TR;TR

• Process-to-process

• port

• multiplexing and demultiplexing

  demultiplexing:

  UDP: use dest port to deliver to the correct dest

  TCP: use src IP, src port + destport + dest ip + infamous port + TCP to deliver sockets to the correct dest

1. Process-to-Process Communication

1.1 Multiplexing and demultiplexing

• UDP: dest IP
• TCP the four-tuple → *(src IP, src port, dest IP, dest port)*

1.2 Recall: producer-consumer

• Two modes:
  • pushing(producers initiate): producers provide data when it produces data
  • pulling(consumers initiate): producers only provide data if consumers ask for.

pushing

• Goal: producer cannot overwhelm consumers
• it requires flow control to signal when there is:
  • not enough space
  • enough space

pulling

• no flow control

1.3 Flow control

• We need buffers to implement flow control

1.4 Error control

1) reliability: