Following the Explain Me Like I'm 5 question about the role of the Internet Service Provider[1] i got curious on how is the internet infrastructure "between ISPs"? I don't know if it's correct to call "node" the point where all end connection are gathered by an ISP, but how common are these "nodes", how many people do they serve? What are average data rate limits of connection between "nodes"? It's all fiber optic cable. The connections between the ISPs is called the backbone network. The data rate in the backbone networks is in the range of 10-100 Gbit/s. You can find out more about this here: Fiber Optic Specs Internet Backbone When I did simulations, a "node" is any physical item that has some sort of network connection. This can be a cellphone, a computer, a router, a modem, or any other networking device. A node can also have many sub-nodes. For example, we might call a building that holds all the ISP's routing infrastructure a "node", but within that building there will also be many network devices that can be called "nodes" as well. Here's a couple papers about the back bone networks: Modeling Internet Service Provider Backbone Networks Structural Overview of ISP Networks What connects europe and the americas? Is there a huge bundle of optical fibers the runs under the atlantic ocean or we're connected via satellite? When where these infrastructure build? (i suppose late 90s) There's an underwater fiber optic network that connects all the continents. Here's some good information about it: http://www.submarinecablemap.com/ http://twistedsifter.com/2012/07/the-undersea-cables-that-connect-the-world/ http://en.wikipedia.org/wiki/Submarine_communications_cable Edit: I found this site with a bunch of maps of ISP networks: http://www.telecomramblings.com/network-maps/usa-fiber-backbone-map-resources/ More on reddit.com

The coaxial (cable)/twisted pair (ADSL) leaves your house and goes to a building that's nearby (a mileish) called a Central Office (CO). These cables are buried underground, usually down the street in front of your house or alleyway, or carried on poles if you get your telephone or cable that way. In the CO all of the copper lines from all of the houses in the area come together and are plugged into some devices there. The step from the local office to your house is called the "last mile". These devices detect amplitude (how big) and/or frequency (how often) changes in the voltage on the line and convert it into digital data (ones and zeros). This process is called demodulation. From here your data is lumped together with all the other data coming into the CO and sent over a fibre optic line, usually buried under the street or hung on a pole, to a big data center where your ISP's routers are. Fibre optics can go very far, so there are usually only a few of these big data centers in a city. These data centers are physically connected to one another with buried fibre optic cables, and then one or more of the data centers in each city are directly connected to one or more of the data centers in neighbouring cities. So the fibre goes from your neighbourhood CO a mile or so away to a much bigger building somewhere in the city, which then has connections to other data centers in the city and in neighbouring cities. Electrical signals are converted into light using a transceiver. The light then bounces down the fibre optic line to the transceiver on the other end, where it's turned back into electrical signals. In the data center your ISP's routers look at the data. Routers are responsible for moving data between different networks. They look at the destination IP address and figure out which IP network the data is destined for. Then they look at these big tables (500,000+ entries) that match each IP network to an ISP based on the ISP's autonomous system number (ASN), which is how the internet sees an ISP. You see "Verizon", the internet sees ASN 701. Having it's own ASN, and having a copy of the table listing all of the IP network to ASN assignments is basically what makes an ISP an ISP (well, that and connecting to other ISPs). Once the router knows which ASN the data has to go to, it looks for the edge router that is closest to the destination ASN, and then sends the data bouncing through its data centers, city by city, until it gets to that edge router. More about edge routers later. ISPs connect to one another by burying fibre optic cable from one of their own data centers to an internet exchange (IX), which is a place where a bunch of other ISPs have agreed to drag fibre lines to as well. For obvious reasons, ISPs will also just designate one of their own data centers a Point of Presence (POP) and "allow" other ISPs to bring fibre cables there and rent rack space in the building. ISPs themselves, or companies that specialize in this, will also sometimes bury cables directly between IXs and POPs that are far apart (e.g. on different continents). These connections can be very, very long and very, very expensive. They will bury it over land or sea, farmland, forest, mountain, coral reef or deep ocean. These lines are usually one big continuous unbroken link, minus a few repeaters/amplifiers/regenerators which keep the signal strength up, and go for thousands of miles. In an IX or POP, which is basically a warehouse, each ISP is given space on computer racks in the building. So your ISP has brought their fibre optic cable hundreds of miles from their data center to the IX or POP and routed it through the building to their racks. They then place their edge router in the rack and hook up their backhaul fibre cable to it. A physical fibre optic or copper cable is then ran from your own ISPs edge router, through the building, to the other ISPs edge router, which is connected to its own long distance fibre cable back to that ISP's data centers. And that's how babies are made Edge routers tell whatever ISP they are connected to which IP networks your ISP owns, and then, importantly, they also usually say which additional ISPs your ISP is connected to as well. ISPs will then sign agreements between themselves regarding how much, if anything, they will charge one another for data going between them, and whether or not they are allowed to send data only to that particular ISP, or if they are allowed to also send to ISPs that THAT ISP is connect to as well. This is called peering. It should go without saying, this is a huge simplification and stereotypification of something that can go a billion different ways. One usual variation is that there are companies that specialize in burying fibre optic lines between IXs and POPs, so that if ISP A wants to talk directly to ISP B, but is far away from ISP B, they can pay to use part of one of these companies fibre lines to get from an IX where ISP A is to an IX where ISP B is, rather than paying to construct their own long distance cable. Edit I realize this is more of a ELI 1st year college student... but there you go... Second Edit Obligatory thank you for the gold, kind stranger. May your internet be forever fast and reliable... Third Edit(s) Good points from some great folks that newer implementations of DSL move the aggregation point (where your DSL line ends and your data is sent onwards over fibre optics) much closer to you and it is likely just a cabinet down the block. This makes things faster for you. Also remembered what a CMTS was, corrected a few typos, and added a few terms. More on reddit.com

