The document summarizes key aspects of the transport layer in the OSI model. It discusses how the transport layer interfaces with applications using sockets and handles host-to-host packet transmission. It also covers some of the main transport layer protocols, including UDP which is connectionless and unreliable, and TCP which is more complex but reliable by ensuring delivery and order through mechanisms like acknowledgments and resending lost packets.

1. Transport layer

3. Interface to applications using socket

4. Interface to host-to-host packets

6. Hides the network issues

7. Data stream just arrives as streams

8. Transport layer (sending)

9. Transport layer (receiving)

11. Out-of-order segments?

16. Order ensured

17. Packets are resend on failure

18. Advanced features like congestion control.

19. TCP sending data

20. TCP - handshakes Initial handshake Closing handshake

22. Dissect and understand a simple http request