This test has twelve questions on the whole course. Answer each one, then read the explanation. If you get a question wrong, go back to the lesson named in its explanation.
1. A packet has reached the right PC, which is running a browser, an email app and a chat app. What does the transport layer add that IP alone does not?
2. Your laptop picks source port 51515 for a new connection to a web server. What kind of port is this?
3. Two PCs connect to the same server on TCP 443, both from source port 50000. How does the server keep them apart?
4. You are checking a list of firewall rules. Which service and port pair is correct?
5. A capture shows a TCP segment with no options. How long is its TCP header?
6. A client opens a TCP connection to a web server. In what order are the handshake messages sent?
7. A client sends a SYN, and the server immediately replies with RST. What error does the client application report?
8. A segment with sequence number 2001 carries 500 bytes and arrives safely. Which acknowledgement number confirms it?
9. A TCP sender resends a segment straight away, before its retransmission timer runs out. What caused this?
10. A fast server sends a file to a slow laptop. Which device sets the window size that stops the server from overwhelming the laptop?
11. A client finishes a download and closes the connection first. Which side then waits in the TIME_WAIT state?
12. A company is choosing a transport protocol for its internet phone calls. Why do voice calls normally use UDP instead of TCP?