Basic of MSC Networking

MSC Networking

The MSOFTX3000 supports various protocols, such as the H.248, BSSAP, RANAP, MAP, CAP, ISUP, TUP, and BSSAP+. It can work as the mobile switching center (MSC) server and the VLR in the network. When deployed with UMG8900 and the Shared InterWorking Function (SIWF), theMSOFTX3000 supports the BSS, UTRAN and SBC access and can function as the 2G VMSC, 3G VMSC, or 2G/3G integrated VMSC in the network.

Typical MSC networking

BSS: GSM Base Station Subsystem

UTRAN: UMTS Terrestrial Radio Access Network

SBC: Session Border Controller

GMSC: Gateway Mobile Switching Center

BC: Billing Center

HLR: Home Location Register

HSS: Home Subscriber Server

SMC: Short Message Center

GMLC: Gateway Mobile Location Center

SCP: Service Control Point

SGSN: Serving GPRS Support Node

PSTN: Public Switched Telephone Network

PLMN: Public Land Mobile Network

The MSOFTX3000 terminates the mobile subscriber/network signaling defined by the R99 24.008 and R98 04.08 specifications. It converts the signaling to the inter-office signaling transferred on the Nc interface. In addition, the MSOFTX3000 stores the subscription data of mobile subscribers and the related CAMEL data in its embedded VLR. The GMSC realizes the interworking between the MSOFTX3000 and the PSTN/PLMN. Through the Mc interface, the MSOFTX3000 controls the bearer terminal and media stream at the access network and backbone network side in the UMG8900. The interface, protocol and physical interface modes between the MSOFTX3000 and other network elements are as follows:

• MSOFTX3000 <-> UMG8900: Mc interface. It is the standard interface of the control layer and bearer layer in the core network. It adopts the extended H.248 protocol defined by the ITU-T. Through the Mc interface, the MSOFTX3000 controls the bearer resources at the radio access side and trunk side. The interface is an IP-based interface added in the R4 stage.
• MSOFTX3000 <-> BSC: A interface. It is the standard interface in the control layer between the core network and the BSS radio access network, based on the GSM. It adopts the BSSAP protocol, and realizes the termination of the controlling signaling messages for the service access in the circuit switched (CS) domain for the 2G mobile subscribers. The A interface provides the following functions:
• Mobility management
• Call control
• Circuit allocation
• Circuit reset
• Handover
• Short message processing
• It is a TDM-based interface that adopts the BSSAP protocol for the GSM MSC. It can also be connected through the UMG8900 with the SIGTRAN function. In this case, it adopts the M2UA protocol.
• MSOFTX3000 <-> RNC: Iu interface. It is the standard interface in the control layer between the core network and the UTRAN based on the WCDMA. It adopts the RANAP protocol, and realizes termination of the controlling signaling messages for the service access in the CS domain for the 3G mobile subscribers. The Iu interface provides the following functions:
• Mobility management
• Call control
• RAB allocation
• Reset and overload control
• RNC re-allocation
• Short message processing
• This interface inherits the functions in the R99 stage. It can be an IP-based (M3UA) interface. When a direct interface does not exist between the MSOFTX3000 and the RNC, the Iu interface can be connected through the UMG8900.
• MSOFTX3000<->SBC: The interface adopts the SIP protocol. The VoBB subscribers interact with the MSOFTX3000 through the SBC. The SBC processes the service messages of the VoBB subscribers, such as the location update message, and forwards the subscriber messages.
• MSOFTX3000 <-> GMSC/GMSC server: The MSOFTX3000 adopts the ISUP/TUP protocol for interworking with the GMSC. When theMSOFTX3000 interworks with the GMSC server, the interface is called the Nc interface. The Nc interface is the inter-office signaling interface in the control layer of the CS domain. It is an IP-based or TDM-based interface that adopts the ISUP/TUP or BICC protocol. It is added in the R4 stage.
• MSOFTX3000 <-> MSC: E/G interface. It is adopted only between the neighboring MSCs (not shown in the figure). It is a TDM-based or IP-based interface that adopts the MAP protocol, used for inter-office handover and location update.
• MSOFTX3000 <-> HLR: C/D interface. It adopts the MAP protocol; is used for the location update of network level in the CS domain, and the management of routing data and subscription data. It is a TDM-based or IP-based interface directly inherited from the R99 stage.
• MSOFTX3000 <-> HSS: Sh/Cx interface. It adopts the Diameter protocol. The MSOFTX3000 communicates the VoBB subscription data with the HSS through the Sh interface and communicates the VoBB authentication data with the HSS through the Cx interface.
• MSOFTX3000 <-> SCP: The interface adopts the CAP protocol. It provides the following functions:
• Realizing the standard connection between the SSP and SCP in the CS domain integrated in the MSOFTX3000
• Reporting the O/T-BCSM call state event, and executing the commands from the SCP
• Thus, in the R4 stage, the intelligent services in the R99 and GSM stage can be realized in the transparent subscriber mode. The interface is a TDM-based or IP-based interface directly inherited from the R99 stage.
• MSOFTX3000<->SMC: E interface. It adopts the MAP protocol, and transfers the mobile originated and mobile terminated short messages between the SMC and the MSOFTX3000.
• MSOFTX3000<->GMLC: Lg interface. It adopts the MAP protocol. The Lg interface between the MSOFTX3000 and the GMLC supports the location application outside the PLMN to exchange the subscriber authentication data required by the location service and the data (such as the IMSI) required by the network resource allocation with the MSC, through the GMLC, and locate the QoS.
• MSOFTX3000<->SGSN: Gs interface. It adopts the BSSAP+ protocol. The Gs interface between the MSOFTX3000 and the SGSN integrates certain functions of the packet switched (PS) domain and the CS domain (such as the united location update) to save the wireless resources.
• MSOFTX3000<->BC: The interface adopts the FTP/FTAM protocol and enables the BC to automatically fetch the CDRs from the iGWB of theMSOFTX3000.
• MSOFTX3000<->M2000: The interface adopts the MML protocol and supports the MSOFTX3000 to access the iManager M2000network management system.