Although we commonly refer to the transport capacity of an Internet connection as "bandwidth", its correct grammatical name is "throughput". Throughput is the amount of data that can be transferred through a digital connection in a given time period (in other words, the connection's bit rate), usually measured in bits (b) or bytes (B) per second.

Administered by an Internet service provider (ISP) such as a telephone company, a bandwidth cap or download cap limits the transfer of a specified amount of data over a period of time. If a user exceeds the bandwidth cap, the ISP restricts connection speed or other services.

In telecommunications and computing, bit rate is the frequency at which bits are passing a given (physical or metaphorical) "point". It is quantified using the bit per second (bit/s) unit. While often referred to as "speed", bit rate does not measure distance/time but quantity/time.

For large bit rates, prefixes are used:

• 1,000 bit/s = 1 kbit/s (one kilobit or one thousand bits per second)
• 1,000,000 bit/s = 1 Mbit/s (one megabit or one million bits per second)
• 1,000,000,000 bit/s = 1 Gbit/s (one gigabit or one billion bits per second)

You will often see bandwidth and transfer speed quoted in two different units: kilobits per second, abbreviated kbps or Kb/s, and kilobytes per second, abbreviated KB/s. The difference between the two units is the number of bits in a byte, which is 8. The small 'b' stands for bits, and the big 'B' stands for bytes. Transfer speeds are often shown in KB/s, and connect speeds are usually quoted in Kbit/s.

So, for instance, if a progress dialog for a modem shows you a download speed of 4.3 KB/s, it is the same as 34.4 Kbit/s. If a progress dialog for a cable modem shows you a transfer speed of 100 KB/s, it is the same as 800 Kbit/s.

• 1 KiloByte(KB) = 8 Kilobit(Kb)
• 1 MegaByte(MB) = 1024 KiloBytes(KB)
• 1 GigaByte(GB) = 1024 MegaBytes(MB) = 1048576 KiloBytes(KB)

In information technology downstream refers to the transfer speed by which data can be sent from the server to the client. The process by which downstream is utilized is known as downloading.

Optimal 56 k connections are able to send 53 kilobits per second to the client. ADSL and Cable Modems, the two most popular broadband services in the world today, have greatly improved downstream speeds in comparison with 56 k, with speeds reaching over 7 Mbit/s. However, the overall download speed of a file is dependant on both the downstream of the user and the upstream of the server.

In computing, upstream is the speed at which data can be transferred from the client to the server (uploading).

In modern telecommunication business, whereas downstream is important to the average home user for purposes of downloading content, uploads are used mainly for web server applications and similar processes where the sending of data is critical. ADSL and Cable modems are asymmetric, the upstream speed is usually much lower than that of its downstream. In most cases, an Internet connection with 500kbit/s downstreaming, is limited to 50kbit/s or 100kbit/s uploading.

In the case of radio streaming, we are mostly sending data to the Internet. Therefore we have to focus on the upstream capability of our Internet connection, being in most cases lower than the downstream rate! A minimal requirement for radio streaming is 50kbit/s!