It doesn’t matter if you are a gamer playing World Of Warcraft, or a soldier remotely flying a spy drone on the other side of the world. Latency can, and will get you killed, and there isn’t anything you can do about it.
Internet service providers love to hype their services, especially cable providers, talking about the speed of their bandwidth, but you won’t see anyone screaming their latency in advertisements. This isn’t the fault of anyone, no one is being misleading, the fact is that all internet connections, regardless of speed, have inherent latency.
So what is the difference between BANDWIDTH and LATENCY?
I am going to boil this down the the simplest explanation I can: Bandwidth is your connection SPEED, Latency is the inherent time delay before your data flows.
For example, you are home and you go to a favorite website. You type in the URL, and wait…your request has to go through the internet till it hits the server of the website you are visiting, and it has to make a return trip back to you.
Once the website starts to load, it flows in very quickly (Bandwidth)
It is the TIME you waited BEFORE the website was visible, we call (LATENCY).
So what’s the big deal, it was only a second or two…
Well, it is a very big deal. To best illustrate latency, have you ever watched a live news feed where the news anchor is interviewing a correspondent in another country via Satellite feed? The news anchor asks a question, and a second or two passes before the correspondent replies.
The video is nice and clear (this is fast bandwidth), but the DELAY in the conversation between the individuals is LATENCY.
Latency issues have a real effect when trying to do online gaming, for example World Of Warcraft, or VoIP services like SKYPE, or a U.S. soldier remotely flying a spy drone behind enemy lines to provide recognizance information for troops. For example, the soldier fires a missile at his command console, a second later the missile actually fires from the drone. That one second (1000 miliseconds) could mean the difference in hitting the target, or hitting an innocent bystander.
Real time applications are most impacted by latency. Studies show that when absolute delays are below approximately 20 milliseconds, they are generally imperceptible. A total system latency of 50 milliseconds will feel responsive, but still subtly lagging. For the average computer user, gamer, etc. things are not exactly optomized, resulting in an end to end latency of 100 miliseconds or more.
The internet connection in the general consumer’s home set up is twister pair copper ethernet. Let’s take a look at the fastest systems we have available. Fiber Optic.
Latency in Fiber optics: Light in a vacuum travels at 299,792,458 meters per second, and this equates to a latency of 3.33 microseconds per kilometre of path length. Light travels slower in fiber due to the fiber’s refractive index and this increases the latency to approximately 5 microseconds per kilometre. So, while we are using the current generation of optical fibers there is a limit to how low we can drive latency – take the shortest possible route and multiply this by 5 microseconds per kilometre. A 50km link would therefore have a fiber latency of 250 microseconds, a 200km link would have a latency of 1 millisecond and a 1000km link would have a
fiber latency of 5 milliseconds.
Latency is a very frustrating bottleneck, one we will have to live with for quite some time to come, if not forever. Einstein’s famous E=MC2 still holds true. Nothing can travel faster than the speed of light, and this is the limitation inherent in the internet.
J. D. Redmond ~ “Dr. Tech” ~ http://www.DrTech.co