Figure 3-3 to Figure 3-5 show the configuration of boards in the basic subrack respectively for a 2.5G network, 3G network not supporting the Signaling Transport (SIGTRAN) protocol, and 3G network supporting SIGTRAN. U U U U U U U E E E E E E B P P P P P P I I I I I I I U U U U U U G G G G S B B B B P I I I I U U S P U U R C U U U U U U A B A F F C I C S S U U U U U U R C U U O M U U O M U U L A N U G T P U C K I U G T P U C K I U G T P U G T P U A L U U P W R U P W R U P W R U P W R Figure 3-3 Boards in the basic subrack (2.5G network) Commercial in Confidence Page 14 of 14 HUAWEI SGSN9810 System Description U U U U U E E E E B P P P P I I I I I U U U U U U I I S S S C C P P P P P U U U U S P U U U U U U A B A F F C I C S S U U U U U U R C U U R C U U O M U U O M U U L A N U G T P U C K I U G T P U C K I U G T P U G T P U A L U U P W R U P W R U P W R U P W R Figure 3-4 Boards in the basic subrack (3G network not supporting SIGTRAN) U B I U U U U U U A B A F F C I C S S U U U U U U U U U U U U I I S S S S R C C P P I I C P P U U G G U U R C U U O M U U O M U U L A N U G T P U C K I U G T P U C K I U G T P U G T P U A L U U P W R U P W R U P W R U P W R Figure 3-5 Boards in the basic subrack (3G network supporting SIGTRAN) Table 3-2 briefs the functions of the boards in the basic subrack. Table 3-2 Functions of the boards in the basic subrack Board Function Clock unit (UCKI) Provides operational clock for the SGSN9810. Packet service signal processing unit (USPU) Implements application layer protocols such as Session Management (SM), Mobility Management (MM), and Customized Applications for Mobile network Enhanced Logic (CAMEL). Processes Signaling System No.7 (SS7) L3 messages. Gb interface unit (UGBI) Iu_PS control processing unit (UICP) GTP processing unit (UGTP) Implements Gb interface protocols. Implements Iu-PS control plane protocols. Forwards GPRS tunnelling protocol for control plane (GTP-C) signaling messages and implements the charging function of GPRS tunnelling protocol for user plane (GTP-U) data. Implements NTP, DNS client and IPSec functions. Packet service O&M unit (UOMU) Commercial in Confidence Implements the operation and maintenance functions of the SGSN9810. Page 15 of 15 HUAWEI SGSN9810 System Description Board Function PSM flashdisk storage unit (UFSU) Provides external interfaces and a hard disk for the UOMU. E1 processing interface unit (UEPI) Provides external E1 interfaces for the Packet Service Signal Processing Unit (USPU) or Gb Interface Unit (UGBI). T1 processing interface unit (UTPI) Provides external T1 interfaces for the USPU or UGBI. LAN switch card (ULAN) Implements the functions of a local area network (LAN) switch to provide a connection between the UOMU and URCU. SIGTRAN process unit (USIG) Implements the MTP3 User Adaptation Layer (M3UA) and Stream Control Transmission Protocol (SCTP) functions of the SIGTRAN. Commercial in Confidence Page 16 of 16 HUAWEI SGSN9810 System Description Chapter 4 Services and Functions 4.1 About This Chapter This chapter describes the services and functions provided by the SGSN9810. These contents help you further understand the roles of the SGSN9810 in a GPRS or UMTS network. 4.2 Services The SGSN9810 provides a full range of services to meet the demands of various subscribers. This section introduces the following services: IP/PPP bearer services Short message services (SMS) Location services CAMEL Phase 3 services Lawful interception 4.2.1 IP/PPP Bearer Services The GPRS/UMTS network supports protocols such as the Internet Protocol version 4 (IPv4), Internet Protocol version 6 (IPv6), and Point-to-Point Protocol (PPP). The IP/PPP packets can travel transparently on the GPRS/UMTS network. Subscribers can use various IP and PPP applications, such as web browsing, File Transfer Protocol (FTP), and Virtual Private Network (VPN), through the GPRS/UMTS network. Figure 4-1 and Figure 4-2 respectively shows the structure of the protocol stack that provides IP and PPP bearer services in a 3G network and a 2.5 network. Application E.g., IP,PPP E.g., IP,PPP Relay Relay GTP-U PDCP PDCP GTP-U GTP-U RLC RLC UDP/IP UDP/IP MAC MAC L2 L1 L1 L1 Uu MS UTRAN L2 L1 Iu-PS GTP-U UDP/IP UDP/IP L2 L2 L1 3G-SGSN L1 Gn 3G-GGSN Gi Figure 4-1 IP/PPP bearer protocols (3G) Commercial in Confidence Page 17 of 17 HUAWEI SGSN9810 System Description Application IP IP Relay SNDCP SNDCP LLC LLC Relay GTP-U GTP-U UDP UDP RLC RLC BSSGP BSSGP IP IP MAC MAC Network Service Network Service L2 L2 GSM RF L1bis L1bis L1 GSM RF Um Gb MS BSS L1 Gn Gi SGSN GGSN Figure 4-2 IP/PPP bearer protocols (2.5G) 4.2.2 Short Message Services Short message services (SMS) include normal SMS and enhanced SMS. Normal SMS allows for the messages that contain up to 160 bytes (including control bytes). Enhanced SMS allows for formats in a message in addition to texts. These formats may include objects such as animations and images. A short message can contain more than one object. SMS consists of two types of basic service: mobile terminated short message (SM-MT) and mobile originated short message (SM-MO). SM-MT is the capability that enables the GSM/UMTS system to deliver the short messages submitted by the service center (SC) to the specified MS. At the same time, result (success or failure) of the message delivery is provided. In the case of delivery failure, a repeat strategy is implemented. SM-MO is the capability that enables the GSM/UMTS system, with the help of the SC, to forward the short messages submitted by an MS to the short message entity (SME). At the same time, result (success or failure) of the message submission is provided. Figure 4-3 shows the basic network structure of the SMS. SME .. SC Outside the scope of the GSM specifications SMS-GMSC / * SMS-IWMSC MSC/SGSN** MS Inside the scope of the GSM specifications Figure 4-3 Basic network structure of the SMS Commercial in Confidence Page 18 of 18 HUAWEI SGSN9810 System Description The GPRS-attached MSs or the GPRS-attached but international mobile subscriber identity (IMSI) -unattached MSs submit and receive short messages through the PS domain. The GPRS-attached and IMSI-attached MSs submit and receive short messages through either the PS domain or the circuit switching (CS) domain. If the messages are submitted through the CS domain, the SGSN can be used for paging. 