243.4 Terabits per Month - The Speed of Hosting

There are a lot of different types of hosting. You can use shared hosting, a VPS, or a dedicated server. You can use Windows or Unix. You can use Apache or IIS. You can use something more off-the-beaten-path. But one thing remains the same. At the bottom, underneath all those details, there is still a server and that server connects to the internet, probably by ethernet.

So what does this commonality mean? Well, it means one very important thing. There is a top speed of hosting.

The form of ethernet most hosts use is 100BASE-T, which can move 100 megabits, or 12.5 megabytes, of information each second. One and a quarter megabytes per second doesn’t sound so bad, unless you are downloading something really big like Linux DVD ISO.

Unfortunately, ethernet isn’t quite as good as all that. Like everything else in life, there is overhead. Phil Dykstra did a good analysis of ethernet overhead that we can use. It is a few years old, but ethernet hasn’t changed, so the numbers are good. Phil gives us a maximum efficiency of ethernet between 93.9040% and 94.9285%. Let’s be pessimistic and use the lower number. This gives us a new top data transfer rate:

Okay, so that is our top speed of data per second. Now, we have to need to know how many seconds we get per month. Obviously, some months are longer than others, but we’ll use 30 days to make life easier.

If we multiply our top data speed by our seconds per month we get:

Now, a proper geek question at this point would be: is there any way around this limit? And the answer, of course, is yes. One way is to add more physical network interfaces to the server. If the server has twice as many interfaces, it can get twice the bandwidth, and so on. Note that these are physical interfaces, not virtual interfaces on the same hardware. Simply put, to get more bandwidth from your server, you need more wires.

A second way to break the speed limit is to have more than one server. This could be as simple as mirrored servers, your own custom distributed solution, or using one of the big content delivery networks like Akamai. In any case, the limit per server still exists.

Oh, the title? That was just putting the number back into bits instead of bytes, as that is how network speeds are generally measured.

Next, we’ll take a look at what this means to the typical webmaster just looking for a decent web host.