How does bandwidth work and does it really affect internet speed?

Bandwidth is the width of your ‘pipe’, so it’s a measure of the capacity of your connection, i.e. the maximum amount of data that can be transported on the connection in a second. So, a 10 megabit per second (or 10 meg, or 10 mbit) connection can (theoretically) carry 10 Million (10,000,000) bits of data in a single second. If you have 25 megabits per second, you can carry 25,000,000 and so on.

If you have more bandwidth available to you that the amount you are using to perform the task at hand, then more bandwidth will make no difference. For example, if you are streaming a Netflix movie to an HD (1080p) TV, that uses about 5 megabits per second. Whether you have 10, 25, 50, 100 or more megabits available on your connection will make no difference to you at all, provided you have enough. (If you have less, the quality of the image will degrade to 720p, then 480p and so on to adapt).

If you’re looking at Instagram or sending email, or most other interactive tasks, having more bandwidth than you need to do those things will not make it any faster.

Most ‘performance’ problems on Internet connection are not to do with running out of bandwidth - unless you have a cable modem and your cable company is sharing the bandwidth between everyone in your neighborhood. Then you don’t have enough to perform your tasks, and then it will affect speed as everything will slow down waiting for enough bandwidth.

 

​What is the amount of data bandwidth that the average person consumes from all sources, such as home, mobile, work, etc., in a year?

​Based on a sizable sample of undergraduate US college students, the annual average across all owned devices is approximately 1,803 Gigabytes downloaded and 103 Gigabytes uploaded.

​Obviously that is data consumed, not bandwidth. Assuming the average person sleeps 8 hours, that’s an average waking data rate over the whole year of 8.7 kbit/sec down and 0.5 kbit/sec up. Average isn’t very useful of course, but most individual’s peak data consumption is 10 Mbit/sec or less.

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​How much bandwidth do I need if I want to become a "cord cutter"?

​In general, a Netflix Stream will be about 5–6 Mbit/sec for 1080p, and 20–25Mbit/sec for 4K. If you’re streaming on a laptop or mobile device you probably don’t care much about 4K.

​As to how much you need - to give yourself some headroom 10 Mbit/sec is enough for HD on a single device. Don’t forget to take into account multiple devices operating at the same time, so:

• 5 x the number of simultaneous 1080p streams plus;

• 25 x the number of simultaneous 4K streams plus;

• about 5–10 contingency.

​However for streaming, latency is more important than bandwidth for a good UX or user experience. A low latency connection is essential for video streaming as streaming takes place over TCP, which is conversational. If you see ‘buffering’ a lot, it could be a latency issue.

If you want more details on that, rather than type it all out, check this out: What Is Latency? | Student Housing Internet Network Design | Campus Technologies Inc (it’s about Student Housing, but the principles still apply).

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​What is the difference between broadband and bandwidth?

​Broadband has some very specific technical meanings, but as it relates to the Internet it is a very generic (and largely obsolete) term that in common use just means ‘better than dial up and always on’. The theory being that broad = more capacity, and being very non-specific it was latched onto as a marketing term.

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In the USA, the FCC says that to define something as broadband, it has to have a minimum capacity of 25 megabits per second download and 3 megabits per second upload. Other countries may have different or even no definition that regulates the use of the word in marketing, so beware.

So - Broadband is a generic marketing term that just vaguely means high capacity. It isn’t very useful.

​Bandwidth, however (once again as it refers to an Internet connection) is the specific capacity of an Internet connection, i.e. how much data it can move in a second, expressed in bits per second. It is not (as marketers and cable companies would like you to believe) the ‘speed’ of a connection.

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​Who pays for Internet bandwidth?

​(Comment details: If I am uploading data to say Sweden, does someone in Sweden pay my ISP. Similarly, if I download from US, does my ISP have to pay someone there? (Upload and Download))

​In general, the party at either end of a conversation will be paying someone for access to the Internet. If you access a website, you’re paying for your ISP connection, and the computer on which the website is hosted will pay their ISP connection.

​Nobody in the middle will pay anything, because (and this is a very poorly understood topic) pure bandwidth is free.

​What you are paying for when you pay an ISP for an internet connection is for access to the Internet at a certain bandwidth limit. You aren’t actually paying for the bandwidth. You’re paying for the hardware owned by the ISP that’s giving you access, and the engineering, and the cost of the wire in the ground, and the support - but you are not paying for bandwidth.

​When two ISP’s interconnect, they do not pay each other for bandwidth.

​Note: This only applies to ‘Tier 1’ ISP’s. These are ISP’s directly connect to peer ISP’s - think AT&T, Verizon, NTT, Cogent, Level3. Smaller ISP’s may pay for bandwidth to connect to a Tier 1 ISP, essentially being a middle-man.

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How do I know if my ISP is giving me dedicated or shared bandwidth?

​All Internet access bandwidth is shared, at some point, between you and your target server. Other people will be using the links between you and it, so even if your last-mile provider (aka ISP) is not oversubscribing (unlikely) the effect is the same.

​Also important to understand there are different levels of oversubscription. A careful ISP will oversubscribe only to a level at which you can still get your subscribed capacity on demand. However, not all ISP’s are created equal and some will work more with an eye to the dollar sign than the user experience.

​Typically you only ‘feel’ oversubscription if your ISP hasn’t got the resources or network in place to keep that ratio correct. Typically, cable providers who are struggling with their hybrid fiber-coax plant that was originally designed primarily for CATV will be less able to deal with oversubscription issues and that’s where you see the typical ‘homework time slowdown’.