the typical way its explained is with the analogy of a bucket of water.let say your have a CIR for water.. it fill your bucket at a steady state.. but your do not use the water at a steady state.. you use it in burst.. the fastest you can drain from the bucket is you burst rate.. this is faster then your CIR.. keep running at you burst rate and you empty the bucket.. now your running at the slower CIR rate the rate that bucket can fill at..the effect is your download rate becomes throttle back ....
but still there's another thing called over-burst...
the Internet pipeline come to your house is a shared media with other people and as long as no one else is using a shared media the company wants to let you use that empty bandwhith
They'll start feeding you data into your bucket at your higher burst rate in other words faster than your Cir because no one else is using it on the back side so they can fill that bucket as fast as you want.. however that overburst to you is marked discard eligible in other words if anybody else needs data you get drop back to the slower speed ...that over burst is flying standby
And the kicker.. this just apply on your connection to your ISP..because the ISP does not own the Internet end to end so they can only guarantee up to their door they cannot predict what the traffic is on the overall internet no more than you can predict what the traffic will be on the freeway with everybody going for it..your ISP the best is what's called an AS autonomous system in the Internet is made up of multiple interconnected AS’s that your traffic might pass through
The flip side these content providers like Netflix...if the stream... they need a guaranteed bandwidth all CIR in the pipe end to end passing through multiple AS that your ISP is no control over to begin with and they have to come first and their bandwidth hogs they don't play well on shared media there data is special has to pay a higher rate..
this is a highly highly highly simplified version of what really goes on I'm not going to get into multicast QoS traffic shaping policies inter AS routing all the different formulas .... traffic shaping is a highly complex subject this is just insane what they're trying to pass ...
Let me “say this about that” ... :-) ...
I would want to know about ANY and EVERY Internet service I am able to purchase — TWO THINGS ... (1) the highest speed that is guaranteed, steady and deliverable. (2) the possible maximum speed [and that is just a “bone” I throwing to the telcom dogs, so they can use it for advertising]. I really ONLY want to know and pay for ... just #1.
Also, it must be made clear (and most do already) what the total bandwidth allowed is.
If there is one thing I would want from the FCC is that I would want them to enforce “truth in advertising” in that the ONLY THING that can be advertised (for “speed”) is what can be GUARANTEED ... steady and without fail! THAT is the ONLY THING I want to pay for, in a consumer service ... NO HYPE from the Telcoms!