Not quite the place for this question, this is specifically for career questions. There are other subs that should be able to help you. There's a couple things that go against the assumptions you are making (not that they're bad assumptions, as you said you are learning :) ) Not all Internet lines are fiber. There is also coax which uses electricity over metal instead of light. This does not travel at light speeds, so that could be part of the slowdown. Your Internet traffic has to get processed by a lot of in between devices. You aren't just sending your ping on a straight line from where you are to your destination. Your Internet service provider has to take your traffic and figure out where to send it, and there may be a couple more places it hits before getting to the destination, then it has to get all the way back to you. I'm assuming you're asking all of this because you are playing video games and want to lower your ping. You unfortunately might not have much control over this. Your Internet service provider could possibly provide you with a better connection if you paid for it, or you could have a network card or router that isn't great. Likely this is all fine though and you're pretty much just getting ping appropriate to where you live. More on reddit.com

this is a really complex topic, the best analogy I could come up with is "how is air transportation funded?" its a mix of different mechanisms, depending on who its for. its an interdependent web of mostly commercial entities. At least in the US, there isn't much government funding, outside of grants for broadband rollouts in under-served areas. There are a lot of different kinds of commercial entities involved. The easiest to understand are backbone provides, they run global networks that you can pay to connect to. They pay to run cables and build points of presences, and you pay them per-byte to 'transit' traffic across their network. There are datacenter colocation providers, who have real estate holdings, near points of presence that allow connecting to the backbone providers, where you can rent space for servers. There are internet service providers like Spectrum, Rogers, and smaller regional ISPs, that run smaller regional networks that end-users can pay to connect to. They might need to pay for backbone connections, or, in some cases, they might 'peer' with a backbone provider in an even exchange, because the backbone provider needs to both connect the users to the services, as well as give the services access from the end customers. When you get to various 'service providers' there is a ton of diversity. From my employer, a big tech company, that owns data center real estate, as well as our own dedicated backbone network and content distribution network. We make money almost entirely from ads. There's amazon, who makes most of its profit from AWS, where they rent servers and other kinds of computer capacity to third parties. They also own lots of datacenter real estate. or little fish like this here reddit site, I suspect they rent capacity to run the site from Amazon. The big undersea fiber optic lines are either owned outright by the backbone providers, or there are per-project corporations where a handful of investors that need capacity between the endpoints will combine to pay for it to be laid, and to maintain and repair it, while it provides individual 'pairs' out of the big bundle to each of them. More on reddit.com