Advantages of VSAT | Disadvantages of VSAT
This page covers advantages and disadvantages of VSAT. It mentions VSAT advantages or merits or benefits and VSAT disadvantages or demerits or drawbacks.
The term VSAT is the short form of Very Small Aperture Terminal. It requires GEO satellite to be available in the space in order to provide the service. Depending upon applications of use, VSATs are used at various frequency bands viz. L Band, C Band, Extended C Band, Ku Band and Ka Band.
The figure-1 depicts typical block diagram of VSAT terminal. There are two VSAT network topologies viz. Star and mesh. In Star topology, VSAT to VSAT communication happens through Hub Station and Satellite in two hops. In mesh topology, VSAT to VSAT communication happens directly without the need of central Hub Station.
The figure-2 depicts these network architectures. It can be used to transmit any type of information such as voice, video and data.
Advantages of VSAT
Following are the advantages of VSAT:
➨Installation: VSAT services are deployed in hours or minutes.
➨Coverage: It can be available anywhere with clear line of sight between VSAT antenna disc and satellite over the earth. It is popular in hilly areas where other mode of communication is either not available or difficult to install.
➨Price: VSAT terminals are cheaper.
➨Upgradaion: It is flexible to add a VSAT site and increase the bandwidth as per future requirements.
➨Service charges: It depends on the bandwidth allocated as per user requirements.
➨Most modern VSAT systems use TCP/HTTP and other acceleration protocols to have superior performance inspite of latency limitation as outlined below.
➨VSAT provides same quality of service and speed at all the locations across the entire VSAT network.
➨VSAT services are independant of other wired and wireless mediums used as transmission network service provider. Hence it is a great backup system which is available during disaster and emergency situations.
➨VSAT terminals and indoor/outdoor hardwares can be installed on truck or van and can be used even in mobility conditions.
➨There are no last mile issues in VSAT operation.
Disadvantages of VSAT
Following are the disadvantages of VSAT:
➨As mentioned it requires clear Line of Sight between VSAT dish and satellite in the space.
➨The malfunctioning of satellite and Hub station (in case of star topology) will lead to disruption of VSAT services. To avoid this situation, redundant systems and switch over units are needed to have backup systems available for hot switching in faulty situations. But this increases overall cost of the VSAT system as a whole.
➨Latency for packet transmission from source to destination is higher due to distance of satellite from earth is about 36000 Km. Latency further increases in star topology of VSAT, as it requires two hops to reach at final destination.
➨VSAT services get affected in bad weather conditions.
➨As information transmitted by VSAT goes over the air till it reaches destination, it is prone to intrusion by hackers. Hence encryption-decryption units are needed to have secure communication. This increases the overall VSAT terminal cost.