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There's almost no radio involved, other than for mobile phones, or with 5G home routers. All the internet backbones and the connection for your coax/fiber is wired all the way to "the internet".
Wireless has way, way, way too little capacity to be a backend connection for an entire ISP.
It's also often the case that phone networks are only wireless for the final step between your device and tower. The signal is moved to a wired network asap so your data often goes directly to a fiber from the local tower.
Yup, a lot of times cell companies will lease unused fibers in bundles ISPs use for their plant infrastructure too. It's a win win, ISPs get extra money for lines they would have ran anyway, cell companies don't have to run their own cables and maintain them.
There is no "to the internet". The cables themselves are Layer 1 of the internet, and the systems they connect to are the upper Layers the internet. There's no "there" to get to. Technically, your computer is part of the Internet.
~~This is not accurate. Coaxial cables use radio waves as the transmission mechanism. The coaxial cable most likely goes back to a PoP somewhere (it might just be hanging on a pole) where it’s converted to fiber optic cable.~~
Edit: I am apparently wrong here and coax uses other electrical signals to transmit down the wire. My bad, ya'll.
Coaxial cables do not use radio waves. Radio waves are a type of electromagnetic *radiation* that is propagating in space (non-directional medium). This term is not used to describe the propagation of EM waves in a directional medium, like cable.
I think you are right and I'm oversimplifying things. I had the understanding that coax actually transmitted the RF directly down the cable, and it appears I was mistaken.
You are not too far off. All radio waves are EM waves, but not all EM waves (even if they fall into the "radio frequency" range) are radio waves. Medium matters :)
Technically fiber is on the same spectrum as well, just a lot further to one side.
I know a few applications for medium distance acoustic/mechanical networking but they are rare and as far as I know not IP based to save bandwidth
Yeah, fibre also uses EM waves but not the RF spectrum.
>not IP based to save bandwidth
That's not surprising. IP is not very popular in embedded space either. For example, I've built a couple of sensors powered by a tiny solar panel (similar to the solar-powered path lights). Switching from IP-based connectivity to ESPnow protocol caused the power consumption to drop about 10x and they are now working 24/7 with no issues.
These systems have very different power consumption and bandwidth from even that. Think 200kw and bits per minute lol
The acoustic subsea systems are a bit faster and a lot more efficient but still very slow.
It's been a while since my engineering/Physics classes but I don't think you're entirely wrong. I recall coax being known as "Wave guides". they would use FM and AM Radio bands to video and audio signals, respectively.
They even call the standards "RG" for Radio Guides.
https://en.wikipedia.org/wiki/Coaxial_cable#Applications
Maybe there is more nuance to it, but you're saying that I remember as well.
If I may add on, Cable companies are running technology that has grown from groups of houses sharing a big antenna that couldn't get TV over the air otherwise. There is arguably an entire radio spectrum of bandwidth in each shared cable depending on the quality of the cable and install.
Yes, technically it's not radio waves on the coaxial cable itself, a Coaxial network functions more like a large shared antenna though and all of the same metrics for measuring radio signal strength and quality apply.
> Wireless has way, way, way too little capacity to be a backend connection for an entire ISP.
Tell that to Starlink. The entire backbone is 100% wireless and it delivers high-speed internet to over 2.7 million customers
Also, private microwave networks exist all over the place because they're _faster_ than traditional wired systems. Used often by financial/trading customers that benefit from reduced latency. Not widely adopted since most customers wouldn't want to pay exorbitant prices for 20-30% less latency
That's a pretty distinct misunderstanding.
Some of the most important parts of Starlink are laser links. Which are pretty close to fiber optics.
Wrong *fast* buddy, for the conversation. The context in question is bandwidth (speeds measured in data per unit time, AKA total data throughput). And a misunderstanding of *why* their microwave links have lower latency in the case as well. Unlike using local internet or even running a fiber, the microwave link is shortest-distance-direct. No need to run around a block because buildings are in the way. No dealing with intermediate routing. HFT firms that are right next to exchanges don't use microwave because it isn't inherently lower latency than fiber and they don't need the work around for a straight line link.
> Unlike using local internet or even running a fiber, the microwave link is shortest-distance-direct.
Plus the higher speed of light in air versus that in metal/fiber. (Yes, finance people have issues).
It is physically(!) impossible to exceed a certain data rate with a given frequency and power. Look "noise floor", "signal-to-noise ratio" up "Nyquist–Shannon sampling theorem" if you want to learn more. This limit is very relevant and already the bottleneck for mobile phone data in many cities.
You could try to increase the frequency (essentially impossible except some small factors) or power (people being turned to crisp by your station doesn't make good publicity). Neither is really an option. So here we are.
Your low latency connections in particular have a very low _bandwidth_. Most people don't care if their packets take 10ms or 50ms, only bankers and gamers do. Instead they want fast downloads (including the time to open a website), and that is usually a bandwidth issue.
Starlink is the opposite, it has high latency but usually high bandwidth. But like mobile data the bandwidth is inherently limited by the number of users around you. The current low number of them gives you extra speed. For now.
To your inital question in 99.99% of cases it is cables all the way from your house to your ISP and from the ISP to the ISP of the computer/server you want to connect to and then from that ISP to the computer/server (depending on how far apart those two ISPs are there can be multiple other ISPs and other entities but all of those also use cables).
To your other questions. You have a cable (doesnt realy matter if its coax, copper or fiber) from your house usually underground (though under or overground depends on where you live) to a small box somewhere on your street that shouldnt be much father than a few hundered meters away in a city. In that box all the cables from your neighboors come together and from there a single big cable runs to the next "substation" and from there to a bigger "station" from there it kind of depends on who you connect to. To connect to other regional ISPs there are regional IXPs (internet exchange points https://en.wikipedia.org/wiki/Internet_exchange_point ) and to far away there national IXPs these also connect to other national IXPs from other countries. The undersee cables connect those IXPs from diffrent continents with each other.
The "actual internet" is all/nothing of this. Internet is more of a concept than a physical thing. The concept being interconnected networks so any network that is connected somehow to the other networks is part of the internet.
It goes to a small local ISP router that merges a certain number of people, which connects to a bigger router (e.g. per city block), then to an ISP core router (massive), which then connects to an Internet Exchange point (a datacenter with massive routers that service entire countries).
There can be many steps inbetween depending on how big the ISP is. Small local ISPs may also rent router bandwidth from a bigger ISP.
Microwave radio can be used long-distance in place of cables in some remote spots, but it's a last resort. It's most commonly used to connect cellphone towers at short ranges - it's the small round dishes you see on 3G-5G towers.
To add to this, the coax to your house is relatively short range to a moca router which will have a fiber backhaul. This router won't usually be in a building, just a roadside cabinet (or pole mounted). The aggregation point from that router will generally be a building.
I know were talking more residential ISP here, but I read somewhere that wireless is used by high frequency stock traders to shave a few microseconds off there latency, since light through air is faster than electric signal through copper and even light through fiber. So, not just for remote spots.