4.2.3 Location Services The LCS enables the GPRS/UMTS network to determine the location of an MS in the network and provide the geographic location of the MS after data conversion and calculation. The location data can be applied internally or externally. For internal purposes, the location data can be used by the operator to fulfill certain requirements such as location-based charging. For external purposes, the location data of the MS can be used by the network to provide various location-based services such as on-demand services, customized messages, and customized services. Figure 4-4 shows the network of the LCS. 2GMSC A gsmSCF GERAN Gb Um Lg Proprietary 2GSGSN OSA SCS Lc Lg Proprietary Iu UE GMLC Iu Uu Lg Iu Le 3GSGSN Iu MSC server External LCS Client LIF-MLP Lh Lg UTRAN OSA API HSS Figure 4-4 Network of the LCS The LCS network includes the following main entities: LCS client: The LCS client originates location requests. Corresponding to the application of LCS, the LCS client includes the internal LCS client and external LCS client. Gateway mobile location center (GMLC): The GMLC provides an access for the LCS client to communicate with the public land mobile network (PLMN). After receiving the location request from the LCS Commercial in Confidence Page 19 of 19 HUAWEI SGSN9810 System Description client, the GMLC demands routing data from the home location register (HLR) or Home Subscriber Server (HSS). At the same time, the GMLC forwards the request to the visited mobile switching center (VMSC), SGSN, or MSC server after authentication. The location result is also forwarded through the GMLC. MSC/ Visitor location register (VLR), MSC server, and SGSN: These entities connect to the GMLC through the Lg interface. They receive, process, and respond to the location request. 4.2.4 CAMEL Phase 3 Services The CAMEL enables operators to provide subscribers special services such as the prepaid service. Figure 4-5 shows how the SGSN supports CAMEL Phase 3 services in a GPRS/UMTS network. Home Network HLR gsmSCF MAP CAP gprsSSF SGSN Interrogating Network MS Visiting Network Home/Interrogating/Visiting Network Figure 4-5 SGSN support to CAMEL Phase 3 services As shown in the figure, the SGSN integrates the GPRS service switching function (gprsSSF) and provide CAMEL Phase 3 services under the control of the GSM service control function (gsmSCF). 4.2.5 Lawful Interception The lawful interception is a capability of the mobile network to provide the content of communication (CC) of MSs and intercept related information (IRI) to a law enforcement agency (LEA). Figure 4-6 shows the procedure of lawful interception. Commercial in Confidence Page 20 of 20 HUAWEI SGSN9810 System Description Intercept request Intercept reques X1-1 Network node ADMF LEA X2 DF2 X3 IRI CC DF3 Figure 4-6 Procedure of lawful interception The procedure for lawful interception is as follows: 1 The LEA sends an intercept request to the administration function (ADMF) entity. 2 The ADMF forwards the request to the network node. 3 The network node starts intercepting the CC of the target subscriber. 4 The network node forwards the IRI and CC of the target subscriber to the LEA through the delivery function (DF). As shown in Figure 4-6, the logical entities relating to the interception in a mobile network include the network nodes (SGSN and GGSN), ADMF, and DF. The ADMF controls the interception while the DF collects and forwards the IRI and the CC. Relevant interfaces include the X1-1 interface, X2 interface, and X3 interface. X1-1 interface is between the ADMF and the network node. It transfers interception-related management messages from the ADMF to the network node. X2 interface is between the DF2 and the network node. It transfers the IRI. X3 interface is between the DF3 and the network node. It transfers the CC. 4.3 Functions The SGSN9810 provides powerful functions to meet the requirements of network operators. This section introduces the following functions: Mobility management Session management Routing IPv6 support IPSec and logical link control (LLC) encryption Charging QoS Commercial in Confidence Page 21 of 21 HUAWEI SGSN9810 System Description Iu-FLEX/Gb-FLEX RAN sharing in connected state MVNO UESBI-Iu Multi-SPs and 2 Mbit/s signaling link NTP client functions Network assisted cell change (NACC) SIGTRAN support Gb over IP Differential services Handover strategy control 4.3.1 Mobility Management The MM function is used to control an MS access to the GPRS/UMTS network and trace the location of the MS, such as the routing area (RA) and SGSN information of the MS. The MM function is fulfilled mainly by attach, detach, and route updating procedures. It ensures that the location of the MS is updated while the MS is moving, such as the updating of the current SGSN information in the HLR. 4.3.2 Session Management The SM carries out Packet Data Protocol (PDP) context management. The PDP context is a group of messages related to the PDP. The network elements, such as the MS, SGSN, and GGSN, send and manage the PDP data based on the PDP context. Session management includes PDP context activation, modification, and deactivation. Before the MS transmits data, it must activate the PDP context. During the data transfer, the PDP context can be modified based on the requirement of the QoS. After data transfer, the PDP context must be deactivated to release network resources. 4.3.3 Routing The SGSN9810 supports various routing protocols to ensure the flexible networking using the Gn/Gp interface. I. Static Routing Static routes are manually configured by the administrator. Users can configure static routes to set up a connected network. When the network is faulty, the static route cannot adjust itself and requires reconfiguration. Commercial in Confidence Page 22 of 22 HUAWEI SGSN9810 System Description In a simple network, static routes can be used to ensure the stable operation of the router. Well configured static routes can improve the performance of the network and ensure the bandwidth for critical applications. II. OSPF The open shortest path first (OSPF) is an interior gateway protocol (IGP) developed by the internet engineering task force (IETF). The OSPF is implemented based on link status. It has the following features: Large scope: The OSPF can be used for the networks of various sizes and support up to hundreds of routers. Fast convergence: After the network topology is changed, an update message is sent at once to synchronize the data in the autonomous system. Loop free: The OSPF uses the shortest path algorithm to determine a route based on the link status. The algorithm ensures that the route is loop free. Area division: The network of the autonomous system can be divided into several areas so that the network is easy to manage. The route information transferred between the areas is abstracted, so the required bandwidth is further reduced. Equivalent route: Multiple equivalent routes to the same destination are supported. Hierarchical routes: Routes are classified into four categories. They are (from high to low priority) intra-area routes, inter-area routes, class-1 external routes, and class-2 external routes. III. RIP II The routing information protocol (RIP) is a simple IGP that is used in small networks. The RIP is widely used in networks thanks to the following features: Easy to implement Little protocol overhead, which makes almost no impact on the network performance. Easy to configure and maintain compared with the OSPF and intermediate system-to-intermediate system (IS-IS) intra-domain routing information exchange protocol. 