• A protocol defines:
    • Format
    • Order of messages sent and received
    • Actions taken on message transmission
    • Receipt
  • e.g. TCP
  • If there’s no controller to monitor what’s going on and one of the computers involved stops following the protocol, then
    • that malfunctioning computer’s messages may just be discarded
    • but it may disrupt other computers’ communications
  • So you want to set up protocols so they discourage bad behavior/protect other computers from bad computers