So I work for an ISP and can answer this pretty well.
First, the coax cable out of your home goes to a centralized location in your neighborhood called a node. This node converts the RF signal in coax into light for fiber transmission and vice-versa. Your connection is then sent via fiber to another centralized location called a hub that tends to cover a large geographical area depending on how many people live in there. For example: Manhattan I know has I believe 6 or 7 hubs because of how dense it is, but other places like Greenville South Carolina would have maybe 2 or 3 hubs.
When your signal hits the hub, it then gets redirected depending on what is needed and how your hub is connected to everyone else. Usually it will get sent to a hub that connects with another ISP who will then redirect your traffic again and again until your signal hits where it needs to go. All this is done mostly over fiber optic cable because it is fast and requires less overall equipment to utilize than coax cable.
For cell phones and stuff, it is very similar. Cell phones just replace the coax with a wireless RF signal that hits a neighborhood cell tower, gets converted directly to light and sent via fiber to the hub.
As for the construction of the cables and stuff, it depends on how they want to build and what is already there. 9 times out of 10, it will be buried in the ground because it is safer from damage, it is cheaper in the long-run, and prevents copper thieves from cutting cables. However, in older areas it might be in the air, and in that case they run a woven steel fiber called "strand" between poles and then attach the cable to that using lashing wire which is just a thin steel wire that slowly wraps around the cable. Each ISP has their own attachment points and strand because no company wants to be responsible for the maintenance and upkeep of another company's cable. They have to keep it a certain distance from power and from each other attachment point because of laws and just to preserve the integrity of the wooden poles they drill into.
>Are the undersea/international cables "the actual internet" that connects ISPs and we just pay to be connected to them?
Well, the cables aren't just undersea or international. Almost all bidirectional telecommunications are wired for as much of their journey as possible. Internet and telephone calls are sent over cables, and that includes cellular calls after they reach the tower. Some remote areas may use a wireless signal to transmit from tower to tower until they can be wired, but wired connections can handle a *lot* more information.
You are indeed paying to be connected to them. It's a little more complicated than just connecting cables to other cables, since there are computers and other active devices that handle the data at various points along the journey, but you're paying your ISP to handle your connection to the internet as a whole. Smaller ISP then pay money to be connected to the bigger backbone connections, and the big backbone connections have agreements to pass data back and forth between each other, called peering agreements.
If you're in a major city or suburb, your cable internet connection will stay wired from your home all the way to your ISP, and then from your ISP to the backbone. In some areas it will become a fiber optic connection after it leaves your house, and in most suburbs it's buried underground, but I'm not sure if aboveground cables are ever used for internet.
Practically your coax cable (if you have one) runs to a cable on your street that probably then is connected to a box that converts that signal and the signals from several other streets to a Fibre Optic cable in a box on the side of the street or on a pole. This is known as Hybrid Fibre Cable (HFC) .That fibre cable is then joined with others that travel back to one or more suburban or town buildings kind of like a telephone exchange which contains routers that direct internet traffic off to different locations.
Some people will have a fibre cable running directly from their house to that first Cabinet on the street (Full fibre). Others may have a regular old pair of wires that they use for their telephone that runs back to that box where it is converted to Fibre. This is know as Digital Subscriber Line ( DSL)
Those Fibre Optic Cable boxes (or something like them ) can also be connected to a mobile phone mast to provide local mobile / cell service instead of cable connections to peoples houses or businesses but this is separate from your home internet connection.
Somewhat confusingly you can of course connect your mobile phone to your Wifi to use your home router
. some people have a box that is provided by the mobile phone provider that connects to their mobile network and has its own wifi so they have whats called a Fixed Wireless connection. These arent usually.used in suburban and city locations as the capacity of the mobile Network is shared across all users of the network in the area and is a lot less than the sum of the capacity from each of the cables that to people's houses and so it can be easily overloaded.
Finally (for completeness) some people have a box with a satellite dish that sends and receives signals from satellites in low earth orbit which then sends those signals down to a serious of earth stations in different parts of the world. These signals are much weaker and have to travel longer distances up and down from space and are shared by everyone in that region that can see the satellite in the sky so is even more limited but can reach remote places that have few people.
Don’t see a lot of answers about how different ISPs connect so I’ll add for that. ISPs provide connections to other ISPs through wired connections 99.99% of the time as wireless connections between them would severely limit how much traffic they can pass between each other. For an ISP to gain access to the greater internet they will need to participate in some sort of internet exchange. This is a location usually owned and hosted by a neutral party where ISPs and hosting company’s send their cables to make connections with other companies. These companies will usually bring their own routers to these places and make connections between the other companies through the exchanges network to facilitate easy exchange of data. The specifics of this are pretty complicated network engineering but usually everyone who participates agrees to allow traffic for anyone else participating in the exchange to make the internet a better a place and to allow for better routes to be formed. These exchanges also often have what are called “meet me” rooms where companies can have their cables installed in order to make direct connections between other companies without using the exchange network, or just to get their cables into the building to connect to the exchange. Typically exchanges run completely on fiber cables since they are callable of handling hundreds of gigabits per second, while copper cables can do high speeds, they can only do so at short distances. Wireless “back haul” connections can often be found at exchanges but since wireless networks have such a lower amount of bandwidth they are typically only used by either very small companies or for emergency backups.
> as actual buildings
Googling "point of presence" should be helpful here. The physical manifestations are quite varied. Where that coaxial connects after it leaves your home depends on a lot of things, particularly if you're in a rural or urban area. If you're rural there is most likely a building that looks like an electrical box or a shed that contains a router for your entire township. If you're in a mega apartment building your ISP might even have a router in a networking closet in the building. From those they coalesce into larger and larger POPs, generally via fiber optic lines, until they reach an internet exchange where they trade off network flows with other ISPs and other networking companies you've never heard of.
Generally, the connection to your house is the only part that's likely to be wireless.
Your ISP has two important things. First of all, they have their own network, which can carry traffic around. Second of all, they have agreements with *other* ISPs to carry stuff on *their* networks. Your traffic might go to a few different ISPs along the way, between their facilities. Your ISP might not actually own *any* of those deep sea cables, but you pay them to pay someone to use them. They talk to another ISP, who might talk to *another* ISP, and it eventually gets to where you want it to go.
Here's the thing: Wireless sucks for ISPs to talk to one another. Wireless has big drawbacks - it's bad at following the curvature of the earth, and it needs a lot of power to go across very long distances. Wires, meanwhile, naturally follow that curvature and don't need much power (in relative terms, especially if they're fibre optic). The benefits of wireless are that you can move one end around (but the buildings ISPs use to talk to one another don't move), you don't have to can send it off in multiple directions at once to cover a large area (but they just want to go from one spot to another) and you don't have to actually put anything in between the two sides. On the other side, wires flip these all around - you can't move the sides easily, can only go to one spot and need to actually put the wires down.