4.3.4 IPv6 Support The rapid development of Internet services requires more and more IP addresses, which are beyond the capability of the IPv4 protocol. As a result, the IPv6 is developed to address this problem. Compared with the IPv4, the IPv6 boasts of the following advantages: Commercial in Confidence Page 23 of 23 HUAWEI SGSN9810 System Description Extended IP addresses: IP addresses are extended from 32 bits in the IPv4 to 128 bits in the IPv6, indicating that the address resources are abundant. This address structure also improves routing efficiency. Simplified packet header format: The packet header is simplified to minimize the processing by routers; thus it improves routing efficiency. Enhanced support for extension and option capability: The IPv6 satisfies additional requirements without affecting the routing of normal packets or special packets. Flow identity: The flow identity is used to improve the processing of packet flows, especially real-time applications. Identity verification and security: Enhanced identity verification and security measures make IPv6 especially suitable for sensitive commercial information. The data plane and the signaling plane of the SGSN9810 Gn/Gp interface supports both IPv4 and IPv6 addresses. Operators can choose one of the following four operational modes: Supporting IPv6 addresses only Preferring IPv6 addresses Supporting IPv4 addresses only Preferring IPv4 addresses 4.3.5 IPSec and LLC Encryption To ensure the security of data transfer, the SGSN9810 supports IPSec encryption for the signaling massages on the Gn/Gp interface and data encryption for the Gb interface messages. I. IPSec The SGSN9810 encrypts the Gn/Gp signaling messages by using the IP Security (IPSec) protocols. The IPSec is a series of protocols developed by the IETF to ensure the security of the data that is transmitted on the Internet. Through encryption and data source verification on the IP layer, the privacy and integrity of data packets can be guaranteed when the packets are transferred on the Internet. II. LLC Encryption In a 2.5G system, the encryption on the Logical Link Control (LLC) layer between the MS and SGSN is the traditional stream encryption using the GPRS-A5 algorithm. The data to be encrypted includes the information field and the authentication field carried by LLC frames. Commercial in Confidence Page 24 of 24 HUAWEI SGSN9810 System Description 4.3.6 Charging Figure 4-7 shows the GPRS/UMTS charging network. The SGSN and GGSN collect the charging information relating to radio network resource usage and core network (CN) resource usage by each MS. Then they generate CDRs and send them to the CG through the Ga interface. UTRAN SGSN Gn Ga MS GGSN Ga CG BSS Billing Centre Figure 4-7 GPRS/UMTS charging network The SGSN9810 can generate the following seven CDRs: SGSN generated - CDR(S-CDR): records the information relating to certain PDP contexts in the SGSN Mobility management generated - CDR(M-CDR): records the mobility-related information SGSN delivered short message mobile originated - CDR(S-SMO-CDR): records the information relating to SM-MO services SGSN delivered short message mobile terminated - CDR(S-SMT-CDR): records the information relating to SM-MT services Mobile terminated LCS CDR(LCS-MT-CDR): records the information relating to mobile-terminated location services Mobile originated LCS CDR(LCS-MO-CDR): records the information relating to mobile-originated location services Network induced LCS CDR(LCS-NI-CDR): records the information relating to network-initiated location services 4.3.7 QoS The 3GPP R99 specifications define four classes of QoS, as described in Table 4-1. Commercial in Confidence Page 25 of 25 HUAWEI SGSN9810 System Description Table 4-1 UMTS QoS classes Traffic class Characteristics Example of the application Conversational class Preserve time relation between entities of the stream Conversational pattern (high quality, low delay) Voice Streaming class Interactive class Background class Preserve time relation between entities of the stream Request response pattern Destination does not expect the data within a certain time. Video Web browsing Download or e-mails The SGSN9810 support the four QoS classes by using the following mechanisms: Access control When the subscriber activates the PDP context, the SGSN9810 negotiates the QoS with the MS. If the negotiation fails, the SGSN9810 denies the MS access. QoS queue management The data packets are assigned to corresponding QoS queues based on the QoS class. The SGSN9810 dispatch the queues using the class-based weighted fair queuing (CBWFQ) algorithm to decide the order of transmission. In case of congestion, the SGSN9810 decides the discard criteria of packets by using the weighted random early detection (WRED) algorithm. This ensures the transmission reliability of the high-priority data. Differential services (DiffServ) DiffServ is an IP QoS model that is used in a backbone network to meet various service requirements. In the DiffServ system, the network node determines the per-hop behavior (PHB) according to the differentiated services code point (DSCP) in the IP header. The SGSN9810 supports the following PHBs: expedited forwarding (EF), assured forwarding (AF), and best-effort (BE). It also supports the three discard priorities of the AF. QoS mapping QoS mapping converts the QoS attributes of different bearer protocols. It includes the mapping between the 3GPP QoS and DSCP, between the DSCP and the ATM QoS, and between the R97/98 and the R99 QoS attributes. CAR and Remarking Commercial in Confidence Page 26 of 26 HUAWEI SGSN9810 System Description If the actual data packet stream requires the QoS higher than the requested one, the SGSN9810 handles the packets based on the committed access rate (CAR) and discard the extra packets. It can also carry out a Remarking process to lower the QoS of the data packet. 