Fundamentals of communication and networking flashcards

Topic 9: Fundamentals of communication and networking

What is the difference between serial and parallel transmission?

Serial: bits sent one after another along a single wire. Parallel: several bits sent at once on separate wires. Serial is used over longer distances because parallel suffers from skew and crosstalk.

What is the difference between baud rate and bit rate?

Baud rate: the number of signal changes per second. Bit rate: the number of bits sent per second. Bit rate can exceed baud rate when each signal change encodes more than one bit.

What are start and stop bits used for?

In asynchronous serial transmission, a start bit tells the receiver a byte is coming and a stop bit marks its end, so sender and receiver keep in step.

How does CSMA/CA with RTS/CTS work on WiFi?

A device listens and transmits only when the channel is free. With RTS/CTS it sends a Request to Send and waits for the access point’s Clear to Send before transmitting.

What are the four layers of the TCP/IP stack?

Application (e.g. HTTP), Transport (TCP: splits data into numbered segments and adds port numbers), Network (IP: adds IP addresses and routes packets), Link (adds MAC addresses for the physical network).

What is a socket?

The combination of an IP address and a port number, which identifies one end of a connection to a particular process on a host.

What does network address translation (NAT) do?

It lets devices with private IP addresses share one public IP address: the router replaces the private address with its public one on outgoing packets and keeps a table to route replies back.

What does DHCP do?

Dynamic Host Configuration Protocol automatically gives a device an IP address (and settings such as the gateway) from a pool when it joins a network.

What is a subnet mask used for?

ANDing an IP address with the subnet mask gives the network identifier, showing whether another host is on the same subnet or must be reached through a router.

What is the difference between JSON and XML for data exchange?

Both are text formats. JSON is shorter, easier for people to read and quicker for computers to parse. XML is more verbose but allows more complex structures and validation.

What is the difference between symmetric and asymmetric encryption?

Symmetric: one shared key encrypts and decrypts. Asymmetric: data encrypted with the recipient’s public key can only be decrypted with their private key.