This may sound dumb but, how does the internet work?

Forums › LAN (ethernet/Wifi/routers/Bluetooth) › This may sound dumb but, how does the internet work?

hamish225

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#96167 21-Jan-2012 13:13

I realise there are servers and routers and they are all connected together.

But what i don't understand is say i connect to a website at the ip address 123.156.78.90

and my computer sends that request to my router and then over chorous's network to my ISP.

How then, do the many routers and servers of the internet know where to sent my request?

What if i physicly moved the IP address to another country, how does the rest of the interenet know it's moved?

*Insert big spe*dtest result here*

robjg63

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#571617 21-Jan-2012 13:42

Not dumb at all.
I bet many people just use it and never give a though to how it actually works.

This is a good place to start:
http://www.howstuffworks.com/internet/basics/internet.htm

Nothing is impossible for the man who doesn't have to do it himself - A. H. Weiler

bazzer

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#571936 22-Jan-2012 15:27

It's a series of tubes.

Batman

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#572288 23-Jan-2012 11:16

robjg63: Not dumb at all.
I bet many people just use it and never give a though to how it actually works.

This is a good place to start:
http://www.howstuffworks.com/internet/basics/internet.htm

it says when you type in ip address it goes to isp and isp passes on to the next bigger and better server until it is found ...

SO: who/where are the biggerer and betterer servers located/run by??

YadaMe

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#572312 23-Jan-2012 11:57

Could also try http://twit.tv/show/security-now/309 , explains probably a bit more than you want but...

Decal

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#572455 23-Jan-2012 17:18

SO: who/where are the biggerer and betterer servers located/run by??

ISP's, Hosting companies and Data centres. They are usually located where they can pair easily with other ISP's or upstream providers.

If you don't understand how your router knows where to go, I can try to explain it to you (currently studying networking).

Cheers

EDIT: Grammar

sleemanj

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#572459 23-Jan-2012 17:29

Each router (including your computer) has a table, which lists IP ranges and what physical link packets for those IP ranges should be sent on.

Your computer's routing table will likely be quite simple, it will likely say send every request via your ethernet/usb port to your modem, that's all it needs to know to pass a request "up the chain".

Your modem's routing table will be something like "send every request that's not in this local network, down the phone line, and every request for the local network send out to the LAN ports", again, it knows that if it's a local address it should be sent out on the LAN ports to local computers, and if it's not then pass it up the line to the ISP.

Your ISP's routing table (yes we are generalising vastly here for effect) says, send every request for a NZ IP out via this link, send every request for an international IP out via that link, send every request for one of our IP's out by another link.

Their up-stream link will further differentiate, send every request for this network range should go over this cable...

Of course, the routing tables are not static, the ISPs, transits etc routers broadcast their routes ("I can get to X, Y, Z in 1 hop" from here) and their partners listen to those broadcasts to add to their own routes ("since I'm connected to them, then I can get to X, Y, Z in 2 hops from here"), the this routing protocol is called BGP, the "Border Gateway Protocol" because it is the protocol by which the routers (gateways) at the border of a network communicate with each other.

---
James Sleeman
I sell lots of stuff for electronic enthusiasts...

Decal

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#572469 23-Jan-2012 17:50

sleemanj: Each router (including your computer) has a table, which lists IP ranges and what physical link packets for those IP ranges should be sent on.

Your computer's routing table will likely be quite simple, it will likely say send every request via your ethernet/usb port to your modem, that's all it needs to know to pass a request "up the chain".

Your modem's routing table will be something like "send every request that's not in this local network, down the phone line, and every request for the local network send out to the LAN ports", again, it knows that if it's a local address it should be sent out on the LAN ports to local computers, and if it's not then pass it up the line to the ISP.

Your ISP's routing table (yes we are generalising vastly here for effect) says, send every request for a NZ IP out via this link, send every request for an international IP out via that link, send every request for one of our IP's out by another link.

Their up-stream link will further differentiate, send every request for this network range should go over this cable...