4.3.8 Iu-FLEX/Gb-FLEX The Iu-FLEX/Gb-FLEX function allows one RAN or base station subsystem (BSS) to connect to several CN nodes in the same domain. The Iu-FLEX/Gb-FLEX function introduces the concept of pool areas. Similar to an MSC or SGSN service area, a pool area contains one or more RAN/BSS service areas, but it is served by multiple CN nodes (MSC or SGSN) at the same time. See Figure 4-8 for details. MSC 6 MSC 5 MSC 4 MSC 3 MSC 2 MSC 1 CS poolarea 2 CS poolarea 1 RAN node Area 1 RAN node Area 5 RAN node Area 6 Area 3 Area 4 RAN node Area 7 RAN node Area 8 PS poolarea 2 SGSN 3 SGSN 4 SGSN 5 SGSN 2 RAN node RAN node RAN node Area 2 PS poolarea 1 SGSN 1 MSC 7 SGSN 6 Figure 4-8 Example of pool area configuration The Iu-FLEX/Gb-FLEX function expands the service areas of each CN node and reduces the effort required for the inter-node update, handover, relocation, and HLR update. This function also improves system availability. If one CN node in the pool area is faulty, other nodes can provide services. Commercial in Confidence Page 27 of 27 HUAWEI SGSN9810 System Description 4.3.9 RAN Sharing in Connected State Figure 4-9 shows the scenario of RAN sharing in connected state. In this scenario, the networks of operator A and operator B together cover a large area in which an overlap area exists. The RANs of operator A and operator B are connected through the CNs, so the user equipment (UE) of operator B can operate in the network of operator A. In the overlap area, the UE of operator B must access the RAN of operator B rather than the network of operator A. Core Network A Radio Access Network A Core Network B Radio Access Network B Figure 4-9 RAN sharing between operators To solve the problem mentioned above, the R5 protocol introduces the concept of shared network area (SNA). An SNA corresponds to one or more location areas (Las) that control the UE access. The SNA is configured in the CN. The CN provides the SNA information (an SNA ID list) of the specified UE to the RAN. The SNA ID list contains the SNAs that the UE can access. If the location area (LA) is in the SNA that the UE can access, the RAN allows the UE to access the network. Otherwise, it denies the UE. 4.3.10 MVNO A mobile virtual network operator (MVNO) uses the resources authorized by a mobile network operator (MNO) to provide services and maintain the authorized resources. The MVNO function enables more operators to invest on and share the network to lower investment risk and maximize resources usage. The network resources authorized by the MNO can be the RAN, part of the CN, or the whole CN. Figure 4-10 shows the example of partial CN sharing. In the example, the MNO shares its SGSN with the MVNO, and the MVNO owns the GGSN, CG, and other network equipment. Commercial in Confidence Page 28 of 28 HUAWEI SGSN9810 System Description MNO CG UTRAN MS SGSN GERAN GGSN GGSN CG PDN MVNO GGSN MVNO CG Figure 4-10 MVNO network 4.3.11 UESBI-Iu Different UEs may have potential standard or manufacture problems. The RAN needs UE-specific behavior information (UESBI) regarding 3GPP features to help the lower layer process the local 3GPP features. UESBI corresponds to the following two sets of information: UESBI-Uu: The messages are sent by the UE to the RAN through the messages defined by the Radio Resource Control (RCC) protocol. UESBI-Iu: The message is obtained by the CN from the International Mobile Station Equipment Identity and Software Version number (IMEISV) of the UE. The CN then sends the messages to the RAN through the Iu interface. Figure 4-11 shows the network structure of the UESBI-Iu. Attach and IMEISV interrogation 1 2 3 IMEISV Storage UESBI IMEISV UE BTS SRNC SGSN/MSC Figure 4-11 Network structure of the UESBI–Iu When the UE accesses the VLR or SGSN, the IMEISV from the UE is saved in the VLR or SGSN. When an Iu connection (such as CS voice session and PS data transfer) is set up later, the IMEISV is read from the MM context of the VLR or SGSN to obtain the UESBI. The UESBI is then sent to the serving RNC (SRNC). Commercial in Confidence Page 29 of 29 HUAWEI SGSN9810 System Description 4.3.12 Multi-SPs and 2 Mbit/s Signaling Links Ever increasing equipment capacity boosts the signaling flow between signaling points. The 16 signaling links specified by the protocol are far from enough to fulfill actual networking requirements. To solve this problem, the SGSN9810 provides the multiple signaling points (multi-SPs) function and 2 Mbit/s signaling links. I. Multi-SPs Function The SGSN9810 entity can be divided virtually into several logical signaling points. Thus the restriction of 16 signaling links between two signaling points is broken. As shown in Figure 4-12, from the aspect of other signaling points, the SGSN9810 contains multiple signaling points, and there are 16 links for each signaling point. 16 SP SP SGSN 16 SP1 SP SP2 SGSN 16 Figure 4-12 Multiple signaling points supported by the SGSN9810 II. 2 Mbit/s Signaling Links A 2 Mbit/s signaling link bundles multiple timeslots into an E1/T1 link to increase the throughput of a link. 4.3.13 NTP Client Functions The NTP is a protocol that broadcasts precise time over the entire IP network. The transmission of messages is based on the user datagram protocol (UDP). To ensure the accuracy of clock synchronization, the RFC1305 standard defines the algorithm used by the NTP. Commercial in Confidence Page 30 of 30 HUAWEI SGSN9810 System Description The SGSN9810 supports a remote server that is configured as the local time server. In this case, the SGSN9810 acts as the client. 4.3.14 Network-Assisted Cell Change When an MS initiates cell reselection between base station controllers (BSCs) during data transfer, the network assisted cell change (NACC) function is used to reduce the time delay and improve the QoS. In most cases, service interruption can be controlled within 300 ms to 700 ms, which is a great improvement compared with the normal 1 second or 2 seconds. To assist fast cell reselection, the MS must know the system information of the target cell. If the target cell belongs to another BSC or RNC, the system information is transferred across the BSCs or RNCs. In this case, the system information is included in the RAN-Information message and sent to the target BSC or RNC by the SGSN. 4.3.15 SIGTRAN Support The Signaling Transport (SIGTRAN) protocol stack is defined by the Internet Engineering Task Force (IETF) to enable the interworking between SS7 and IP networks. The SIGTRAN enables an IP network to transfer the signals of a legacy switched circuit network (SCN). It supports the standard inter-layer primitive interfaces defined in the SCN signaling protocol model to ensure that SCN signaling messages can be used without any modification. With the standard IP transport protocol as its lower layer, the SIGTRAN provides special functions to meet the requirements for SCN signaling transfer. Functionally, the SIGTRAN protocol stack is classified into the following two types: General signaling transmission protocols, which fulfills the efficient and reliable transfer of SS7 signaling messages on an IP network. The Stream Control Transmission Protocol (SCTP) is now used for this purpose. SS7 signaling adaptation protocols, which are designed to adapt the various signaling protocols used by the SCN. They include M2UA, M3UA, IUA, and V5UA. Figure 4-13 shows the SIGTRAN protocol stack model. Commercial in Confidence Page 31 of 31 HUAWEI SGSN9810 System Description M3UA M2UA IUA SUA M2PA V5UA SCTP IP M3UA: MTP3 User Adaptation Layer IUA: ISDN Q.921 User Adaptation Layer V5UA: V5 User Adaptation Layer SCTP: Stream Control