《铁路数字移动通信系统(GSM-R)设计规范(TB10088-2015)(英文版)》:
3.1 GeneraIRequirements
3.1.1 The design of core network shall include the following contents:
1 Switching Subsystem(SSS).
2 Intelligent Network(IN)Subsystem,
3 Core network equipment of General Packet Radio Service(GPRS)subsystem.
4 Equipment related to the packet switched(PS)domain application system.
3.1.2 The setting location of the core network equipment shall comply with the communication network planning.
3.1.3 The subscriber capacity,quantity of interfaces and processing capacity of all the subsystems of the core network shall be under unified planning and design and should satisfy the demand in the short term.
3.1.4 The bandwidth of links for interconnection between the core network equipment should satisfy the demand for the 5th year after commercial operation and should be provided with the conditions for future expansion
3.2 Switching Subsystem(SSS)
3.2.1 According to the network scale,the network structure of SSS may be designed as:
1 One-level structure of local network.
2 Two-Ievel structure of tandem network and local network.
3.2.2 The design of tandem network includes the TMSCs and the trunk links connecting these nodes and shall comply with the following provisions:
1 The whole network may be divided into several mobile service tandem areas.
2 Each tandem area should be provided with a standalone TMSC.
3 The interconnection between the TMSCs shall be in the form of a mesh network structure.
3.2.3 The local network shall be provided with the Mobile Switching Center(MSC), Visitor Location Register(VLR), Group Call Register(GCR),InterWorking Function(IWF), Gateway Mobile Switching Center(GMSC), Home Location Register(HLR),Authentication Center(AuC), Acknowledgement Center(AC),etc.,and may be provided with the Short Message Service Center(SMSC)and Equipment Identity Register(EIR)as required.
3.2.4 The setting and networking of MSC shall comply with the following provisions:
1 MSC should be set in a centralized manner with redundancy configuration.
2 The 1+1 active/standby mode or the load sharing redundancy mode may be adopted for MSC.
3 A direct link should be provided between the adjacent handover MSCs for a Base Station Subsystem(BSS).
4 For the SSS designed with a two-level network structure,the MSC shall be connected to two home fMSCs respectively.
5 When R4 network architecture is adopted for MSC and TMSC,transmission links should be employed for the interconnection between the adjacent MSCs,between MSC and TMSC as well as between TMSCs.
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