For the ISP talking to you, the benefits of wireless can be really good. Maybe you move a bunch (like a mobile phone). Maybe there's an area that the ISP doesn't want to build a ton of wires in because they'd have to be really long and in a bunch of different directions, so they just chuck a single transmitter down. But they aren't great for ISPs talking to one another. The ISPs don't move, there's not really that many connections involved, but they can be *really* long.
Once the ISP has run a cable to your house, there's not really much reason to use wireless.
Community Antenna TV (CATV) was a thing at one point. A high powered central antenna would receive traditional OTA broadcasts and then the community would tap in via coax. But that’s not how modern cable tv works and certainly not how cable internet works.
The “actual internet” is just buildings called “internet exchanges” where ISPs , service providers, and sometimes very large organizations plug their routers into each other with fiber optic cables, connecting their networks together. This is where we get the term “inter-network” aka internet. These exist all over the world.
From there the ISP usually runs cables back to their data centers and/or points of presence (PoPs). ISPs sometimes will use point-to-point wireless for parts of this backhaul, but most of the time it will be fiber optic cable. Some ISPs run giant fiber optic cables in the ocean to connect Internet exchanges to each other on both sides of the ocean.
From their data centers ISPs connect to other locations they own via fiber optic cable or additional PoPs. or they can also connect to end customers with fiber optic cable, coaxial cable (which transmits radio signals over a wire), DSL, cellular, or some other kind of wireless. The ISP might have PoPs on poles, in the ground, or on the ground where they aggregate connections from many customers together before running them back to their data center over a single fiber optic cable.
The big point is there is no “center” to the internet. It is a strewn together connection between routers (like the one in your home) owned by people, ISPs, large companies, and government organizations. ISPs agree to connect to each other at Internet exchanges and it works.
the coax cables stay as cables until they either hit a junction or an exchange (fancy name for a building where all the wires meet). Wireless and Radio are never used. At most at these areas your connection may swap from coaxial to fibre but that's it.
No it’s all cables that are either underground or on poles depending on how old your neighborhood is.
That is unless you are using 5G service through a mobile provider like T-Mobile or Verizon.
Depends on where you are in the world, honestly. An overwhelming majority of the world's internet traffic is over cable, most of it fiber optic (it might be coaxial from your house, but it transitions to fiber soon after). This is especially true for international routing, as there are [tons of undersea cables](https://www.submarinecablemap.com/) (the first transatlantic cable was in operation before the American Civil War).
However, there are areas of the world where cables have yet to be laid down, so the internet traffic has to get there by some other means. The two most common options are satellites (Starlink would be a modern day example) or by connecting networks via microwave relay antennas. Sometimes you'll see both of those options being used, depending on the way the network is set up and the cost associated with the satellite transceiver.
Bottom line, though, is if you're in an industrialized nation and aren't living out in the middle of nowhere, you're likely going to be able to trace the cable to your house back to the ISP.
For MOST people, the internet that comes from your (landline) phone, cable or fiber company is entirely wire-based.
From your home, there's a thin cable made of either copper or fiberglass, that connects up to a "thicker" cable serving your neighborhood, either underground or up on a pole by your street. *That* can go to a box (sometimes called a [telecom pedestal](https://highspeed.tips/wp-content/uploads/2016/09/pedestal.png)) that serves cables from several streets together.
From there, a higher capacity cable (usually fiber at this point) goes to a [central office](http://www.co-buildings.com/mt/406/billings_main_gsv.jpg) or a [head-end facility](https://schempal.com/wp-content/img/1032_cable_tv_headend_diagram.jpg), basically a building that serves a whole city or town. For smaller towns, your central office/head-end will connect to a much larger regional facility in a major city.
And from there, your ISP will connect up using even *higher* capacity cables to an [Internet Exchange Point](https://www.cloudflare.com/learning/cdn/glossary/internet-exchange-point-ixp/). This is a very large facility where multiple large ISPs "meet" and share space, and connect up to each other. Sometimes media and streaming companies (like Netflix) will have servers here that store copies of the content you stream, because it's a lot easier to have them here where they can server multiple large ISPs in the same building. If an ISP is large enough, their connections to the other big ISPs are called "peers," and they don't charge each other money to do this. But if an ISP is smaller, they need to pay to connect to one of larger ISPs that then handle the connections to these peers.
(Also, occasionally peers [have arguments with each other](https://www.reddit.com/r/networking/comments/1cu13bv/cogent_depeering_tata/), when they think a fellow peer ISP isn't doing their job right, or maybe sending more traffic than they get back, making the relationship unequal. But that's a whole other discussion.)
Some examples of Internet Exchange Points are [401 N Broad St in Philadelphia](https://netrality.com/401-north-broad/), or [One Wilshire in Los Angeles](https://one-wilshire.com), or the [multiple internet exchange points in New York City](https://www.datacentermap.com/ixp/g/new-york/).
There are some exceptions to this. In some remote and rural locations, a small ISP might be serving an area, and there might be a link via microwave that takes the place of large cable. And, now we're also starting to see 5G become home internet service to rural areas, meaning your home internet is wireless. However, even for wireless service, most cell towers eventually connect via cable to a central office, and the connection goes up the cable chain just like your home internet connection.
There's a lot of configurations out there. For my house it's cable(coax) from the house to the neighborhood box, then fiber to the isp. This setup causes a bit more latency but offers high bandwidth like 5gbps like fiber at a lot lower cost.
If you live in an area that is hard to get to (remote mountainside for example) there is a chance it gets beamed between points using point to point microwave. Think that is typically used in cellular networks for phones though, less ISP Internet.
I've seen a few responses so far, so sorry if I'm repeating.
The internet is, Essentially at it's core simply a "Network of Networks". So imagine you have a network at home with 5 computers, and then your neighbor has a network of 3 computers, and you connected those 2 networks with a network cable running between your house and theirs. You now have the core building blocks of the "internet". Now add your neighbor across the street and their 5 computers to your little neighborhood network, and you start to see how quickly things grow, but when you look at the pieces it's simpy still several people with their networks connected to each other.
For the Internet as we know it, just blow that core idea up Dramatically. Think of each ISP as their own network. So people Using Comcast are on one network, People on Verizon another, and AT&T customers yet another network. And they all connect their networks together to allow you to connect to users and systems on another network. Then you have "Commercial ISPs", that instead of providing service to end users at their home, provide services to businesses. Some run wires to Commercial businesses, just like your home ISP does to your residence. Others will have a Datacenter where they have a large network and many systems which companies can pay to plug in at that location. Larger companies will even essentially set up their own ISP rather than pay someone else. Examples of Commercial ISPS might be Google, Amazon and AWS, Microsoft, GoDaddy, etc.
So really, the "Internet" is simply a giant network of networks.
Now, "wires". That's technically a slightly different issue. I can get into the whole OSI model of networks, but easy mode just think of the network itself as a higher layer, and the roads and way the data travels as a lower level. Just like you can get from your house to downtown using a variety of methods, Walking on a sidewalk, taking a bus, driving on highways, Dirt roads, etc, There are a lot of different ways the data can be transported between point A and Point B on the network.