Transmission Protocol M2UA: MTP2 User Adaptation Layer M2PA: MTP2 Peer Adaptation Layer SUA: SCCP User Adaptation Layer IP: Internet Protocol Figure 4-13 SIGTRAN protocol stack model Note: This manual introduces only the SCTP and M3UA used by the SGSN9810. In the SGSN9810, the SIGTRAN protocols are applied on the Iu-PS interface signaling plane and the SS7 interface. Figure 4-14 shows how the SGSN9810, RNC, and HLR communicate on an IP network using the SIGTRAN protocols. Commercial in Confidence Page 32 of 32 HUAWEI SGSN9810 System Description IP RNC/HLR.etc SGSN SCCP SCCP M3UA M3UA SCTP SCTP IP IP Figure 4-14 Communication with the RNC and HLR on an IP network using the SIGTRAN protocols The SGSN9810 can also use a signaling gateway (SG) to communicate with the signaling points that do not support SIGTRAN functions, as shown in Figure 4-15. No.7 HLR IP SG NIF SCCP SGSN SCCP MTP3 MTP3 M3UA M3UA MTP2 MTP2 SCTP SCTP MTP1 MTP1 IP IP Figure 4-15 Communication between an SS7 network and an IP network using the SIGTRAN (M3UA) Commercial in Confidence Page 33 of 33 HUAWEI SGSN9810 System Description 4.3.16 Gb over IP On the Gb interface, the Network Service (NS) layer implements the following functions for the upper layer: Service data unit (SDU) transfer between the SGSN9810 and the BSS. Network congestion indication Status indication Figure 4-16 shows the protocol stacks on the Gb interface. LLC RELAY BSSGP RLC BSS GP MAC NS NS L1 L1 Gb BSS SGSN Figure 4-16 Protocol stacks on the Gb interface The NS layer consists of two sublayers — NS control protocol and Sub-NS protocol — as shown in Figure 4-17. Network Service Network Service Control / Network Service Control protocol Sub-Network Service / Sub-Network Service protocol Figure 4-17 Structure of the NS layer The 3GPP protocols specify that Sub-NS messages can be carried by a frame relay network or an IP network. The SGSN9810 version earlier than V800R006 supports frame relay network. In version V800R006, the Gb over IP feature is added to support Sub-NS message transfer over an IP network on the Gb interface. The end-to-end communication on the Gb interface between two remote networks is implemented through network service – virtual circuits (NS-VC). An NS-VC is a virtual path between two peer entities on the NS control layer. It is defined by a quadruple Commercial in Confidence Page 34 of 34 HUAWEI SGSN9810 System Description consisting of the SGSN IP address, SGSN UDP port number, BSS IP address, and BSS UDP port number. 4.3.17 Differential Services The differential service provides various access control strategies according to subscriber priorities and service levels. Subscribers are grouped into three classes according to their priorities: Special subscribers High-end subscribers Common subscribers The service level depends on the following QoS parameters in the PDP context: Traffic class Guaranteed bit rate for downlink Traffic handling priority Operators offer different services to different subscribers through the following two methods: Specify the threshold of system resource usage to restrict the attach and routing area update (RAU) operations of some subscribers. Specify the threshold of PDP context resources to restrict certain services of some subscribers. 4.3.18 Handover Strategy Control The handover strategy control helps operators in distributing traffic and balancing load between 2G networks and 3G networks. This function is applicable to the 2G and 3G supportive terminals that are allowed to access these two types of network. When a terminal is in a 3G network, the handover strategies include: Handover to 2G network recommended Handover to 2G network not recommended Stay in the 3G network The handover strategy control information is sent as a cell to the RNC during radio access bearer (RAB) Assignment and Relocation procedures. When a terminal is in a 2G network, the handover strategies include: Handover to 3G network recommended Handover to 3G network not recommended Stay in the 2G network The handover strategy control information is sent as a cell to the BSS during the Create-BSS-PFC procedure. Commercial in Confidence Page 35 of 35 HUAWEI SGSN9810 System Description Commercial in Confidence Page 36 of 36 HUAWEI SGSN9810 System Description Chapter 5 Operation and Maintenance 5.1 About This Chapter This chapter introduces the structure and functions of the SGSN9810 O&M system. It includes the following contents: O&M System Configuration Management Equipment Management Tracing Management Performance Management Fault Management Security Management Online Help 5.2 O&M System Figure 5-1 shows the structure of the O&M system. LMT SGSN9810 SNMP Client M2000 Client M2000 Server M2000 Client SNMP Server SNMP Client Figure 5-1 O&M system of the SGSN9810 As shown in Figure 5-1, the SGSN9810 provides three O&M methods: Commercial in Confidence Page 37 of 37 HUAWEI SGSN9810 System Description Local maintenance through the local O&M terminals: This method is applicable to original system installation and fault location. Central maintenance through the iManager M2000: This is the main method for regular maintenance. Reporting the maintenance information to the SNMP-based network management system through the SNMP interface: Only alarms and performance data are reported. 5.3 Configuration Management Configuration management includes operations such as the addition, deletion, modification, and query of system data. The SGSN9810 provides two ways of data configuration: Dynamic configuration: Data can be configured when the system is running. Static configuration: The text data file (MML or TXT) is edited offline and the data takes effect when the system is reset. 5.4 Equipment Management Equipment management monitors, controls and tests system entities such as hardware components and links. The SGSN9810 provides the following equipment management features: Status query The SGSN9810 allows operators to query the operational status of the system entities. The entities include boards, optical ports, E1 ports, SS7 links, Frame Relay (FR) links, Signaling ATM Adaptation Layer (SAAL) links, GTP path, Bear Channels (BCs), NS-VCs, destination signaling point, subsystems, Point To Point (PTP) BSSGP Virtual Connections (BVCs), and Special Interest Group (SIG) BVCs. Status control The status control function allows for the following operations: − Board reset and switchover − Blocking, unblocking, and reset of optical ports, E1 ports, SS7 links, FR links, − SAAL links, GTP paths and BCs − Inhibiting and enabling of destination signaling points and subsystems. Test function Testing is an effective way to locate faults. The SGSN9810 supports loopback tests on E1 ports and SAAL links, as well as GTP path tests. Commercial in Confidence Page 38 of 38 HUAWEI SGSN9810 System Description 5.5 Tracing Management The SGSN9810 provides interface tracing and subscriber tracing. It is a powerful tool for equipment maintenance. The interface tracing can trace messages on standard interfaces such as the Gb, Iu, Gn/Gp, Gs/Gd/Gr, and Ga. It can also trace messages based on the protocol layer. The subscriber tracing traces the messages of the specified IMSI or mobile station international ISDN number (MSISDN). Operators can save the trace results to handle any queries in the future. 