Providers use shared bandwidth schemes in order to lower the cost of providing internet service. By predicting how frequently a channel will be used, they can split usage of expensive dedicated channels among multiple customers. Shared bandwidth systems typically cost the customer 1/4 to 1/10 as much as dedicated bandwidth.

Shared bandwidth is best suited to small business and home users, and sites supporting less than 30 users on a single VSAT.

Dedicated bandwidth is very flexible, and usually comes in a number of upload and download levels from 32kbit to 8mbit, depending on the hardware. It is also possible to purchase a dedicated channel and share it across a number of systems that belong to the same customer.

Dedicated bandwidth is best suited to large-enterprise customers such as Internet Service Providers (ISP's) and sites supporting more than 50 users on a single VSAT.

Some providers offer CIR on systems with shared bandwidth for an additional monthly cost. Vyrix Systems only offers it on iDirect systems.

Terrestrial broadband services have faster round-trip ("ping") times, but similiar actual download rates. Geosyncronous satellites orbit at an altitude of 36,000 km. Because round-trip traffic must make this trip 4 times for each two-way communication, ping times are commonly 500-2000 ms as opposed to the 50-200 ms times seen in terrestrial data links. This means that every single web page loaded requires a minimum of 500-2000 ms to begin loading. However, the data rates are comparable - once a file download begins, it runs at speeds similiar to terrestrial traffic. This limitation is most visible when sending and receiving small data packets.

Because VSAT Internet Service is transmitted as radio waves through the atmosphere, it can be affected by weather conditions at the customer site, the Network Operations Center, and in space. Interference by solar wind and solar flares is a rare occurence, but does happen a few times a year for a few minutes.

Finally, the subscription cost for VSAT Internet Service is typically more expensive than terrestrial services. Terrestrial lines are subsidized by governments and have lower operating and install costs than expensive orbital communications satellites.

Previously, Hughes service used a simple "sharing ratio" system. Under this system, each channel is shared at rates similiar to 10:1, 20:1, and so on. This system has been replaced by the advertised average system described above.

Sites that are throttled for violation of the Fair Access Policy will have slower download rates than other customers. Customer usage is reevaluated regularly, and will be lifted automatically when usage is reduced. For some customers, this may require 24 hours of reduced usage. This system is entirely automatic; neither Hughes nor Vyrix Systems notifies customers who are in violation of the FAP.

Customers familiar with the DW4020 and who have spare parts for this unit may prefer it for ease of repair. For new customers the only difference is cost.

Users who send email attachments via mail software such as Mozilla Thunderbird and Microsoft Outlook are not affected. Mail software typically uses the industry-standard SMTP protocol to send mail. We recommend that our customers use mail software instead of webmail interfaces.

When a customer with Tachyon Enterprise service goes over MVT, their traffic is "deprioritized". Without priority, service is much slower and less reliable. When a customer with Tachyon Express service goes over MVT, their service is suspended. Express customers can purchase additional blocks of data to increase their MVT for the month. Tachyon service is sold by both bandwidth (upload and download in kilobits) and MVT (in megabytes).

Tachyon service also uses a profile system. This system assumed the customer's traffic is used at a ratio of 3:1 download to upload for normal service levels, and 1:1 for symmetric service (128x128, 256x256). If a customer uses bandwidth outside this ratio, their traffic can also be deprioritized. This is called "out of profile" usage.

With Tachyon Express service, MVT is reset each month, and the customer can purchase additional blocks of data as needed.

Mozilla Firefox users can set their proxy as follows:

1. Open Firefox.
2. Click on the "Tools" menu.
3. Select "Options". An options dialog will appear.
4. Click on the "General" icon on the left.
5. Click on the "Connection Settings" button. Another options dialog will appear.
6. Check "Manual proxy Configuration". Uncheck "Use the same proxy for all protocols".
7. In the "HTTP Proxy:" field, put the Tachyon Gateway IP address. In the "Port:" field, put "3128".
8. Clear the "SSL", "FTP", "Gopher", and "SOCKS" proxy settings.
9. Click "OK" twice to close both dialogs.

