Envistacom White Paper Comparative Analysis of VSATs and Deployable Earth Terminals in a Dynamic, Growing High-Data Environment By Tom Cox May 2014
Overview Providing satellite communications solutions for a dynamic enterprise can be a significant challenge. Engineers continuously manage various trade-offs and analyses to find the correct solution for an environment where the bandwidth needs are in a continuous state of flux. This paper serves to identify the key variables in making a good decision on the type, size, and robustness of a deployable communications platform. Our aim is to provide consumers of satellite communications in a large, growing C2 environment with a primer to choose the best solution. This paper serves to identify the key variables in making a good decision on the type, size, and robustness of a deployable communications platform. Generally speaking, there are three classes of satellite communications solutions: 1. Very Small Aperture Terminal (VSAT) 2. Deployable Earth Terminal Terminal 3. Teleport Each class provides a different level of communications infrastructure for the local Enterprise as well as the global Enterprise networks. This paper will discuss the tradeoffs of VSATs and Deployable Earth Terminals specifically in the case of the Balad Airbase Network. Assumptions: Location - Balad, Iraq Throughput Requirement - 10MBPS up / 10MBPS down Committed Information Rate - 100% Contention Ratio - 1:1 Frequency Band - Ku-Band Comparative Analysis of VSATs and Deployable Earth Terminals Envistacom 2014. All rights reserved. Page 2
Very Small Aperture Terminals (VSATs) With more than 40 million terminals deployed across the globe, VSATs represent the most common and least expensive solution for deployable communications. A VSAT typically includes a small antenna in the 0.5-3.0 meter range and a transmitter with two to 20 Watts of output power. VSATs provide consumer and enterprise customers with up to 4 MBPS uplink throughput and 10 MBPS of downlink throughput. More typically, VSATs provide up to 1 MBPS up and 4-6 MBPS down. They are easy to install and relatively inexpensive, typically costing between $15K - $200K per terminal depending on throughput and ruggedness. The biggest advantage of a VSAT is its size and simplicity. VSATs install quickly and have very few active components. They can be shipped commercially and typically weigh less than 200 lbs. Once manually aligned to the satellite, they operate autonomously and are easy to manage. Figure 1. Typical VSAT Terminal The biggest disadvantages of VSATs are their reliability, cost of bandwidth, and actual throughput. VSATs are single-threaded systems, so if a component fails, the entire network fails. Satellite operators treat VSATs as disadvantaged terminals because they are power-limited. Remote terminals have to transmit with more power, which costs end users more money per megahertz of bandwidth. VSATs have a limited amount of power to transmit with as well, so they can only transmit a limited amount of data. VSATs typically operate in large networks that have high contention ratios. A typical VSAT will have a contention ratio of 10:1, meaning at peak usage times, the VSAT may only be able to use 1/10th of the maximum throughput. Contention ratios can be as high as 100:1 in peak load times, meaning that users may be forced to a total aggregated circuit speed of 32-64KBPS, resulting in lost data or dropped VoIP calls. Paying for a lower contention ratio becomes prohibitively expensive and may require a dedicated circuit. A dedicated circuit on a VSAT is the least cost-effective satellite option. Comparative Analysis of VSATs and Deployable Earth Terminals Envistacom 2014. All rights reserved. Page 3
Deployable Earth Terminals Deployable Earth Terminal terminals are in between VSATs and teleports. They represent the class of terminals that provide the greatest flexibility in enterprise communications solutions. The US military and other Foreign Military Sales (FMS) programs have made extensive use of deployable earth terminals - more than 100 systems - throughout the Southwest Asia region in support of Command & Control (C2) operations at all bases in the region. Balad, AB had seven (7) such deployable terminals providing inter-theater and global reach back connectivity during US operation of the airbase. VSATs are typically used for smaller, temporary tactical C2 operations as well as Morale, Welfare and Recreation (MWR) services for the stationed soldiers, civilians and contractors. A Deployable Earth Terminal typically includes a medium-sized antenna in the 3.0-7.0 meter range. These terminals require a greater upfront investment in ground equipment than a VSAT, and can cost anywhere from $500K up to $2M depending on the level of reliability, capacity, transportability, and ruggedness. The biggest advantages of a Deployable Earth Terminals are their flexibility, reliability, and expandable capacity. Deployable Earth Terminals can be shipped commercially and can be fully operational within 8 hours of delivery. They are fully redundant systems meaning they rarely fail and they can support up to 100 MBPS up / 200 MBPS down of throughput. Deployable terminals also have a lower cost per megahertz of bandwidth than VSATs. Typically VSATs are able to transmit 1 MBPS per 1 MHz of bandwidth, whereas