Glossary

The rotational axis of a mobile satellite system. Most mobile systems have a greater-than-360-degree rotation so that scanning for a signal is not impeded by a physical limit on the mobile dish.

Is simply high-speed internet access that’s much faster than dial-up internet access. Normally, broadband is anything faster than 300 Kbps.

The C-band is primarily used for voice and data communications as well as backhauling. Because of its weaker power, it requires a larger antenna, usually above 1.8m (6ft). However, due to the lower frequency range, it performs better under adverse weather conditions on the ground. It operates in the frequency range for VSAT satellite communication from 3.7 to 4.2GHz for downlink and 5.925 to 6.425GHz for uplink communication. C-band systems are light-heartedly referred to as a ‘BUD’ – or big ugly dish.

Refers to the number of subscribers that are sharing the connection at the same time. Many ‘consumer’ organizations like Hughesnet have contention ratios that approach 400 to 1, which makes the speeds crawl. Ground Control posts its contention ratios so you can predict your connection speed at any time. Most of our standard iDirect plans are between 10:1 and 20:1.

Dynamic host configuration protocol is a protocol for assigning dynamic IP addresses to devices on a network. With dynamic addressing, a device may have a different IP address each time it connects to the network. DHCP also supports a mix of static and dynamic IP addresses. Windows ICS uses the address range of 192.168.0.2 through 192.168.0.255 when it assigns addresses. It also works fine when computers on the ICS network are assigned addresses in that range statically, but it’s a good idea to use high numbers to avoid conflicts.

Information that comes to your computer from the internet. The typical download speeds of an iDirect connection is between 2500Kbps and 4500Kbps (kilobits per second).

Effective isotropic radiated power is the measure of the strength of the signal leaving a satellite antenna in a particular direction, equal to the product of the power supplied to the satellite transmit antenna and its gain in that direction.

Fair access policy, pronounced as a word. Satellite connections, while always on, are not unlimited. Bandwidth is a finite resource, so the method used to provide high download bandwidth for all while preventing any one user from hogging that bandwidth is FAP.

Internet protocol, pronounced as two separate letters. IP specifies the format of packets and the addressing scheme used on the internet. The internet combines IP with a higher-level protocol called transmission control protocol (TCP), which establishes the connection between a destination and a source. IP by itself is something like the postal system. It lets you address a package and drop it in the system, but there’s no direct link between you and the recipient. TCP/IP, on the other hand, establishes a connection between two hosts so that they can send messages back and forth for a period of time.

IP addresses are in the form of a 32-bit numeric address written as four numbers separated by periods. Each number can be zero to 255. For example, 10.249.101.24 could be an IP address. Within a LAN, you can assign IP addresses at random as long as each one is unique; addresses which are public to the internet must be within assigned ranges in order to avoid duplication. The authorities that assign public internet addresses have designated certain ranges as never to be used on the internet. By convention, those are normally used as private addresses on a LAN. The ranges for private addresses are all addresses starting with 10 (e.g. 10.200.44.36), addresses between 172.16.0.0 and 72.31.255.255, and addresses between 192.168.0.0 and 192.168.255.255.

Kilobits per second. Thousands of bits that are transferred in one second. KBps represents (Upper case B) represents thousands of bytes (a byte is made up of 8 bits) in one second.

Pronounced ‘kay-yoo’, the Ku-band is used typically for consumer direct-to-home access, distance learning applications, retail and enterprise connectivity. The antenna sizes, ranging from 0.7m to 2.4m, are much smaller than C-band because the higher frequency means that higher gain can be achieved with smaller antenna sizes than C-band. Networks in this band are more susceptible to rain fade, especially in tropical areas. Ku communication is the microwave range of the electromagnetic frequency from 11.7 to 12.7GHz (downlink frequencies) and 14 to 14.5GHz (uplink frequencies). An interesting note is that older and gray-market radar detector/jammers operate on the Ku-band frequency and have caused interference to disable VSAT satellite systems.