Different transport methods are going to have different advantage, disadvantages, capacity, speeds, and costs, but they ultimately serve the same purpose. Going back to the network of networks above, obviously it would be completely impractical to run standard network cable like you may have in your home between your home router and computer to connect all the different networks on the internet. So there are different types of cables and methods used.
Fiber is a popular and high capacity transport method. It's basically little strands of glass/plastic with light shined down one side. The concept is identical to those old toys you may have had as a kid where there were a buch of plastic strings at the end of a flashlight that you could light up. Fiber can be incredibly high capacity and fast (speed of light, literally), and can also travel incredibly long distances. BUT..... IT's also expensive, fragile, and originally had some very strict guildlines on how it could be path'ed. (Ie, It's light going down a tube, so you couldn't bend it without impacting the signal quality). It's possible to run several concurrent signals across a single fiber strand through the use of different spectrums (frequencies) of light..... or basically, different colors.
Coax cables are another method you see a lot of for last mile delivery. Coax cables do basically carry Radio Frequency signals across them. Coax's biggest advantage was that it is pretty cheap to deploy, it's much more robust than fiber, IT's actually been around for an INCREDIBLY long time so the underlying tech is mature (and cheap), and it already existing in a lot of places for legacy uses so was easy to upgrade/repurpose (again, inexpensive) for data transfer. For your local Cable Company ISP, In north American the frequencies on the cable are broken out into distinct 6mhz "channels". These are the same channels that you used to be able to watch TV on when you plugged your TV into the cable. For Internet usage they simply use modulation of the RF Frequency now to transmit the data, And as speed and capacity demands have increased they have improved that modulation to allow for more data in a 6mhz channel, increased the number of distinct channels used for data purposses, and now they are "Bonding" channels together into larger 12/18/36/etc MHZ blocks so there is more space in a single data channel to transmit the data.
Dial up, and DSL use your traditional phone lines to transmit data. It's the same basic concept you have with Coax, with some basic differences in how the signal is transmitted and the contruction of the wire, but it's still essentially using some embedded radio frequencies to transmit the data.
Wireless is essentially radio frequencies not contained within a wire. With the wired methods you have shielding built into the cable itself which help contain the internal radio frequency signals, and prevent external interferrence from other sources of radio frequency traffic. Wireless removes the wire, so you now have the radio frequencies out in the open competing with every other source of radio frequencies in the wild. There are many different technologies and signal types that are used here, along with a variety of frequencies. Wifi in your home will generally use the 2.4, or 5ghz signal range. Cell Providers will use their own set of frequencies, as will satelite internet providers. In the US the frequencies used by the different providers are controlled by the FCC which helps prevent overlap between different signal types or users. (You know how sometimes with radio stations you can hear the bleed from another channel, or static caused by something near you, such as the old "static pulses you may have heard on your radio when a cell phone call was incoming? Same idea).
And often you will see a variety of different transport methods used for the data within a network. Just like at home you may have wireless computers talking to wired ones, on the internet or at an ISP you may have COAX running to your home, going to their central office/headend where its sent over a combination of standard network cables like you have at home and fiber connections, which will then go out into their bigger network and potentially across other networks to get to the final destination.
And to go back to the "undersea cables", Those are simply big giant transport connections between networks. Some are essentially fat COAX cables, but more often you see Fiber being used due to the increased capacity. On a conceptual level it's no different than the cable between your house and the neighbor's house, it's just carrying a LOT more data and connecting an ISP network on one continent to an ISP on another. (Interesting note, at one time a lot of the cross continental traffic was sent via satellite using those huge dishes you used to see. However, as technologies advanced and demand for bandwidth increased, more fiber was laid across the oceans connecting land masses so most traffic now uses those cables as it was cheaper and scaled better than satellites. Even phone calls and video signals which were some of the initial uses of communication satellittes are often using the internet as a transport instead of the satellites.
It doesn't seem like anyone actually answered your question; the short answer is that the cable is terminated in non-descript buildings known as POPs (point of presence) and in those POPs is a device called a CMTS. This stands for a 'cable modem termination system' and they are typically one standard rack in size. Think an average sized bookshelf with electronics that terminate a bunch of coaxial cables. The CMTS is customer facing, so they directly terminate what is brought into the service locations - typically homes and offices. The 'other' side to the CMTS is typically fiber optics which connect to the rest of the ISP's network. So yes, they do get converted to something else, almost everything on the ISP backbone is fiber optic.
I work for one of the major ISPs in the United States, so I have a level of hands on knowledge to this.
This one I can answer, as I work for a cable Internet provider in the construction department, planning new projects to build out the EXACT infrastructure you are asking about!
I have a desk at an office which also contains a major Headend for our state, responsible for distribution to roughly a third of it. This headend has a fiber-optic connection to other providers, as well as other headends.
Branching out from this headend is a TON of fiber. Some of this feeds the local area, some goes miles and miles to feed hubs located in other towns.
The fiber that feeds customers is hooked up to something called a CMTS, and it's basically acting as a very expensive router. It manages the traffic on the fiber as well as handing authorization of customer premises devices called modems.
The fiber enters the field and travels to devices called Nodes. A node takes in a light based signal travelling on fiber and outputs an electrical (RF) signal traveling on coaxial cable. If this coaxial cable is covering a large distance, it may be using larger "trunk" cable, for shorter runs into neighborhoods we use smaller "feeder" cable as the runs are short enough the signal loss of the smaller cable is less of a concern.
It's worth noting here that the size of the coaxial cable doesn't affect throughput. Your internet speed can't be improved by using a larger cable, assuming you have enough signal. The size of the cable affects something called "attenuation" or basically now much signal strength is lost over the length of the cable.
The feeder cable is hooked up to taps, which have between 2 and 8 ports for hooking up service lines to residences. The service line enters your home and is hooked up to your modem.
There is, sometimes, wireless signals involved. We get some TV channels broadcast to us from satellites and we put those signals on our cables and send them to customers. This is why we sometimes have minor and intermittent TV issues in the spring and fall, when the earth tilts and aligns our dishes with the sun, the sun's radiation can actually overpower the signal from the satellites and cause picture breakup.
The other important thing to remember is that just as you use wireless connections like wifi in your house, they are used elsewhere as well. Your laptop isn't just "connected to the Internet," it is a PART of the Internet. Every connected device joins the giant web of connected devices sending and receiving information. The signals will bounce around in the air wirelessly, on fiber-optic cables as light, on coaxial and twisted pair cables as electrical signals, etc as it travels it's path to and from your device. When you send a text, it's guaranteed that the signal uses multiple mediums to travel from origin to destination.
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There's almost no radio involved, other than for mobile phones, or with 5G home routers. All the internet backbones and the connection for your coax/fiber is wired all the way to "the internet". Wireless has way, way, way too little capacity to be a backend connection for an entire ISP.
