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Computer Networks · Module 5 of 10

Transport layer: TCP and UDP

Deliver data reliably or quickly.

📖 Key ideas

  1. TCP is connection-oriented, reliable and ordered.
  2. Three-way handshake: SYN, SYN-ACK, ACK.
  3. Flow control and congestion control manage speed.
  4. UDP is connectionless and fast, with no guarantees.
  5. Ports identify applications: 80, 443, 53, 22.
💡 Real-life example: TCP is registered post with tracking; UDP is dropping a postcard in the box.
TCPReliable connection-oriented protocol
UDPFast connectionless protocol
PortNumber identifying an application
HandshakeConnection setup