5.6 Performance Management Performance management assesses the SGSN9810 system and the surrounding networks and provides the data relating to network operation. The SGSN9810 performance management system has the following features: Wide range of measurements Diversified time attributes Measurement templates Measurement customization Suspension and resuming of measurement tasks Modification of measurement tasks View of real-time data regarding performance measurement Setting of measurement thresholds 5.7 Fault Management The alarm system monitors the operational status of the SGSN9810 and reports faults. The alarm system has the following features: Comprehensive alarm information and accurate alarm identification The SGSN9810 provides over 300 types of alarm covering all software functions, hardware components, and system peripherals. The alarms are grouped into different categories with different severity levels. This ensures that all faults can be detected and handled in time. Flexible and easy alarm handling The alarm terminal of the SGSN9810 provides flexible and convenient operations to ensure that you can handle the alarm effectively and in time. 5.8 Security Management The SGSN9810 ensures the security in two ways: Privilege management Commercial in Confidence Page 39 of 39 HUAWEI SGSN9810 System Description The privilege of an operator is defined by a command set that contains a group of commands. Commands are assigned to a command set, and then a command set is assigned to an operator. Operating log The operating log records all the user operation information, including the user name, user ID, login IP address, command, time, and result. 5.9 Online Help Both the SGSN9810 LMT and the iManager M2000 provide compressive and easy-to-use online help. The help allows operators to quickly access required information during operation and maintenance. Commercial in Confidence Page 40 of 40 HUAWEI SGSN9810 System Description Chapter 6 Reliability 6.1 About this Chapter This chapter introduces the reliability of the SGSN9810 hardware, software, and charging devices. It includes the following sections Hardware Reliability Software Reliability Charging Reliability 6.2 Hardware Reliability The SGSN9810 uses the following reliability designs. Board backup Load sharing Board fault detection and isolation System fault detection and isolation 6.2.1 Board Hot Backup The SGSN9810 boards are configured in the 1+1 backup or N+1 redundancy. The following are the two major considerations in the backup design: Board fault detection When a board is powered on, it checks its memory and key external chips such as the network chips. Key signals (such as the clock signal) used by the board are monitored online. Loopback test of service code flow is conducted when the board is idle. Switchover mechanism The active-standby switchover is carried out by two cross-connected signals between the active board and the standby board. They are the output signal effective to the active board and the input signal effective to the standby board. 6.2.2 ASIC Technology All the network chips used in the boards are special application specific integrated circuits (ASICs). These ASICs provide reliable measures to detect and report internal (chip-level) errors. Commercial in Confidence Page 41 of 41 HUAWEI SGSN9810 System Description 6.2.3 Quality Components The SGSN9810 uses quality components that have passed burn-in tests and proved to meet stringent requirements. The hardware is assembled under strict control to ensure that the system remains stable and reliable in the long term. 6.2.4 Load Sharing Load sharing means that two or more boards perform relevant functions under normal operation. When one of the boards is faulty, other boards perform the task of the faulty board to ensure certain performance indexes (such as call loss). Load sharing is applied to secondary power modules, signaling links, and STM-1 interfaces. 6.2.5 Power Supply Reliability The SGSN9810 uses a distributed power supply. Each subrack or functional module has its own high-frequency DC/DC secondary power module that is highly efficient and stable. The secondary power supply adopts the active/standby hot backup design to ensure the reliable power supply. The power inputs and the external interfaces (such as the E1 interfaces) of boards provide protection against high voltages and current surges. The measures meet the international telecommunication union - telecommunication standardization sector (ITU-T) recommendation G.703 and other relevant specifications. 6.3 Software Reliability This section describes the measures that build up the reliability of the SGSN9810 software. 6.3.1 Reliability Building at Different Phases The key to improve software reliability is reducing software defects. The reliability of the SGSN9810 software is ensured at various phases from system requirements analysis to system test. From the requirements analysis phase, the software development is carried out under the guidance of various capability maturity model (CMM) specifications. This reduces errors in the initial phase. The SGSN9810 software is designed in modules. The modules are loosely coupled so that the fault of one module does not affect the performance of other modules. In additional, measures such as error check, error isolation, and recovery, are added to improve system reliability. Commercial in Confidence Page 42 of 42 HUAWEI SGSN9810 System Description Code walk-through, inspection, and tests at every phase further improve the software reliability. 