POLNET is a satellite based wide area network for the modernization of Police Telecommunication of the country. POLNET is an amalgamation of different latest VSAT technologies ie TDM/TDMA, SCPC/DAMA and DVB-S. It is a huge network consisting of about 1000VSATs (Very Small Aperture Terminals at each state capital, District HQrs and selected locations of CPMFs (BSF, ITBP, CISF, CRPF, Assam Rifles, SSB) and CPOs . At present POLNET caters to 961 no. of VSATs through a HUB installed in New Delhi with 11 mtr antenna with necessary Outdoor and Indoor equipments to support total VSAT Network of about 1500 locations for VOICE, DATA, FAX facilities. Out of existing 961 V-SAT Terminals, 41 VSAT Terminals of 3.8 mtr antenna size installed at the Capital of each State / UT and some of the CPOs locations based on Hybrid technology which can support both TDM / TDMA and SCPC / DAMA scheme for Star and Mesh connectivity, 811 TDM/TDMA V-SAT Terminals with 1.8 / 2.4 M Antenna size installed at District Hqrs of all states and UTs and other important locations of CPMFs, MHA., NCRB, and CPOs etc. , remaining 109 are broadband VSAT terminals based on DVB-S technology installed at various locations of BSF and ITBP. The TDM/TDMA VSATs works on double hop link through the central Hub at New Delhi for communication with other sites. State Hqrs. with Hybrid vsat tml can communicate directly with better voice quality utilizing single hop SCPC /DAMA Channel. The connectivity from District Hqrs is being extended upto Police Stations / Police Posts through local Radio Network using MART (Multi Access Radio Telephone) system.
The POLNET network is also providing connectivity for interlinking NCRB computers to SCRB and DCRB computers provided to State/District HQrs. for online transaction processing.
2. The POLNET Network configuration is as shown in the diagram -
3. The salient features of POLNET captive network are summarized below :
a) Network size :
At present 961 NO. of VSATs are operational and network can support upto 1500 VSAT terminals.
b) Services :
VOICE - (1)Using VOIP on H.323 protocol & G.723.1 Coder in
TDM/TDMA (Star Topology). (2) SCPC in Mesh topology
FAX – Group III
Data Communication (i) Using TCP/IP protocol over Ethernet
(ii) Over x.25 network using Serial port
Data Message Broadcast from any remote.
Video and Audio data Broadcast from HUB on scheduled basis
c) Connectivity :
The IDU (Satellite modem) provides two type ports
(i) Ethernet 10Base T (RJ-45)
(ii) Serial Port (X.28)
4. Futuristic Goals :
The captive POLNET satellite network has further broadened its utility on satisfactory inputs / requirements from the users i.e. States / UT’s and CPMFs. The CPMFs specially found enhanced scope for exploring the POLNET capabilities for their organizational requirements. Accordingly the technology up-gradation in the POLNET has been undertaken by inducting 109 Broadband VSATs with latest technology i.e. DVB-S by providing Outroute of 2Mbps data rate and Inroute of 512Kbps data rate for providing highly enriched quality of voice and data services with efficient utilization of the Bandwidth.
Realizing the demands projected by many Police organizations, MHA constituted a High level committee under the Chairmanship of Director, ISRO. The committee has submitted its report to MHA on communication requirements of CPMFs / feasibility of POLNET Project. The committee recommended VSATs with latest technology features like DVB-S2, which will support Voice , video conferencing and Data services with efficient space bandwidth utilization to meet the communication requirements of CPMFs. The new upgraded VSAT network will have the capability not only to accommodate the present requirements of the CPMFs but also have the capability to accommodate the expansion of the network in terms of both Inroutes and Outroutes depending upon the future requirement of each CPMF .