Stills from the net №2
Pass it on! - Sure. - Ta! - Where to?
The Internet
The servers just wouldn’t talk to each other…
Ping!
Lost packet
I’m lost! - Where are you TCP?
I’m lost! - And nobody cares.
These images depict life of servers.
Image 1: Basic computer network protocol is a packet-switched TCP/IP, where your data travels hop by hop. This isn’t really true on the backbone of The Internet, but we don’t talk about that. To you, it all seems like shown in the image.
Image 2: Sysadmins often talk about servers not talking to each other. This doesn’t mean the servers are sulking, but rather that something like a broken switch or software is preventing communication. I still prevent the sulking image though.
Image 3: “Ping” is a type of a packet suitable for checking if the destination server is responding, and likewise the activity of “pinging” is checking if the link works.
Image 4: On a packet-switched network, packets can get lost through misconfiguration of the network, or because of an overload. The image shows a poor packet lost on the internet.
Image 5: NAT is a special server that sits between two groups of computers, and makes it appear as if the group was in fact a single computer. You might think this has nothing to do with you, but actually your WiFi router is a NAT and hides your home computers from the baddies on the internet.
Image 6: There is two main types of IP packed-switched communication (I lie, there is way more). TCP is for reliable connectivity where we would prefer to not lose any messages, such as browsing the web. UDP is for fire-and-forget connectivity where a few lost messages don’t matter that much, such as video calling. The image tries to show this difference.