6.3.2 Error Tolerance The error tolerance of a software system indicates the resilience of the system under minor software faults. That means the system does not break down on minor faults and has self-healing ability when an error occurs. The error tolerance of software involves the following measures: Regular check of key resources For various software resources in the system (such as the network board resources), long-time seizure check mechanism is provided. If resources do no respond due to a software exception, the check mechanism releases the resources and generates logs and alarms. Task monitoring Output channels are provided for the internal software faults and some of the hardware faults detected during system operation. These output channels monitor the status of a task and report system exceptions to external devices. Storage protection The software system uses the segment and page protection mechanism for the CPU memory management unit (MMU) to protect the storage of codes and important data segments. It also provides functions of online query, modification of variables and data, and memory monitoring. Data check To ensure the consistency of the data on various service processing boards, the system performs regular or event-triggered consistency checks. It can also restore data consistency based on certain criteria and generate logs and alarms. Operation log storage The SGSN9810 records user operations at a certain period and stores them in the system log. Faults can be located by analyzing the operation log for unknown errors in the system. Load control In the case of CPU overload or resource congestion, the load control mechanism adjusts the load smoothly to avoid system down. 6.4 Charging Reliability The SGSN9810 generates CDRs on various service processing boards and sends them to the UCDR board. The UCDR board then sends the CDRs to the CG over the Ga interface. Commercial in Confidence Page 43 of 43 HUAWEI SGSN9810 System Description If the CG or the network is faulty, the CDRs in the CDR pool are saved to the hard disk on the UCDR board. The CDRs can be written back to the CDR pool and sent to the CG when the CG recovers. Commercial in Confidence Page 44 of 44 HUAWEI SGSN9810 System Description Chapter 7 Technical Specifications 7.1 About This Chapter This chapter lists the technical specifications of the SGSN9810. It includes the following sections: Performance Specifications Engineering Specifications Reliability Specifications Physical Interfaces 7.2 Performance Specifications Table 7-1 lists the performance specifications of the SGSN9810. Table 7-1 Performance specifications of the SGSN9810 Parameter Value (2.5G) Value (3G) Maximum number of attached subscribers 2 million 2 million Maximum number of PDP context can be activated simutaneously 2 million 2 million Maximum packet data transfer capacity (pps) 600,000 4 million Maximum packet data transfer flow 600 Mbit/s 10 Gbit/s 7.3 Engineering Specifications Engineering specifications include the power consumption of the SGSN9810, dimensions and weight of cabinets, and environment requirements. 7.3.1 Power Consumption Table 7-2 lists the power consumption of the SGSN9810. Table 7-2 Power consumption of the SGSN9810 Parameter Value Power consumption of a PSM switching subrack 560 W Power consumption of a PSM service subrack 460 W Commercial in Confidence Page 45 of 45 HUAWEI SGSN9810 System Description Parameter Value Power consumption of a power distribution subrack 20 W Maximum configuration for 3G systems (3 cabinets, 11 subracks, not supporting SIGTRAN) 5,220 W Maximum configuration for 3G systems (3 cabinets, 12 subracks, supporting SIGTRAN) 5,680 W Maximum configuration for 2.5G systems (5 cabinets, 19 subracks) 8,940 W 7.3.2 Dimensions and Weight of Cabinets Table 7-3 lists the dimensions and weight of a SGSN9810 cabinet. Table 7-3 Dimensions and weight of a SGSN9810 cabinet Parameter Value Cabinet dimension (H x W x D) 2200 mm x 600 mm x 800 mm Cabinet weight ≤ 350 kg 7.3.3 Environment Requirements I. Storage Environment The SGSN9810 complies with the "not temperature-controlled storage" requirements specified in European ETS 300 019-1-1. The SGSN9810 must be stored in the following environment: Relative humidity: 10% to 100% Temperature: –40°C to +70°C II. Transportation Environment The SGSN9810 complies with "Class 2.3 Public transportation" requirements specified in European ETS 300 019-1-2. The SGSN9810 must be transported in the following environment: Temperature: –40 °C to +70 °C Relative humidity: 5% to 100% III. Operational Environment The SGSN9810 complies with "Temperature-controlled locations" requirements specified in European ETS 300 019-1-3. The SGSN9810 must operate in the following environment: Commercial in Confidence Page 46 of 46 HUAWEI SGSN9810 System Description Normal operation: Temperature (0°C to + 45°C), humidity (5% to 85%) Safe operation: Temperature (–5 °C to + 55 °C), humidity (5% to 95%) Safe operation indicates the conditions in which the SGSN9810 must not work for continuously over 96 hours and accumulated over 15 days in a year. IV. Electromagnetic Compatibility The SGSN9810 complies with the GR-1089-CORE standard on electromagnetic compatibility. V. Power Supply Power voltage range: –40 V to –57 V DC Input current: 50 A for a cabinet 7.4 Reliability Specifications Table 7-4 shows the reliability specifications of the SGSN9810. Table 7-4 Reliability specifications of the SGSN9810 Parameter Value System availability in typical configuration ≥ 99.999% Mean time between failure (MTBF) ≥ 300,000 hours Mean time to repair (MTTR) ≤ 30 minutes 7.5 Physical Interfaces Table 7-5 shows the physical interfaces provided by the SGSN9810. Table 7-5 Physical interfaces provided by the SGSN9810 Interfaces Iu-PS (control plane) Iu-PS (user plane) Commercial in Confidence Physical characteristics Protocol STM-1 (single-mode and multi-mode) ATM STM-4 (single-mode and multi-mode) ATM STM-1 (single-mode and multi-mode) ATM STM-4 (single-mode and multi-mode) ATM Gigabit Ethernet(GE) IP Maximum ports 80 40 80 40 80 Page 47 of 47 HUAWEI SGSN9810 System Description Physical characteristics Interfaces Gn, Gp, Ga, X1-1, X2, and X3 Gb Protocol Maximum ports Fast Ethernet(FE) IP 80 GE IP 80 FE IP 80 STM-1 IP over ATM (IPOA) 80 STM-4 IPOA 40 E1/T1 FR 800 SS7 2 Mbit/s signaling links: 34; Or 64 kbit/s signaling links: 1,088 IP 2 SS7 E1/T1 O&M FE Note: The Gn, Gp, Ga, X1-1, X2, and X3 interfaces share 160 STM-1, 160 FE, 160 GE, and 80 STM-4 ports or a combination of these four types physical port. Commercial in Confidence Page 48 of 48 HUAWEI SGSN9810 System Description Chapter 8 Installation The installation of the SGSN9810 includes the hardware, the terminal software, and the board software. Hardware The cabinets, subracks and cables are installed before delivery. Installation engineers only need to install external cables and boards. For board installation, the SGSN9810 provides coding slots so that installation engineers can insert boards only in the correct slots. This avoids damage to boards when engineers attempt to install boards in the wrong slots. Terminal software The SGSN9810 provides a standard Windows installation wizard to guide the installation of the terminal software. Following the instructions, field engineers can complete the installation easily. Board software The SGSN9810 provides MML commands for engineers to install software for all the boards or only specified boards. Note: For detailed installation procedures, refer to the installation manuals delivered with the product. Commercial in Confidence Page 49 of 49 HUAWEI SGSN9810 System Description Appendix Acronyms and Abbreviations 3 3GMS 3rd Generation Mobile Communications System 3GPP 3rd