Computer network is the product of the close combination of communication technology and computer technology
Communication system model:
A computer network is a communication network
A computer network is an interconnected, self-consistent collection of computers.
Interconnection: interconnection
Self-consistent: no master-slave relationship
Interconnecting hosts through a switched network
Internet: A collection of millions of interconnected computing devices
Communications links: fiber optic, copper cable, radio, satellite
Packet switching: forwarding packets (packets): routers and switches
Network protocol:
Data exchange in computer networks must follow pre-agreed rules
Network protocol, referred to as protocol, is a rule, standard or convention established for data exchange in the network.
A protocol specifies the format, meaning, sequence of messages exchanged between communicating entities, and actions taken in response to information received or events that occur.
Three elements:
- Syntax
- Semantics
- Timing
TCP、IP、HTTP、802.11