deployable earth terminals can transmit 2 MBPS per 1 MHz of bandwidth, representing a 50% recurring bandwidth cost savings. Figure 2. Deployable Earth Terminal A Deployable Earth Terminal may not be appropriate for a use case where less than 1MBPS up / 4MBPS down of throughput is required, or if the users can tolerate outages or bandwidth throttling during peak usage times of the day. Deployable earth terminals typically operate dedicated circuits and do not deal with contention ratios or degraded service issues at peak usage times. This guarantees 100% of the satellite bandwidth is available 100% of the time. The major disadvantage of a deployable earth terminal is the upfront cost of the terminal. Comparative Analysis of VSATs and Deployable Earth Terminals Envistacom 2014. All rights reserved. Page 4
Terminal Size VSAT antennas are typically between 0.5M and 2.4M in aperture diameter, whereas deployable earth terminals range in size from 3.0M to 7.0M. The larger surface area of the deployable earth terminal reflector allows for far greater signal gain, and can transmit far more power. A 1.0M (40 ) VSAT antenna provides 3.142 m2 of surface area, which translates to 40dBi of passive gain. A 3.7M deployable earth terminal antenna provides 43.0 m2 of surface area (1300% increase), which translates to 51dBi of gain. This passive gain difference is critical in determining several factors, including the cost of bandwidth, maximum transmit bandwidth, susceptibility to weather (rain fade), and how far out to the edge of a satellite beam the terminal can be located. At an aperture size of 3.3M, satellite earth terminals have enough receive sensitivity (gain) to access the noise floor of most commercial satellites. This means that a 3.3M antenna operates at the same signal-to-noise ratio as a far larger teleport antenna. Any antenna smaller than 3.3M will have a degraded signal-tonoise ratio, meaning that for every db of lost gain, the transmitting station must transmit 1 db more in power to close the satellite link to the VSAT terminal. Figure 3. Comparison of aperture size Maximum Data Rates At the high end, VSATs have a maximum data rate throughput of 4 MBPS up and 10 MBPS down. More typical VSATs that are provided by commercial service providers - such as the one currently fielded at the Balad Airbase - provide 1 MBPS up and 4-6 MBPS down with a contention ratio of 10:1. Therefore, at peak usage times, this leaves the remote user with as little as 128KBPS uplink and 640KBPS downlink for their entire user population. Additionally if the end user wishes to increase the throughput beyond these levels, a new larger terminal will be required to upgrade the link. Deployable earth terminals can provide as much as 100 MBPS up and 200 MBPS down, and with newer satellite technology called High Throughput Satellites (such as Inmarsat GX and Viasat-1), can potentially even provide up to 1 Comparative Analysis of VSATs and Deployable Earth Terminals Envistacom 2014. All rights reserved. Page 5
GBPS of throughput in both directions. Deployable earth terminals typically operate dedicated circuits resulting in a guaranteed Committed Information Rate (CIR) of 100%, or a contention ratio of 1:1. This means the throughput will never drop below the minimum CIR delivering higher performance and reliability for voice, video, and data services. Cost of Bandwidth VSATs provide an inexpensive communications solution in highcontention networks, however as the user increases the minimum Committed Information Rate (CIR), the cost increases significantly. If a VSAT is used to deliver a dedicated circuit (100% CIR, 1:1 contention ratio), the cost of bandwidth per megahertz is typically 25-30% higher than a deployable earth terminal. This is because the distant end teleport must transmit a more powerful carrier, and the satellite uses more resources to provide the link. Additionally, VSATs can typically provide 1 MBPS of data for every 1 MHz of bandwidth, whereas a deployable earth terminal can typically provide 2 MBPS of data for every 1 MHz of bandwidth. Since satellite providers charge based on power and bandwidth, this means the cost of bandwidth for a deployable earth terminal is substantially lower than that of a VSAT. Scalability VSATs are limited in their throughput, therefore in order to scale the network service beyond their 1 MBPS up / 4-6 MBPS down capacity, a second VSAT or a larger terminal is needed. If additional modems or baseband gear is needed, these must be stored in additional transit cases or inside a customer-provided building within 100 feet of the VSAT antenna. Deployable earth terminals are miniature teleports and have anywhere from 3 to 6 full racks of electronic hardware space inside an environmentally-controlled shelter co-located with the antenna, allowing for expansion of up to 20 satellite modems and network connections. Additionally, with the bandwidth capacity of a typical deployable earth terminal, no hardware changes are necessary to scale from a 10 MBPS/10 MBPS circuit all the way up to a 100 MBPS/200 MBPS circuit. Comparative Analysis of VSATs and Deployable Earth Terminals Envistacom 2014. All rights reserved. Page 6
