I typically abhor comparing computer items to “real world” items; your computer is not a house and your network isn’t a neighborhood. However bandwidth is amazingly like a highway and I’d like to talk about it here because, frankly, I’m tired of talking about it at 3am with the sales team.
Bandwidth is like a highway because the more lanes you have, the more cars can travel through. The more bandwidth you have, the more packets can squeeze through. During certain times of the day, like rush hour(burstable), there is just too much traffic and everybody slows down. The highway and network connection are totally interchangeable here, so it may not be clear which I’m talking about, because I’m talking about both.
What is rate limiting? Its like closing down a few lanes of the highway.
Traffic shaping? You know how (in the US at least) a highway has a Local and a Bypass as you approach a city? You segment traffic by type. Local or bypass, web or voice. The Jersey Turnpike splits in two just south of NYC, and trucks are forced to stay on the right side of the highway, while cars can choose between any of the lanes.
QOS? How about HOV? You get a lane all to yourself if you meet a certain criteria. That criteria may be having 3 people in the car, or maybe you have to be a voice packet. Either way, just because you meet the criteria, if there is too much traffic you still get jammed up.
kB/kb? Just listen to the network admin here.
Oversold bandwidth? Just imagine the two right lanes are so full of pot holes you can’t use them, but you still had to pay the full toll to get on the road.
Upstream bandwidth? Typically small 1 or 2 lane roads merge onto 4 or 5 lane highways. However, in every major city I can think of there is a 5 lane highway that narrows down to a 2 lane bridge or a tunnel or something. Next time you are stuck in traffic because of this situation, think about how you feel. This is how your network admin feels when you ask her to upgrade to a gigabit LAN because “The Internet” is slow.
How much bandwidth do you need? Nobody would construct a highway to handle rush hour with no delays. You’d need 30 lanes. Once you got those 30 lanes, people would start streaming 3D Super fun HD anyway and fill your pipe, so don’t even bother. Trust the network admin that a 5 minute smoothed MRTG graph will give you a good idea of how much bandwidth you consume.
