4

I know its a dummy question, but I couldn't find any information about it around the Internet.

I know about modems and routers and how they work, but I don't get how the ISP connects me to the internet? I mean...

Or, in other words, my question is: what prevents me from buying a modem and a router and doing this by myself and free?

  • 3
    And what would you connect your modem to? – Ron Trunk Mar 1 '17 at 18:05
  • Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you could provide and accept your own answer. – Ron Maupin Aug 17 '17 at 3:52
3

You really don't seem to understand what the Internet is. It is simply a bunch of ISPs all connected to each other. The ISPs comprising the Internet have agreed to certain protocols. Each ISP is connected to at least one, and probably multiple, other ISP(s).

When you send or receive traffic on the Internet, it probably crosses multiple ISPs to reach its destination. It may be that the source or destination of your traffic is on the same ISP you are, but that may be unlikely.

3

It connects you to the Internet very much the same way your home network connects your PC to the router, using IP (Internet Protocol).

The ISP doesn't have any magic equipment; just more of it than you are likely to have at home. i.e., at home you may have just a few computers, but the ISP services hundreds or thousands of users.

You are free to buy your own routers and such, but your ISP will want some way to charge you for the service. For a modem it might be a password. For a cable network the ISP will likely lease you a combination modem/router as part of the service. Their systems recognize the address of your device so they know it is you.

2

To get your packets to their destination and the replies back to you there needs to be a route there and a route back.

There are two (there are a few other cases as well but we don't need to consider those here) main types of relationships networks have with each other.

In a peering relationship two networks connect to each other so that network A and it's customers can talk to network B and it's customers. Peering connections may run over a direct point to point link or over an Internet exchange point that connects multiple providers.

Different networks have different policies on peering. Pretty much all of them will require you have your own IP space and AS number. Some networks will peer with almost anyone who gets themselves an AS number and buys a link to an Internet exchange point where they have a presence. Some will only peer with networks they see as equals. Some will only peer with you if you build your own international network and peer with them in multiple cities around the world. Some may expect you to pay for the physical connection to them or even pay them for the privilege of peering.

In a transit relationship there is a provider/customer relationship. A transit provider provides a transit customer with connectivity to the Internet in general. The transit provider will almost certainly charge the transit customer money for this service.

At the top of the pile there are a small number of providers who do not buy any transit, relying entirely on peering connections to serve their customers. It's very difficult to join this group as most of the existing transit-free providers are not friendly to new peers.

When you have a small ammount of traffic it's not worth playing the peering game yourself, it's cheaper to pay an ISP to do it for you. As your average traffic needs start to get into the gigabits per second it can make sense to start playing the peering game yourself.

  • is this why south korea has a much better internet service per buck than the us? If the Internet is run by the government, or one entity, you don't have this hodge-podge of private ISPs to send packets through. – 0tyranny 0poverty Jan 10 '18 at 4:15

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.