Module 07
TCP and UDP
Reliable delivery, built on an unreliable network. Perform the three-way handshake, lose a segment and watch it be resent, then compare with UDP's fire-and-forget.
Start lesson 1
Which program gets this packet? · 7 min · free, no account
TransportOpen now
What you'll operate
- The three-way handshake
- Windows and retransmission
- UDP, and when it is the right call
- lessons
- 6
- minutes
- 49
Lessons in this module
- 1Which program gets this packet?Follow port numbers from a browser tab to a server and back, and see how four values name one conversation.Free, no account7 min
- 2When is UDP the right call?Send a DNS lookup in a single datagram, read the 8-byte header, and decide which jobs are better off without TCP.Plus7 min
- 3What numbers open a TCP connection?Play the three-way handshake and work out every sequence and acknowledgment number in it.Plus8 min
- 4What acknowledgment comes back?Send data, lose a segment, and predict every acknowledgment until the gap is repaired.Plus9 min
- 5How fast may the sender go?Fill a receiver's buffer until its window closes, then grow and cut a congestion window.Plus9 min
- 6How does a connection end, or get refused?Close a connection in four segments, read a reset, and watch a SYN flood fill a server's backlog.Plus9 min
Lesson 1 is open to everyone, with no account. The other lessons in this module are part of Plus.