A Very Small Aperture Terminal (VSAT) is a remote terminal in a satellite communications network. The term VSAT refers to the smaller size of the antenna dish, which is normally 2.4 meters or smaller in diameter.
The satellite mentioned above is essentially a repeater or mirror that reflects transmissions from the terminal back to earth. This enables one terminal in the network to communicate with another terminal located in a remote distant location. It also enables transmission of information from one terminal to other terminals, as the retransmission of the signals from the satellite back to earth normally covers a large geographical area.
Actually, it acquires data from its attached terminals and transmits it in the form of radio signals to a geo-stationary communication satellite. The satellite amplifies and translates these signals and sends them back to a master earth station (often called as a Hub). The Hub then sends the data to the host computer for processing. The processed data traverses the reverse path and reaches the originating station. The host computer can either be co-located with the Hub or it may be at another geographical area. In the latter case, it is connected with Hub using either the leased or another VSAT. During stock share trading
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Typical VSAT architectures can be of different types. It can be either star, full mesh or hybrid. ‘Star’ means that one central site communicates with all the remote sites. This is the architecture of satellite TV broadcasting, in which one large central antenna transmits data to many remote antennas. However, VSATs can offer two-way communication, with the remotes also by transmitting to, as well as receiving from, the central site. If two remotes communicate, the sending remote transmits to the central site. The central site retransmits the message to the intended remote. This means two trips to the satellite.
‘Full-mesh’ means that any terminal in the network can communicate with any other network with only one trip to the satellite. There is no intermediate stop at a central site. ‘Hybrid’ means the network architecture employs both star and full-mesh. An example of this is a network that uses star for data transmissions to a central site and also provides voice communications between all remote terminals (full-mesh).