Most ISP (Internet Service Provider) and Datacenters giving you 2 types of bandwidth calculations: metered or unmetered. An ISP in Indonesia for example has internet packages which have data transfer quota (also means metered) and unlimited data transfer (also means unmetered). Same does with datacenters, usually they offer a server with specified monthly data transfer quota or capped unmetered bandwidth.
As user we must be a little bit smart on deciding whether we will subscribe for metered or unmetered bandwidth. In the case of renting server on a datacenter, usually they put your server on 100Mbps port if you subscribe for metered bandwidth. In other side, most datacenter cap your bandwidth in the range of 1Mbps to 10Mbps (depends on datacenter) so your server can only use up to that range even the network card on your server is 100Mbps NIC.
Now, incase you found two servers offering with the same specs and price, and the datacenter gives you option to choose 1000GB per month bandwidth on 100Mbps port or unmetered bandwidth on 3Mbps capped bandwidth. Which one you will choose?
Yeah I know.. “unmetered” seems more eye catching :D but do you know how much data you can transfer per month on 3Mbps bandwidth? I use this bandwidth calculator I found here: http://web.forret.com/tools/bandwidth.asp and found out that 3Mbps bandwidth can roughly transfer 972GB per month. From the calculation 3Mbps have 28GB less data transfer per month compared to 1000GB per month data transfer quota.
Which one you choose is up to you.. do you need to burst the data transfer rate up to 100Mbps or 3Mbps bandwidth is enough? 100Mbps bandwidth, although you can’t use it fully 100Mbps constantly, it’s still far faster than the 3Mbps bandwidth.
But if you choose the 1000GB data transfer on 100Mbps port, you should be careful as if your website become popular and traffic start coming in, 1000GB surely will be eaten fast!