What are the different classes of Internet Connection and how do they differ?

What I learned so far (correct me if any of it is wrong):

  • Consumer/small office connections are typically asymmetrical, offering much less upload bandwidth, which is critical for a server, than download bandwidth.
  • Consumer and small business broadband providers usually only list maximal bandwidth with no guarantees. By contrast, the "pro-grade" connections come with either guaranteed bandwidth (CIR) or guaranteed data transfer per month.
  • The consumer connections typically have no SLAs.
  • The connections at data centers are (always?) redundant and utilizing two or more providers. If you want full redundancy in your office, and host public services from it, then having two connections from two providers is not enough, because they would have different IPs. To have redundant routes to a single IP address, you would have to obtain your own IP address class and an AS number from your Regional Internet Registry, have a BGP router and set up BGP multihoming.
  • IP Addresses: [Connection type] typically comes with [base IPs], and typically costs [monthly cost] for additional IP addresses.
    • Consumer, 1 IP, $5/mo per IP
    • Business, /28 or /29, $1-2/mo per IP.
    • Datacenter, 1 IP, $1/mo per IP.
  • Rarely, Consumer connections come with a 1918 IP and "Carrier Grade" NAT.

Essentially, "Consumer" grade networks connect thousands of users to a single "Carrier Grade" network. That is, the bandwidth is there, it's just over-sold.

Here are a few things you'll get in a datacenter that you won't get at home:

  • Guaranteed Bandwidth - This is by far the biggest one. You may get 50Mbit/s from your cable provider, but you'll probably only hit that rate at 3am on a Tuesday. A "business-grade" connection means they reserve a certain amount of bandwidth for you whether you use it or not.

  • Uptime SLA - You should be guaranteed 100% uptime w/ credits for downtime. Consumer network providers may simply shut off the network several times a year for upgrades, maintenance, or just mistakes.

  • Latency - If you're in the datacenter with the carrier, you'll get a snappier connection

  • Peering and such - This one's pretty obvious.