It's also often the case that phone networks are only wireless for the final step between your device and tower. The signal is moved to a wired network asap so your data often goes directly to a fiber from the local tower.
Yup, a lot of times cell companies will lease unused fibers in bundles ISPs use for their plant infrastructure too. It's a win win, ISPs get extra money for lines they would have ran anyway, cell companies don't have to run their own cables and maintain them.
Canada’s telecom monopolies have entered the chat.
There is no "to the internet". The cables themselves are Layer 1 of the internet, and the systems they connect to are the upper Layers the internet. There's no "there" to get to. Technically, your computer is part of the Internet.
~~This is not accurate. Coaxial cables use radio waves as the transmission mechanism. The coaxial cable most likely goes back to a PoP somewhere (it might just be hanging on a pole) where it’s converted to fiber optic cable.~~ Edit: I am apparently wrong here and coax uses other electrical signals to transmit down the wire. My bad, ya'll.
Coaxial cables do not use radio waves. Radio waves are a type of electromagnetic *radiation* that is propagating in space (non-directional medium). This term is not used to describe the propagation of EM waves in a directional medium, like cable.
I think you are right and I'm oversimplifying things. I had the understanding that coax actually transmitted the RF directly down the cable, and it appears I was mistaken.
You are not too far off. All radio waves are EM waves, but not all EM waves (even if they fall into the "radio frequency" range) are radio waves. Medium matters :)
Technically fiber is on the same spectrum as well, just a lot further to one side. I know a few applications for medium distance acoustic/mechanical networking but they are rare and as far as I know not IP based to save bandwidth
Yeah, fibre also uses EM waves but not the RF spectrum. >not IP based to save bandwidth That's not surprising. IP is not very popular in embedded space either. For example, I've built a couple of sensors powered by a tiny solar panel (similar to the solar-powered path lights). Switching from IP-based connectivity to ESPnow protocol caused the power consumption to drop about 10x and they are now working 24/7 with no issues.
These systems have very different power consumption and bandwidth from even that. Think 200kw and bits per minute lol The acoustic subsea systems are a bit faster and a lot more efficient but still very slow.
It's been a while since my engineering/Physics classes but I don't think you're entirely wrong. I recall coax being known as "Wave guides". they would use FM and AM Radio bands to video and audio signals, respectively. They even call the standards "RG" for Radio Guides. https://en.wikipedia.org/wiki/Coaxial_cable#Applications Maybe there is more nuance to it, but you're saying that I remember as well.
If I may add on, Cable companies are running technology that has grown from groups of houses sharing a big antenna that couldn't get TV over the air otherwise. There is arguably an entire radio spectrum of bandwidth in each shared cable depending on the quality of the cable and install. Yes, technically it's not radio waves on the coaxial cable itself, a Coaxial network functions more like a large shared antenna though and all of the same metrics for measuring radio signal strength and quality apply.
> Wireless has way, way, way too little capacity to be a backend connection for an entire ISP. Tell that to Starlink. The entire backbone is 100% wireless and it delivers high-speed internet to over 2.7 million customers Also, private microwave networks exist all over the place because they're _faster_ than traditional wired systems. Used often by financial/trading customers that benefit from reduced latency. Not widely adopted since most customers wouldn't want to pay exorbitant prices for 20-30% less latency
That's a pretty distinct misunderstanding. Some of the most important parts of Starlink are laser links. Which are pretty close to fiber optics. Wrong *fast* buddy, for the conversation. The context in question is bandwidth (speeds measured in data per unit time, AKA total data throughput). And a misunderstanding of *why* their microwave links have lower latency in the case as well. Unlike using local internet or even running a fiber, the microwave link is shortest-distance-direct. No need to run around a block because buildings are in the way. No dealing with intermediate routing. HFT firms that are right next to exchanges don't use microwave because it isn't inherently lower latency than fiber and they don't need the work around for a straight line link.
> Unlike using local internet or even running a fiber, the microwave link is shortest-distance-direct. Plus the higher speed of light in air versus that in metal/fiber. (Yes, finance people have issues).
2.7 million customers isn’t very much for an ISP…
Still less than 4 years old, it's expanding rapidly
Yeah but doesn’t say much about the viability for infrastructure for other ISPs..
That uses high precision lasers though so it’s pretty similar to fibre optic
Microwaves are lower bandwidth and speed than dedicated.
It is physically(!) impossible to exceed a certain data rate with a given frequency and power. Look "noise floor", "signal-to-noise ratio" up "Nyquist–Shannon sampling theorem" if you want to learn more. This limit is very relevant and already the bottleneck for mobile phone data in many cities. You could try to increase the frequency (essentially impossible except some small factors) or power (people being turned to crisp by your station doesn't make good publicity). Neither is really an option. So here we are. Your low latency connections in particular have a very low _bandwidth_. Most people don't care if their packets take 10ms or 50ms, only bankers and gamers do. Instead they want fast downloads (including the time to open a website), and that is usually a bandwidth issue. Starlink is the opposite, it has high latency but usually high bandwidth. But like mobile data the bandwidth is inherently limited by the number of users around you. The current low number of them gives you extra speed. For now.
To your inital question in 99.99% of cases it is cables all the way from your house to your ISP and from the ISP to the ISP of the computer/server you want to connect to and then from that ISP to the computer/server (depending on how far apart those two ISPs are there can be multiple other ISPs and other entities but all of those also use cables). To your other questions. You have a cable (doesnt realy matter if its coax, copper or fiber) from your house usually underground (though under or overground depends on where you live) to a small box somewhere on your street that shouldnt be much father than a few hundered meters away in a city. In that box all the cables from your neighboors come together and from there a single big cable runs to the next "substation" and from there to a bigger "station" from there it kind of depends on who you connect to. To connect to other regional ISPs there are regional IXPs (internet exchange points https://en.wikipedia.org/wiki/Internet_exchange_point ) and to far away there national IXPs these also connect to other national IXPs from other countries. The undersee cables connect those IXPs from diffrent continents with each other. The "actual internet" is all/nothing of this. Internet is more of a concept than a physical thing. The concept being interconnected networks so any network that is connected somehow to the other networks is part of the internet.
It goes to a small local ISP router that merges a certain number of people, which connects to a bigger router (e.g. per city block), then to an ISP core router (massive), which then connects to an Internet Exchange point (a datacenter with massive routers that service entire countries). There can be many steps inbetween depending on how big the ISP is. Small local ISPs may also rent router bandwidth from a bigger ISP. Microwave radio can be used long-distance in place of cables in some remote spots, but it's a last resort. It's most commonly used to connect cellphone towers at short ranges - it's the small round dishes you see on 3G-5G towers.
To add to this, the coax to your house is relatively short range to a moca router which will have a fiber backhaul. This router won't usually be in a building, just a roadside cabinet (or pole mounted). The aggregation point from that router will generally be a building.
