I-4 satellite

The I-4 satellites are made up of the INMARSAT BGAN, FleetBroadband and SwiftBroadband communications network. They provide Internet and telecom connections on the L band everywhere on Earth, except in polar regions.

Data services

Two general types of data services are currently provided:

1. Streaming
2. Background

Streaming

Streaming is a service that guarantees the delivery of data. In this service, a terminal requests a specific bandwidth (currently available in 8, 16, 32, 64, 128, or 256 kbit/s), and if the current spot beam has sufficient resources, the requested bandwidth is allocated to the terminal. For example, if a terminal requests an 8 kbit/s streaming context, it will be able to send data at 8 kbit/s consistently. Consequently, streaming services are billed based on the duration of usage.

Background

Background service is a best-effort approach to data delivery. Each spot beam provides a certain amount of usable bandwidth, and any bandwidth not used by streaming contexts is allocated for background contexts. This means that the actual bandwidth received with a background context may vary over time. The theoretical maximum bandwidth available is approximately 400 kbit/s. As a result, background contexts are billed based on data volume rather than duration of usage.

See also

• Inmarsat-4 F1
• Inmarsat-4 F3
• Inmarsat-4A F4