Error Correction and Detection, Data Link & Control Protocol WAN and LAN Discussion

• Error Correction and Detection,
• Data Link & Control Protocol
• WAN and LAN Discussion

1- What is the CRC? And why would you expect a CRC to detect more errors than a parity bit?
2-Describe stop-and-wait flow control and What is the advantage of sliding-window flow control compared to stop-and-wait flow control?
3- Suppose that there are two networks: one is a circuit-switched network and the other is a packet-switched network. How would you build a translator that translates data from the packet-switched network to the circuit-switched network, and vice versa? Note: This is an open-ended question that requires some outside research. Try your best to come up with the best possible solution. Please make sure you properly cite any sources used.
From your point of view and understanding LAN
4- An asynchronous device, such as a teletype, transmits characters one at a time with unpredictable delays between characters. What problems, if any, do you foresee if such a device is connected to a LAN and allowed to transmit at will (subject to gaining access to the medium)? How might such problems be resolved?