- Point-to-point
- One sender, one receiver
- Reliable, in order byte stream
- No "message boundaries"
- Pipelined
- TCP congestion and flow control set window size
- Full duplex data
- Bi-directional data flow in same connection
- MSS: Maximum segment size
- Connection-oriented
- Handshaking (exchange of control messages) inits sender, receiver state before data exchange
- Flow controlled:
- Sender will not overwhelm receiver