Protocols

Protocols

1. A network protocol is a set of rules that defines how devices talk to each other

2. Flow Control

   • Manages the flow of data so that the sender doesn’t send too fast for the receiver
   • Messages are broken into frames

3. Signalling

   • Receiver tells sender when it's ready to receive
   • Prevents receiver buffer overflow

4. Sliding Window

   • Have a maximum of i frames on the wire at any time
     • i is the window size
   • Window does not move until earliest frame has been ACKed. Then it can slide down one place
   • The window field in a TCP header tells a receiver how much space there is in the sender's receive buffer

5. Selective Repeat

   • Any frame can be ACKed, specifying its sequence number
   • Frames arriving out of sequence are buffered until earlier frames have been ACKed
   • When a NAK is received, only the NAKed frame is resent (not the whole window)

6. Protocol Layers

   • An abstraction. They provide a simple view of what happens in a communication system