Understanding BGAN Internet Speed and Cost?

Confused by all the terminology of bits and bytes and kbps? It's easy to get confused. However, there is more to understand than raw data speed and file size. Many issues can affect the performance and usage cost of your BGAN. For example, applications that handle data such as your email or ftp program can add a significant amount of data transfer overhead. Do you know how to measure this effect? Also, poor positioning of the BGAN terminal's antenna or external interference from other radio transmitters can degrade the performance of your BGAN. We have briefly discussed some of the important issues below and recommend that you call Outfitter Satellite technical support for additional assistance with your BGAN terminal.

What data speed can I expect from my BGAN terminal?

Internet speed is usually measured in "bits per second" or "bps". BGAN offers background internet speeds (up to) 492 "kilobits per second" (or 492 kbps), which is its maximum theoretical data rate. This is much faster than old fashioned "dial-up" services which typically achieved 28.8 kbps. Since BGAN reaches speeds of almost half a megabit per second, it is more comparable to modern terrestrial cable modem services. Cable services often boast 0.3 "Megabits per second" (or 0.3 Mbps) upload speed and 5 Mbps download speed, but in practice rarely see download speeds faster than 1.54 Mbps since this is the speed of the T1 lines that connect most servers to the public internet.

STANDARD IP INTERNET ACCESS MODE: The BGAN network is a young network that started commercial service in December 2005. Its performance has improved since that time. As of April 2007, typical performance of a class I BGAN terminal is 0.41 Mbps (down) and 0.32 Mbps (up) when in the shared bandwidth "standard IP" mode. This is the mode that is generally the most effective for programs such as email and web browsing. For comparison, this author's experience is that typical terrestrial cable modem service download speeds are 0.3 to 1.1 Mbps.

STREAMING IP MODE: The 32, 64, 128, and 256 kbps streaming modes of BGAN are performing according to specifications. These modes of BGAN are useful for applications that need a guaranteed minimum data rate. A good example is videoconferencing. The 32 kbps mode can be effective for certain voice over IP applications. It is important to understand that the streaming IP speeds apply to the space leg of the communication only. If streaming IP data is routed onto to the internet instead of, for example to a customer's dedicated line, some degradation of data speed would be expected. Streaming data can also be routed to a customer's ISDN line. If this is done, two BRI ISDN lines are needed to support 256 kbps streaming. Some initial setup is required. Contact Outfitter Satellite for assistance. Routing to the internet is the default configuration.

How long will it take to transmit a 1 MegaByte file?

Data rates are measured in "bits per second" or "bps". Well, just to make things confusing, the size of files stored on your computer is measured in "bytes" (or B) where 8 "bits" equal 1 byte. Notice that an uppercase "B" means bytes while the lowercase "b" means bits. To get the number of seconds to transmit, multiply the number of megabytes (in MB) of data to be transferred by 8 and divide by the data speed (in Mbps). So, for example, if you transmit 1 MB of data at 0.4 Mbps, it will take 1 MB x 8 / 0.4 Mbps = 20 seconds.

When you transmit a 1 MB file, it is not unusual for much more than 1 MB of data to actually be transferred. Why? Often the software you are using to transfer the original data file (e.g. MS Outlook email client transmitting an email attachment or an FTP application transferring a file) puts an "envelope" around the data file. There are a variety of reasons that this is done. One reason is to provide a means of error correction to assure that the data file arrives at its destination undamaged. Another would be to encrypt the data file against interception. The "envelope" added by your software application is called "overhead". It is the user's responsibility to understand how this slows down the "effective" transmission speed and increases the effective transfer volume.

IT IS A GOOD IDEA TO MAKE YOUR OWN TESTS: Outfitter Satellite suggests that a good idea is to transmit a "test file" of known size, e.g. 1 MB, and measure with a stop watch how long it takes to transmit through your BGAN to your destination. If you are using a Scratch & Web plan, you will have a realtime "meter" available on your web browser to actually see the number of MBs transferred. Now, you have a good idea what the effective data speed will be and how much overhead is caused by error correction and other protocols used by your application software.

