Transport Layer (Layer 4)
- Responsible for transporting application payloads across network connections
- Two main protocols:
- TCP
- Makes connection with end host
- Checks whether or not data was received
- Connection-oriented protocol
- If messages are too large, breaks them into segments
- UDP
- Does not guarantee delivery
- Connectionless protocol
- Message is called a datagram
- Protocols add their own control info at the beginning of a payload
- A header
- Process of adding a header to data from layer above is called encapsulation
- Communicates between the session layer and the network layer
Computer Science Networking OSI Model