• Transmission Control Protocol
• Breaks data into segments, tracks their delivery, and automatically resends any lost or corrupted packets
• Connection-oriented
  • Before transmission, TCP establishes a connection using a three-way handshake
    • SYN
    • SYN-ACK
    • ACK
• Reliability
  • Receiver sends back acknowledgment messages
  • If a segment doesn’t arrive intact, TCP resends it
• Flow & Congestion Control
  • TCP regulates transmission speed so the sender doesn’t overwhelm the receiver or the network itself