25. What is the difference between buying gigs of transfer and megabits of transit?
This is a tough question that takes a LONG answer....but whoever gave Sleazy this question knew that I had already written a long explanation and have saved it for many years. So in aneffort to conserve time, I am going to just paste it here.....remember, this this was written about 6 years ago and I didnt read over it today so there may have been some small changes since then.....but here goes.....
OK....let's see if I can make this easy enough to explain.....when buying hosting you can purchase the bandwidth portion in one of two ways, either TRANSFER or THROUGHPUT. Lets look at them individually....
Throughput is the actual total SIZE of the combined files that are sent by the server. Throughput is sold in Gigabytes (GB) and is an aggregate monthly total. So, for example, lets say you have a web page called THISPAGE.HTML and the actual page is 25k and on this page you have 3 graphic images that are 25k each then that is a total of 100k, right?? If 100,000 people come to that page over the course of a month then your Throughput would be calculated as 100kB X 100,000 = 10,000,000kB or 10GB. So for that month your THROUGHPUT would be 10GB. This does not take into account if all 100,000 people hit the server at the same time or were evenly spread out over the course of the month it is still 10GB of THROUGHPUT for the month.
Now....onto TRANSFER....but before we begin let me state that in *NO* circumstances can you mix Throughput and Transfer. It is physically impossible and you will see that in a second.
TRANSFER is measured in Megabits Per Second (Mbps) and measures how much information is traveling through the "pipe" at any given time. This is usually used for larger clients because in order to push more information through the pipe, you need a bigger pipe. I like to compare TRANSFER to Water in a series of water pipes. Imagine that your home PC has a water hose connected to it instead of a telephone line. The water hose is 1/2" and is connected to the side of your house where it meets a 2" PVC pipe and your house is connected to the Water Main, which is a 12" Pipe. In this example your water hose is your home telephone line and your house is your ISP and the Water Main is the backbones. It does not matter how hard you try you are only going to get 1/2" of water into your PC at any given time because the "pipe" is only a 1/2" water hose.
Now if I were going to sell you water BY THE GALLON, that would be called Throughput (see above)....or I can sell you a PIPE and just charge you for the amount of water that you push through the pipe at any given time...this is called TRANSFER. So for example, if I take a measurement right now and you are pushing 1" of water through the pipe and I look again in 5 minutes and you are pushing 1" still and I look again in 5 more minutes and you are pushing 1/2" and I look again in 5 more minutes and you are pushing 2" then how big of a pipe do you need to accommodate your traffic flow without any water being backed up like a funnel??? You would need a 2" pipe....but you are not using 2" all the time so why do you have to pay for a 2" pipe all the time?? That?s where the 95% comes in.
The 95th percentile (which is fast becoming the industry standard) simply means that the hosting company will look at your pipe every 5 minutes and take a reading and add that reading to a long list that they keep for an entire month. At the end of the month that lists will be 8640 readings (there are 12 5minute intervals in an hour, 24 hours a day for 30 days). They will then take that list and sort it from the biggest number to the smallest number so that your largest 5 minute reading is on the top and the second largest is next and the third largest is next and so on and so forth. The top 432 entries (5%) are discarded and the 433rd is considered your "95th Precentile" and that is the figure that you pay for. The 95th percentile was designed to help chop off wild peeks and just bill you for what you are sustaining on a regular basis.
As for what is more advantageous it totally depends on your situation and what is most important to you. With THROUGHPUT you have little control over the size of your connection so that means that if you are filling your connection up and it is getting backed up or bottle knecked like a funnel, you will never know it because you are only seeing what the server actually transferred...not what it couldn?t get around to because it was backed up. With transfer you should have access to your Hosting Companies graphs (usually MRTG graphs is the industry standard) and you can see your transfer yourself and if you see a flat line across the top of the graphs then you know that your hosting company doesn't have enough bandwidth to handle your needs (and this is much more common than one would think). ***IF YOU ARE BEING BILLED ON 95TH PERCENTILE MAKE SURE YOUR HOSTING COMPANY PROVIDES YOU WITH THOSE GRAPHS...if they refuse, they obviously have something to hide. If you have your own Sysadmin then you can actually install your own copy of MRTG on your server and double-check their graphs. (I can tell you that is what we do to our providers and we welcome people to put us through the same scrutiny).
What does MRTG mean and do you have an example of one so I can see what it looks like?
The Multi Router Traffic Grapher (MRTG) is a tool to monitor the traffic load on network-links. MRTG generates HTML pages containing GIF images, which provide a LIVE visual representation of this traffic. You can read up on it and even download and use it from:
http://ee-staff.ethz.ch/~oetiker/web...mrtg/mrtg.html On the site you can see examples of the graphs and how they work. WARNING: This site is written FOR GEEKS, BY GEEKS. Do not expect to understand it thoroughly unless you are a little bit of a geek, too! :-)
>Also, with 95 Percentile can I have my transfer rate limited to some upper limit so that I have a cap on what my bandwidth cost will be each month? I would worry that if I had 2 or 3 days with 10x my normal traffic I would have a heart attack when I get the bill.
In a word, YES, you can have your bandwidth CAPPED if you like, and if your Hosting Company will do it. With that said, and I can only speak for NationalNet, we do not allow our clients to cap their bandwidth and this is based on sound business practices. Example #1: You own a web site that is getting hammered with traffic, bandwidth goes UP....but so do REVENUES...and thus so do PROFITS! Example #2: You own a 3rd party feed that your clients are putting onto their web sites and one of them gets hammered with traffic and bandwidth goes up....if you are capped then it bottlenecks and surfers have to WAIT for the page to load until the people in line ahead of them are done...then your clients start canceling their service because their surfers are complaining that the pages never load...then you go out of business because you can't pay your bills. It?s a vicious cycle, I know.
>Also, you say this is becoming the industry standard. Is that the way that your providers are charging you now?
Yes, again! Because we are a major player in this arena we have been charged this way since the beginning (1997).
Some hosting providers will sell you bandwidth for a dedicated server based on Gigs of transfer, much like a shared server account, instead of the 95th percentile. Why would they do this, when dedicated servers take up almost 85-90% of their total bandwidth? Because, this usually means that THEY are capped by THEIR upstream providers at their request and don't have to worry about overages, as they are on a fixed rate. So...what is the problem with this? What happens when some site on another server gets hit with a password trader? They suck up all the bandwidth, and the surfers attempting to get to YOUR sites are left waiting in line, which translates to lost sales.
Traffic in our industry is very spiky...on any given day, it goes up and down in fairly wild extremes. For instance, our own MRTG graphs look like mountains and valleys. Joe surfer gets out of work, and the bandwidth goes up...and keeps going up until about midnite, when it starts going down. Password traders, special traffic deals, etc, all contribute to this "spikiness" (did I just make up a word?) Any host worth it's salt must make sure that they have lots of overhead to cover this spikiness, so that the actions of one or two webmasters does not affect everyone else.
It's very expensive for a good host to pay for all that "bandwidth overhead", but in the long run, it's well worth it.