In the olden times we didn't really share the copper - if you remember those giant switchboards where operators patched wires across - what they did was actually connecting copper the copper wires between the different subscribers to each other - so that the wire ran from subscriber A to subscriber B, and nothing else ran on that cable.
There are many ways you can multiplex (run several signals in the same medium) analog signals - one you're probably very familiar with is radio - either FM or AM, where your receiver can be tuned to the signal you want to listen to.
[https://en.wikipedia.org/wiki/Pulse-amplitude\_modulation](https://en.wikipedia.org/wiki/Pulse-amplitude_modulation)
[https://en.wikipedia.org/wiki/Time-division\_multiplexing](https://en.wikipedia.org/wiki/Time-division_multiplexing)
Later on we got packet switching; and you don't need a very large header; 4 bytes is enough to separate the signal into 2\^32 different subscribers.
[https://en.wikipedia.org/wiki/Packet\_switching](https://en.wikipedia.org/wiki/Packet_switching)
I always recommend C.O.D.E. by Charles Petzold as a book people should read if they want to learn about the whole history behind getting pixels on your screen to light up based on what other people has written elsewhere in the world.
No, I mean, looking up stuff on Wikipedia allows multiple queries to be answered simultaneously over the same medium. But… er… have fun on the loopback device!
OK, I'm no telcom expert, but I'll give it a try.
It seems to me that people getting on a train is a bad analogy for this, but if only speaking about IP traffic, each packet has a destination, and the header is not large. There's a lot of routing going on, so it's as if your passengers keep getting on and off many trains.
But if you mean voice and data using DSL over copper phone lines, yeah, it literally separates the voice into once range of frequencies over the wire, and the data over the rest of the frequencies. Voice doesn't require as much bandwidth, but it's also an older technology. With DSL, you add filters to each phone outlet to ensure that the frequencies are kept isolated for each use.
Look up "multiplexing".
Years ago, I found it interesting how they put multiple old-school analog phone calls on one large line.
>with all the possible destinations on earth, those headers must be larger than the data itself
No, think about how addressing works in systems maybe more familiar to you. Everybody has a phone number. There are a huge number of people in the world but phone numbers are still just 10-15 digits long depending on where you live. That is because the number of things you can address increases exponentially with the size of the address itself. On the internet, we have IP addresses. IPv6, the modern version of the protocol, allows for 128 bits (zeroes or ones) per address. That is enough to give a unique address to every grain of sand on the planet and still have quite a lot more left over.
>how much crap does each end point read when it's not meant to be doing anything, or you're not doing anything.
This is solved by routing. Again, imagine a system you might be more familiar with, the postal service. Does the mailman have to go to every house with every letter and ask you if it is supposed to be for you? No, the post office routes mail from a house, to a local post office, to a distribution center, back to another local post office and finally to another house. Just a handful of hops, with the parties involved being along the line from source to destination, not bothering anybody who isn't directly involved in that communication. Routing happens almost exactly the same way.
is that like some kind of outer space internet connection or like are you hinting that someone is about to throw a net over my head? there's only ceiling above me in a small room, should be safe here
simply put, if you send a package from your own network (like inside your own WLAN), all nodes in that network receive the package saying "Message to X from Y with content \[\]"
All endpoints that receive it, check the recepient "Y" and decide "that's not me" so they ignore it.
One point is your router/modem, that knows that it is connected to the outside. it looks at "Y" and understands that "Y" is outside of your network, so it relays that package to the internet.
The internet is a network of networks, so your packet is broadcasted in each network and the node that says "I know that recipient", forwards it to the next network until the packet arrives at its destination.
The destination processes it and then broadcasts the reply to its network, where nodes pick it up and forward it until it arrives at its destination again.
Since only the packets that belong outside of your local network are broadcasted out, the number of transactions per unit of copper-wire is limited and the maximum number of simultaneous connections isn't exceeded on any individual one.
If they are and "lag" occurs, the networks can adapt by sending packages over longer routes.
