Telecommunication and Data Handling Systems at NMC, China LI Xiang Telecommunication Division, NMC, China E-mail: lixiang@cma.gov.cn 2019/4/25

County level weather centers 2000 CMA’s domestic communications system GTS system at RTH Beijing City level weather centers 300 NICC data management system GTS GTS system Provincial level weather centers 24 LAN Regional level weather centers 6 PCVSAT data broadcasting system SWAN (Satellite Wide Area Network) CHINAPAC (X.25 network) Dial up lines or leased lines

1. Domestic communications system (1) Operating environment of NICC data management system Data management and storage Hardware IBM RS/6000 H50 data management minicomputer equipped with color graphics terminal Duplicated system (HACMP) Operating System: AIX V4.1 PCVSAT Mux PC Windows NT 2019/4/25

1. Domestic communications system (2) Data collection at NICC Regional, provincial, city level offices pushing data to NICC by ftp via SWAN Backup means: regional, provincial offices pushing data to NICC by ftp via CHINAPAC 2019/4/25

1. Domestic communications system (3) Data distribution at NICC PCVSAT data broadcasting IP Multicast over SWAN (partial data backup to PCVSAT broadcasting) Request-reply mechanism for regional, provincial and city level offices in case of incomplete reception Data request sent to NICC by ftp over SWAN Required data sent to remotes over PCVSAT by NICC Backup means: regional, provincial offices pulling data from NICC by ftp over CHINAPAC 2019/4/25

1. Domestic communications system (4) Data handling at NICC File level handling File transmission control table A DBM database A record including a key and its content Key: filename Content: estimated time of receiving, modes of send, IP address of receiving host, …… Accessed by using system calls such as dbm_open, dbm_store and dbm_fetch, which are provided by UNIX operation system. 2019/4/25

2. GTS system at RTH Beijing (1) Asynchronous circuits Hanoi, Pyongyang, Ulan bator X.25 circuits Bangkok, Moscow, New Delhi, Offenbach Frame relay links Tokyo, Seoul 2019/4/25

2. GTS system at RTH Beijing (2) LL 128K Equant Global Frame Relay NMC end user Port 128K CNC DTU DDN DTU CIR 48K Cisco Router Cisco Router Port 128K LL 128K CMA DWD Beijing-Offenbach GTS Link 2019/4/25

2. GTS system at RTH Beijing (3) Operating environment of MSS Hardware Alpha 1000 Duplicated system (VaxCluster) Operating System VMS 2019/4/25

2. GTS system at RTH Beijing (4) Data handling bulletin level handling bulletin transmission control table TTAAii, CCCC Source circuit Destination circuit or IP Time information …… 2019/4/25

3. Data exchanging between NICC and MSS File level data exchanging MSS host pushing GTS data to NICC by ftp via LAN Domestic data pushed from NICC to MSS host via LAN 2019/4/25

Thank you 2019/4/25