Youve probably seen the bandwidth advertised if youve ever shopped for a new internet connection.
Youve probably seen your actual measured bandwidth if youve performed an internet speed test.
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What Is Bandwidth?
Bandwidth is a measure of the maximum possible transmission rate of a connection.
Generally large, the proportion of the customer base.
ISPs typically provide a little more than advertised to avoid potential lawsuits if this is the case.
As with any measure of data, bandwidth is measured in bits or bytes.
A bit is a single unit of binary data, either 1 or 0.
A byte is composed of eight bits, the standard number of a group of bits.
Thankfully, modern bandwidth is very high.
The standard unit contraction for these is Mbps, Gbps, MBps, and GBps, respectively.
Note:Units measured in bits always use a lowercase b, i.e., Gb/s.
Bytes are always represented with a capital B, i.e., MB/s.
For example, a 1 gigabit per second fiber connection provides 125 megabytes per second.
While file sizes are generally listed in multiples of bytes per second.
Latency is another important measure to take into account.
Latency often isnt felt by the user for connections internal to their computer or local web connection.
However, that doesnt mean that it doesnt have an effect.
Latency is the measure of delay between a request being sent and the recipient starting to receive it.
On the internet, latency can vary with the distance to the server youre communicating with.
For example, a standard ping to the US from the UK is around 100 milliseconds.
On local networks, you’re able to get millisecond or sub-millisecond pings.
On locally connected memory devices, latency can be low enough to be measured in nanoseconds.
It doesnt matter how good your bandwidth is.
If youve got a big latency, you will have a poor experience.
Take Mars, for example.
This isnt great for browsing the web or trying to drive Mars rovers.
Throughput
Throughput is another measure.
Its very similar to bandwidth but measures the useful data bandwidth currently being used.
For example, take a SATA cable.
It has a bandwidth of 6Gb/s or 750MB/s.
SATA is traditionally used to connect HDDs.
An HDD, however, can typically only read data at around 230MB/s.
This is the real measure of data transmitted rather than the theoretical peak bandwidth of the connection.
Throughput is critical when the bandwidth of a connection is not the limiting factor.
This diagram clearly explains the difference between bandwidth, throughput, and latency.
Imagine a company that has had a disaster strike that corrupted several critical hard drives.
Say, a power surge fried the drives.
Now, however, is when they realize the bandwidth problem.
They store data on speedy PCIe Gen3 SSDs, but the backup is stored remotely.
The remote site has a gigabit ethernet connection.
This, of course, is bad.
This is where an engineer offers a solution.
Where the data was collected to the supercomputer that will process it.
Conclusion
Bandwidth is a measure of the peak possible transfer speed of a connection.
Its an important measure of connection speed, but generally only if it is the limiting factor.
Its important to be aware when bandwidth is an important limiting factor and when it isnt.
Other connection speed measures, such as latency and throughput, can also be important limiting factors.
Some server systems, mainly cloud server usage dashboards, often refer to bandwidth.
In this case, they generally dont mean peak transfer rate.
Technically this shouldnt be referred to as bandwidth.
