Bandwidth is a measurement of the amount of data that can be transferred through a connection under optimal conditions. Picture it as a pipeline from one data communications device to another. Just like water flowing through a pipe can be measured in gallons per second (gps), bandwidth is usually measured in bits per second (bps). It is important to note that the word "bits," when abbreviated, is a lower-case "b" and not an upper-case "B" which is used to represent "bytes" when identifying storage capacities e.g., 500 gigabytes of hard drive space would be abbreviated as 500 GB. Also just like water, the bigger the pipe is the more the data can flow through it. In the case of the connection provided you by your Internet Service Provider (ISP) to access a remote location and/or the Internet you're going to have to pay for that pipeline, and its size. Yes, size does matter!
A full page of English text is about 16,000 bits (16 Kb).
- Full-motion, high-definition video requires roughly 10,000,000 bits per second (10 Mbps), depending on compression.
- A DSL connection can move about 1,544,000 bits in one second (1.544 Mbps).
- Newer Internet Service Provider (ISP) connection options use fiber-based media and offer speeds up to 100,000,000 bits per second (100 Mbps).
- Many modern day local area networks (LANs) used in homes and businesses operate at connection speeds of 1,000,000,000 bits per second (1 Gbps).
If you're lucky enough to be living in one of the newer housing tracks built after about the turn of the 21st century, you are probably able to access "High-Speed" Internet. "High-Speed" being a relative term, relative to whatever is the fastest and most affordable access method of the moment. Most residential nodes are still using one flavor or another of Digital Subscriber Line (DSL). Originally DSL service meant that the subscriber was receiving data at a rate of 1.544 million bits per second (Mbps), but would only be able to transmit data at a rate of 384 thousand bits per second (Kbps). This is because the most common type of DSL offered by ISPs is "asymmetrical" DSL (aDSL) which means your uplink speed is not the same as your download speed. If the up and the down speed are the same, then that would be "symmetrical" DSL or sDSL, which is more expensive." Today, with "High Speed" Internet, subscribers are receiving rates up to 100 Mbps
and more and are transmitting at rates of 10 Mbps and higher.
Another term you want to be familiar with is "throughput" which is how much data actually gets through to its destination. Due to weather conditions causing "noise" on the telephone wires, congestion on the Internet or your own network, data doesn't always make it to its destination on the first try. Fortunately the TCP/IP protocol is smart enough to recognize this and when errors do occur TCP/IP simply re-transmits the lost "packets." What this means is that if your bandwidth (pipeline) is 10 Mbps and due to poor line conditions or network congestion 50% of those packets don't make it to their destination the first time, then your throughput is only 5 Mbps. Fortunately, the modern day data communication networks in most areas are fairly noise free and extremely reliable.