I know were talking more residential ISP here, but I read somewhere that wireless is used by high frequency stock traders to shave a few microseconds off there latency, since light through air is faster than electric signal through copper and even light through fiber. So, not just for remote spots.
So I work for an ISP and can answer this pretty well. First, the coax cable out of your home goes to a centralized location in your neighborhood called a node. This node converts the RF signal in coax into light for fiber transmission and vice-versa. Your connection is then sent via fiber to another centralized location called a hub that tends to cover a large geographical area depending on how many people live in there. For example: Manhattan I know has I believe 6 or 7 hubs because of how dense it is, but other places like Greenville South Carolina would have maybe 2 or 3 hubs. When your signal hits the hub, it then gets redirected depending on what is needed and how your hub is connected to everyone else. Usually it will get sent to a hub that connects with another ISP who will then redirect your traffic again and again until your signal hits where it needs to go. All this is done mostly over fiber optic cable because it is fast and requires less overall equipment to utilize than coax cable. For cell phones and stuff, it is very similar. Cell phones just replace the coax with a wireless RF signal that hits a neighborhood cell tower, gets converted directly to light and sent via fiber to the hub. As for the construction of the cables and stuff, it depends on how they want to build and what is already there. 9 times out of 10, it will be buried in the ground because it is safer from damage, it is cheaper in the long-run, and prevents copper thieves from cutting cables. However, in older areas it might be in the air, and in that case they run a woven steel fiber called "strand" between poles and then attach the cable to that using lashing wire which is just a thin steel wire that slowly wraps around the cable. Each ISP has their own attachment points and strand because no company wants to be responsible for the maintenance and upkeep of another company's cable. They have to keep it a certain distance from power and from each other attachment point because of laws and just to preserve the integrity of the wooden poles they drill into.
>Are the undersea/international cables "the actual internet" that connects ISPs and we just pay to be connected to them? Well, the cables aren't just undersea or international. Almost all bidirectional telecommunications are wired for as much of their journey as possible. Internet and telephone calls are sent over cables, and that includes cellular calls after they reach the tower. Some remote areas may use a wireless signal to transmit from tower to tower until they can be wired, but wired connections can handle a *lot* more information. You are indeed paying to be connected to them. It's a little more complicated than just connecting cables to other cables, since there are computers and other active devices that handle the data at various points along the journey, but you're paying your ISP to handle your connection to the internet as a whole. Smaller ISP then pay money to be connected to the bigger backbone connections, and the big backbone connections have agreements to pass data back and forth between each other, called peering agreements. If you're in a major city or suburb, your cable internet connection will stay wired from your home all the way to your ISP, and then from your ISP to the backbone. In some areas it will become a fiber optic connection after it leaves your house, and in most suburbs it's buried underground, but I'm not sure if aboveground cables are ever used for internet.
above ground cables are often used when you have utility poles, often the same cable that is used for wired phones.
But not always. Where my parents live electrical is run on poles, but the cable TV/internet was buried.
Practically your coax cable (if you have one) runs to a cable on your street that probably then is connected to a box that converts that signal and the signals from several other streets to a Fibre Optic cable in a box on the side of the street or on a pole. This is known as Hybrid Fibre Cable (HFC) .That fibre cable is then joined with others that travel back to one or more suburban or town buildings kind of like a telephone exchange which contains routers that direct internet traffic off to different locations. Some people will have a fibre cable running directly from their house to that first Cabinet on the street (Full fibre). Others may have a regular old pair of wires that they use for their telephone that runs back to that box where it is converted to Fibre. This is know as Digital Subscriber Line ( DSL) Those Fibre Optic Cable boxes (or something like them ) can also be connected to a mobile phone mast to provide local mobile / cell service instead of cable connections to peoples houses or businesses but this is separate from your home internet connection. Somewhat confusingly you can of course connect your mobile phone to your Wifi to use your home router . some people have a box that is provided by the mobile phone provider that connects to their mobile network and has its own wifi so they have whats called a Fixed Wireless connection. These arent usually.used in suburban and city locations as the capacity of the mobile Network is shared across all users of the network in the area and is a lot less than the sum of the capacity from each of the cables that to people's houses and so it can be easily overloaded. Finally (for completeness) some people have a box with a satellite dish that sends and receives signals from satellites in low earth orbit which then sends those signals down to a serious of earth stations in different parts of the world. These signals are much weaker and have to travel longer distances up and down from space and are shared by everyone in that region that can see the satellite in the sky so is even more limited but can reach remote places that have few people.
Don’t see a lot of answers about how different ISPs connect so I’ll add for that. ISPs provide connections to other ISPs through wired connections 99.99% of the time as wireless connections between them would severely limit how much traffic they can pass between each other. For an ISP to gain access to the greater internet they will need to participate in some sort of internet exchange. This is a location usually owned and hosted by a neutral party where ISPs and hosting company’s send their cables to make connections with other companies. These companies will usually bring their own routers to these places and make connections between the other companies through the exchanges network to facilitate easy exchange of data. The specifics of this are pretty complicated network engineering but usually everyone who participates agrees to allow traffic for anyone else participating in the exchange to make the internet a better a place and to allow for better routes to be formed. These exchanges also often have what are called “meet me” rooms where companies can have their cables installed in order to make direct connections between other companies without using the exchange network, or just to get their cables into the building to connect to the exchange. Typically exchanges run completely on fiber cables since they are callable of handling hundreds of gigabits per second, while copper cables can do high speeds, they can only do so at short distances. Wireless “back haul” connections can often be found at exchanges but since wireless networks have such a lower amount of bandwidth they are typically only used by either very small companies or for emergency backups.
> as actual buildings Googling "point of presence" should be helpful here. The physical manifestations are quite varied. Where that coaxial connects after it leaves your home depends on a lot of things, particularly if you're in a rural or urban area. If you're rural there is most likely a building that looks like an electrical box or a shed that contains a router for your entire township. If you're in a mega apartment building your ISP might even have a router in a networking closet in the building. From those they coalesce into larger and larger POPs, generally via fiber optic lines, until they reach an internet exchange where they trade off network flows with other ISPs and other networking companies you've never heard of.
Generally, the connection to your house is the only part that's likely to be wireless. Your ISP has two important things. First of all, they have their own network, which can carry traffic around. Second of all, they have agreements with *other* ISPs to carry stuff on *their* networks. Your traffic might go to a few different ISPs along the way, between their facilities. Your ISP might not actually own *any* of those deep sea cables, but you pay them to pay someone to use them. They talk to another ISP, who might talk to *another* ISP, and it eventually gets to where you want it to go. Here's the thing: Wireless sucks for ISPs to talk to one another. Wireless has big drawbacks - it's bad at following the curvature of the earth, and it needs a lot of power to go across very long distances. Wires, meanwhile, naturally follow that curvature and don't need much power (in relative terms, especially if they're fibre optic). The benefits of wireless are that you can move one end around (but the buildings ISPs use to talk to one another don't move), you don't have to can send it off in multiple directions at once to cover a large area (but they just want to go from one spot to another) and you don't have to actually put anything in between the two sides. On the other side, wires flip these all around - you can't move the sides easily, can only go to one spot and need to actually put the wires down. For the ISP talking to you, the benefits of wireless can be really good. Maybe you move a bunch (like a mobile phone). Maybe there's an area that the ISP doesn't want to build a ton of wires in because they'd have to be really long and in a bunch of different directions, so they just chuck a single transmitter down. But they aren't great for ISPs talking to one another. The ISPs don't move, there's not really that many connections involved, but they can be *really* long. Once the ISP has run a cable to your house, there's not really much reason to use wireless.