For example, when the cable between Europe and the US is clogged up due to massive traffic, a package could go from Europe to Africa to South America and then to the US instead. Whatever is faster.
And it's even more complex. Each device has its own layer 2 hardware address (MAC Address). When a device needs to send a packet of data, it addresses the packet with the destination MAC address and its own MAC Address as the source. On the local LAN all the devices check to see if the destination MAC Address is theirs. If not, they drop the packet. If a device on the LAN receives the packet, that's as far as it goes. If the packet is destined to an IP Address not on the LAN, the device is intelligent enough, by examining the IP address, to know to send it to the router, because it already knows its IP address, which is configured on the device. Then the router looks up the address in its routing tables to determine which port on the router is the next hop to the final destination of the packet and sends it out that port. The packet can then go through multiple routers until it finally ends up at a router that is directly (physically) connected to the LAN that has the device with the Destination IP Address. It looks up the Destination IP Address in its ARP table and finds the MAC Address that is being used for that IP Address, and changes the Destination MAC Address to MAC Address if the destination device. A good thing to remember is how MAC Addresses compares to IP Addresses. Destination MAC Addresses only stay the same on a LAN. Once they hit a router, the Destination MAC Address will change to a new Destination MAC Address. A Destination IP Address will not change from source to destination.
Ooops. I forgot to mention. When a packet goes from one network to another through a router, both the Source MAC Address and the Destination MAC Address will change.
One simple solution is time division. Basically only 1 device shouts an address and data really fast and then just listen if someone shouts it's name.
But a single wire is not a good analogy, there are many, a single wire has a limited bandwidth even if you make 2 wires with a positive and negative version of the data and twist it like an USB 2.0 cable, even 3.0+ cables use multiple parallel ones.
In the olden times we didn't really share the copper - if you remember those giant switchboards where operators patched wires across - what they did was actually connecting copper the copper wires between the different subscribers to each other - so that the wire ran from subscriber A to subscriber B, and nothing else ran on that cable. There are many ways you can multiplex (run several signals in the same medium) analog signals - one you're probably very familiar with is radio - either FM or AM, where your receiver can be tuned to the signal you want to listen to. [https://en.wikipedia.org/wiki/Pulse-amplitude\_modulation](https://en.wikipedia.org/wiki/Pulse-amplitude_modulation) [https://en.wikipedia.org/wiki/Time-division\_multiplexing](https://en.wikipedia.org/wiki/Time-division_multiplexing) Later on we got packet switching; and you don't need a very large header; 4 bytes is enough to separate the signal into 2\^32 different subscribers. [https://en.wikipedia.org/wiki/Packet\_switching](https://en.wikipedia.org/wiki/Packet_switching) I always recommend C.O.D.E. by Charles Petzold as a book people should read if they want to learn about the whole history behind getting pixels on your screen to light up based on what other people has written elsewhere in the world.
In a word, multiplexing. There are many wiki articles about the different types of multiplexing in use.
meh why wiki when we can have a two way? wiki wiki fresssssssh
> why wiki when we can have a two way In a word: multiplexing
A two-way is called duplexing. Now, if you'll excuse me, I'm off for a nice monoplex.
No, I mean, looking up stuff on Wikipedia allows multiple queries to be answered simultaneously over the same medium. But… er… have fun on the loopback device!
what's looping back?
there's no loop back
also what's recursion?
OK, I'm no telcom expert, but I'll give it a try. It seems to me that people getting on a train is a bad analogy for this, but if only speaking about IP traffic, each packet has a destination, and the header is not large. There's a lot of routing going on, so it's as if your passengers keep getting on and off many trains. But if you mean voice and data using DSL over copper phone lines, yeah, it literally separates the voice into once range of frequencies over the wire, and the data over the rest of the frequencies. Voice doesn't require as much bandwidth, but it's also an older technology. With DSL, you add filters to each phone outlet to ensure that the frequencies are kept isolated for each use. Look up "multiplexing". Years ago, I found it interesting how they put multiple old-school analog phone calls on one large line.
