networking - Are bandwidth hogging users simply a myth for ISPs to charge more money? (Analysis inside)

From my understanding of networking, how can a single user hog all the bandwidth. Bandwidth is not something that is used. Packets are simply queued and sent on their way as fast as they can no matter their origin. For this example imagine an office with a 45 Mbit/s DS-3. You have the following scenarios.

First assume no one on the network is doing anything. A user, A, downloads a file from a large CDN. This CDN has sufficient bandwidth (multi-Gig lines). The user will max out the line at 45 Mbit/s (assuming no losses or overhead). User A is not wasting bandwidth. He is maxing the line because no one else is doing anything.

Now we have user B jump on. He downloads a file from a crappy Hostgator server. The server has a line rate of 10 Mbit/s. He isn't prohibited from accessing the network and he will not only get a little bandwidth since User A got there first. No! His packets will be queued along with User A's. Naturally the network will slow down User A and User B. For example User A will download at 40 Mbit/s and User B will download at 5 Mbit/s.

If user B downloaded from the CDN User A and B would download at 22.5 Mbit/s.

If 8 users were on downloading from the CDN they would all download at 5 Mbit/s

My point is that no user can take up or hog any amount of bandwidth. If he is maxing out the line he will slow down when other users come on. Am I right?

There is a level of performance that customers consider acceptable and a level they consider unacceptable. A given network can accommodate only so much traffic before the performance gets unacceptable and either users will leave or costly network upgrades will be needed. So the more traffic a user creates for the network, the fewer users the network can accommodate before its performance becomes unacceptable.

Imagine a network that can accommodate 50,000 average users before performance becomes unacceptable. If you use twice as much bandwidth as average, only 25,000 users like you can be accommodated -- each of you effectively takes up two slots.

If user A is continuously using the pipe at full speed, such as seeding a large amount of torrents, then that user is arguably 'hogging' the connection. In every discussion I've seen of in relation to 'hogging' it invariably involves using bandwidth over a lengthy period of time, not a short snapshot in time as your analysis does.

If that network's main purpose is not for the seeding of torrents but some other use, then that user is decreasing the amount of available bandwidth for it's intended purpose. I would consider that hogging.

There are also limits on how many packets each device on the network can queue up, and it's not much. If these limits are exceeded, packets may be dropped which may trigger (tcp) retransmissions, thereby increasing the amount of bandwidth required to do the job had user A not been (mis)using the network or even dropped/failed connections.

The ISP is in the business of selling a service: the ability for you to connect to the Internet. As such, they set forth rules (Terms of Service or TOS) whereas they want to get paid for the traffic you sent through their equipment. If one person is constantly sending traffic through their equipment, they can decide to enforce their TOS by limiting your bandwidth. Or they will ask you to upgrade to a different tier with more bandwidth. Remember, your ISP pays their backbone carrier for all traffic going thru, so if one person is constantly generating traffic while on a $25/month plan, the ISP loses money. This is not their business model, so we all end-up paying more for a service, or they enforce throttling to avoid such issues.

Another thing to keep in mind is QOS. A business account will have better QOS (but not always) than a home user. They pay more, thus they get better service. Or so is the rationale. The point of this "answer" is that, no matter what, someone pays for the service being provided. You pay more money...or you get less "service provided" to you.