Networking Overview

TODO:

this page is abysmal. fix.

Tutorials

code a TCP/IP stack

https://www.saminiir.com/lets-code-tcp-ip-stack-1-ethernet-arp/

5-layer TCP/IP model

-	layer	protocol	unit	address
1	physical	10 Base T, 802.11	Bits	n/a
2	datalink	Ethernet, WiFi	Frames	MAC addr
3	network	IP	Datagram	IP addr
4	transport	TCP, UDP	Segment	Ports
5	application	HTTP, SMTP, ..	Messages	n/a

Information sent over a network is layered like an onion.
As you progress from datalink to transport layers, the outer layers are removed from the packet
leaving only information that is useful to each stage.

Example Transaction

TODO:

this takes a lot of space, and is not very helpful. Find a better way to describe this.

An example might help this sink in.

visit a website: #(GET request on server's port 80)

transport (HTTP)
   request is sliced into segments(transport) of 536 bytes or smaller

network (TCP/IP)
   if network knows how to reach destination, each segment is wrapped in
   TCP/IP info, and handed off to the datalink layer.

datalink (MAC,ARP)
   Adds information about the physical protocol (ethernet, token-ring, ...) 
   and fires the data to a target MAC address.

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physical
   the information is sent over the wire

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On the receiving end, datalink, and network layers are stripped off, and all 
segments (transport) are re-assembled to form the request. This is handed to
the web-server, which then repeats the above with a reply.