Reliability VSATs provide limited reliability for their end users. A typical VSAT will provide approximately 98% availability (175 hours per year of downtime), and the Mean-Time-To-Repair (MTTR) a VSAT is between 30 minutes and 2 hours, depending on the availability of trained technicians. VSATs are single-threaded systems, meaning they have several single points of failure in active components. Additionally, most VSAT antennas are manually pointed, so if the antenna is misaligned by a wind gust or an accidental bump, a trained operator must realign the antenna. Deployable earth terminals are extremely reliable systems, which is a key reason they are chosen for critical C2 operations and base-wide infrastructure support. Since 1999, Deployable earth terminals fielded by US CENTCOM and US AFRICOM in Southwest Asia have provided 99.95% availability (4.3 hours per year of downtime) in the harsh conditions like those at the Balad AB. The downtime is mostly attributable to satellite/sun conjunctions, which happen twice a year at each equinox (spring and fall) and impact every satellite link in the world. Additionally, the Mean- Time-To-Repair (MTTR) is less than 1 second. These terminals have 1:1 or 1:2 redundancy in all active components, along with state-of-the-art monitor and control (M&C) software which exponentially increases their reliability and gives engineers remote troubleshooting, control, and configuration capability. Deployable earth terminal antennas are automatically controlled, positioned, and continuously track the satellite. This helps to avoid issues such as the antenna losing the satellite link by being moved by wind gusts or other forces. This motorization of the antenna also increases satellite options to use inclined orbit satellites that are typically lower in cost, and to quickly and simply switch to a different satellite if necessary. Comparative Analysis of VSATs and Deployable Earth Terminals Envistacom 2014. All rights reserved. Page 7
Tradeoffs For users seeking a backhaul connection to a larger enterprise network or the Internet, the tradeoffs in determining the appropriate class of terminal are many. Below is a list of the common tradeoffs, and how to weigh them when making a determination. Parameter 1.2M VSAT 3.8M Deployable Earth Terminal Antenna Aperture Size 1.2M 3.8M Passive Antenna Gain (Ku-Band) 40 dbi 51 dbi Maximum Transmit EIRP 58.6 dbw 82.1 dbw Maximum G/T 20.8 db/k 32 db/k Antenna Positioning Manual (typ) Auto-Track Scalability 1 Carrier 20 Carriers MBPS of Throughput per MHz of Bandwidth 1.0 1.8-2.2 Max Uplink Throughput 4 MBPS 100 MBPS Max Downlink Throughput 20 MBPS 200 MBPS % Link Availability 98.0% (typ.) 99.95% Outage Hours Per Year (max) 175 Hours (typ.) 4.3 Hours Mean-Time-Between-Critical-Failure (MTBCF) 25,000 Hours 1,000,000+ Hours Mean-Time-To-Repair (MTTR) 30 min. - 2 hrs. < 1 sec User Interface Modem Console M&C Software Suite Electronics Enclosure Customer Provided Integrated Shelter UPS Power N/A 15 minutes Automatic Power Transfer to Generator N/A Integrated Generator & Transfer Switch Redundancy & Protection None 1:1 or 1:2 Comparative Analysis of VSATs and Deployable Earth Terminals Envistacom 2014. All rights reserved. Page 8
Historical Use Cases AT&T Calling Center, Bagram Afghanistan This system was installed by AT&T to provide 12 simultaneous phone conversations or 2 simultaneous video teleconferences (via Skype) between soldiers and family members back home. The terminal was replaced with a larger 3.8M terminal two weeks after installation due to the high demand for service. Tactical C2 Forward Operations - Battalion This SIPR/NIPR Access Portal (SNAP) terminal provides forward operating bases (Battalion level operations center) with 8 VoIP phone lines and a total throughput of 4MBPS/4MBPS in a TDMA network. SNAP provides secure C2 communications and nonsecure Internet access for non-critical operations. Deployable Ku-Band Earth Terminals (DKETs) Since 1999, DataPath (now Rockwell Collins) has provided more than 100 DKET terminals to the US Army and other US and FMS users. The vast majority of these terminals have been fielded to SWA. They provide heavy backhaul traffic and intra-theater networking support, and are an integral component to the C2 network for CENTCOM and AFRICOM. Comparative Analysis of VSATs and Deployable Earth Terminals Envistacom 2014. All rights reserved. Page 9
About Envistacom Headquartered in Atlanta, Envistacom is a privatelyowned technology company providing end-to-end telecommunications networking, data analytics, mobile application and security solutions to defense, government and commercial enterprises. Envistacom designs and delivers the right technology solutions to meet unique and complex business challenges. Their reputation is built on a solid foundation of creative innovation and technical excellence, coupled with superior design, consulting, and customer service. Envistacom partners with Emcien to provide customers with superior and integrated data analytics solutions. To learn more about Envistacom, please visit: www.envistacom.com Corporate Headquarters Six Concourse Parkway Suite 550 Atlanta, GA 30328 www.envistacom.com We can help your operation Envistacom delivers end-to-end communications, networking, and security solutions to the diverse markets of defense, government, and commercial enterprises. Contact us today to learn more about what we can do for you. 470-255-2500 sales@envistacom.com Envistacom 2014. All rights reserved. (V2_5-14-2014)