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Have you ever done a speed test on your Internet connection? A lot of people have, and they see Internet speed numbers like 500 Kbps or 2 Mbps or sometimes even higher numbers. Then they turn around try to watch a streaming video on YouTube and the video stutters or stops for seconds at a time.
More often than not, an average computer use will blame the Internet connection speed with a question, such as “Why does the speed test tell me I can download this 3 Mb video in 2 secs, yet it keeps stopping?” Or, “My speed test tells me my upload and download speeds are 512kBps. Why won’t my Skype work better?”
Hopefully, I’ll be able to shed some light on this issue for you and help with understanding Internet speeds. Your Internet speed test only tells you part of the picture. What a speed test measures is how long a certain amount of data takes to travel to the test server and back to your computer. Based on the size of the file and the time from which it leaves their server to get to your computer, the test calculates your download speed. The size of the file and the time it takes to leave your computer and get to their server determines your upload speed.
Usually your download speed is greater than your upload speed. Why is that? Well, with average web usage, you typically send a few letters here, a click there. That’s your upload overhead. The website or video that you watch as a result of those clicks and letters is the download over head.
It’s like you sending a Smart Car to request that they send you a fleet of tractor trailers. You only need one lane for the Smart Car, but you might need 14 lanes for the tractor trailers. This is known as asynchronous communications. This is why your upload speed is usually less than your download speed.
So, what does that have to do with your 3mbps connection resulting in jittery video? Exactly that, those speed tests don’t measure jitter! Yes, jitter is a real technical term. Imagine a train coming into the station. Each car on that train arrives at the station at the same intervals, because each car is the same distance apart. However, if each car came in with different distances between the cars, well, you can imagine what a mess that would make!
It’s the same thing for packets of information on the Internet. The fluctuation of the time between those packets, even if ALL the packets are traveling at 3 Mbps causes jitter. Significantly high jitter levels can cause your VoIP to not work. When we talk our voice is a continuous stream of information, so the data needs to be continuous too! Same with video!
Another cause of Internet speed not being what it seems, is the number of hops a communication needs to make to get to the final server. Let’s say you test your speed against server XYZ. Let’s also say that there are no hops between your computer and server XYZ. Then you are told your download speed is 3 Mbps. Awesome!
Now you try to download something from server DFG. Yet, there are 14 hops, or servers, that your communications have to go to, to hit server DFG. Well, whichever one of those hops is the slowest to respond sets the maximum speed of your communication. We like to call that a bottleneck. You can have a Ferrari, but if you’re on a dirt road, you can still only go so fast. You never get to go the full speed you are capable of.
There are many different points for bottlenecks to show up, between the server you’re connecting to, and seeing the final event on your monitor. Your Internet router may be capable of less speed than your Internet connection. That’s a bottleneck. Your Network Interface Card may be capable of less speed than your router. That’s a bottleneck. Your video card may only be capable of processing the information at a lower speed than your NIC card can deliver it to your computer. There’s another bottleneck.
One more point to consider is that your bandwidth may be getting divided amongst a number of computers in your home. If my Internet modem is capable of 3 Mbps but I have four computers downloading things at the same time through the same modem via a router, that 3 Mbps resources is now shared amongst those computers. At any point in time, any one of those four computers is going to have an Internet access speed less than that of the modem.
Well, what can we do about this then? That depends. What do you want to do about it? What can you deal with? Me, I’m patient enough to download the whole video to my computer and watch it that way. You might not like that. Maybe you’ll want to upgrade those computer components that are causing bottlenecks. A new video card with greater processing power. A better wireless router — maybe something in the N class. A different Internet service provider or a higher speed package might be in order.
My opinion is to kick back and relax and enjoy the fact that we have this amazing technology. Only five minutes to download a song instead of driving to the record store and waiting in line for the latest Rush album. But then again, that’s just me!