Generation Partnership Project A AAA Authentication, Authorization, and Accounting ADMF Administration Function AF Assured Forwarding APN Access Point Name ASIC Application Specific Integrated Circuit ATM Asynchronous Transfer Mode AUC Authentication Center B BC Bear Channel BE Best-Effort BG Border Gateway BITS Building Integrated Timing Supply BSC Base Station Controller BSS Base Station Subsystem BSSGP Base Station Subsystem GPRS Protocol BVC BSSGP Virtual Connection C CAMEL Customized Applications for Mobile network Enhanced Logic CAR Committed Access Rate CBWFQ Class-Based Weighted Fair Queuing CBR Constant Bit Rate CC Content of Communication Commercial in Confidence Page 50 of 50 HUAWEI SGSN9810 System Description CDMA Code Division Multiple Access CDR Call Data Record CG Charging Gateway CGF Charging Gateway Functionality CLNP Connectionless Network Protocol CMM Capability Maturity Model CN Core Network CN-CS Core Network – Circuit Switch domain CN-PS Core Network – Packet Switch domain CORBA Common Object Request Broker Architecture CPU Central Processing Unit D DC Direct Current DF Delivery Function DiffServ Differential Services DNS Domain Name Server DOPRA Distributed Object-oriented Programmable Real-time Architecture DSCP Differentiated Services Code Point E EDGE Enhanced Data rates for GSM Evolution EF Expedited Forwarding EIR Equipment Identification Register EMS Enhanced Messaging Service ETS European Telecommunication Standards F FA Foreign Agent FE Fast Ethernet FR Frame Relay FTP File Transfer Protocol Commercial in Confidence Page 51 of 51 HUAWEI SGSN9810 System Description G GE Gigabit Ethernet; Gigabit Ethernet GERAN GSM/EDGE Radio Access Network GGSN Gateway GPRS Support Node GMLC Gateway Mobile Location Center GPRS General Packet Radio Service gsmSCF GSM Service Control Function gprsSSF GPRS Service Switching Function GSM Global System for Mobile Communications GSN GPRS Support Node GTP GPRS Tunneling Protocol GTP-C Control plane part of GPRS tunneling protocol GTP-U User plane part of GPRS tunneling protocol GUI Graphic User Interface H HA Home Agent HLR Home Location Register HPLMN Home PLMN HSDPA High Speed Downlink Packet Access HSS Home Subscriber Server I I-CSCF Interrogating- Call State Control Function IETF Internet Engineering Task Force IGP Interior Gateway Protocol IMEISV International Mobile station Equipment Identity and Software Version number IMS IP Multimedia Subsystem IMSI International Mobile Subscriber Identity IP Internet Protocol IPSec Internet Protocol Security extensions IRI Intercept Related Information ISDN Integrated Services Digital Network Commercial in Confidence Page 52 of 52 HUAWEI SGSN9810 System Description IS-IS Intermediate System-Intermediate System ISO International Organization for Standardization ITU-T International Telecommunication Union Telecommunication Standardization Sector IUA ISDN Q.921 User Adaptation Layer L LA Location Area LAN Local Area Network LCS Location Service LEA Law enforcement agency LIS Logical IP Subnet LLC Logical Link Control LMT Local Maintenance Terminal M M2PA MTP2 Peer Adaptation Layer M2UA MTP2 User Adaptation Layer M3UA MTP3 User Adaptation Layer MAC Media Access Control MAP Mobile Application Part MBR Mobility Binding Record MIP Mobile IP MM Mobility Management MML Man-Machine Language MMU Multiplication and Management Unit MNO Mobile Network Operator MO Mobile Originated MS Mobile Station MSC Mobile Service Switching Center MSISDN Mobile Station International ISDN Number MT Mobile Terminated MTBF Mean Time Between Failures MTP3 Message Transfer Part 3rd Layer Commercial in Confidence Page 53 of 53 HUAWEI SGSN9810 System Description MTP3B Message transfer part (broadband) MVNO Mobile Virtual Network Operator N NACC Network Assisted Cell Change NS Network Service NS-VC Network Service Virtual Connection NTP Network Time Protocol O OS Operational System OSI Open Systems Interconnection OSPF Open Shortest Path First P P-CSCF Proxy CSCF PDN Public Data Network PDP Packet Data Protocol PDU Packet Data Unit PHB Per-Hop Behaviors PLMN Public Land Mobile Network POS Packet Over SDH PPP Point-to-Point Protocol PS Packet Switched PSM Packet Service Module PSTN Public Switched Telephone Network PTP Point To Point Q QoS Quality of Service R RA Commercial in Confidence Routing Area Page 54 of 54 HUAWEI SGSN9810 System Description RADIUS Remote Authentication Dial in User Service RAN Radio Access Network RANAP Radio Access Network Application Part RRC Radio Resource Control RIP Routing Information Protocol RIPng RIP next generation RNC Radio Network Controller S SAAL Signaling ATM Adaptation Layer SC Service Center SCCP Signaling Connection and Control Part SCP Service Control Point S-CSCF Serving CSCF SCTP Stream Control Transmission Protocol SDH Synchronous Digital Hierarchy SDU Service Data Unit SGSN Serving GPRS Support Node SIGTRAN Signaling Transport protocol SIP Session Initiation Protocol SM Session Management SME Short Message Entity SMS Short Message Service SM-SC Short Message Service - Service Centre SMS-GMSC Short Message Service Gateway MSC SMS-IWMSC Short Message Service Interworking MSC SNA Shared Network Area SNDCP Subnetwork Dependent Convergence Protocol SNMP Simple Network Management Protocol SPF Shortest Path First SRNC Serving RNC SS7 CCITT Signaling System No.7 SSP Service Switching Point Commercial in Confidence Page 55 of 55 HUAWEI SGSN9810 System Description STM-1 SDH Transport Module -1 STM-4 SDH Transport Module -4 SUA SCCP User Adaptation Layer T TCP Transport Control Protocol TE Terminal Equipment TEID Tunnel End ID U UACU Auxiliary Control Unit UALU PSM Alarm Unit UBIU PSM Back Interface Unit UBR Unspecified Bit Rate UBSU Back Storage Unit UCDR Charging Detail Record unit UCKI Clock Unit UDP User Datagram Protocol UE User Equipment UEPI E1 Processing Interface unit UESBI UE Specific Behavior Information UFCU Frame Connect Unit UFSU Flash Storage Unit UGBI Gb Interface unit UGFU GTP Forwarding Unit UGTP GTP processing unit UICP Iu-PS Control Processing unit ULAN LAN switch card ULIP Lawful Interception Processing unit UMTS Universal mobile telecommunication services/Universal Mobile Telecommunications System UOMU Packet Service O&M Unit UPIU Packet Interface Unit UPWR PSM PoWeR module Commercial in Confidence Page 56 of 56 HUAWEI SGSN9810 System Description URCU Subrack Control Unit USIG SIGTRAN Process Unit USPU Packet Service Signal Processing Unit USS7 SS7 Signaling Link Processing Unit UTPI T1 Processing Interface unit UTRAN UMTS Terrestrial radio access network V V5UA V5 User Adaptation Layer VBR Variable Bit Rate VLR Visitor Location Register VMSC Visited Mobile Switching Center , Visited MSC VPLMN Visited PLMN VPN Virtual Private Network W WCDMA Wideband Code Division Multiple Access WRED Weighted Random Early Detection Commercial in Confidence Page 57 of 57