What happens when a request comes to a laptop §
- Data reception in NIC (Network Interface Card)
- Physical layer
- The NIC receives electrical signals from the network medium (copper wire, fibre optics, wireless signals, etc)
- It converts the received analog signals to digital data
- Datalink layer
- Frames are extracted from the data
- Error checking is done and passed frames are stored in the NIC buffer
- NIC sends an interrupt signal to the CPU
- OS’s network stack takes over
- OS’s datalink layer checks if the MAC address matches the NICs and if yes, then it performs some more error checks
- OS’s datalink layer then strips off the data link layer header and passes the payload to the OS’s network layer
- Network layer
- Checks the packet IP and determines if it’s meant for this system or has to be routed to some other system
- If it’s meant for this system, then extracts the packet from the frame and send it to higher layers
- datalink layer, frame, frame looks like
Refs §