Tier One
Definition
ISP Tiers
The “tier” terminology has arisen mainly in the Internet Service Provider (ISP) industry press to describe ISP size and connectivity. The lower the tier number, the bigger the ISP.
“Tier One” providers are the national/international backbones. There are between one and two dozen of them, and include the original bad boys Sprint, MCI, UUNet and BBN Planet, plus newer Fiber Optic Networks like Global Crossing, and Qwest. To be a Tier One provider, you need cross-national backbone links of T3 speeds or higher (45Mbps), and peer at one or more of the major peering points (multi-company POPs for sharing Internet traffic). Some Tier Ones have dial-up access arms, but they tend to focus on high-speed, high-reliability leased lines.
A “Tier Two” provider is an ISP who is connected to a Tier One provider. These tend to be regional (multi-city) networks, although this does include some nationals and some locals. Most Tier Two ISPs provide a wide range of services from dial-up to web hosting and dedicated lines.
A Tier Three provider would be one connected to a Tier Two provider, and so on. These ISPs tend to be smaller shops that focus on one service, such as dial-up access or web hosting.
Tier One is Better?
The “tier” terminology is a useful metaphor for describing the ISP industry today. However, like any metaphor, it is a simplification. Many people mistakenly believe that lower-numbered tiers are “better” than higher-numbered tiers. In reality, a provider at any tier can have good connectivity, and different solutions are appropriate for different needs.
The first misconception is that more bandwidth is always better than less. While that sounds obvious, what is much more important is bandwidth utilization. I’d rather be on a T1 that peaks at 50% use than a T3 that is always clogged at 100%. Providers at every tier go through periods of overutilization, and providers usually have different levels of utilization at different POPs. While UUNet may be a great choice in Chicago, it may be a lousy choice in San Francisco (a fictitious example!).
The second misconception is that bandwidth is the only important aspect of an upstream provider. Connectivity and reliability can be as important, or even more important to some organizations.
Connectivity is how far the network is from the major backbones. A provider that has a T1 to Sprint and a T1 to MCI has better connectivity than a provider that has two T1s to the same company.
Reliability is affected by the type of link you choose and by your provider’s redundancy. A leased line (56Kbps or T1) will be more reliable (and more expensive) than a switched service like ISDN. Redundancy is how many ways out your Internet traffic can take. Again, this varies not only from provider to provider, but from city to city. Big Net may have five T1s leaving its home city, but only one leaving yours.
How to Choose
In the end, it doesn’t matter a gnat’s whisker what tier your provider is on. What matters is cost, service, bandwidth utilization, connectivity and reliability.
If money is no object while 24-hour availability is crucial, a tier one provider may be your best choice. On the other hand, if you need technical assistance, web hosting, and other services besides a simple data pipe, a tier two provider makes sense. And so on.
What tier are you on? It may not matter that much.