Of course, the routing tables are not static, the ISPs, transits etc routers broadcast their routes ("I can get to X, Y, Z in 1 hop" from here) and their partners listen to those broadcasts to add to their own routes ("since I'm connected to them, then I can get to X, Y, Z in 2 hops from here"), the this routing protocol is called BGP, the "Border Gateway Protocol" because it is the protocol by which the routers (gateways) at the border of a network communicate with each other.

Quic Broadband

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hamish225

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#572566 23-Jan-2012 23:20

awwwwwwwwww so the routers talk to eachother so they know where everything connected to the routers they're connected too is?

*Insert big spe*dtest result here*

Decal

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#572577 24-Jan-2012 00:06

Yes and no. It depends on the routing protocol they are using but now days most routers talk to each other and update each other automatically if things change

webwat

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#573294 25-Jan-2012 21:00

Yes it does sound dumb, but then the answer is really complex so its not a dumb question at all once you know the answer!

Each router's job is to work out which network to send traffic to that is destined for another network. Internet means its an "inter-network" of many networks, so traffic may be routed through several networks to get to its destination and each network uses IP numbers to work out what's on its own network and what connection to use for destinations that are on someone elses network. So inter-network traffic hops across lots of nodes between and within different networks to reach its destination.

Time to find a new industry!

jaymz

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#573306 25-Jan-2012 21:23

I am reminded of this cartoon, sums it up nicely i think :)

DrStrangelove

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#574239 27-Jan-2012 22:22

I use to use the postal system as an overview of how the internet works.

You deliver a letter with an address on it to your local postal shop.
The lady in the shop has no idea where your letter goes, but just processes it and drops it in the mail bag.

It then get collected in a van and goes to a local central postal office. At this point it may be processed and diverted locally or sent on to the national sorting office.

At this point they become aware and know the country it'll be sent to and despatch it or if it's a national location start processing it back down the chain to the end point of the local postman.

If it goes to another country is starts to be processed down the chain from that countries national sorting office where each office down the chain only knows about the local areas it administers or they send the letter back up the chain as miss addressed.

NOW, their is security checks on mail at most national postal offices in the same way 'spooks' vet IP traffic. i.e China's great firewall and etc.

Also your mail may not be delivered as your dog bites the postman or a plane crashes. And the person that sent the letter can't understand why she never got a reply.

You can send mail registered or just normal and this is like the transport protocols TCP and UDP, such that if the next node is unreachable a message is sent back saying the message/letter was not delivered.

You may have moved and the mail is returned to sender as no longer at this address.

In transit, your letter may go in vans, trucks, trains, planes, boats and etc.
This is like the different data transport protocols on the Internet, and like your letter, most carriers have no idea of your letters destination or it's source, they're just interested in getting it from point a to point b or loose their job.
And like the Internet all these modes of transport have different speeds and volumes.

And when your letter arrives at the persons postbox, they read it and send you a letter back.

The key thing to understand is there is only one (generalising) office (core network group) that knows where each of regional address are.

In the Internet these are Latin America, North America, Africa, Europe and Asia.
These are then broken down into regional hubs, which are then broken down into ISPs which then manage 'your' network.

Anyway I found less people went to sleep if I used the postal system analogy than when I tried to explain why NetBios used 7 explorer packets or DECnet phase IV was different to DECnet phase V.

hashbrown

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#574419 28-Jan-2012 15:11

DrStrangelove: The key thing to understand is there is only one (generalising) office (core network group) that knows where each of regional address are.

In the Internet these are Latin America, North America, Africa, Europe and Asia.
These are then broken down into regional hubs, which are then broken down into ISPs which then manage 'your' network.

Your analogy was good up till this point. Most ISPs will have a full routing table and so know a path to where every other ISP network on the planet is. The regional authorities purpose is to allocate addresses. They don't participate in routing and there are no regional routing hubs for these areas.

firewire

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#574439 28-Jan-2012 17:01

Just to add to that - Most routing between ISPs goes through a peering exchange.