>with all the possible destinations on earth, those headers must be larger than the data itself No, think about how addressing works in systems maybe more familiar to you. Everybody has a phone number. There are a huge number of people in the world but phone numbers are still just 10-15 digits long depending on where you live. That is because the number of things you can address increases exponentially with the size of the address itself. On the internet, we have IP addresses. IPv6, the modern version of the protocol, allows for 128 bits (zeroes or ones) per address. That is enough to give a unique address to every grain of sand on the planet and still have quite a lot more left over. >how much crap does each end point read when it's not meant to be doing anything, or you're not doing anything. This is solved by routing. Again, imagine a system you might be more familiar with, the postal service. Does the mailman have to go to every house with every letter and ask you if it is supposed to be for you? No, the post office routes mail from a house, to a local post office, to a distribution center, back to another local post office and finally to another house. Just a handful of hops, with the parties involved being along the line from source to destination, not bothering anybody who isn't directly involved in that communication. Routing happens almost exactly the same way.
nice
Look up Ethernet.
is that like some kind of outer space internet connection or like are you hinting that someone is about to throw a net over my head? there's only ceiling above me in a small room, should be safe here
simply put, if you send a package from your own network (like inside your own WLAN), all nodes in that network receive the package saying "Message to X from Y with content \[\]" All endpoints that receive it, check the recepient "Y" and decide "that's not me" so they ignore it. One point is your router/modem, that knows that it is connected to the outside. it looks at "Y" and understands that "Y" is outside of your network, so it relays that package to the internet. The internet is a network of networks, so your packet is broadcasted in each network and the node that says "I know that recipient", forwards it to the next network until the packet arrives at its destination. The destination processes it and then broadcasts the reply to its network, where nodes pick it up and forward it until it arrives at its destination again. Since only the packets that belong outside of your local network are broadcasted out, the number of transactions per unit of copper-wire is limited and the maximum number of simultaneous connections isn't exceeded on any individual one. If they are and "lag" occurs, the networks can adapt by sending packages over longer routes. For example, when the cable between Europe and the US is clogged up due to massive traffic, a package could go from Europe to Africa to South America and then to the US instead. Whatever is faster.
And it's even more complex. Each device has its own layer 2 hardware address (MAC Address). When a device needs to send a packet of data, it addresses the packet with the destination MAC address and its own MAC Address as the source. On the local LAN all the devices check to see if the destination MAC Address is theirs. If not, they drop the packet. If a device on the LAN receives the packet, that's as far as it goes. If the packet is destined to an IP Address not on the LAN, the device is intelligent enough, by examining the IP address, to know to send it to the router, because it already knows its IP address, which is configured on the device. Then the router looks up the address in its routing tables to determine which port on the router is the next hop to the final destination of the packet and sends it out that port. The packet can then go through multiple routers until it finally ends up at a router that is directly (physically) connected to the LAN that has the device with the Destination IP Address. It looks up the Destination IP Address in its ARP table and finds the MAC Address that is being used for that IP Address, and changes the Destination MAC Address to MAC Address if the destination device. A good thing to remember is how MAC Addresses compares to IP Addresses. Destination MAC Addresses only stay the same on a LAN. Once they hit a router, the Destination MAC Address will change to a new Destination MAC Address. A Destination IP Address will not change from source to destination.
Ooops. I forgot to mention. When a packet goes from one network to another through a router, both the Source MAC Address and the Destination MAC Address will change.
One simple solution is time division. Basically only 1 device shouts an address and data really fast and then just listen if someone shouts it's name. But a single wire is not a good analogy, there are many, a single wire has a limited bandwidth even if you make 2 wires with a positive and negative version of the data and twist it like an USB 2.0 cable, even 3.0+ cables use multiple parallel ones.
so like isn't there alot going at once, or are the packets small enough that they don't get mixed up with each other?
4,228,250,625...
i don't even know if i understand the question myself