Why Should an Application Use TCP?

• When reliability and robustness of data transmission is important

• • Email, web access, telnet, FTP

• Significant overhead compared to UDP

• • Larger headers
  • “Pure ACK” packets with no payload
  • Three packets for connection establishment
  • Four packets for connection teardown
  • Congestion control and avoidance slows down data rates

• Good for medium to long lived, non-real-time packet flows