Advantages of VSAT – Why Satellite Networks make a good choice for WAN and Internet connectivity
We do not generally consider VSAT satellite technology for providing primary WAN links in our organizations or broadband Internet access at our homes. This article elucidates the advantages and benefits of VSAT and tells you why VSAT Networks are becoming a compelling alternative to terrestrial WAN links and broadband connectivity.
With the advent of high speed mobile Internet technologies like LTE and proposed high speed direct fiber to home technologies, Satellite technologies like VSAT sound very old and meant for remote weather forecasting/ broadcasting etc? Think again – A lot of action is going on in the Satellite technologies and the home cable network like DTH is a result of such advancements. In fact, VSAT networks are now competing for home Internet broadband access and primary corporate WAN connectivity. As usual, IP is in the forefront and enabled such developments.
What is VSAT?
VSAT is the short form for Very Small Aperture Terminals. In short, there are three main components of the VSAT Technology – The Satellite, A Central Hub (With a Big Dish Antenna) and a number of smaller nodes (smaller dish antenna) kept at various remote locations that together form a Star topology (Even Mesh topologies are possible for small networks) using the satellite network. So essentially, all the nodes communicate with the central hub through the satellite as the medium for such communications. In case additional networks (Internet, terrestrial MPLS, etc) need to be integrated with this VSAT network, they can be done at a NOC (Network Operations Center) at the central hub.
Lately, the Geo-Synchronous satellites are used more for WAN/ broadband Internet connectivity as it can provide a permanent coverage over a fixed area. After C, Ku bands it is the Ka band which is hogging the limelight for its high throughput performance capabilities (Excess of 100 Gbps per satellite).
Advantages / Benefits of VSAT Satellite Networks:
Access in Remote Locations: This has been the traditional strength of Satellite Networks. A Satellite in the Geo Synchronous orbit can cover around 33% of the earth’s surface and can provide connectivity to any region covered by it. A satellite can also focus on a particular high density region and multiple satellites can work together to provide global coverage. This is very useful for remote locations (rural areas, ships and coastal regions, hills, etc) where there is limited or no terrestrial connectivity.
A VSAT network can today carry data as well as latency sensitive applications like voice and video as well. That’s why the DTH (Cable TV), Internet Radio and other technologies have found applications in real life situations. Even IP based Multi-cast applications like audio and video streaming are possible (Eg. Digital Signage applications).
Internet Access: A VSAT Network can provide Internet access in addition to the point to point WAN links. Its all set to create a next major wave in the consumer broadband industry with the launch of satellites operating in the Ka band offering very high throughput, especially in the non metro regions. ‘Always ON’ broadband Internet services are possible with VSAT networks.
Rapid deployment: Once the Satellite is put in to its orbit, the deployment at the customer premises can be done (usually in hours) if the equipment is available, with minimum training. And the deployment can be done in any region, irrespective of where it is located.
VPN: Satellites support encryption of all data transmitted between two sites or multiple sites, which make the creation of Virtual Private Networks (VPN) possible. This is one reason why the VSAT networks could find more acceptance in the corporate and Government/ Defense connectivity requirements.
QoS: VSAT Networks support QoS (Quality of Service) and Layer 2 prioritization policies to be applied across the WAN link which enables real time applications to be deployed across the network.
Mobile Access: Mobile access has been another traditional strength of a satellite network. This makes TV broadcasters (for example) make broadcasts from anywhere – even when they are on the move. Another possible application could be mobile Internet access, while on the move.
Bandwidth Allocation: It is possible to allocate/ restrict bandwidth based on individual applications – this could be a very useful feature for business communications, ensuring that critical business applications like ERP always have a certain dedicated bandwidth across the VSAT networks.
Scalable: VSAT networks can be easily and cost effectively be scaled to accommodate multiple locations across the globe. In fact, some of the largest customers of VSAT networks have as many as 10,000 sites on a single network!
Cost: Though the initial investment (service provider perspective) might be high in terms of the cost of satellites and putting them in the orbit, the running cost (end point terminals and on going subscription) is coming down rapidly – That’s why applications like Direct To Home (Cable TV) are broadcasted directly from satellites to homes at a reasonable cost to the subscriber.
Standards based: VSAT networks are standards based and support IP (Internet Protocol) and its variants through a protocol called IPoS (Internet Protocol over Satellite – TIA 1008). Since the developments are standards based, it enables the creation of a healthy ecosystem of terminal, hub and ancillary equipment manufacturers and hence new innovations and improvements are faster.
Reliable: Satellite Networks are very reliable (having up-times in the magnitude of 99.5% and above) and have been field tested for many years now. Mission critical applications like Bank ATM’s, Navy and Point of Sale appliances use VSAT!
Back-up to Terrestrial Networks: VSAT networks have always found applications in this area – they make a good back up network to the terrestrial networks (Leased Lines, MPLS circuits, Broadband DSL Connectivity, Internet Leased Lines, etc) and there are certain customized plans available for backup exclusively with satellite service providers that charge for only 5% of the monthly capacity when the VSAT connection is used exclusively for backup. And yes, VSAT networks are not affected by natural calamities like earthquakes, storms etc. Some network routers come with optional VSAT modules for terminating the VSAT links and providing auto fail-over during the failure of terrestrial network links.
Inter-operation with Terrestrial Networks: An interesting area where the VSAT service providers are getting stronger is the comprehensive network provision (through partnerships with terrestrial service providers) and management. Through this, they can give (for example), MPLS networks in the metro areas and VSAT networks in the rural areas for the same company – both of them can inter-operate with each other acting as a single network!
Single Hop: Satellite transmissions are single hop (mostly) when compared to the multiple hops that the communications based on terrestrial networks need to take to reach to their destination. Some factors like router performance etc, depends on multiple service providers and hence end to end QoS may not be possible with terrestrial public networks.
Bandwidth on Demand: VSAT networks support and are better suited for Bandwidth on Demand services than their terrestrial counterparts.
Cost per connection is independent of the location/ distance: With a VSAT network, the cost per node is independent on the number of nodes and also distance between the various nodes. Compare that with Leased Lines, where the cost increases with more nodes and distance between the two locations. IPLC/International MPLS and other such global communication links are very expensive on terrestrial networks.
Limitations of VSAT Technology:
Like any other technology, VSAT has its limitations too. Some of them include the extremely high initial cost needed for building and launching satellites in the Geo-Synchronous orbit, higher initial cost and recurring monthly costs for terminal equipments needed for providing Internet over broadband when compared to terrestrial DSL networks, Bit Error Rate is common for satellite based technologies, Rain Attenuation might affect the performance of VSAT communications under rainy conditions, latencies (>200 ms) are still higher than their terrestrial equivalent technologies (<100 ms), careful direction of subscriber side terminals and dish antennas are critical for proper working, trained man power is required for installation and maintenance, other competitive technologies (Internet Leased Lines, 3G/HSDPA/4G Cellular technologies etc) offer much higher bandwidth at a lower cost than what is possible by VSAT based networks, the antennas need to be fixed outside the offices or homes hence making them susceptible to damage or theft, the cost of VSAT modules for Network Routers/ Video Conferencing systems are quite high, etc.
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