I am currently taking a networking course and am bombarded with information which is different from 100's of sources and want to get some things straight.
The last 3 layers of the OSI mode (Network, Data link, and physical) run on every single host in a network. Let's say in a network there is a network switch (with 4 computers attached to that network switch using Ethernet) and that network switch is finally connected to a router.
- If a computer connected to that network switch wants to send data to the Internet (via the router), the computer will first encapsulate the data into a frame since it knows that it is attached to a switch and switches can only forward frames (correct?). So this computer will only use protocols in the Data Link layers (and not the network and physical layer right?).
- Then the switch will forward the frame to the router (where the data link protocol's on the router will unpack the frame) and then the network protocol's on the router will route the packet using the IP address? Now since the computer that sent the frame was attached to a switch is there an IP address in the frame sent to by the computer?