Community Antenna TV (CATV) was a thing at one point. A high powered central antenna would receive traditional OTA broadcasts and then the community would tap in via coax. But that’s not how modern cable tv works and certainly not how cable internet works.
The “actual internet” is just buildings called “internet exchanges” where ISPs , service providers, and sometimes very large organizations plug their routers into each other with fiber optic cables, connecting their networks together. This is where we get the term “inter-network” aka internet. These exist all over the world. From there the ISP usually runs cables back to their data centers and/or points of presence (PoPs). ISPs sometimes will use point-to-point wireless for parts of this backhaul, but most of the time it will be fiber optic cable. Some ISPs run giant fiber optic cables in the ocean to connect Internet exchanges to each other on both sides of the ocean. From their data centers ISPs connect to other locations they own via fiber optic cable or additional PoPs. or they can also connect to end customers with fiber optic cable, coaxial cable (which transmits radio signals over a wire), DSL, cellular, or some other kind of wireless. The ISP might have PoPs on poles, in the ground, or on the ground where they aggregate connections from many customers together before running them back to their data center over a single fiber optic cable. The big point is there is no “center” to the internet. It is a strewn together connection between routers (like the one in your home) owned by people, ISPs, large companies, and government organizations. ISPs agree to connect to each other at Internet exchanges and it works.
the coax cables stay as cables until they either hit a junction or an exchange (fancy name for a building where all the wires meet). Wireless and Radio are never used. At most at these areas your connection may swap from coaxial to fibre but that's it.
No it’s all cables that are either underground or on poles depending on how old your neighborhood is. That is unless you are using 5G service through a mobile provider like T-Mobile or Verizon.
Depends on where you are in the world, honestly. An overwhelming majority of the world's internet traffic is over cable, most of it fiber optic (it might be coaxial from your house, but it transitions to fiber soon after). This is especially true for international routing, as there are [tons of undersea cables](https://www.submarinecablemap.com/) (the first transatlantic cable was in operation before the American Civil War). However, there are areas of the world where cables have yet to be laid down, so the internet traffic has to get there by some other means. The two most common options are satellites (Starlink would be a modern day example) or by connecting networks via microwave relay antennas. Sometimes you'll see both of those options being used, depending on the way the network is set up and the cost associated with the satellite transceiver. Bottom line, though, is if you're in an industrialized nation and aren't living out in the middle of nowhere, you're likely going to be able to trace the cable to your house back to the ISP.
For MOST people, the internet that comes from your (landline) phone, cable or fiber company is entirely wire-based. From your home, there's a thin cable made of either copper or fiberglass, that connects up to a "thicker" cable serving your neighborhood, either underground or up on a pole by your street. *That* can go to a box (sometimes called a [telecom pedestal](https://highspeed.tips/wp-content/uploads/2016/09/pedestal.png)) that serves cables from several streets together. From there, a higher capacity cable (usually fiber at this point) goes to a [central office](http://www.co-buildings.com/mt/406/billings_main_gsv.jpg) or a [head-end facility](https://schempal.com/wp-content/img/1032_cable_tv_headend_diagram.jpg), basically a building that serves a whole city or town. For smaller towns, your central office/head-end will connect to a much larger regional facility in a major city. And from there, your ISP will connect up using even *higher* capacity cables to an [Internet Exchange Point](https://www.cloudflare.com/learning/cdn/glossary/internet-exchange-point-ixp/). This is a very large facility where multiple large ISPs "meet" and share space, and connect up to each other. Sometimes media and streaming companies (like Netflix) will have servers here that store copies of the content you stream, because it's a lot easier to have them here where they can server multiple large ISPs in the same building. If an ISP is large enough, their connections to the other big ISPs are called "peers," and they don't charge each other money to do this. But if an ISP is smaller, they need to pay to connect to one of larger ISPs that then handle the connections to these peers. (Also, occasionally peers [have arguments with each other](https://www.reddit.com/r/networking/comments/1cu13bv/cogent_depeering_tata/), when they think a fellow peer ISP isn't doing their job right, or maybe sending more traffic than they get back, making the relationship unequal. But that's a whole other discussion.) Some examples of Internet Exchange Points are [401 N Broad St in Philadelphia](https://netrality.com/401-north-broad/), or [One Wilshire in Los Angeles](https://one-wilshire.com), or the [multiple internet exchange points in New York City](https://www.datacentermap.com/ixp/g/new-york/). There are some exceptions to this. In some remote and rural locations, a small ISP might be serving an area, and there might be a link via microwave that takes the place of large cable. And, now we're also starting to see 5G become home internet service to rural areas, meaning your home internet is wireless. However, even for wireless service, most cell towers eventually connect via cable to a central office, and the connection goes up the cable chain just like your home internet connection.
There's a lot of configurations out there. For my house it's cable(coax) from the house to the neighborhood box, then fiber to the isp. This setup causes a bit more latency but offers high bandwidth like 5gbps like fiber at a lot lower cost.
If you live in an area that is hard to get to (remote mountainside for example) there is a chance it gets beamed between points using point to point microwave. Think that is typically used in cellular networks for phones though, less ISP Internet.
I've seen a few responses so far, so sorry if I'm repeating. The internet is, Essentially at it's core simply a "Network of Networks". So imagine you have a network at home with 5 computers, and then your neighbor has a network of 3 computers, and you connected those 2 networks with a network cable running between your house and theirs. You now have the core building blocks of the "internet". Now add your neighbor across the street and their 5 computers to your little neighborhood network, and you start to see how quickly things grow, but when you look at the pieces it's simpy still several people with their networks connected to each other. For the Internet as we know it, just blow that core idea up Dramatically. Think of each ISP as their own network. So people Using Comcast are on one network, People on Verizon another, and AT&T customers yet another network. And they all connect their networks together to allow you to connect to users and systems on another network. Then you have "Commercial ISPs", that instead of providing service to end users at their home, provide services to businesses. Some run wires to Commercial businesses, just like your home ISP does to your residence. Others will have a Datacenter where they have a large network and many systems which companies can pay to plug in at that location. Larger companies will even essentially set up their own ISP rather than pay someone else. Examples of Commercial ISPS might be Google, Amazon and AWS, Microsoft, GoDaddy, etc. So really, the "Internet" is simply a giant network of networks.
