1. Telecommunication and Data Handling Systems at NMC, China
LI Xiang
Telecommunication Division, NMC, China
2019/4/25

2. 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

3. 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

4. 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

5. 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

6. 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

7. 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

8. 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

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

10. 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

11. 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

12. Thank you
2019/4/25