Ok, so every few days I see topics or posts about something happening with the internet (ACTA/SOPA/PIPA).
I thought that since so many people seem to now be interested in the workings of this beautiful thing called the internet, I would try to explain how
it (specifically Ethernet) works in a pretty slimmed-down way. So let's look at the simplicity, the beauty, and the chaos of Ethernet.
Simplified, the function of TCP is to ensure the reliability of data, along with (like everything else...) congestion control. TCP
TCP uses number sequencing to allow the sender and receiver of data to know that data was received correctly, and which piece of data needs to be sent
next. Imagine you have an e-mail that needs to be broken down into 17 packets. TCP numbers those packets being sent and received to ensure the proper
data is being transmitted, that it is not corrupted, and that it is received in the correct order.
This is very important due to collisions (multiple signals on the same medium, corrupting the data).
Conversely, this sequencing is also one of TCPs biggest security vulnerabilities.
So let's look at how that data gets sent from start to finish.
1) The data is broken down into packets at the source, labeled with a source and destination address, and sent into the great blue yonder. The source
hardware doesn't actually care how it get's there, or if the destination even exists... it simply frames the data and sends it.
2) The router sees this data, and decides where to forward it to. If the destination is on the router's network, the data never leaves the network
and is forwarded straight to the recipient. If the destination is on an external network, the router forwards the data out of its gateway and onto the
3) If the data is sent to the web to look for its destination, it is then forwarded to a second router, and that router looks in its tables. If the
destination isn't in its table, it forwards it on to the next router and the next until the destination network is finally reached.
4) The router that the destination network is on then sees the packet, filters it to the network the destination is located on, and then forwards the
data to the address stored in its routing/forwarding table.
5) When the recipient finally recieves the data, it sends a "recieved packet" to let the sender know to send the next one, and the process repeats
until all the data is finally transfered.
In it's simplist form... that is all there is to Ethernet, and the internet in general. And as you can see, it's actually rather chaotic. Billions
of random bits of data are constantly being sent, recieved, destroyed, lost, and corrupted every second. The loss of data is the nature of the beast.
That is why we use TCP to ensure the integrity of the data sent and recieved. Conversely there is the send and pray form of transfer known as UDP:
This is also why network security is so important. With all that data flying around the internet, you want to make sure you keep the bad data out, and
that you keep your good data safe. Everything on the internet is connected together, and you want to make sure your connection stays secure. There is
no magical barrier you can install to keep all the bad data away all of the time, but the more troublesome you make it for something bad to happen,
the less likely that it will. The only 100% safe piece of equipment is one that isn't connected to the internet.
Anywho, I just thought a few people might be interesting in knowing more about the internet they use everyday. I know it isn't exactly technical but
it isn't really meant to be. I'll be happy to try and expand on anything that I may have butchered above.
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