(Also known as ping time.) Internet traffic travels at the speed of light – a New York to California fiber optic connection will take 0.03 seconds (30 milliseconds) as a round trip. In reality, the overhead processes of a dozen or more routers and switches adds a bit of time, so an average connection would be about 50 to 90 milliseconds. With satellite connections, the distances are so vast that even light speed isn’t fast enough. Why? Because all stationary satellites are located 22,300 miles above the equator, so the round trip is 90,000 miles or more. The speed of light is 186,000MPH, so the time it takes for a round trip is just under 500 milliseconds (half a second). Ground Control’s iDirect services have very low overhead processes, so you can expect a latency period of just over 500 milliseconds. This half-second latency is outstanding for VOIP voice communication over satellite, as the pause between speakers is barely noticed. Many other satellite providers, such as Hughesnet, have a latency of over one second. Latency is not good for real-time gaming because the time it takes for the game to notice you’ve pulled the trigger is half a second or longer.

The orbiting satellite acts as a “router in space” and can direct traffic to other VSAT dishes on the ground. This topology cuts satellite latency (ping times) in half because data doesn’t need to make two round trips to the orbiting satellite as with the more common star topology satellite network. Mesh networks can also be a combination of star and mesh where some traffic may be routed through an Earth-based NOC.

Outdoor unit. Refers to the radio BUC and LNB on the satellite dish.

Quality of service is a term used to show the requirements of some applications and users are more critical than others, which means that some traffic needs preferential treatment. By using QoS mechanisms, network administrators can use existing resources efficiently and ensure the required level of service without reactively expanding or over-provisioning their networks.

Traditionally, the concept of quality in networks meant that all network traffic was treated equally. The result was that all network traffic received the network’s best effort, with no guarantees for reliability, delay, variation in delay, or other performance characteristics. With best-effort delivery service, however, a single bandwidth-intensive application can result in poor or unacceptable performance for all applications.

Satellite latency refers to how long it takes a single piece of information to make a round trip back and forth over a satellite connection (aka ping time). Data over satellite travels at the speed of light – 186,000 miles per second. The orbiting satellite is 22,300 miles above earth, and must travel that distance four times (computer to satellite, satellite to internet, internet to satellite, satellite to computer). This adds up to a latency of about half a second. This isn’t long, but some applications like real-time gaming don’t like this time delay.

The theoretically fastest possible ping time over a geostationary satellite would be 476 milliseconds, or just under half a second. Ground Control iDirect services have a latency time between 500 to 650 milliseconds, which is half that of consumer-grade service providers. Low latency reduces the length of the pause between talking parties over a satellite VoIP phone connection, among numerous other benefits.

These use an Earth-based NOC (network operations center) to route all traffic to and from the orbiting satellite to the smaller VSAT dish clients. Star networks differ from mesh networks because mesh networks avoid an Earth-based NOC, and route traffic from the orbiting satellite. The obvious advantage is mesh networks’ latency (ping time) is half as much as a star network’s because mesh doesn’t need to take two round trips to the satellite in order for information to be requested and received from a client star network VSAT site. Mesh networks are also inherently more secure because data is transmitted from VSAT dish to VSAT dish.

Uploading is transmitting information from your computer to a location on the internet. Typical upload speeds of an iDirect system are 500 to 900Kbps (kilobits per second).

Standing for very small aperture terminal, VSAT is two-way (transmit and receive) satellite dish that’s normally under three square meters in size. VSAT dishes only communicate with geosynchronous orbiting satellites, and they’re on the client-side of the satellite network (where the network operations center or NOC is on the other side).

Frequency bands used by VSAT dishes are C-band, Ku-band, Ka-band and X-band. A VSAT system is comprised of the reflector (dish or antenna), the transmitter (BUC), the receiver (LNB), the waveguide, and the indoor unit (IDU). More about how satellite internet works.