How much will it cost to transmit 1 MB?

STANDARD IP INTERNET ACCESS MODE: In this mode, which is the recommended mode for most basic applications such as email or web browsing, Outfitter Satellite bills for the number of megabytes or "MB" that your BGAN terminal sends or receives including error correction and other protocols. A user with limited usage on a Standard Plan can expect to pay $6.95/MB plus tax/USF, though the rate drops for higher volume plans. A minimum 50 KB charge will apply to each 12 hour session, so the cost of staying connected all the time is fairly small.

VOICE AND PREMIUM DATA SERVICES: If you are using a Premium Data mode such as streaming IP or ISDN or if you are making a voice call, then you are billed on a per minute connection time basis. For more information, download an overview of Outfitter Satellite's BGAN rate plans. If you expect to use a lot of streaming service, consider a dedicated line. Inmarsat BGAN terminals can stream (depending on the model) as fast as 256 kbps. This mode gives you a guaranteed a data rate of 256 kbps on the "space leg" of communication. However, after your data reaches the Inmarsat earth station it is connected directly to a POP or Point of Presence, where by default your data moves directly onto the terrestrial internet to its destination. An alternative is to set up a dedicated line from this POP directly to your headquarters or other destination. A T1 line can handle traffic from 6 BGAN terminals simultaneously when they are streaming at 256 kbps. If you intend to use a lot of streaming service, a dedicated line should be considered. As a rule of thumb, the cost for a dedicated line from the POP to a location in the US is between $1000 and $2000 per month with a one-year term contract, but the actual cost is dependent on the location and would have to be determined by quote for each application.

A few suggestions on how to keep your BGAN usage bill smaller:

HINT #1: Use Anti-Virus and Firewall Techology. Many applications use internet access. For example, web browsers, email programs, instant messenger programs, file transfer programs (FTP), and unfortunately undesired programs inserted into your computer by viruses. Outfitter Satellite's experienced technical support staff can help you understand what programs are using internet access in your Windows or Macintosh computer, but in the end it is your responsibility to understand and to monitor internet access by these programs. Make sure you have a good anti-virus program on your computer. Viruses can use large amounts of internet access and generate enormous bills. Firewalls prevent hackers and unauthorized access of the computers and equipment connected to your BGAN. Outfitter Satellite uses and recommends SonicWall firewall technology.

HINT #2: Turn off streaming and ISDN services at the network level and prepay your internet access. The best solution for most users is to place common sense limits on your BGAN terminal. For example, very few users will use video conferencing or high performance virtual private network (VPN) applications that require 128 kbps and 256 kbps streaming. If all you need is email, ftp, or web browsing then Outfitter Satellite recommends, using our Scratch & Web Rate Plan -- which by default disables these services at the network level. Our Scratch & Web Rate Plan lets you make as many voice calls as you want and be billed monthly while background IP internet access is purchased in prepaid 10 MB increments. A realtime "counter" lets you see exactly the amount of data being sent or received by you BGAN terminal and how many MBs remain on your prepaid account. Just call or email us to add more MBs to your prepaid internet account when you need them. You are in complete control of your budget.

HINT #3: Turn off your BGAN terminal when you are not using it. Viruses never sleep. Power down your BGAN terminal when it is not in use. This is the ultimate protection against unintended and expensive usage such as your email program checking for new mail all night while you are asleep or viruses transmitting data through your terminal. If your BGAN terminal is off, this cannot happen!

HINT #4: Go through the "set up procedure" again if your BGAN terminal has been bumped. When you first start an active session with your BGAN terminal, you put it in "pointing mode" using the LaunchPad Software. This procedure lets the BGAN network optimize the BGAN terminal's performance for your session based on how you have positioned the BGAN terminal's antenna. If you accidently bump your BGAN terminal, it may still work but it is possible that a larger amount of "error correction" will be needed. This means that more of the data you are transmitting (and paying for) will be used to do error correction -- running up your bill without a lot of benefit.

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