The location of your ISP will go a long way to determining both the cost of the service, and the speed your visitors will perceive. By location, we’re talking not just about the physical, real world location of your ISP, but rather the location in the not so real Internet world.
When you connect to the Internet from your computer at home through a normal modem, you dial into your ISP’s network (possibly through something as low-bandwidth as a telephone) and become part of their network. Unless you’re using a really big ISP provider, they’ll also have an account with another ISP that provides a slightly larger line to them that gets shared between you and the other dial-up customers that your ISP has.
This continues up the chain until, eventually, all of the ISPs’ networks are connected together. The largest lines connecting the bigger networks together are termed backbones, and these are typically owned by telecommunications companies such as MCI, AT & T and Sprint.
Obviously, when provisioning service for your site, you have to pay attention to where your ISP is in the general scheme of things. For example, if your ISP is buying bandwidth from an ISP, who’s buying bandwidth from another ISP, who’s then buying bandwidth from another, customers are going to have to be routed through three networks in order to get to your site. This is undesirable because it will take more time to download and navigate through your site.
The size of the ISP will generally decide its buying power. Remember, all of the bandwidth they buy has to be shared between their entire set of dial-up customers (if they have any) and all of their hosting customers. Therefore, if they only have a single Tl line (more later) to their ISP, everyone’s going to be sharing that small pipe. When choosing an ISP, pay attention to their commitment to ensuring the bandwidth they buy is sufficient for their customers’ needs, and the frequency with which they upgrade their networks capability in response to an expanding customer base.
Wherever possible, buy your service from an ISP that’s directly connected to an Internet backbone. This reduces the number of hops that your customer has to go through to get to your site, which should help in making your site more responsive.
An ISP will have to buy a connection to the Internet through either a single dedicated line, or a set of dedicated lines. Each type of line available has a standard designation so you know its capacity. Here’s a quick breakdown of the capacity of those lines:
|TO||56Kb/s||The speed of a standard new home computer modem
European (includingUK) equivalent of a Tl
|OC-3||155Mb/s||Average speed of an Internet backbone connection|
Remember, MB means megabytes, whereas Mb means megabits. OC is used to describe the speeds of the next generation of high-speed connections. They always run over fiber and one OC means approximately one T3.
Rony has chosen to host his site with a second tier provider, meaning that her ISP buys bandwidth from a large ISP. Whenever traffic needs to get in or out of her server, it has to be squeezed down a T3. This is fine for a single customer using a dial-up connection, but if he had around a thousand concurrent connections, this would create a bottleneck. If he hosted at the large ISP directly, he wouldn’t experience a bottleneck unless she had around 11,000 concurrent connections.
Another consideration when going for an ISP is how many pipes they have. They may well have a 45Mb/s connection to the Internet, but what happens when the provider of that connection experiences a problem and can no longer route traffic in or out? If the ISP buys bandwidth from a number of different providers, there is a level of redundancy, much like the redundancy we saw when building our server clusters, and therefore the good news is that there will be a reduced possibility that you’ll discover your site has no connectivity.