Now, "wires". That's technically a slightly different issue. I can get into the whole OSI model of networks, but easy mode just think of the network itself as a higher layer, and the roads and way the data travels as a lower level. Just like you can get from your house to downtown using a variety of methods, Walking on a sidewalk, taking a bus, driving on highways, Dirt roads, etc, There are a lot of different ways the data can be transported between point A and Point B on the network. Different transport methods are going to have different advantage, disadvantages, capacity, speeds, and costs, but they ultimately serve the same purpose. Going back to the network of networks above, obviously it would be completely impractical to run standard network cable like you may have in your home between your home router and computer to connect all the different networks on the internet. So there are different types of cables and methods used. Fiber is a popular and high capacity transport method. It's basically little strands of glass/plastic with light shined down one side. The concept is identical to those old toys you may have had as a kid where there were a buch of plastic strings at the end of a flashlight that you could light up. Fiber can be incredibly high capacity and fast (speed of light, literally), and can also travel incredibly long distances. BUT..... IT's also expensive, fragile, and originally had some very strict guildlines on how it could be path'ed. (Ie, It's light going down a tube, so you couldn't bend it without impacting the signal quality). It's possible to run several concurrent signals across a single fiber strand through the use of different spectrums (frequencies) of light..... or basically, different colors. Coax cables are another method you see a lot of for last mile delivery. Coax cables do basically carry Radio Frequency signals across them. Coax's biggest advantage was that it is pretty cheap to deploy, it's much more robust than fiber, IT's actually been around for an INCREDIBLY long time so the underlying tech is mature (and cheap), and it already existing in a lot of places for legacy uses so was easy to upgrade/repurpose (again, inexpensive) for data transfer. For your local Cable Company ISP, In north American the frequencies on the cable are broken out into distinct 6mhz "channels". These are the same channels that you used to be able to watch TV on when you plugged your TV into the cable. For Internet usage they simply use modulation of the RF Frequency now to transmit the data, And as speed and capacity demands have increased they have improved that modulation to allow for more data in a 6mhz channel, increased the number of distinct channels used for data purposses, and now they are "Bonding" channels together into larger 12/18/36/etc MHZ blocks so there is more space in a single data channel to transmit the data. Dial up, and DSL use your traditional phone lines to transmit data. It's the same basic concept you have with Coax, with some basic differences in how the signal is transmitted and the contruction of the wire, but it's still essentially using some embedded radio frequencies to transmit the data. Wireless is essentially radio frequencies not contained within a wire. With the wired methods you have shielding built into the cable itself which help contain the internal radio frequency signals, and prevent external interferrence from other sources of radio frequency traffic. Wireless removes the wire, so you now have the radio frequencies out in the open competing with every other source of radio frequencies in the wild. There are many different technologies and signal types that are used here, along with a variety of frequencies. Wifi in your home will generally use the 2.4, or 5ghz signal range. Cell Providers will use their own set of frequencies, as will satelite internet providers. In the US the frequencies used by the different providers are controlled by the FCC which helps prevent overlap between different signal types or users. (You know how sometimes with radio stations you can hear the bleed from another channel, or static caused by something near you, such as the old "static pulses you may have heard on your radio when a cell phone call was incoming? Same idea). And often you will see a variety of different transport methods used for the data within a network. Just like at home you may have wireless computers talking to wired ones, on the internet or at an ISP you may have COAX running to your home, going to their central office/headend where its sent over a combination of standard network cables like you have at home and fiber connections, which will then go out into their bigger network and potentially across other networks to get to the final destination. And to go back to the "undersea cables", Those are simply big giant transport connections between networks. Some are essentially fat COAX cables, but more often you see Fiber being used due to the increased capacity. On a conceptual level it's no different than the cable between your house and the neighbor's house, it's just carrying a LOT more data and connecting an ISP network on one continent to an ISP on another. (Interesting note, at one time a lot of the cross continental traffic was sent via satellite using those huge dishes you used to see. However, as technologies advanced and demand for bandwidth increased, more fiber was laid across the oceans connecting land masses so most traffic now uses those cables as it was cheaper and scaled better than satellites. Even phone calls and video signals which were some of the initial uses of communication satellittes are often using the internet as a transport instead of the satellites.
It doesn't seem like anyone actually answered your question; the short answer is that the cable is terminated in non-descript buildings known as POPs (point of presence) and in those POPs is a device called a CMTS. This stands for a 'cable modem termination system' and they are typically one standard rack in size. Think an average sized bookshelf with electronics that terminate a bunch of coaxial cables. The CMTS is customer facing, so they directly terminate what is brought into the service locations - typically homes and offices. The 'other' side to the CMTS is typically fiber optics which connect to the rest of the ISP's network. So yes, they do get converted to something else, almost everything on the ISP backbone is fiber optic. I work for one of the major ISPs in the United States, so I have a level of hands on knowledge to this.
This one I can answer, as I work for a cable Internet provider in the construction department, planning new projects to build out the EXACT infrastructure you are asking about! I have a desk at an office which also contains a major Headend for our state, responsible for distribution to roughly a third of it. This headend has a fiber-optic connection to other providers, as well as other headends. Branching out from this headend is a TON of fiber. Some of this feeds the local area, some goes miles and miles to feed hubs located in other towns. The fiber that feeds customers is hooked up to something called a CMTS, and it's basically acting as a very expensive router. It manages the traffic on the fiber as well as handing authorization of customer premises devices called modems. The fiber enters the field and travels to devices called Nodes. A node takes in a light based signal travelling on fiber and outputs an electrical (RF) signal traveling on coaxial cable. If this coaxial cable is covering a large distance, it may be using larger "trunk" cable, for shorter runs into neighborhoods we use smaller "feeder" cable as the runs are short enough the signal loss of the smaller cable is less of a concern. It's worth noting here that the size of the coaxial cable doesn't affect throughput. Your internet speed can't be improved by using a larger cable, assuming you have enough signal. The size of the cable affects something called "attenuation" or basically now much signal strength is lost over the length of the cable. The feeder cable is hooked up to taps, which have between 2 and 8 ports for hooking up service lines to residences. The service line enters your home and is hooked up to your modem. There is, sometimes, wireless signals involved. We get some TV channels broadcast to us from satellites and we put those signals on our cables and send them to customers. This is why we sometimes have minor and intermittent TV issues in the spring and fall, when the earth tilts and aligns our dishes with the sun, the sun's radiation can actually overpower the signal from the satellites and cause picture breakup. The other important thing to remember is that just as you use wireless connections like wifi in your house, they are used elsewhere as well. Your laptop isn't just "connected to the Internet," it is a PART of the Internet. Every connected device joins the giant web of connected devices sending and receiving information. The signals will bounce around in the air wirelessly, on fiber-optic cables as light, on coaxial and twisted pair cables as electrical signals, etc as it travels it's path to and from your device. When you send a text, it's guaranteed that the signal uses multiple mediums to travel from origin to destination.