Microsoft Internet Explorer users can set their proxy as follows:

1. Open Internet Explorer.
2. Click on the "Tools" menu.
3. Select "Internet Options". An options dialog will appear.
4. Click on the "Connections" tab.
5. Click on the "Lan Settings" button. Another options dialog will appear.
6. Uncheck "Automatically detect settings" and "Use automatic configuration script".
7. Check "Use a proxy server for your LAN".
8. In the "Address:" field, put the Tachyon Gateway IP address. In the "Port:" field, put "3128".
9. Check "Bypass proxy server for local addresses".
10. Click "OK" twice to close both dialogs.

PCs that move from the Tachyon network to another Internet connection must remember to disable or change this proxy. Otherwise Internet access will be very slow for that PC and will consume the MVT of your Tachyon service. Also remember that each Tachyon system has a different Gateway IP address. Vyrix Systems cautions laptop users that frequently travel between connections to be aware of their proxy settings at all times.

The Tachyon IDU tracks all open TCP connections as part of its TCP acceleration system. Each open connection requires a small amount of memory. This memory is recycled for new connections as old ones are closed or time out. A virus that is scanning the network for hosts to infect opens many thousands of connections at one time. This can cause the Tachyon IDU to run out of memory. Once this happens, the operating system may behave erratically, including blocking other network traffic. Sometimes this stops all network traffic, and sometimes it only stops certain protocols (such as HTTP) while allowing others (such as chat/messengers) to run normally.

This problem can be temporarily solved by rebooting the Tachyon IDU. However, the problem will return if the virus on the network is not removed. This cycle can repeat every few hours or every 10 minutes.

Normal software - web browsers, chat, even file sharing services - do not cause this problem. Only scanning viruses do. There is no fix to prevent the Tachyon IDU from locking up, except to keep the network free of viruses.

VOIP service through Vyrix Systems VOIP requires 7 kbit upload CIR to guarantee voice quality. This price is specially noted on the iDirect pricing options.

To find the CIR needed for other VOIP, webcam, video, or other services, please consult the documentation for that service.

Early termination of a contract is possible by prior agreement between Vyrix Systems and the customer. Early termination for any reason may require a fee of up to 50% of the service fee of the entire subscription. Please contact us if you require service for less than one year.

• Worms that flood the network seeking other PCs to infect, and infect them automatically due to a vulnerability in MS Windows. MS Blaster and its derivatives are an example.
• Spam-sending software that "zombies" a PC, causing it to send spam to potentially thousands of other people without the PC user knowing it.
• Microsoft Outlook viruses that spread via email attachments, causing Outlook to automatically mail copies to other user in your addressbook, MSN chat list, or at random. This mail may even be faked to appear to come from your email address or from someone else in your addressbook.
• Any virus that spreads over a network and consumes bandwidth.

All of the above viruses are detectable by a network scan by your ISP, and can result in your service being suspended.

Users who follow these steps will keep their network free of 99% of viruses.

• Run Windows Update regularly, and set your PC to automatically download and install updates.
• Install commercial antivirus software such as Norton AntiVirus, and set it update regularly and automatically.
• Install Lavasoft Ad-Aware and regularly scan for trojans, spyware, and other commercial tracking/spam software.
• Do not allow your users to visit software pirate warez sites, pornographic sites, or others that attempt to install "download accelerators" or other "tools" that infect the PC with viruses, trojans, or spyware.
• Consider browsers and mail readers that are less prone to viruses or vulnerabilities, such as Mozilla Firefox and Thunderbird. Avoid Microsoft Internet Explorer and Microsoft Outlook, or install third-party software that prevents pop-ups, bad javascript, and other vulnerabilities.
• Strictly enforce all of the above policies with mobile (laptop) users, who regularly carry viruses from one site to another, even causing virus suspensions and moving on without knowing it.

If you do not have access to antivirus software, try using the Trendmicro free online virus checker.

• Disconnect the affected PC from your network. If the entire network is affected, disconnect the entire network or power off the network switch.
• Use any of the above antivirus software to completely clean the affected PC, or group of PCs one at a time. If your virus definitions are not up to date, connect it to the network and update your virus definition, then disconnect the network again and run the virus scan. If you leave an infected PC on the network, you risk having your VSAT Internet Service suspended.
• Once clean, connect the PC to the network.
• Run Windows Update and a Lavasoft Ad-Aware scan.
• Repeat for each PC.
• If you do not find any viruses but have reason to suspect you still have an infection (for instance, if you have been suspended for virus traffic), consider scanning with different antivirus software or the Trendmicro free online virus checker.
• If your antivirus software finds a virus but cannot remove it, reboot Windows in Safe Mode and run the scan again.